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Repository: zach-klippenstein/compose-undo
Branch: main
Commit: 274fe613693b
Files: 40
Total size: 79.6 KB

Directory structure:
gitextract_r4b_iw8e/

├── .gitignore
├── LICENSE
├── README.md
├── build.gradle
├── demo/
│   ├── .gitignore
│   ├── build.gradle
│   ├── proguard-rules.pro
│   └── src/
│       ├── androidTest/
│       │   └── java/
│       │       └── com/
│       │           └── zachklipp/
│       │               └── statehistory/
│       │                   └── demo/
│       │                       └── DemoTest.kt
│       └── main/
│           ├── AndroidManifest.xml
│           ├── java/
│           │   └── com/
│           │       └── zachklipp/
│           │           └── statehistory/
│           │               └── demo/
│           │                   ├── App.kt
│           │                   ├── AppWithInspector.kt
│           │                   ├── MainActivity.kt
│           │                   ├── StateHistoryInspector.kt
│           │                   └── ui/
│           │                       └── theme/
│           │                           ├── Color.kt
│           │                           ├── Shape.kt
│           │                           ├── Theme.kt
│           │                           └── Type.kt
│           └── res/
│               ├── drawable/
│               │   └── ic_launcher_background.xml
│               ├── drawable-v24/
│               │   └── ic_launcher_foreground.xml
│               ├── mipmap-anydpi-v26/
│               │   ├── ic_launcher.xml
│               │   └── ic_launcher_round.xml
│               ├── values/
│               │   ├── colors.xml
│               │   ├── strings.xml
│               │   └── themes.xml
│               └── xml/
│                   ├── backup_rules.xml
│                   └── data_extraction_rules.xml
├── gradle/
│   └── wrapper/
│       ├── gradle-wrapper.jar
│       └── gradle-wrapper.properties
├── gradle.properties
├── gradlew
├── gradlew.bat
├── settings.gradle
└── statehistory/
    ├── .gitignore
    ├── build.gradle
    ├── gradle.properties
    ├── proguard-rules.pro
    └── src/
        ├── androidTest/
        │   └── java/
        │       └── com/
        │           └── zachklipp/
        │               └── statehistory/
        │                   └── demo/
        │                       └── StateHistoryTest.kt
        ├── main/
        │   ├── AndroidManifest.xml
        │   └── java/
        │       └── com/
        │           └── zachklipp/
        │               └── statehistory/
        │                   └── StateHistory.kt
        └── test/
            └── java/
                └── com/
                    └── zachklipp/
                        └── statehistory/
                            └── demo/
                                └── StateHistoryTest.kt

================================================
FILE CONTENTS
================================================

================================================
FILE: .gitignore
================================================
# Built application files
*.apk
*.aar
*.ap_
*.aab

# Files for the ART/Dalvik VM
*.dex

# Java class files
*.class

# Generated files
bin/
gen/
out/
#  Uncomment the following line in case you need and you don't have the release build type files in your app
# release/

# Gradle files
.gradle/
build/

# Local configuration file (sdk path, etc)
local.properties

# Proguard folder generated by Eclipse
proguard/

# Log Files
*.log

# Android Studio Navigation editor temp files
.navigation/

# Android Studio captures folder
captures/

# IntelliJ
*.iml
.idea/workspace.xml
.idea/tasks.xml
.idea/gradle.xml
.idea/assetWizardSettings.xml
.idea/dictionaries
.idea/libraries
# Android Studio 3 in .gitignore file.
.idea/caches
.idea/modules.xml
# Comment next line if keeping position of elements in Navigation Editor is relevant for you
.idea/navEditor.xml

# Keystore files
# Uncomment the following lines if you do not want to check your keystore files in.
#*.jks
#*.keystore

# External native build folder generated in Android Studio 2.2 and later
.externalNativeBuild
.cxx/

# Google Services (e.g. APIs or Firebase)
# google-services.json

# Freeline
freeline.py
freeline/
freeline_project_description.json

# fastlane
fastlane/report.xml
fastlane/Preview.html
fastlane/screenshots
fastlane/test_output
fastlane/readme.md

# Version control
vcs.xml

# lint
lint/intermediates/
lint/generated/
lint/outputs/
lint/tmp/
# lint/reports/

# From android studio
*.iml
.gradle
/local.properties
/.idea/caches
/.idea/libraries
/.idea/modules.xml
/.idea/workspace.xml
/.idea/navEditor.xml
/.idea/assetWizardSettings.xml
.DS_Store
/build
/captures
.externalNativeBuild
.cxx
local.properties

.idea/*


================================================
FILE: LICENSE
================================================
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================================================
FILE: README.md
================================================
# compose-undo ![Maven Central](https://img.shields.io/maven-central/v/com.zachklipp.compose-undo/statehistory)

Track changes to any snapshot state object and restore state from any point in the past.

## Usage

```groovy
implementation 'com.zachklipp.compose-undo:statehistory:{version}'
```

The simplest way to get started is to use the `WithStateHistory` composable:

```kotlin
@Composable
fun App() {
    WithStateHistory { history ->
        var text by remember { mutableStateOf(TextFieldValue("")) }.trackStateChanges()
        TextField(text, onValueChange = { text = it })

        Button(onClick { history.undo() }) {
            Text("Undo")
        }
    }
}
```

The key is to call `trackStateChanges` on every snapshot state object you want to track. If you're
creating state objects outside a composition, call `StateHistory.startTrackingState` yourself.

## Advanced usage

The main API is the `StateHistory` class. See
[its kdoc](/statehistory/src/main/java/com/zachklipp/statehistory/StateHistory.kt) for more detailed
information.

## Demo

This repo includes a demo app you can run and tinker with if you fork the repo. Here's a little
preview:

https://user-images.githubusercontent.com/101754/190877868-160456a2-5bd1-498d-9c76-147fb04958e6.mp4

## How it works

`StateHistory` keeps a set of all the state objects that were registered on it. It registers an
apply listener to the snapshot system, and any time a snapshot is applied to the global snapshot it
checks if any of the objects changed by that snapshot are being tracked. For every tracked changed
object, it makes a copy of its latest state record. It collects all changes to tracked objects in a
map (called a "frame"), then when `saveFrame` is called, it pushes that map onto the list of frames
that represents the history.

When asked to restore states to a particular frame, it goes through every tracked state object and
searches the frame list from the requested frame to find the latest frame that captured a change to
that object. It then asks the snapshot system for a writable record for that object and copies the
saved record back into the writable record, effectively setting the state object's value.

This is a very unconventional and probably unsupported use case of the
[`StateObject`](https://developer.android.com/reference/kotlin/androidx/compose/runtime/snapshots/StateObject)
and 
[`StateRecord`](https://developer.android.com/reference/kotlin/androidx/compose/runtime/snapshots/StateRecord)
APIs, but it allows the library to support any type of state object, even custom third-party ones.
The actual implementation for saving and restoring state values looks something like this
(`stateObject` is a `StateObject`):

```kotlin
// Save a state object's current value
val savedRecord = stateObject.firstStateRecord.create()
stateObject.firstStateRecord.withCurrent { currentRecord ->
    savedRecord.assign(currentRecord)
}

// Restore the value
stateObject.firstStateRecord.writable(stateObject) {
    assign(savedRecord)
}
```


================================================
FILE: build.gradle
================================================
buildscript {
    ext {
        compose_ui_version = '1.3.0-beta02'
    }
}// Top-level build file where you can add configuration options common to all sub-projects/modules.
plugins {
    id 'com.android.application' version '7.4.0-alpha10' apply false
    id 'com.android.library' version '7.4.0-alpha10' apply false
    id 'org.jetbrains.kotlin.android' version '1.7.10' apply false
    id 'com.vanniktech.maven.publish' version '0.22.0' apply false
}


================================================
FILE: demo/.gitignore
================================================
/build

================================================
FILE: demo/build.gradle
================================================
plugins {
    id 'com.android.application'
    id 'org.jetbrains.kotlin.android'
}

android {
    namespace 'com.zachklipp.statehistory.demo'
    compileSdk 33

    defaultConfig {
        applicationId "com.zachklipp.statehistory.demo"
        minSdk 21
        targetSdk 33
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        vectorDrawables {
            useSupportLibrary true
        }
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
    buildFeatures {
        compose true
    }
    composeOptions {
        kotlinCompilerExtensionVersion '1.3.1'
    }
    packagingOptions {
        resources {
            excludes += '/META-INF/{AL2.0,LGPL2.1}'
        }
    }
}

dependencies {
    implementation project(':statehistory')
    implementation 'androidx.core:core-ktx:1.9.0'
    implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.5.1'
    implementation 'androidx.lifecycle:lifecycle-viewmodel-compose:2.5.1'
    implementation 'androidx.activity:activity-compose:1.5.1'
    implementation "androidx.compose.ui:ui:$compose_ui_version"
    implementation "androidx.compose.ui:ui-tooling-preview:$compose_ui_version"
    implementation 'androidx.compose.material:material:1.2.1'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
    androidTestImplementation "androidx.compose.ui:ui-test-junit4:$compose_ui_version"
    androidTestImplementation 'com.google.truth:truth:1.1.3'
    debugImplementation "androidx.compose.ui:ui-tooling:$compose_ui_version"
    debugImplementation "androidx.compose.ui:ui-test-manifest:$compose_ui_version"
}

================================================
FILE: demo/proguard-rules.pro
================================================
# Add project specific ProGuard rules here.
# You can control the set of applied configuration files using the
# proguardFiles setting in build.gradle.
#
# For more details, see
#   http://developer.android.com/guide/developing/tools/proguard.html

# If your project uses WebView with JS, uncomment the following
# and specify the fully qualified class name to the JavaScript interface
# class:
#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
#   public *;
#}

# Uncomment this to preserve the line number information for
# debugging stack traces.
#-keepattributes SourceFile,LineNumberTable

# If you keep the line number information, uncomment this to
# hide the original source file name.
#-renamesourcefileattribute SourceFile

================================================
FILE: demo/src/androidTest/java/com/zachklipp/statehistory/demo/DemoTest.kt
================================================
package com.zachklipp.statehistory.demo

import androidx.compose.ui.semantics.SemanticsActions
import androidx.compose.ui.semantics.SemanticsProperties
import androidx.compose.ui.semantics.progressBarRangeInfo
import androidx.compose.ui.test.*
import androidx.compose.ui.test.junit4.createComposeRule
import androidx.test.ext.junit.runners.AndroidJUnit4
import com.google.common.truth.Truth.assertThat
import org.junit.Rule
import org.junit.Test
import org.junit.runner.RunWith

@RunWith(AndroidJUnit4::class)
class DemoTest {

    @get:Rule
    val rule = createComposeRule()

    @Test
    fun typingUpdatesFrameCount() {
        rule.setContent {
            AppWithInspector()
        }

        rule.onNode(hasSetTextAction()).performTextInput("a")
        rule.onNodeWithText("Frame 1 of 1").assertIsDisplayed()

        rule.onNode(hasSetTextAction()).performTextInput("b")
        rule.onNodeWithText("Frame 2 of 2").assertIsDisplayed()
    }

    @Test
    fun addingToListUpdatesFrameCount() {
        rule.setContent {
            AppWithInspector()
        }

        rule.onNode(hasSetTextAction()).performTextInput("a")
        rule.onNodeWithText("Add to list").performClick()

        rule.onNodeWithText("Frame 2 of 2").assertIsDisplayed()
    }

    @Test
    fun sliderScrubsHistory() {
        rule.setContent {
            AppWithInspector()
        }

        rule.onNode(hasSetTextAction()).performTextInput("a")
        rule.onNode(hasSetTextAction()).performTextInput("b")
        rule.onNode(hasSetTextAction()).assertTextEquals("ab")

        rule.onNode(hasSetProgressAction()).assertProgressValue(2f)
        rule.onNode(hasSetProgressAction()).performSetProgress(1f)

        rule.onNode(hasSetTextAction()).assertTextEquals("a")
        rule.onNodeWithText("Frame 1 of 2").assertIsDisplayed()
    }

    private fun hasSetProgressAction() = SemanticsMatcher("has setProgress action") {
        it.config.contains(SemanticsActions.SetProgress)
    }

    private fun SemanticsNodeInteraction.assertProgressValue(value: Float) {
        assertThat(
            fetchSemanticsNode().config[SemanticsProperties.ProgressBarRangeInfo].current
        ).isEqualTo(value)
    }

    private fun SemanticsNodeInteraction.performSetProgress(value: Float) {
        fetchSemanticsNode().config[SemanticsActions.SetProgress].action!!.invoke(value)
    }
}

================================================
FILE: demo/src/main/AndroidManifest.xml
================================================
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.StateHistoryDemo"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true"
            android:label="@string/app_name"
            android:theme="@style/Theme.StateHistoryDemo"
            android:windowSoftInputMode="adjustResize">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

            <meta-data
                android:name="android.app.lib_name"
                android:value="" />
        </activity>
    </application>

</manifest>

================================================
FILE: demo/src/main/java/com/zachklipp/statehistory/demo/App.kt
================================================
package com.zachklipp.statehistory.demo

import androidx.compose.foundation.border
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.foundation.text.KeyboardActions
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.material.Button
import androidx.compose.material.Text
import androidx.compose.material.TextField
import androidx.compose.runtime.*
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.text.input.ImeAction
import androidx.compose.ui.text.input.TextFieldValue
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import com.zachklipp.statehistory.trackStateHistory

@Preview(showBackground = true, showSystemUi = true)
@Composable
fun AppPreview() {
    App()
}

@Composable
fun App() {
    var textValue by remember { mutableStateOf(TextFieldValue("")) }.trackStateHistory()
    val valueList = remember { mutableStateListOf<String>() }.trackStateHistory()

    fun addValueToList() {
        valueList += textValue.text
        textValue = TextFieldValue("")
    }

    Column(Modifier.padding(8.dp)) {
        TextField(
            modifier = Modifier.fillMaxWidth(),
            value = textValue,
            onValueChange = { textValue = it },
            keyboardOptions = KeyboardOptions(imeAction = ImeAction.Send),
            keyboardActions = KeyboardActions { addValueToList() }
        )
        Button(
            modifier = Modifier.fillMaxWidth(),
            onClick = { addValueToList() }
        ) {
            Text("Add to list")
        }

        LazyColumn(
            reverseLayout = true,
            modifier = Modifier
                .border(1.dp, Color.Black)
                .fillMaxWidth()
        ) {
            items(valueList) {
                Text(it, modifier = Modifier.padding(16.dp))
            }
        }
    }
}

================================================
FILE: demo/src/main/java/com/zachklipp/statehistory/demo/AppWithInspector.kt
================================================
package com.zachklipp.statehistory.demo

import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material.MaterialTheme
import androidx.compose.material.Surface
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewmodel.compose.viewModel
import com.zachklipp.statehistory.StateHistory
import com.zachklipp.statehistory.demo.ui.theme.StateHistoryDemoTheme

@Composable
fun AppWithInspector() {
    val stateHistory = viewModel<StateHistoryViewModel>().stateHistory
    StateHistoryDemoTheme {
        // A surface container using the 'background' color from the theme
        Surface(
            modifier = Modifier.fillMaxSize(),
            color = MaterialTheme.colors.background
        ) {
            StateHistoryInspector(stateHistory) {
                App()
            }
        }
    }
}

class StateHistoryViewModel : ViewModel() {
    val stateHistory = StateHistory()
}

================================================
FILE: demo/src/main/java/com/zachklipp/statehistory/demo/MainActivity.kt
================================================
package com.zachklipp.statehistory.demo

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material.MaterialTheme
import androidx.compose.material.Surface
import androidx.compose.ui.Modifier
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewmodel.compose.viewModel
import com.zachklipp.statehistory.StateHistory
import com.zachklipp.statehistory.demo.ui.theme.StateHistoryDemoTheme

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            AppWithInspector()
        }
    }
}

================================================
FILE: demo/src/main/java/com/zachklipp/statehistory/demo/StateHistoryInspector.kt
================================================
package com.zachklipp.statehistory.demo

import androidx.compose.foundation.layout.*
import androidx.compose.material.*
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.ArrowBack
import androidx.compose.material.icons.filled.ArrowForward
import androidx.compose.runtime.*
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.dp
import com.zachklipp.statehistory.*
import kotlin.math.roundToInt

@Composable
fun StateHistoryInspector(
    stateHistory: StateHistory,
    modifier: Modifier = Modifier,
    content: @Composable () -> Unit
) {
    Column(modifier) {
        Box(propagateMinConstraints = true, modifier = Modifier.weight(1f)) {
            CompositionLocalProvider(LocalStateHistory provides stateHistory, content = content)
        }
        HistoryScrubber(stateHistory)
    }
}

@Composable
private fun HistoryScrubber(stateHistory: StateHistory, modifier: Modifier = Modifier) {
    var recording by remember { mutableStateOf(true) }

    if (recording) {
        LaunchedEffect(stateHistory) {
            stateHistory.recordChanges {
                // Save a new frame every time something changes. This could also be done on a
                // timer, or only after significant actions.
                stateHistory.saveFrame()
            }
        }
    }

    Column(modifier.padding(8.dp)) {
        if (stateHistory.frameCount > 1) {
            Text(
                "Frame ${stateHistory.currentFrame} of ${stateHistory.frameCount - 1}",
                modifier = Modifier.align(Alignment.CenterHorizontally),
                style = MaterialTheme.typography.caption,
            )

            Row(
                modifier = Modifier.fillMaxWidth(),
                verticalAlignment = Alignment.CenterVertically,
            ) {
                Slider(
                    value = stateHistory.currentFrame.toFloat(),
                    valueRange = 0f..(stateHistory.frameCount - 1).toFloat(),
                    steps = stateHistory.frameCount - 2,
                    onValueChange = { stateHistory.setCurrentFrameGlobally(it.roundToInt()) },
                    modifier = Modifier
                        .weight(1f)
                        .padding(horizontal = 16.dp)
                )
            }

            Row(modifier = Modifier.fillMaxWidth()) {
                IconButton(
                    onClick = { stateHistory.undo() },
                    enabled = stateHistory.canUndo,
                    modifier = Modifier.weight(1f)
                ) {
                    Icon(Icons.Default.ArrowBack, contentDescription = "undo")
                }
                Button(onClick = { recording = !recording }) {
                    Text(if (recording) "Stop recording" else "Start recording")
                }
                IconButton(
                    onClick = { stateHistory.redo() },
                    enabled = stateHistory.canRedo,
                    modifier = Modifier.weight(1f)
                ) {
                    Icon(Icons.Default.ArrowForward, contentDescription = "redo")
                }
            }
        }
    }
}

================================================
FILE: demo/src/main/java/com/zachklipp/statehistory/demo/ui/theme/Color.kt
================================================
package com.zachklipp.statehistory.demo.ui.theme

import androidx.compose.ui.graphics.Color

val Purple200 = Color(0xFFBB86FC)
val Purple500 = Color(0xFF6200EE)
val Purple700 = Color(0xFF3700B3)
val Teal200 = Color(0xFF03DAC5)

================================================
FILE: demo/src/main/java/com/zachklipp/statehistory/demo/ui/theme/Shape.kt
================================================
package com.zachklipp.statehistory.demo.ui.theme

import androidx.compose.foundation.shape.RoundedCornerShape
import androidx.compose.material.Shapes
import androidx.compose.ui.unit.dp

val Shapes = Shapes(
    small = RoundedCornerShape(4.dp),
    medium = RoundedCornerShape(4.dp),
    large = RoundedCornerShape(0.dp)
)

================================================
FILE: demo/src/main/java/com/zachklipp/statehistory/demo/ui/theme/Theme.kt
================================================
package com.zachklipp.statehistory.demo.ui.theme

import androidx.compose.foundation.isSystemInDarkTheme
import androidx.compose.material.MaterialTheme
import androidx.compose.material.darkColors
import androidx.compose.material.lightColors
import androidx.compose.runtime.Composable

private val DarkColorPalette = darkColors(
    primary = Purple200,
    primaryVariant = Purple700,
    secondary = Teal200
)

private val LightColorPalette = lightColors(
    primary = Purple500,
    primaryVariant = Purple700,
    secondary = Teal200

    /* Other default colors to override
    background = Color.White,
    surface = Color.White,
    onPrimary = Color.White,
    onSecondary = Color.Black,
    onBackground = Color.Black,
    onSurface = Color.Black,
    */
)

@Composable
fun StateHistoryDemoTheme(
    darkTheme: Boolean = isSystemInDarkTheme(),
    content: @Composable () -> Unit
) {
    val colors = if (darkTheme) {
        DarkColorPalette
    } else {
        LightColorPalette
    }

    MaterialTheme(
        colors = colors,
        typography = Typography,
        shapes = Shapes,
        content = content
    )
}

================================================
FILE: demo/src/main/java/com/zachklipp/statehistory/demo/ui/theme/Type.kt
================================================
package com.zachklipp.statehistory.demo.ui.theme

import androidx.compose.material.Typography
import androidx.compose.ui.text.TextStyle
import androidx.compose.ui.text.font.FontFamily
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.unit.sp

// Set of Material typography styles to start with
val Typography = Typography(
    body1 = TextStyle(
        fontFamily = FontFamily.Default,
        fontWeight = FontWeight.Normal,
        fontSize = 16.sp
    )
    /* Other default text styles to override
    button = TextStyle(
        fontFamily = FontFamily.Default,
        fontWeight = FontWeight.W500,
        fontSize = 14.sp
    ),
    caption = TextStyle(
        fontFamily = FontFamily.Default,
        fontWeight = FontWeight.Normal,
        fontSize = 12.sp
    )
    */
)

================================================
FILE: demo/src/main/res/drawable/ic_launcher_background.xml
================================================
<?xml version="1.0" encoding="utf-8"?>
<vector xmlns:android="http://schemas.android.com/apk/res/android"
    android:width="108dp"
    android:height="108dp"
    android:viewportWidth="108"
    android:viewportHeight="108">
    <path
        android:fillColor="#3DDC84"
        android:pathData="M0,0h108v108h-108z" />
    <path
        android:fillColor="#00000000"
        android:pathData="M9,0L9,108"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M19,0L19,108"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M29,0L29,108"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M39,0L39,108"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M49,0L49,108"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M59,0L59,108"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M69,0L69,108"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M79,0L79,108"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M89,0L89,108"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M99,0L99,108"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M0,9L108,9"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M0,19L108,19"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M0,29L108,29"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M0,39L108,39"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M0,49L108,49"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M0,59L108,59"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M0,69L108,69"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M0,79L108,79"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M0,89L108,89"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M0,99L108,99"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M19,29L89,29"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M19,39L89,39"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M19,49L89,49"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M19,59L89,59"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M19,69L89,69"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M19,79L89,79"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M29,19L29,89"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M39,19L39,89"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M49,19L49,89"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M59,19L59,89"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M69,19L69,89"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
    <path
        android:fillColor="#00000000"
        android:pathData="M79,19L79,89"
        android:strokeWidth="0.8"
        android:strokeColor="#33FFFFFF" />
</vector>


================================================
FILE: demo/src/main/res/drawable-v24/ic_launcher_foreground.xml
================================================
<vector xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:aapt="http://schemas.android.com/aapt"
    android:width="108dp"
    android:height="108dp"
    android:viewportWidth="108"
    android:viewportHeight="108">
    <path android:pathData="M31,63.928c0,0 6.4,-11 12.1,-13.1c7.2,-2.6 26,-1.4 26,-1.4l38.1,38.1L107,108.928l-32,-1L31,63.928z">
        <aapt:attr name="android:fillColor">
            <gradient
                android:endX="85.84757"
                android:endY="92.4963"
                android:startX="42.9492"
                android:startY="49.59793"
                android:type="linear">
                <item
                    android:color="#44000000"
                    android:offset="0.0" />
                <item
                    android:color="#00000000"
                    android:offset="1.0" />
            </gradient>
        </aapt:attr>
    </path>
    <path
        android:fillColor="#FFFFFF"
        android:fillType="nonZero"
        android:pathData="M65.3,45.828l3.8,-6.6c0.2,-0.4 0.1,-0.9 -0.3,-1.1c-0.4,-0.2 -0.9,-0.1 -1.1,0.3l-3.9,6.7c-6.3,-2.8 -13.4,-2.8 -19.7,0l-3.9,-6.7c-0.2,-0.4 -0.7,-0.5 -1.1,-0.3C38.8,38.328 38.7,38.828 38.9,39.228l3.8,6.6C36.2,49.428 31.7,56.028 31,63.928h46C76.3,56.028 71.8,49.428 65.3,45.828zM43.4,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2c-0.3,-0.7 -0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C45.3,56.528 44.5,57.328 43.4,57.328L43.4,57.328zM64.6,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2s-0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C66.5,56.528 65.6,57.328 64.6,57.328L64.6,57.328z"
        android:strokeWidth="1"
        android:strokeColor="#00000000" />
</vector>

================================================
FILE: demo/src/main/res/mipmap-anydpi-v26/ic_launcher.xml
================================================
<?xml version="1.0" encoding="utf-8"?>
<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
    <background android:drawable="@drawable/ic_launcher_background" />
    <foreground android:drawable="@drawable/ic_launcher_foreground" />
</adaptive-icon>

================================================
FILE: demo/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml
================================================
<?xml version="1.0" encoding="utf-8"?>
<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
    <background android:drawable="@drawable/ic_launcher_background" />
    <foreground android:drawable="@drawable/ic_launcher_foreground" />
</adaptive-icon>

================================================
FILE: demo/src/main/res/values/colors.xml
================================================
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="purple_200">#FFBB86FC</color>
    <color name="purple_500">#FF6200EE</color>
    <color name="purple_700">#FF3700B3</color>
    <color name="teal_200">#FF03DAC5</color>
    <color name="teal_700">#FF018786</color>
    <color name="black">#FF000000</color>
    <color name="white">#FFFFFFFF</color>
</resources>

================================================
FILE: demo/src/main/res/values/strings.xml
================================================
<resources>
    <string name="app_name">State History Demo</string>
</resources>

================================================
FILE: demo/src/main/res/values/themes.xml
================================================
<?xml version="1.0" encoding="utf-8"?>
<resources>

    <style name="Theme.StateHistoryDemo" parent="android:Theme.Material.Light.NoActionBar">
        <item name="android:statusBarColor">@color/purple_700</item>
    </style>
</resources>

================================================
FILE: demo/src/main/res/xml/backup_rules.xml
================================================
<?xml version="1.0" encoding="utf-8"?><!--
   Sample backup rules file; uncomment and customize as necessary.
   See https://developer.android.com/guide/topics/data/autobackup
   for details.
   Note: This file is ignored for devices older that API 31
   See https://developer.android.com/about/versions/12/backup-restore
-->
<full-backup-content>
    <!--
   <include domain="sharedpref" path="."/>
   <exclude domain="sharedpref" path="device.xml"/>
-->
</full-backup-content>

================================================
FILE: demo/src/main/res/xml/data_extraction_rules.xml
================================================
<?xml version="1.0" encoding="utf-8"?><!--
   Sample data extraction rules file; uncomment and customize as necessary.
   See https://developer.android.com/about/versions/12/backup-restore#xml-changes
   for details.
-->
<data-extraction-rules>
    <cloud-backup>
        <!-- TODO: Use <include> and <exclude> to control what is backed up.
        <include .../>
        <exclude .../>
        -->
    </cloud-backup>
    <!--
    <device-transfer>
        <include .../>
        <exclude .../>
    </device-transfer>
    -->
</data-extraction-rules>

================================================
FILE: gradle/wrapper/gradle-wrapper.properties
================================================
#Fri Sep 16 16:06:11 PDT 2022
distributionBase=GRADLE_USER_HOME
distributionUrl=https\://services.gradle.org/distributions/gradle-7.5-bin.zip
distributionPath=wrapper/dists
zipStorePath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME


================================================
FILE: gradle.properties
================================================
# Project-wide Gradle settings.
# IDE (e.g. Android Studio) users:
# Gradle settings configured through the IDE *will override*
# any settings specified in this file.
# For more details on how to configure your build environment visit
# http://www.gradle.org/docs/current/userguide/build_environment.html
# Specifies the JVM arguments used for the daemon process.
# The setting is particularly useful for tweaking memory settings.
org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
# When configured, Gradle will run in incubating parallel mode.
# This option should only be used with decoupled projects. More details, visit
# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
# org.gradle.parallel=true
# AndroidX package structure to make it clearer which packages are bundled with the
# Android operating system, and which are packaged with your app's APK
# https://developer.android.com/topic/libraries/support-library/androidx-rn
android.useAndroidX=true
# Kotlin code style for this project: "official" or "obsolete":
kotlin.code.style=official
# Enables namespacing of each library's R class so that its R class includes only the
# resources declared in the library itself and none from the library's dependencies,
# thereby reducing the size of the R class for that library
android.nonTransitiveRClass=true

================================================
FILE: gradlew
================================================
#!/usr/bin/env sh

#
# Copyright 2015 the original author or authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

##############################################################################
##
##  Gradle start up script for UN*X
##
##############################################################################

# Attempt to set APP_HOME
# Resolve links: $0 may be a link
PRG="$0"
# Need this for relative symlinks.
while [ -h "$PRG" ] ; do
    ls=`ls -ld "$PRG"`
    link=`expr "$ls" : '.*-> \(.*\)$'`
    if expr "$link" : '/.*' > /dev/null; then
        PRG="$link"
    else
        PRG=`dirname "$PRG"`"/$link"
    fi
done
SAVED="`pwd`"
cd "`dirname \"$PRG\"`/" >/dev/null
APP_HOME="`pwd -P`"
cd "$SAVED" >/dev/null

APP_NAME="Gradle"
APP_BASE_NAME=`basename "$0"`

# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'

# Use the maximum available, or set MAX_FD != -1 to use that value.
MAX_FD="maximum"

warn () {
    echo "$*"
}

die () {
    echo
    echo "$*"
    echo
    exit 1
}

# OS specific support (must be 'true' or 'false').
cygwin=false
msys=false
darwin=false
nonstop=false
case "`uname`" in
  CYGWIN* )
    cygwin=true
    ;;
  Darwin* )
    darwin=true
    ;;
  MINGW* )
    msys=true
    ;;
  NONSTOP* )
    nonstop=true
    ;;
esac

CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar


# Determine the Java command to use to start the JVM.
if [ -n "$JAVA_HOME" ] ; then
    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
        # IBM's JDK on AIX uses strange locations for the executables
        JAVACMD="$JAVA_HOME/jre/sh/java"
    else
        JAVACMD="$JAVA_HOME/bin/java"
    fi
    if [ ! -x "$JAVACMD" ] ; then
        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME

Please set the JAVA_HOME variable in your environment to match the
location of your Java installation."
    fi
else
    JAVACMD="java"
    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.

Please set the JAVA_HOME variable in your environment to match the
location of your Java installation."
fi

# Increase the maximum file descriptors if we can.
if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
    MAX_FD_LIMIT=`ulimit -H -n`
    if [ $? -eq 0 ] ; then
        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
            MAX_FD="$MAX_FD_LIMIT"
        fi
        ulimit -n $MAX_FD
        if [ $? -ne 0 ] ; then
            warn "Could not set maximum file descriptor limit: $MAX_FD"
        fi
    else
        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
    fi
fi

# For Darwin, add options to specify how the application appears in the dock
if $darwin; then
    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
fi

# For Cygwin or MSYS, switch paths to Windows format before running java
if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`

    JAVACMD=`cygpath --unix "$JAVACMD"`

    # We build the pattern for arguments to be converted via cygpath
    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
    SEP=""
    for dir in $ROOTDIRSRAW ; do
        ROOTDIRS="$ROOTDIRS$SEP$dir"
        SEP="|"
    done
    OURCYGPATTERN="(^($ROOTDIRS))"
    # Add a user-defined pattern to the cygpath arguments
    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
    fi
    # Now convert the arguments - kludge to limit ourselves to /bin/sh
    i=0
    for arg in "$@" ; do
        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option

        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
        else
            eval `echo args$i`="\"$arg\""
        fi
        i=`expr $i + 1`
    done
    case $i in
        0) set -- ;;
        1) set -- "$args0" ;;
        2) set -- "$args0" "$args1" ;;
        3) set -- "$args0" "$args1" "$args2" ;;
        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
    esac
fi

# Escape application args
save () {
    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
    echo " "
}
APP_ARGS=`save "$@"`

# Collect all arguments for the java command, following the shell quoting and substitution rules
eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"

exec "$JAVACMD" "$@"


================================================
FILE: gradlew.bat
================================================
@rem
@rem Copyright 2015 the original author or authors.
@rem
@rem Licensed under the Apache License, Version 2.0 (the "License");
@rem you may not use this file except in compliance with the License.
@rem You may obtain a copy of the License at
@rem
@rem      https://www.apache.org/licenses/LICENSE-2.0
@rem
@rem Unless required by applicable law or agreed to in writing, software
@rem distributed under the License is distributed on an "AS IS" BASIS,
@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@rem See the License for the specific language governing permissions and
@rem limitations under the License.
@rem

@if "%DEBUG%" == "" @echo off
@rem ##########################################################################
@rem
@rem  Gradle startup script for Windows
@rem
@rem ##########################################################################

@rem Set local scope for the variables with windows NT shell
if "%OS%"=="Windows_NT" setlocal

set DIRNAME=%~dp0
if "%DIRNAME%" == "" set DIRNAME=.
set APP_BASE_NAME=%~n0
set APP_HOME=%DIRNAME%

@rem Resolve any "." and ".." in APP_HOME to make it shorter.
for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi

@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"

@rem Find java.exe
if defined JAVA_HOME goto findJavaFromJavaHome

set JAVA_EXE=java.exe
%JAVA_EXE% -version >NUL 2>&1
if "%ERRORLEVEL%" == "0" goto execute

echo.
echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
echo.
echo Please set the JAVA_HOME variable in your environment to match the
echo location of your Java installation.

goto fail

:findJavaFromJavaHome
set JAVA_HOME=%JAVA_HOME:"=%
set JAVA_EXE=%JAVA_HOME%/bin/java.exe

if exist "%JAVA_EXE%" goto execute

echo.
echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
echo.
echo Please set the JAVA_HOME variable in your environment to match the
echo location of your Java installation.

goto fail

:execute
@rem Setup the command line

set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar


@rem Execute Gradle
"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*

:end
@rem End local scope for the variables with windows NT shell
if "%ERRORLEVEL%"=="0" goto mainEnd

:fail
rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
rem the _cmd.exe /c_ return code!
if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
exit /b 1

:mainEnd
if "%OS%"=="Windows_NT" endlocal

:omega


================================================
FILE: settings.gradle
================================================
pluginManagement {
    repositories {
        google()
        mavenCentral()
        gradlePluginPortal()
    }
}
dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        google()
        mavenCentral()
    }
}
rootProject.name = "State History"
include ':demo'
include ':statehistory'


================================================
FILE: statehistory/.gitignore
================================================
/build

================================================
FILE: statehistory/build.gradle
================================================
plugins {
    id 'com.android.library'
    id 'org.jetbrains.kotlin.android'
    id 'com.vanniktech.maven.publish'
}

android {
    namespace 'com.zachklipp.statehistory'
    compileSdk 33

    defaultConfig {
        minSdk 21
        targetSdk 33
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
    buildFeatures {
        compose true
    }
    composeOptions {
        kotlinCompilerExtensionVersion '1.3.1'
    }
    packagingOptions {
        resources {
            excludes += '/META-INF/{AL2.0,LGPL2.1}'
        }
    }
}

dependencies {
    api "androidx.compose.runtime:runtime:$compose_ui_version"
    testImplementation 'junit:junit:4.13.2'
    testImplementation 'com.google.truth:truth:1.1.3'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
    androidTestImplementation "androidx.compose.ui:ui-test-junit4:$compose_ui_version"
    androidTestImplementation 'com.google.truth:truth:1.1.3'
    debugImplementation "androidx.compose.ui:ui-tooling:$compose_ui_version"
    debugImplementation "androidx.compose.ui:ui-test-manifest:$compose_ui_version"
}


================================================
FILE: statehistory/gradle.properties
================================================
SONATYPE_HOST=DEFAULT
RELEASE_SIGNING_ENABLED=true

GROUP=com.zachklipp.compose-undo
POM_ARTIFACT_ID=statehistory
VERSION_NAME=0.2.0

POM_NAME=Compose Undo State History
POM_DESCRIPTION=Undo snapshot state changes in Compose.
POM_INCEPTION_YEAR=2022
POM_URL=https://github.com/zach-klippenstein/compose-undo/

POM_LICENSE_NAME=The Apache Software License, Version 2.0
POM_LICENSE_URL=https://www.apache.org/licenses/LICENSE-2.0.txt
POM_LICENSE_DIST=repo

POM_SCM_URL=https://github.com/zach-klippenstein/compose-undo/
POM_SCM_CONNECTION=scm:git:git://github.com/zach-klippenstein/compose-undo.git
POM_SCM_DEV_CONNECTION=scm:git:ssh://git@github.com/zach-klippenstein/compose-undo.git

POM_DEVELOPER_ID=zachklipp
POM_DEVELOPER_NAME=Zach Klippenstein
POM_DEVELOPER_URL=https://github.com/zach-klippenstein/


================================================
FILE: statehistory/proguard-rules.pro
================================================
# Add project specific ProGuard rules here.
# You can control the set of applied configuration files using the
# proguardFiles setting in build.gradle.
#
# For more details, see
#   http://developer.android.com/guide/developing/tools/proguard.html

# If your project uses WebView with JS, uncomment the following
# and specify the fully qualified class name to the JavaScript interface
# class:
#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
#   public *;
#}

# Uncomment this to preserve the line number information for
# debugging stack traces.
#-keepattributes SourceFile,LineNumberTable

# If you keep the line number information, uncomment this to
# hide the original source file name.
#-renamesourcefileattribute SourceFile

================================================
FILE: statehistory/src/androidTest/java/com/zachklipp/statehistory/demo/StateHistoryTest.kt
================================================
package com.zachklipp.statehistory.demo

import androidx.compose.runtime.mutableStateOf
import androidx.compose.ui.test.junit4.createComposeRule
import androidx.test.ext.junit.runners.AndroidJUnit4
import com.google.common.truth.Truth.assertThat
import com.zachklipp.statehistory.StateHistory
import com.zachklipp.statehistory.WithStateHistory
import com.zachklipp.statehistory.trackStateHistory
import org.junit.Rule
import org.junit.Test
import org.junit.runner.RunWith

@RunWith(AndroidJUnit4::class)
class StateHistoryTest {

    @get:Rule
    val rule = createComposeRule()

    @Test
    fun withStateHistory_recordsChanges() {
        val state = mutableStateOf(0)
        lateinit var stateHistory: StateHistory
        rule.setContent {
            WithStateHistory {
                stateHistory = it
                state.trackStateHistory()
            }
        }

        rule.runOnIdle {
            assertThat(stateHistory.frameCount).isEqualTo(0)
            state.value = 1
        }

        rule.runOnIdle {
            assertThat(stateHistory.frameCount).isEqualTo(1)
        }
    }
}

================================================
FILE: statehistory/src/main/AndroidManifest.xml
================================================
<?xml version="1.0" encoding="utf-8"?>
<manifest />

================================================
FILE: statehistory/src/main/java/com/zachklipp/statehistory/StateHistory.kt
================================================
package com.zachklipp.statehistory

import androidx.compose.runtime.*
import androidx.compose.runtime.collection.mutableVectorOf
import androidx.compose.runtime.snapshots.*
import kotlinx.coroutines.awaitCancellation
import java.util.*
import kotlin.contracts.ExperimentalContracts
import kotlin.contracts.contract

private const val DEBUG = true
private const val TAG = "StateHistory"

val LocalStateHistory: ProvidableCompositionLocal<StateHistory?> = staticCompositionLocalOf { null }

/**
 * Convenience function for simple usage of [StateHistory].
 *
 * Inside [content], call [MutableState.trackStateHistory], [SnapshotStateList.trackStateHistory],
 * and [SnapshotStateMap.trackStateHistory] to register state objects for change tracking, or pass
 * them to [StateHistory.startTrackingState]. Then use the [StateHistory.undo], [StateHistory.redo],
 * and [StateHistory.setCurrentFrameGlobally] methods to restore state.
 */
@Composable
fun WithStateHistory(content: @Composable (StateHistory) -> Unit) {
    val stateHistory = remember { StateHistory() }

    LaunchedEffect(stateHistory) {
        stateHistory.recordChanges {
            stateHistory.saveFrame()
        }
    }

    CompositionLocalProvider(LocalStateHistory provides stateHistory) {
        content(stateHistory)
    }
}

/**
 * Records changes to state objects that are registered via [startTrackingState] (or
 * [trackStateHistory]) and allows restoring state to previous values.
 *
 * ## Usage
 *
 * ### Simple
 *
 * 1. Wrap your composition in [WithStateHistory].
 * 2. Call [MutableState.trackStateHistory] on the states you want to track. (See also
 *  [SnapshotStateList.trackStateHistory], [SnapshotStateMap.trackStateHistory].)
 * 3. Call [StateHistory.undo] to undo changes.
 *
 * ### Advanced
 *
 * 1. Create an instance of this that will live across recompositions (e.g. use remember or store
 *  near the top of your DI object graph).
 * 1. Provide the instance to your composition through the [LocalStateHistory] composition local.
 * 1. Call [recordChanges] from a coroutine to start recording changes. To save a new history frame
 *  every time some state changes are applied, pass a callback that calls [saveFrame].
 * 1. Register states you want to track with [startTrackingState]. Make sure to call
 *  [stopTrackingState] when finished with the state object to allow it to be garbage-collected.
 *  If creating the state directly in a composition (e.g. with [remember]), you can also pass the
 *  state object to [trackStateHistory] to automatically stop tracking it when it leaves the
 *  composition.
 * 1. Call [setCurrentFrameGlobally] to restore the state of all tracked objects to the states they
 *  had at the given frame, or call the convenience methods [undo]/[redo] to move the frame by one.
 *
 * ## Defining save points
 *
 * History frames will only be pushed onto the stack when [safeFrame] is called. You can call this
 * method whenever you want, so the granularity of the history is up to you. To get the most detail,
 * call it from the [recordChanges] callback, which will be invoked every time a snapshot is applied
 * to the global snapshot that changes one or more tracked state objects. If that's too much detail
 * for your use case, you can pass a null callback to [recordChanges] and call [saveFrame] only
 * whenever something significant happens in your app, at regular intervals with a timer, etc.
 *
 * **Key point: State changes from a single snapshot will always be saved to the same frame.**
 *
 * @sample WithStateHistory
 */
@Stable
class StateHistory {

    /**
     * Used to guard access to [frames], [trackedStates], and [nextFrame].
     */
    private val lock = Any()

    /**
     * The set of all state objects we're currently tracking via [startTrackingState].
     */
    private val trackedStates = WeakHashMap<StateObject, Unit>()
    private var handle: ObserverHandle? = null

    /**
     * By storing and restoring [StateRecord]s directly, we don't have to care what types the state
     * objects are or even what data they hold. The records already implement all the operations
     * we need.
     */
    private val frames = mutableVectorOf<WeakHashMap<StateObject, StateRecord>>()

    /**
     * We "start" recording the next frame as soon as the previous one is committed to the [frames]
     * list. This way we can eagerly record the initial value of newly-tracked objects from
     * [startTrackingState] so that their initial values will be saved on the next frame, even if
     * they're not recorded as changed. Maybe unnecessary?
     */
    private var nextFrame = WeakHashMap<StateObject, StateRecord>()

    private var onTrackStateApplied: (() -> Unit)? = null

    /**
     * The total number of history frames that have been recorded.
     */
    var frameCount: Int by mutableStateOf(0)
        private set

    /**
     * The index of frame that represents the current state. When the global snapshot is advanced
     * with changes to tracked state, this value will be incremented. It can also be set to a lower
     * value by calling [setCurrentFrameGlobally].
     */
    var currentFrame: Int by mutableStateOf(NoFrame)
        private set

    /**
     * Starts recording changes and suspends until cancelled.
     *
     * @param onTrackStateApplied Called every time a snapshot is applied to the global snapshot
     * that changes any of the state objects tracked via [startTrackingState]. Call [saveFrame] from
     * this callback to save every change to the history.
     */
    suspend fun recordChanges(onTrackStateApplied: (() -> Unit)? = null) {
        if (!startRecording(onTrackStateApplied)) return
        try {
            awaitCancellation()
        } finally {
            stopRecording(clearOnTrackStateApplied = true)
        }
    }

    /**
     * Saves any changes to tracked state objects since the last call to this method to the history.
     *
     * If [currentFrame] is not the last frame, any frames after it will be removed.
     */
    fun saveFrame() {
        // Take the lock outside the snapshot so
        // This won't conflict with the lock in the apply observer when the snapshot is applied
        // because the none of the states changed in this snapshot are tracked.
        synchronized(lock) {
            withGlobalMutableSnapshot {
                if (DEBUG) println("[$TAG] Recording frame ${currentFrame + 1}: $nextFrame")
                // If committing a new frame while peeking into the history, clear the
                // frames after this point and start recording fresh.
                if (frames.lastIndex > currentFrame) {
                    frames.removeRange(currentFrame + 1, frames.size)
                }

                frames += nextFrame
                nextFrame = WeakHashMap()
                frameCount = frames.size
                currentFrame = frames.lastIndex
            }
        }
    }

    /**
     * Starts tracking changes [stateObject]. The current value of the object will be recorded in
     * the next frame, i.e. the next time the global snapshot is applied while
     * [recording][startRecording].
     *
     * Calling [stopTrackingState] after this method is optional. If it's not called, the history
     * for the state object will be cleaned up when it's garbage collected.
     *
     * @param stateObject Must be a snapshot state object, such as a [MutableState],
     * [SnapshotStateList], etc. The concrete object must implement [StateObject].
     */
    fun <S : Any> startTrackingState(stateObject: S) {
        ensureValidStateObject(stateObject)
        if (stateObject in trackedStates) return

        // Record the initial state of the object in the next frame to be committed.
        val initialRecord = stateObject.copyCurrentRecord()
        synchronized(lock) {
            trackedStates[stateObject] = Unit
            nextFrame[stateObject] = initialRecord
        }
        if (DEBUG) println(
            "[$TAG] Starting to track object $stateObject with initial record $initialRecord"
        )
    }

    /**
     * Stops tracking changes to [stateObject].
     *
     * Calling this method after [startTrackingState] is optional. If it's not called, the history
     * for the state object will be cleaned up when it's garbage collected.
     */
    fun stopTrackingState(stateObject: Any) {
        stateObject as StateObject
        if (DEBUG) println("[$TAG] Stopping tracking object $stateObject")
        synchronized(lock) {
            trackedStates -= stateObject
            nextFrame -= stateObject
            // Remove all references to the state object from the history so it can be GC'd.
            // TODO Figure out a way to do this without iterating through the entire history.
            //  WeakRefs?
            frames.forEach {
                it -= stateObject
            }
        }
    }

    /**
     * Restores the values of all tracked state objects to the values they had at the frame at
     * [frameIndex]. Calling this method will not change [frameCount] immediately, although the next
     * time a tracked state is changed and applied to the global snapshot, all frames between
     * [currentFrame] and [frameCount] will be removed and replaced with a new frame.
     *
     * The [frameIndex] will be coerced into the valid frame range, and this function will do
     * nothing if equal to [currentFrame].
     */
    fun setCurrentFrameGlobally(frameIndex: Int) {
        if (frameIndex == currentFrame) return

        // Stop recording so we don't record the application of the mutable snapshot below as a
        // new frame. Use the return value instead of isRecording to avoid a race.
        // Don't clear the callback so we can re-use it after.
        val wasRecording = stopRecording(clearOnTrackStateApplied = false)
        if (DEBUG) println(
            "[$TAG] Pausing recording to set current frame (wasRecording=$wasRecording)"
        )

        // Peeking in non-global snapshots is not currently supported.
        synchronized(lock) {
            withGlobalMutableSnapshot {
                @Suppress("NAME_SHADOWING")
                val frameIndex = frameIndex.coerceIn(0, frames.lastIndex)
                if (DEBUG) println("[$TAG] Setting current frame to $frameIndex")
                // Check again after coercing.
                if (frameIndex == currentFrame) return
                currentFrame = frameIndex
                trackedStates.forEach { (stateObject, _) ->
                    // Find the latest frame containing the state object, if any.
                    var readFrameIndex = frameIndex
                    while (readFrameIndex >= 0 && stateObject !in frames[readFrameIndex]) {
                        readFrameIndex--
                    }

                    if (readFrameIndex >= 0) {
                        val frame = frames[readFrameIndex]
                        val record = frame.getValue(stateObject)
                        if (DEBUG) println("[$TAG] Restoring $stateObject to $record")
                        stateObject.restoreFrom(record)
                    } else if (DEBUG) {
                        println("[$TAG] Couldn't find value for $stateObject in history")
                    }
                }

                // When the mutableSnapshot is applied, we'll synchronously get an apply
                // observer callback - or we would, if we hadn't stopped recording. After that,
                // it's safe to stop recording again.
            }
        }

        if (wasRecording) {
            if (DEBUG) println("[$TAG] Resuming recording after setting current frame")
            // Keep using the old callback.
            startRecording(onTrackStateApplied)
        }
    }

    /**
     * Starts recording state changes. This is a no-op if recording has already been started.
     *
     * @return True if recording was successfully started, false if already recording.
     */
    private fun startRecording(onTrackStateApplied: (() -> Unit)?): Boolean {
        if (handle != null) {
            if (DEBUG) println("[$TAG] Recording already started, ignoring start request")
            return false
        }
        if (DEBUG) println("[$TAG] Starting recording")
        synchronized(lock) {
            if (handle != null) return false
            this.onTrackStateApplied = onTrackStateApplied
            handle = Snapshot.registerApplyObserver(this::onApply)
            return true
        }
    }

    /**
     * Stops recording state changes.
     *
     * @return True if recording was stopped, false if it was not started.
     */
    private fun stopRecording(clearOnTrackStateApplied: Boolean): Boolean {
        if (DEBUG) println("[$TAG] Stopping recording")
        if (handle == null) return false
        synchronized(lock) {
            if (handle == null) return false
            handle!!.dispose()
            handle = null
            if (clearOnTrackStateApplied) {
                onTrackStateApplied = null
            }
            return true
        }
    }

    private fun onApply(changedStates: Set<Any>, snapshot: Snapshot) {
        var atLeastOneTrackedStateChanged = false
        // Read values inside the snapshot to avoid race conditions.
        snapshot.withNestedSnapshot {
            synchronized(lock) {
                changedStates.forEach { stateObject ->
                    stateObject as StateObject
                    if (stateObject in trackedStates) {
                        atLeastOneTrackedStateChanged = true
                        nextFrame[stateObject] = stateObject.copyCurrentRecord()
                    }
                }
            }
        }

        if (atLeastOneTrackedStateChanged) {
            if (DEBUG) println("[$TAG] Tracked state changes were applied, invoking callback")
            onTrackStateApplied?.invoke()
        }
    }

    private inline fun withGlobalMutableSnapshot(block: () -> Unit) {
        Snapshot.global {
            Snapshot.withMutableSnapshot(block)
        }
    }

    private inline fun Snapshot.withNestedSnapshot(block: () -> Unit) {
        takeNestedSnapshot().run {
            try {
                enter(block)
            } finally {
                dispose()
            }
        }
    }

    /**
     * Returns a copy of this object's current readable record, without recording a read. The record
     * is a copy since the original record could be reused at any point in the future.
     */
    private fun StateObject.copyCurrentRecord(): StateRecord {
        val newRecord = firstStateRecord.create()
        firstStateRecord.withCurrent { current ->
            newRecord.assign(current)
        }
        return newRecord
    }

    /**
     * Copies [record] into the write record for this state object in the current snapshot.
     */
    private fun StateObject.restoreFrom(record: StateRecord) {
        firstStateRecord.writable(this) {
            assign(record)
        }
    }

    companion object {
        const val NoFrame: Int = -1
    }
}

@Composable
fun <S : Any> trackStateHistory(stateObject: S): S {
    ensureValidStateObject(stateObject)
    val stateHistory = LocalStateHistory.current ?: return stateObject
    DisposableEffect(stateHistory, stateObject) {
        stateHistory.startTrackingState(stateObject)
        onDispose {
            stateHistory.stopTrackingState(stateObject)
        }
    }
    return stateObject
}

val StateHistory.canUndo: Boolean get() = currentFrame > 0
val StateHistory.canRedo: Boolean get() = currentFrame < frameCount - 1

/**
 * Sets the current frame to the previous frame.
 */
fun StateHistory.undo() {
    setCurrentFrameGlobally(currentFrame - 1)
}

/**
 * Sets the current frame to the next frame.
 */
fun StateHistory.redo() {
    setCurrentFrameGlobally(currentFrame + 1)
}

@Suppress("NOTHING_TO_INLINE")
@Composable
inline fun <T> MutableState<T>.trackStateHistory(): MutableState<T> =
    trackStateHistory(this)

@Suppress("NOTHING_TO_INLINE")
@Composable
inline fun <T> SnapshotStateList<T>.trackStateHistory(): SnapshotStateList<T> =
    trackStateHistory(this)

@Suppress("NOTHING_TO_INLINE")
@Composable
inline fun <K, V> SnapshotStateMap<K, V>.trackStateHistory(): SnapshotStateMap<K, V> =
    trackStateHistory(this)

@OptIn(ExperimentalContracts::class)
private fun ensureValidStateObject(stateObject: Any) {
    contract { returns() implies (stateObject is StateObject) }
    require(stateObject is StateObject) {
        "Can only track objects that are instance of StateObject, which this is not: $stateObject"
    }
}

================================================
FILE: statehistory/src/test/java/com/zachklipp/statehistory/demo/StateHistoryTest.kt
================================================
package com.zachklipp.statehistory.demo

import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.snapshots.Snapshot
import com.google.common.truth.Truth.assertThat
import com.zachklipp.statehistory.StateHistory
import com.zachklipp.statehistory.redo
import com.zachklipp.statehistory.undo
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.cancel
import kotlinx.coroutines.launch
import org.junit.After
import org.junit.Test

class StateHistoryTest {

    private val stateHistory = StateHistory()
    private val scope = CoroutineScope(Dispatchers.Unconfined)

    @After
    fun tearDown() {
        scope.cancel()
    }

    @Test
    fun initialFrameCount() {
        assertThat(stateHistory.frameCount).isEqualTo(0)
    }

    @Test
    fun initialCurrentFrame() {
        assertThat(stateHistory.currentFrame).isEqualTo(StateHistory.NoFrame)
    }

    @Test
    fun recordsChanges_whenStartTrackingAfterRecording() {
        scope.launch {
            stateHistory.recordChanges {
                stateHistory.saveFrame()
            }
        }
        val state = mutableStateOf(0)
        stateHistory.startTrackingState(state)
        assertThat(stateHistory.frameCount).isEqualTo(0)

        Snapshot.sendApplyNotifications()
        assertThat(stateHistory.frameCount).isEqualTo(0)

        Snapshot.withMutableSnapshot {
            state.value = 1
        }

        assertThat(stateHistory.frameCount).isEqualTo(1)
        assertThat(stateHistory.currentFrame).isEqualTo(0)
    }

    @Test
    fun recordsChanges_whenStartRecordingAfterTracking() {
        val state = mutableStateOf(0)
        stateHistory.startTrackingState(state)
        assertThat(stateHistory.frameCount).isEqualTo(0)

        Snapshot.sendApplyNotifications()
        assertThat(stateHistory.frameCount).isEqualTo(0)

        scope.launch {
            stateHistory.recordChanges {
                stateHistory.saveFrame()
            }
        }

        Snapshot.withMutableSnapshot {
            state.value = 1
        }

        assertThat(stateHistory.frameCount).isEqualTo(1)
        assertThat(stateHistory.currentFrame).isEqualTo(0)
    }

    @Test
    fun noops_whenChangeCallbackIsNull() {
        scope.launch {
            stateHistory.recordChanges()
        }
        val state = mutableStateOf(0)
        stateHistory.startTrackingState(state)

        Snapshot.withMutableSnapshot {
            state.value = 1
        }

        assertThat(stateHistory.frameCount).isEqualTo(0)
        assertThat(stateHistory.currentFrame).isEqualTo(StateHistory.NoFrame)
    }

    @Test
    fun setCurrentFrameGlobally_restoresState() {
        scope.launch {
            stateHistory.recordChanges {
                stateHistory.saveFrame()
            }
        }
        val state = mutableStateOf(0)
        stateHistory.startTrackingState(state)

        Snapshot.withMutableSnapshot {
            state.value = 1
        }
        Snapshot.withMutableSnapshot {
            state.value = 2
        }
        assertThat(stateHistory.frameCount).isEqualTo(2)
        assertThat(stateHistory.currentFrame).isEqualTo(1)
        assertThat(state.value).isEqualTo(2)

        stateHistory.setCurrentFrameGlobally(0)

        assertThat(stateHistory.frameCount).isEqualTo(2)
        assertThat(stateHistory.currentFrame).isEqualTo(0)
        assertThat(state.value).isEqualTo(1)
    }

    @Test
    fun settingState_afterUndo_clearsPreviousFutureState() {
        scope.launch {
            stateHistory.recordChanges {
                stateHistory.saveFrame()
            }
        }
        val state = mutableStateOf(0)
        stateHistory.startTrackingState(state)

        Snapshot.withMutableSnapshot {
            state.value = 1
        }
        Snapshot.withMutableSnapshot {
            state.value = 2
        }
        assertThat(stateHistory.frameCount).isEqualTo(2)
        assertThat(stateHistory.currentFrame).isEqualTo(1)
        assertThat(state.value).isEqualTo(2)

        // Undo one and change the value.
        stateHistory.setCurrentFrameGlobally(0)
        Snapshot.withMutableSnapshot {
            state.value = 3
        }

        // That should have overwritten the previous frame in which state was 2.
        assertThat(stateHistory.frameCount).isEqualTo(2)
        assertThat(stateHistory.currentFrame).isEqualTo(1)
        assertThat(state.value).isEqualTo(3)

        // But preserve the frame where state is 1.
        stateHistory.setCurrentFrameGlobally(0)
        assertThat(stateHistory.frameCount).isEqualTo(2)
        assertThat(stateHistory.currentFrame).isEqualTo(0)
        assertThat(state.value).isEqualTo(1)
    }

    @Test
    fun tracksMultipleStateChanges() {
        scope.launch {
            stateHistory.recordChanges {
                stateHistory.saveFrame()
            }
        }
        val state1 = mutableStateOf(0)
        stateHistory.startTrackingState(state1)

        Snapshot.withMutableSnapshot {
            state1.value = 1
        }
        assertThat(stateHistory.frameCount).isEqualTo(1)

        val state2 = mutableStateOf(10)
        stateHistory.startTrackingState(state2)

        Snapshot.withMutableSnapshot {
            state2.value = 20
        }
        assertThat(stateHistory.frameCount).isEqualTo(2)
    }

    @Test
    fun restoresMultipleStateChanges() {
        scope.launch {
            stateHistory.recordChanges {
                stateHistory.saveFrame()
            }
        }
        val state1 = mutableStateOf(0)
        stateHistory.startTrackingState(state1)
        Snapshot.withMutableSnapshot {
            state1.value = 1
        }
        val state2 = mutableStateOf(0)
        stateHistory.startTrackingState(state2)
        Snapshot.withMutableSnapshot {
            state2.value = 10
        }
        Snapshot.withMutableSnapshot {
            state2.value = 20
        }

        // Add a frame where both are set at once.
        Snapshot.withMutableSnapshot {
            state1.value = 2
            state2.value = 30
        }

        stateHistory.undo()
        assertThat(state1.value).isEqualTo(1)
        assertThat(state2.value).isEqualTo(20)

        stateHistory.undo()
        assertThat(state1.value).isEqualTo(1)
        assertThat(state2.value).isEqualTo(10)

        stateHistory.redo()
        assertThat(state1.value).isEqualTo(1)
        assertThat(state2.value).isEqualTo(20)
    }

    @Test
    fun stopTracking_whenStateObjectUnregistered() {
        scope.launch {
            stateHistory.recordChanges {
                stateHistory.saveFrame()
            }
        }
        val state = mutableStateOf(0)
        stateHistory.startTrackingState(state)
        Snapshot.withMutableSnapshot {
            state.value = 1
        }
        assertThat(stateHistory.frameCount).isEqualTo(1)
        assertThat(stateHistory.currentFrame).isEqualTo(0)

        stateHistory.stopTrackingState(state)

        Snapshot.withMutableSnapshot {
            state.value = 2
        }
        assertThat(stateHistory.frameCount).isEqualTo(1)
        assertThat(stateHistory.currentFrame).isEqualTo(0)
    }

    @Test
    fun stopTracking_whenRecordingStopped() {
        val job = scope.launch {
            stateHistory.recordChanges {
                stateHistory.saveFrame()
            }
        }
        val state = mutableStateOf(0)
        stateHistory.startTrackingState(state)
        Snapshot.withMutableSnapshot {
            state.value = 1
        }
        assertThat(stateHistory.frameCount).isEqualTo(1)
        assertThat(stateHistory.currentFrame).isEqualTo(0)

        job.cancel()

        Snapshot.withMutableSnapshot {
            state.value = 2
        }
        assertThat(stateHistory.frameCount).isEqualTo(1)
        assertThat(stateHistory.currentFrame).isEqualTo(0)
    }
}
Download .txt
gitextract_r4b_iw8e/

├── .gitignore
├── LICENSE
├── README.md
├── build.gradle
├── demo/
│   ├── .gitignore
│   ├── build.gradle
│   ├── proguard-rules.pro
│   └── src/
│       ├── androidTest/
│       │   └── java/
│       │       └── com/
│       │           └── zachklipp/
│       │               └── statehistory/
│       │                   └── demo/
│       │                       └── DemoTest.kt
│       └── main/
│           ├── AndroidManifest.xml
│           ├── java/
│           │   └── com/
│           │       └── zachklipp/
│           │           └── statehistory/
│           │               └── demo/
│           │                   ├── App.kt
│           │                   ├── AppWithInspector.kt
│           │                   ├── MainActivity.kt
│           │                   ├── StateHistoryInspector.kt
│           │                   └── ui/
│           │                       └── theme/
│           │                           ├── Color.kt
│           │                           ├── Shape.kt
│           │                           ├── Theme.kt
│           │                           └── Type.kt
│           └── res/
│               ├── drawable/
│               │   └── ic_launcher_background.xml
│               ├── drawable-v24/
│               │   └── ic_launcher_foreground.xml
│               ├── mipmap-anydpi-v26/
│               │   ├── ic_launcher.xml
│               │   └── ic_launcher_round.xml
│               ├── values/
│               │   ├── colors.xml
│               │   ├── strings.xml
│               │   └── themes.xml
│               └── xml/
│                   ├── backup_rules.xml
│                   └── data_extraction_rules.xml
├── gradle/
│   └── wrapper/
│       ├── gradle-wrapper.jar
│       └── gradle-wrapper.properties
├── gradle.properties
├── gradlew
├── gradlew.bat
├── settings.gradle
└── statehistory/
    ├── .gitignore
    ├── build.gradle
    ├── gradle.properties
    ├── proguard-rules.pro
    └── src/
        ├── androidTest/
        │   └── java/
        │       └── com/
        │           └── zachklipp/
        │               └── statehistory/
        │                   └── demo/
        │                       └── StateHistoryTest.kt
        ├── main/
        │   ├── AndroidManifest.xml
        │   └── java/
        │       └── com/
        │           └── zachklipp/
        │               └── statehistory/
        │                   └── StateHistory.kt
        └── test/
            └── java/
                └── com/
                    └── zachklipp/
                        └── statehistory/
                            └── demo/
                                └── StateHistoryTest.kt
Condensed preview — 40 files, each showing path, character count, and a content snippet. Download the .json file or copy for the full structured content (88K chars).
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  {
    "path": ".gitignore",
    "chars": 1693,
    "preview": "# Built application files\n*.apk\n*.aar\n*.ap_\n*.aab\n\n# Files for the ART/Dalvik VM\n*.dex\n\n# Java class files\n*.class\n\n# Ge"
  },
  {
    "path": "LICENSE",
    "chars": 11357,
    "preview": "                                 Apache License\n                           Version 2.0, January 2004\n                   "
  },
  {
    "path": "README.md",
    "chars": 3034,
    "preview": "# compose-undo ![Maven Central](https://img.shields.io/maven-central/v/com.zachklipp.compose-undo/statehistory)\n\nTrack c"
  },
  {
    "path": "build.gradle",
    "chars": 455,
    "preview": "buildscript {\n    ext {\n        compose_ui_version = '1.3.0-beta02'\n    }\n}// Top-level build file where you can add con"
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    "path": "demo/.gitignore",
    "chars": 6,
    "preview": "/build"
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  {
    "path": "demo/build.gradle",
    "chars": 2093,
    "preview": "plugins {\n    id 'com.android.application'\n    id 'org.jetbrains.kotlin.android'\n}\n\nandroid {\n    namespace 'com.zachkli"
  },
  {
    "path": "demo/proguard-rules.pro",
    "chars": 750,
    "preview": "# Add project specific ProGuard rules here.\n# You can control the set of applied configuration files using the\n# proguar"
  },
  {
    "path": "demo/src/androidTest/java/com/zachklipp/statehistory/demo/DemoTest.kt",
    "chars": 2374,
    "preview": "package com.zachklipp.statehistory.demo\n\nimport androidx.compose.ui.semantics.SemanticsActions\nimport androidx.compose.u"
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    "path": "demo/src/main/AndroidManifest.xml",
    "chars": 1210,
    "preview": "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n<manifest xmlns:android=\"http://schemas.android.com/apk/res/android\"\n    xmlns:to"
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    "path": "demo/src/main/java/com/zachklipp/statehistory/demo/App.kt",
    "chars": 2168,
    "preview": "package com.zachklipp.statehistory.demo\n\nimport androidx.compose.foundation.border\nimport androidx.compose.foundation.la"
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    "preview": "package com.zachklipp.statehistory.demo\n\nimport androidx.compose.foundation.layout.fillMaxSize\nimport androidx.compose.m"
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    "path": "demo/src/main/java/com/zachklipp/statehistory/demo/MainActivity.kt",
    "chars": 751,
    "preview": "package com.zachklipp.statehistory.demo\n\nimport android.os.Bundle\nimport androidx.activity.ComponentActivity\nimport andr"
  },
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    "path": "demo/src/main/java/com/zachklipp/statehistory/demo/StateHistoryInspector.kt",
    "chars": 3194,
    "preview": "package com.zachklipp.statehistory.demo\n\nimport androidx.compose.foundation.layout.*\nimport androidx.compose.material.*\n"
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    "chars": 226,
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    "chars": 808,
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    "path": "demo/src/main/res/drawable/ic_launcher_background.xml",
    "chars": 5606,
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    "path": "demo/src/main/res/drawable-v24/ic_launcher_foreground.xml",
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    "preview": "<vector xmlns:android=\"http://schemas.android.com/apk/res/android\"\n    xmlns:aapt=\"http://schemas.android.com/aapt\"\n    "
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    "chars": 272,
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    "path": "demo/src/main/res/values/colors.xml",
    "chars": 378,
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  },
  {
    "path": "demo/src/main/res/values/strings.xml",
    "chars": 80,
    "preview": "<resources>\n    <string name=\"app_name\">State History Demo</string>\n</resources>"
  },
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    "preview": "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n<resources>\n\n    <style name=\"Theme.StateHistoryDemo\" parent=\"android:Theme.Mater"
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    "preview": "<?xml version=\"1.0\" encoding=\"utf-8\"?><!--\n   Sample backup rules file; uncomment and customize as necessary.\n   See htt"
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    "path": "demo/src/main/res/xml/data_extraction_rules.xml",
    "chars": 551,
    "preview": "<?xml version=\"1.0\" encoding=\"utf-8\"?><!--\n   Sample data extraction rules file; uncomment and customize as necessary.\n "
  },
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    "path": "gradle/wrapper/gradle-wrapper.properties",
    "chars": 230,
    "preview": "#Fri Sep 16 16:06:11 PDT 2022\ndistributionBase=GRADLE_USER_HOME\ndistributionUrl=https\\://services.gradle.org/distributio"
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    "path": "gradle.properties",
    "chars": 1358,
    "preview": "# Project-wide Gradle settings.\n# IDE (e.g. Android Studio) users:\n# Gradle settings configured through the IDE *will ov"
  },
  {
    "path": "gradlew",
    "chars": 5766,
    "preview": "#!/usr/bin/env sh\n\n#\n# Copyright 2015 the original author or authors.\n#\n# Licensed under the Apache License, Version 2.0"
  },
  {
    "path": "gradlew.bat",
    "chars": 2763,
    "preview": "@rem\r\n@rem Copyright 2015 the original author or authors.\r\n@rem\r\n@rem Licensed under the Apache License, Version 2.0 (th"
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    "preview": "pluginManagement {\n    repositories {\n        google()\n        mavenCentral()\n        gradlePluginPortal()\n    }\n}\ndepen"
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    "chars": 1609,
    "preview": "plugins {\n    id 'com.android.library'\n    id 'org.jetbrains.kotlin.android'\n    id 'com.vanniktech.maven.publish'\n}\n\nan"
  },
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    "path": "statehistory/gradle.properties",
    "chars": 805,
    "preview": "SONATYPE_HOST=DEFAULT\nRELEASE_SIGNING_ENABLED=true\n\nGROUP=com.zachklipp.compose-undo\nPOM_ARTIFACT_ID=statehistory\nVERSIO"
  },
  {
    "path": "statehistory/proguard-rules.pro",
    "chars": 750,
    "preview": "# Add project specific ProGuard rules here.\n# You can control the set of applied configuration files using the\n# proguar"
  },
  {
    "path": "statehistory/src/androidTest/java/com/zachklipp/statehistory/demo/StateHistoryTest.kt",
    "chars": 1106,
    "preview": "package com.zachklipp.statehistory.demo\n\nimport androidx.compose.runtime.mutableStateOf\nimport androidx.compose.ui.test."
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    "path": "statehistory/src/main/AndroidManifest.xml",
    "chars": 51,
    "preview": "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n<manifest />"
  },
  {
    "path": "statehistory/src/main/java/com/zachklipp/statehistory/StateHistory.kt",
    "chars": 16665,
    "preview": "package com.zachklipp.statehistory\n\nimport androidx.compose.runtime.*\nimport androidx.compose.runtime.collection.mutable"
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    "path": "statehistory/src/test/java/com/zachklipp/statehistory/demo/StateHistoryTest.kt",
    "chars": 7910,
    "preview": "package com.zachklipp.statehistory.demo\n\nimport androidx.compose.runtime.mutableStateOf\nimport androidx.compose.runtime."
  }
]

// ... and 1 more files (download for full content)

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