Simplify PageHolder load Job (#9086)

Inline statusJob into loadJob, using supervisorScope to load the page
and track status changes in parallel.
- supervisorScope does not complete until both the child loadPage
  coroutine and statusFlow.collectLatest have completed.
- Cancelling supervisorScope cancels the child loadPage coroutine and
  statusFlow.collectLatest.
- Use supervisorScope instead of coroutineScope to let status
  collection continue if loadPage fails.

Inline progressJob into loadJob, using collectLatest's cancellation
to avoid cancelling the progressFlow collection explicitly.
- collectLatest cancels the previous action block when the flow
  emits a new value. This means the DOWNLOAD_IMAGE
  progressFlow.collectLatest gets automatically cancelled when
  statusFlow emits a new state.

Convert launchLoadJob to suspend function, move job launch to caller,
and rename as loadPageAndProcessStatus.
This commit is contained in:
Two-Ai 2023-02-15 22:24:55 -05:00 committed by GitHub
parent dc2eaf0788
commit 4635e58405
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2 changed files with 54 additions and 144 deletions

View File

@ -19,10 +19,12 @@ import kotlinx.coroutines.Job
import kotlinx.coroutines.MainScope
import kotlinx.coroutines.flow.collectLatest
import kotlinx.coroutines.launch
import kotlinx.coroutines.supervisorScope
import rx.Observable
import rx.Subscription
import rx.android.schedulers.AndroidSchedulers
import rx.schedulers.Schedulers
import tachiyomi.core.util.lang.launchIO
import java.io.BufferedInputStream
import java.io.ByteArrayInputStream
import java.io.InputStream
@ -60,20 +62,10 @@ class PagerPageHolder(
private val scope = MainScope()
/**
* Job for loading the page.
* Job for loading the page and processing changes to the page's status.
*/
private var loadJob: Job? = null
/**
* Job for status changes of the page.
*/
private var statusJob: Job? = null
/**
* Job for progress changes of the page.
*/
private var progressJob: Job? = null
/**
* Subscription used to read the header of the image. This is needed in order to instantiate
* the appropiate image view depending if the image is animated (GIF).
@ -82,7 +74,7 @@ class PagerPageHolder(
init {
addView(progressIndicator)
launchLoadJob()
loadJob = scope.launch { loadPageAndProcessStatus() }
}
/**
@ -91,73 +83,40 @@ class PagerPageHolder(
@SuppressLint("ClickableViewAccessibility")
override fun onDetachedFromWindow() {
super.onDetachedFromWindow()
cancelProgressJob()
cancelLoadJob()
loadJob?.cancel()
loadJob = null
unsubscribeReadImageHeader()
}
/**
* Starts loading the page and processing changes to the page's status.
* Loads the page and processes changes to the page's status.
*
* @see processStatus
* Returns immediately if the page has no PageLoader.
* Otherwise, this function does not return. It will continue to process status changes until
* the Job is cancelled.
*/
private fun launchLoadJob() {
loadJob?.cancel()
statusJob?.cancel()
private suspend fun loadPageAndProcessStatus() {
val loader = page.chapter.pageLoader ?: return
loadJob = scope.launch {
supervisorScope {
launchIO {
loader.loadPage(page)
}
statusJob = scope.launch {
page.statusFlow.collectLatest { processStatus(it) }
}
}
private fun launchProgressJob() {
progressJob?.cancel()
progressJob = scope.launch {
page.progressFlow.collectLatest { value -> progressIndicator.setProgress(value) }
}
}
/**
* Called when the status of the page changes.
*
* @param status the new status of the page.
*/
private fun processStatus(status: Page.State) {
when (status) {
page.statusFlow.collectLatest { state ->
when (state) {
Page.State.QUEUE -> setQueued()
Page.State.LOAD_PAGE -> setLoading()
Page.State.DOWNLOAD_IMAGE -> {
launchProgressJob()
setDownloading()
page.progressFlow.collectLatest { value ->
progressIndicator.setProgress(value)
}
Page.State.READY -> {
setImage()
cancelProgressJob()
}
Page.State.ERROR -> {
setError()
cancelProgressJob()
Page.State.READY -> setImage()
Page.State.ERROR -> setError()
}
}
}
/**
* Cancels loading the page and processing changes to the page's status.
*/
private fun cancelLoadJob() {
loadJob?.cancel()
loadJob = null
statusJob?.cancel()
statusJob = null
}
private fun cancelProgressJob() {
progressJob?.cancel()
progressJob = null
}
/**

View File

@ -24,10 +24,12 @@ import kotlinx.coroutines.Job
import kotlinx.coroutines.MainScope
import kotlinx.coroutines.flow.collectLatest
import kotlinx.coroutines.launch
import kotlinx.coroutines.supervisorScope
import rx.Observable
import rx.Subscription
import rx.android.schedulers.AndroidSchedulers
import rx.schedulers.Schedulers
import tachiyomi.core.util.lang.launchIO
import java.io.BufferedInputStream
import java.io.InputStream
@ -77,16 +79,6 @@ class WebtoonPageHolder(
*/
private var loadJob: Job? = null
/**
* Job for status changes of the page.
*/
private var statusJob: Job? = null
/**
* Job for progress changes of the page.
*/
private var progressJob: Job? = null
/**
* Subscription used to read the header of the image. This is needed in order to instantiate
* the appropriate image view depending if the image is animated (GIF).
@ -106,7 +98,8 @@ class WebtoonPageHolder(
*/
fun bind(page: ReaderPage) {
this.page = page
launchLoadJob()
loadJob?.cancel()
loadJob = scope.launch { loadPageAndProcessStatus() }
refreshLayoutParams()
}
@ -126,8 +119,8 @@ class WebtoonPageHolder(
* Called when the view is recycled and added to the view pool.
*/
override fun recycle() {
cancelLoadJob()
cancelProgressJob()
loadJob?.cancel()
loadJob = null
unsubscribeReadImageHeader()
removeErrorLayout()
@ -136,76 +129,34 @@ class WebtoonPageHolder(
}
/**
* Starts loading the page and processing changes to the page's status.
* Loads the page and processes changes to the page's status.
*
* @see processStatus
* Returns immediately if there is no page or the page has no PageLoader.
* Otherwise, this function does not return. It will continue to process status changes until
* the Job is cancelled.
*/
private fun launchLoadJob() {
cancelLoadJob()
private suspend fun loadPageAndProcessStatus() {
val page = page ?: return
val loader = page.chapter.pageLoader ?: return
loadJob = scope.launch {
supervisorScope {
launchIO {
loader.loadPage(page)
}
statusJob = scope.launch {
page.statusFlow.collectLatest { processStatus(it) }
}
}
/**
* Observes the progress of the page and updates view.
*/
private fun launchProgressJob() {
cancelProgressJob()
val page = page ?: return
progressJob = scope.launch {
page.progressFlow.collectLatest { value -> progressIndicator.setProgress(value) }
}
}
/**
* Called when the status of the page changes.
*
* @param status the new status of the page.
*/
private fun processStatus(status: Page.State) {
when (status) {
page.statusFlow.collectLatest { state ->
when (state) {
Page.State.QUEUE -> setQueued()
Page.State.LOAD_PAGE -> setLoading()
Page.State.DOWNLOAD_IMAGE -> {
launchProgressJob()
setDownloading()
page.progressFlow.collectLatest { value ->
progressIndicator.setProgress(value)
}
Page.State.READY -> {
setImage()
cancelProgressJob()
}
Page.State.ERROR -> {
setError()
cancelProgressJob()
Page.State.READY -> setImage()
Page.State.ERROR -> setError()
}
}
}
/**
* Cancels loading the page and processing changes to the page's status.
*/
private fun cancelLoadJob() {
loadJob?.cancel()
loadJob = null
statusJob?.cancel()
statusJob = null
}
/**
* Unsubscribes from the progress subscription.
*/
private fun cancelProgressJob() {
progressJob?.cancel()
progressJob = null
}
/**