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all: phase out taskguard

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Phase out the dumb hack TaskGuard class in favor of yield.

For some reason, I was under the impression that yield was horribly
slow. It's not, I was just using it wrong. So now TaskGuard is no
longer needed.
This commit is contained in:
Alexander Capehart 2022-09-09 20:40:49 -06:00
parent 189f712eaa
commit 78201e55ee
No known key found for this signature in database
GPG key ID: 37DBE3621FE9AD47
11 changed files with 126 additions and 156 deletions
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14
app/src/main/java/org/oxycblt/auxio/detail/DetailViewModel.kt
View file

@ -24,9 +24,11 @@ import androidx.annotation.StringRes
import androidx.lifecycle.AndroidViewModel
import androidx.lifecycle.viewModelScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Job
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.launch
import kotlinx.coroutines.yield
import org.oxycblt.auxio.R
import org.oxycblt.auxio.music.Album
import org.oxycblt.auxio.music.Artist
@ -40,7 +42,6 @@ import org.oxycblt.auxio.settings.Settings
import org.oxycblt.auxio.ui.Sort
import org.oxycblt.auxio.ui.recycler.Header
import org.oxycblt.auxio.ui.recycler.Item
import org.oxycblt.auxio.util.TaskGuard
import org.oxycblt.auxio.util.application
import org.oxycblt.auxio.util.logD
import org.oxycblt.auxio.util.logW
@ -70,6 +71,8 @@ class DetailViewModel(application: Application) :
val currentSong: StateFlow<DetailSong?>
get() = _currentSong
private var currentSongJob: Job? = null
private val _currentAlbum = MutableStateFlow<Album?>(null)
val currentAlbum: StateFlow<Album?>
get() = _currentAlbum
@ -114,8 +117,6 @@ class DetailViewModel(application: Application) :
currentGenre.value?.let(::refreshGenreData)
}
private val songGuard = TaskGuard()
fun setSongUid(uid: Music.UID) {
if (_currentSong.value?.run { song.uid } == uid) return
val library = unlikelyToBeNull(musicStore.library)
@ -124,7 +125,6 @@ class DetailViewModel(application: Application) :
}
fun clearSong() {
songGuard.newHandle()
_currentSong.value = null
}
@ -159,11 +159,11 @@ class DetailViewModel(application: Application) :
}
private fun generateDetailSong(song: Song) {
currentSongJob?.cancel()
_currentSong.value = DetailSong(song, null)
viewModelScope.launch(Dispatchers.IO) {
val handle = songGuard.newHandle()
currentSongJob = viewModelScope.launch(Dispatchers.IO) {
val info = generateDetailSongInfo(song)
songGuard.yield(handle)
yield()
_currentSong.value = DetailSong(song, info)
}
}

20
app/src/main/java/org/oxycblt/auxio/image/BitmapProvider.kt
View file

@ -25,7 +25,6 @@ import coil.request.Disposable
import coil.request.ImageRequest
import coil.size.Size
import org.oxycblt.auxio.music.Song
import org.oxycblt.auxio.util.TaskGuard
/**
* A utility to provide bitmaps in a manner less prone to race conditions.
@ -38,7 +37,8 @@ import org.oxycblt.auxio.util.TaskGuard
*/
class BitmapProvider(private val context: Context) {
private var currentRequest: Request? = null
private var guard = TaskGuard()
private var currentHandle = 0L
private var handleLock = Any()
/** If this provider is currently attempting to load something. */
val isBusy: Boolean
@ -50,7 +50,9 @@ class BitmapProvider(private val context: Context) {
*/
@Synchronized
fun load(song: Song, target: Target) {
val handle = guard.newHandle()
val handle = synchronized(handleLock) {
++currentHandle
}
currentRequest?.run { disposable.dispose() }
currentRequest = null
@ -62,13 +64,17 @@ class BitmapProvider(private val context: Context) {
.size(Size.ORIGINAL)
.target(
onSuccess = {
if (guard.check(handle)) {
target.onCompleted(it.toBitmap())
synchronized(handleLock) {
if (currentHandle == handle) {
target.onCompleted(it.toBitmap())
}
}
},
onError = {
if (guard.check(handle)) {
target.onCompleted(null)
synchronized(handleLock) {
if (currentHandle == handle) {
target.onCompleted(null)
}
}
}
)

2
app/src/main/java/org/oxycblt/auxio/music/extractor/MetadataLayer.kt
View file

@ -54,7 +54,7 @@ class MetadataLayer(private val context: Context, private val mediaStoreLayer: M
/** Finalize the sub-layers that this layer relies on. */
fun finalize(rawSongs: List<Song.Raw>) = mediaStoreLayer.finalize(rawSongs)
fun parse(emit: (Song.Raw) -> Unit) {
suspend fun parse(emit: suspend (Song.Raw) -> Unit) {
while (true) {
val raw = Song.Raw()
if (mediaStoreLayer.populateRaw(raw) ?: break) {

49
app/src/main/java/org/oxycblt/auxio/music/system/Indexer.kt
View file

@ -25,6 +25,7 @@ import androidx.core.content.ContextCompat
import kotlinx.coroutines.CancellationException
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.withContext
import kotlinx.coroutines.yield
import org.oxycblt.auxio.BuildConfig
import org.oxycblt.auxio.music.Album
import org.oxycblt.auxio.music.Artist
@ -37,7 +38,6 @@ import org.oxycblt.auxio.music.extractor.Api30MediaStoreLayer
import org.oxycblt.auxio.music.extractor.CacheLayer
import org.oxycblt.auxio.music.extractor.MetadataLayer
import org.oxycblt.auxio.ui.Sort
import org.oxycblt.auxio.util.TaskGuard
import org.oxycblt.auxio.util.logD
import org.oxycblt.auxio.util.logE
import org.oxycblt.auxio.util.logW
@ -62,14 +62,11 @@ import org.oxycblt.auxio.util.logW
* directly work with music loading, making such redundant.
*
* @author OxygenCobalt
*
* TODO: Try to replace TaskGuard with yield when possible
*/
class Indexer {
private var lastResponse: Response? = null
private var indexingState: Indexing? = null
private var guard = TaskGuard()
private var controller: Controller? = null
private var callback: Callback? = null
@ -136,21 +133,19 @@ class Indexer {
* complete, a new completion state will be pushed to each callback.
*/
suspend fun index(context: Context) {
val handle = guard.newHandle()
val notGranted =
ContextCompat.checkSelfPermission(context, PERMISSION_READ_AUDIO) ==
PackageManager.PERMISSION_DENIED
if (notGranted) {
emitCompletion(Response.NoPerms, handle)
emitCompletion(Response.NoPerms)
return
}
val response =
try {
val start = System.currentTimeMillis()
val library = indexImpl(context, handle)
val library = indexImpl(context)
if (library != null) {
logD(
"Music indexing completed successfully in " +
@ -171,7 +166,7 @@ class Indexer {
Response.Err(e)
}
emitCompletion(response, handle)
emitCompletion(response)
}
/**
@ -192,16 +187,14 @@ class Indexer {
@Synchronized
fun cancelLast() {
logD("Cancelling last job")
val handle = guard.newHandle()
emitIndexing(null, handle)
emitIndexing(null)
}
/**
* Run the proper music loading process. [handle] must be a truthful handle of the task calling
* this function.
* Run the proper music loading process.
*/
private fun indexImpl(context: Context, handle: Long): MusicStore.Library? {
emitIndexing(Indexing.Indeterminate, handle)
private suspend fun indexImpl(context: Context): MusicStore.Library? {
emitIndexing(Indexing.Indeterminate)
// Create the chain of layers. Each layer builds on the previous layer and
// enables version-specific features in order to create the best possible music
@ -221,7 +214,7 @@ class Indexer {
val metadataLayer = MetadataLayer(context, mediaStoreLayer)
val songs = buildSongs(metadataLayer, handle)
val songs = buildSongs(metadataLayer)
if (songs.isEmpty()) {
return null
}
@ -248,12 +241,15 @@ class Indexer {
* [buildGenres] functions must be called with the returned list so that all songs are properly
* linked up.
*/
private fun buildSongs(metadataLayer: MetadataLayer, handle: Long): List<Song> {
private suspend fun buildSongs(metadataLayer: MetadataLayer): List<Song> {
logD("Starting indexing process")
val start = System.currentTimeMillis()
// Initialize the extractor chain. This also nets us the projected total
// that we can show when loading.
val total = metadataLayer.init()
yield()
// Note: We use a set here so we can eliminate effective duplicates of
// songs (by UID).
@ -263,7 +259,10 @@ class Indexer {
metadataLayer.parse { raw ->
songs.add(Song(raw))
rawSongs.add(raw)
emitIndexing(Indexing.Songs(songs.size, total), handle)
// Check if we got cancelled after every song addition.
yield()
emitIndexing(Indexing.Songs(songs.size, total))
}
metadataLayer.finalize(rawSongs)
@ -351,15 +350,7 @@ class Indexer {
}
@Synchronized
private fun emitIndexing(indexing: Indexing?, handle: Long) {
guard.yield(handle)
if (indexing == indexingState) {
// Ignore redundant states used when the backends just want to check for
// a cancellation
return
}
private fun emitIndexing(indexing: Indexing?) {
indexingState = indexing
// If we have canceled the loading process, we want to revert to a previous completion
@ -371,8 +362,8 @@ class Indexer {
callback?.onIndexerStateChanged(state)
}
private suspend fun emitCompletion(response: Response, handle: Long) {
guard.yield(handle)
private suspend fun emitCompletion(response: Response) {
yield()
// Swap to the Main thread so that downstream callbacks don't crash from being on
// a background thread. Does not occur in emitIndexing due to efficiency reasons.

4
app/src/main/java/org/oxycblt/auxio/music/system/IndexerService.kt
View file

@ -57,6 +57,7 @@ class IndexerService : Service(), Indexer.Controller, Settings.Callback {
private val serviceJob = Job()
private val indexScope = CoroutineScope(serviceJob + Dispatchers.IO)
private var currentIndexJob: Job? = null
private val playbackManager = PlaybackStateManager.getInstance()
@ -118,10 +119,11 @@ class IndexerService : Service(), Indexer.Controller, Settings.Callback {
override fun onStartIndexing() {
if (indexer.isIndexing) {
currentIndexJob?.cancel()
indexer.cancelLast()
}
indexScope.launch { indexer.index(this@IndexerService) }
currentIndexJob = indexScope.launch { indexer.index(this@IndexerService) }
}
override fun onIndexerStateChanged(state: Indexer.State?) {

1
app/src/main/java/org/oxycblt/auxio/playback/PlaybackViewModel.kt
View file

@ -307,6 +307,7 @@ class PlaybackViewModel(application: Application) :
override fun onStateChanged(state: InternalPlayer.State) {
_isPlaying.value = state.isPlaying
_positionDs.value = state.calculateElapsedPosition().msToDs()
// Start watching the position again
lastPositionJob?.cancel()

2
app/src/main/java/org/oxycblt/auxio/playback/state/InternalPlayer.kt
View file

@ -30,7 +30,7 @@ interface InternalPlayer {
/** Whether the player should rewind instead of going to the previous song. */
val shouldRewindWithPrev: Boolean
val currentState: State
fun makeState(durationMs: Long): State
/** Called when a new song should be loaded into the player. */
fun loadSong(song: Song?, play: Boolean)

2
app/src/main/java/org/oxycblt/auxio/playback/state/PlaybackStateManager.kt
View file

@ -342,7 +342,7 @@ class PlaybackStateManager private constructor() {
return
}
val newState = internalPlayer.currentState
val newState = internalPlayer.makeState(song?.durationMs ?: 0)
if (newState != playerState) {
playerState = newState
notifyStateChanged()

144
app/src/main/java/org/oxycblt/auxio/playback/system/PlaybackService.kt
View file

@ -58,6 +58,7 @@ import org.oxycblt.auxio.util.logD
import org.oxycblt.auxio.widgets.WidgetComponent
import org.oxycblt.auxio.widgets.WidgetProvider
import kotlin.math.max
import kotlin.math.min
/**
* A service that manages the system-side aspects of playback, such as:
@ -214,6 +215,60 @@ class PlaybackService :
logD("Service destroyed")
}
// --- CONTROLLER OVERRIDES ---
override val audioSessionId: Int
get() = player.audioSessionId
override val shouldRewindWithPrev: Boolean
get() = settings.rewindWithPrev && player.currentPosition > REWIND_THRESHOLD
override fun makeState(durationMs: Long) =
InternalPlayer.State.new(
player.playWhenReady,
player.isPlaying,
max(min(player.currentPosition, durationMs), 0)
)
override fun loadSong(song: Song?, play: Boolean) {
if (song == null) {
// Stop the foreground state if there's nothing to play.
logD("Nothing playing, stopping playback")
player.stop()
if (openAudioEffectSession) {
// Make sure to close the audio session when we stop playback.
broadcastAudioEffectAction(AudioEffect.ACTION_CLOSE_AUDIO_EFFECT_CONTROL_SESSION)
openAudioEffectSession = false
}
stopAndSave()
return
}
logD("Loading ${song.rawName}")
player.setMediaItem(MediaItem.fromUri(song.uri))
player.prepare()
if (!openAudioEffectSession) {
// Android does not like it if you start an audio effect session without having
// something within your player buffer. Make sure we only start one when we load
// a song.
broadcastAudioEffectAction(AudioEffect.ACTION_OPEN_AUDIO_EFFECT_CONTROL_SESSION)
openAudioEffectSession = true
}
player.playWhenReady = play
}
override fun seekTo(positionMs: Long) {
logD("Seeking to ${positionMs}ms")
player.seekTo(positionMs)
}
override fun changePlaying(isPlaying: Boolean) {
player.playWhenReady = isPlaying
}
// --- PLAYER OVERRIDES ---
override fun onEvents(player: Player, events: Player.Events) {
@ -270,52 +325,27 @@ class PlaybackService :
}
}
// --- CONTROLLER OVERRIDES ---
// --- MUSICSTORE OVERRIDES ---
override val audioSessionId: Int
get() = player.audioSessionId
override val shouldRewindWithPrev: Boolean
get() = settings.rewindWithPrev && player.currentPosition > REWIND_THRESHOLD
override val currentState: InternalPlayer.State
get() =
InternalPlayer.State.new(
player.playWhenReady,
player.isPlaying,
max(player.currentPosition, 0)
)
override fun loadSong(song: Song?, play: Boolean) {
if (song == null) {
// Stop the foreground state if there's nothing to play.
logD("Nothing playing, stopping playback")
player.stop()
if (openAudioEffectSession) {
// Make sure to close the audio session when we stop playback.
broadcastAudioEffectAction(AudioEffect.ACTION_CLOSE_AUDIO_EFFECT_CONTROL_SESSION)
openAudioEffectSession = false
}
stopAndSave()
return
override fun onLibraryChanged(library: MusicStore.Library?) {
if (library != null) {
playbackManager.requestAction(this)
}
logD("Loading ${song.rawName}")
player.setMediaItem(MediaItem.fromUri(song.uri))
player.prepare()
if (!openAudioEffectSession) {
// Android does not like it if you start an audio effect session without having
// something within your player buffer. Make sure we only start one when we load
// a song.
broadcastAudioEffectAction(AudioEffect.ACTION_OPEN_AUDIO_EFFECT_CONTROL_SESSION)
openAudioEffectSession = true
}
player.playWhenReady = play
}
// --- SETTINGSMANAGER OVERRIDES ---
override fun onSettingChanged(key: String) {
if (key == getString(R.string.set_key_replay_gain) ||
key == getString(R.string.set_key_pre_amp_with) ||
key == getString(R.string.set_key_pre_amp_without)
) {
onTracksChanged(player.currentTracks)
}
}
// --- OTHER FUNCTIONS ---
private fun broadcastAudioEffectAction(event: String) {
sendBroadcast(
Intent(event)
@ -337,15 +367,6 @@ class PlaybackService :
}
}
override fun seekTo(positionMs: Long) {
logD("Seeking to ${positionMs}ms")
player.seekTo(positionMs)
}
override fun changePlaying(isPlaying: Boolean) {
player.playWhenReady = isPlaying
}
override fun onAction(action: InternalPlayer.Action): Boolean {
val library = musicStore.library
if (library != null) {
@ -397,27 +418,6 @@ class PlaybackService :
}
}
// --- MUSICSTORE OVERRIDES ---
override fun onLibraryChanged(library: MusicStore.Library?) {
if (library != null) {
playbackManager.requestAction(this)
}
}
// --- SETTINGSMANAGER OVERRIDES ---
override fun onSettingChanged(key: String) {
if (key == getString(R.string.set_key_replay_gain) ||
key == getString(R.string.set_key_pre_amp_with) ||
key == getString(R.string.set_key_pre_amp_without)
) {
onTracksChanged(player.currentTracks)
}
}
// --- OTHER FUNCTIONS ---
/** A [BroadcastReceiver] for receiving general playback events from the system. */
private inner class PlaybackReceiver : BroadcastReceiver() {
private var initialHeadsetPlugEventHandled = false

12
app/src/main/java/org/oxycblt/auxio/search/SearchViewModel.kt
View file

@ -23,9 +23,11 @@ import androidx.annotation.IdRes
import androidx.lifecycle.AndroidViewModel
import androidx.lifecycle.ViewModel
import androidx.lifecycle.viewModelScope
import kotlinx.coroutines.Job
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.launch
import kotlinx.coroutines.yield
import org.oxycblt.auxio.R
import org.oxycblt.auxio.music.Album
import org.oxycblt.auxio.music.Artist
@ -38,7 +40,6 @@ import org.oxycblt.auxio.ui.DisplayMode
import org.oxycblt.auxio.ui.Sort
import org.oxycblt.auxio.ui.recycler.Header
import org.oxycblt.auxio.ui.recycler.Item
import org.oxycblt.auxio.util.TaskGuard
import org.oxycblt.auxio.util.application
import org.oxycblt.auxio.util.logD
import java.text.Normalizer
@ -62,15 +63,16 @@ class SearchViewModel(application: Application) :
get() = settings.searchFilterMode
private var lastQuery: String? = null
private var guard = TaskGuard()
private var currentSearchJob: Job? = null
/**
* Use [query] to perform a search of the music library. Will push results to [searchResults].
*/
fun search(query: String?) {
val handle = guard.newHandle()
lastQuery = query
currentSearchJob?.cancel()
val library = musicStore.library
if (query.isNullOrEmpty() || library == null) {
logD("No music/query, ignoring search")
@ -81,7 +83,7 @@ class SearchViewModel(application: Application) :
logD("Performing search for $query")
// Searching can be quite expensive, so get on a co-routine
viewModelScope.launch {
currentSearchJob = viewModelScope.launch {
val sort = Sort(Sort.Mode.ByName, true)
val results = mutableListOf<Item>()
@ -115,7 +117,7 @@ class SearchViewModel(application: Application) :
}
}
guard.yield(handle)
yield()
_searchResults.value = results
}
}

32
app/src/main/java/org/oxycblt/auxio/util/PrimitiveUtil.kt
View file

@ -21,7 +21,6 @@ import android.os.Looper
import org.oxycblt.auxio.BuildConfig
import java.lang.reflect.Field
import java.lang.reflect.Method
import java.util.concurrent.CancellationException
import kotlin.reflect.KClass
/** Assert that we are on a background thread. */
@ -57,34 +56,3 @@ fun lazyReflectedField(clazz: KClass<*>, field: String) = lazy {
fun lazyReflectedMethod(clazz: KClass<*>, method: String) = lazy {
clazz.java.getDeclaredMethod(method).also { it.isAccessible = true }
}
/**
* An abstraction that allows cheap cooperative multi-threading in shared object contexts. Every new
* task should call [newHandle], while every running task should call [check] or [yield] depending
* on the situation to determine if it should continue. Failure to follow the expectations of this
* class will result in bugs.
*
* @author OxygenCobalt
*/
class TaskGuard {
private var currentHandle = 0L
/**
* Returns a new handle to the calling task while invalidating the handle of the previous task.
*/
@Synchronized fun newHandle() = ++currentHandle
/** Check if the given [handle] is still valid. */
@Synchronized fun check(handle: Long) = handle == currentHandle
/**
* Alternative to [kotlinx.coroutines.yield], that achieves the same behavior but in a much
* cheaper manner.
*/
@Synchronized
fun yield(handle: Long) {
if (!check(handle)) {
throw CancellationException()
}
}
}