fix(editor): Dispatchers.IO thread pool is exhausted if files are continuously opened and closed (fixes #1551)

app/src/main/java/com/itsaky/androidide/ui/CodeEditorView.kt

@@ -83,16 +83,17 @@ import io.github.rosemoe.sora.widget.CodeEditor
 import io.github.rosemoe.sora.widget.component.Magnifier
 import kotlinx.coroutines.CoroutineName
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.DelicateCoroutinesApi
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.newSingleThreadContext
 import kotlinx.coroutines.withContext
 import org.greenrobot.eventbus.EventBus
 import org.greenrobot.eventbus.Subscribe
 import org.greenrobot.eventbus.ThreadMode
 import java.io.Closeable
 import java.io.File
-import kotlin.coroutines.CoroutineContext
-import kotlin.coroutines.EmptyCoroutineContext
 
 /**
  * A view that handles opened code editor.
@@ -112,6 +113,15 @@ class CodeEditorView(
   private val codeEditorScope = CoroutineScope(
     Dispatchers.Default + CoroutineName("CodeEditorView"))
 
+  /**
+   * The [CoroutineContext][kotlin.coroutines.CoroutineContext] used to reading and writing the file
+   * in this editor. We use a separate, single-threaded context assuming that the file will be either
+   * read from or written to at a time, but not both. If in future we add support for anything like
+   * that, the number of thread should probably be increased.
+   */
+  @OptIn(DelicateCoroutinesApi::class, ExperimentalCoroutinesApi::class)
+  private val readWriteContext = newSingleThreadContext("CodeEditorView")
+
   private val binding: LayoutCodeEditorBinding
     get() = checkNotNull(_binding) { "Binding has been destroyed" }
 
@@ -222,8 +232,7 @@ class CodeEditorView(
     val file = this.file ?: return false
 
     if (!isModified && file.exists()) {
-      log.info(file.name)
-      log.info("File was not modified. Skipping save operation.")
+      log.info("File was not modified. Skipping save operation.", file.name)
       return false
     }
 
@@ -232,16 +241,19 @@ class CodeEditorView(
       return false
     }
 
-    disableEditingAndRun(Dispatchers.IO) {
-      // Do not call suspend functions in this scope
-      // the writeTo function acquires lock to the Content object before writing and releases
-      // the lock after writing
-      // if there are any suspend function calls in between, the lock and unlock calls might not
-      // be called on the same thread
-      text.writeTo(file, this@CodeEditorView::updateReadWriteProgress)
-    }
+    withContext(Dispatchers.Main.immediate) {
+
+      withEditingDisabled {
+        withContext(readWriteContext) {
+          // Do not call suspend functions in this scope
+          // the writeTo function acquires lock to the Content object before writing and releases
+          // the lock after writing
+          // if there are any suspend function calls in between, the lock and unlock calls might not
+          // be called on the same thread
+          text.writeTo(file, this@CodeEditorView::updateReadWriteProgress)
+        }
+      }
 
-    withContext(Dispatchers.Main) {
       _binding?.rwProgress?.isVisible = false
     }
 
@@ -267,31 +279,26 @@ class CodeEditorView(
     }
   }
 
-  private suspend inline fun <R> disableEditingAndRun(
-    context: CoroutineContext = EmptyCoroutineContext,
-    crossinline action: CoroutineScope.() -> R
-  ): R {
-    return withContext(Dispatchers.Main) {
+  private inline fun <R : Any?> withEditingDisabled(action: () -> R): R {
+    return try {
       _binding?.editor?.isEditable = false
-
-      val result = withContext(context) {
-        action()
-      }
-
+      action()
+    } finally {
       _binding?.editor?.isEditable = true
-      return@withContext result
     }
   }
 
   private fun readFileAndApplySelection(file: File, selection: Range) {
-    updateReadWriteProgress(0)
-    codeEditorScope.launch {
-      val content = disableEditingAndRun(Dispatchers.IO) {
-        selection.validate()
-        file.readContent(this@CodeEditorView::updateReadWriteProgress)
-      }
+    codeEditorScope.launch(Dispatchers.Main.immediate) {
+      updateReadWriteProgress(0)
+
+      withEditingDisabled {
+
+        val content = withContext(readWriteContext) {
+          selection.validate()
+          file.readContent(this@CodeEditorView::updateReadWriteProgress)
+        }
 
-      withContext(Dispatchers.Main) {
         initializeContent(content, file, selection)
         _binding?.rwProgress?.isVisible = false
       }
@@ -299,12 +306,13 @@ class CodeEditorView(
   }
 
   private fun initializeContent(content: Content, file: File, selection: Range) {
-    binding.editor.apply {
+    val ideEditor = binding.editor
+    ideEditor.postInLifecycle {
       val args = Bundle().apply {
         putString(IEditor.KEY_FILE, file.absolutePath)
       }
 
-      setText(content, args)
+      ideEditor.setText(content, args)
 
       // editor.setText(...) sets the modified flag to true
       // but in this case, file is read from disk and hence the contents are not modified at all
@@ -313,11 +321,11 @@ class CodeEditorView(
       markUnmodified()
       postRead(file)
 
-      validateRange(selection)
-      setSelection(selection)
-    }
+      ideEditor.validateRange(selection)
+      ideEditor.setSelection(selection)
 
-    configureEditorIfNeeded()
+      configureEditorIfNeeded()
+    }
   }
 
   private fun postRead(file: File) {
@@ -514,5 +522,7 @@ class CodeEditorView(
       notifyClose()
       release()
     }
+
+    readWriteContext.use { }
   }
 }

editor-treesitter/src/main/java/io/github/rosemoe/sora/editor/ts/TsAnalyzeWorker.kt

@@ -32,13 +32,14 @@ import io.github.rosemoe.sora.lang.analysis.StyleReceiver
 import io.github.rosemoe.sora.lang.styling.CodeBlock
 import io.github.rosemoe.sora.lang.styling.Styles
 import io.github.rosemoe.sora.text.ContentReference
-import kotlinx.coroutines.CoroutineName
 import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.DelicateCoroutinesApi
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
-import kotlinx.coroutines.withContext
+import kotlinx.coroutines.newSingleThreadContext
+import java.lang.RuntimeException
 import java.util.concurrent.CancellationException
 import java.util.concurrent.LinkedBlockingQueue
 
@@ -61,11 +62,15 @@ internal class TsAnalyzeWorker(
 
   var stylesReceiver: StyleReceiver? = null
 
-  private val analyzerScope = CoroutineScope(Dispatchers.Default + CoroutineName("TsAnalyzeWorker"))
+  @OptIn(DelicateCoroutinesApi::class, ExperimentalCoroutinesApi::class)
+  private val analyzerContext = newSingleThreadContext("TsAnalyzeWorkerContext")
+
+  private val analyzerScope = CoroutineScope(analyzerContext)
   private val messageChannel = LinkedBlockingQueue<Message<*>>()
   private var analyzerJob: Job? = null
 
   private var isInitialized = false
+  private var isDestroyed = false
 
   private var tree: TSTree? = null
   private val localText = UTF16StringFactory.newString()
@@ -74,14 +79,28 @@ internal class TsAnalyzeWorker(
   }
 
   fun init(init: Init) {
+    if (isDestroyed) {
+      log.warn("Received Init after TsAnalyzeWorker has been destroyed. Ignoring...")
+      return
+    }
+
     messageChannel.offer(init)
   }
 
   fun onMod(mod: Mod) {
+    if (isDestroyed) {
+      log.warn("Received Mod after TsAnalyzeWorker has been destroyed. Ignoring...")
+      return
+    }
+
     messageChannel.offer(mod)
   }
 
   fun stop() {
+    log.debug("Stopping TsAnalyzeWorker...")
+    isDestroyed = true
+
+    analyzerContext.close()
     messageChannel.clear()
     analyzerJob?.cancel(CancellationException("Requested to be stopped"))
     localText.close()
@@ -90,7 +109,8 @@ internal class TsAnalyzeWorker(
   }
 
   fun start() {
-    analyzerJob = analyzerScope.launch(Dispatchers.Default) {
+    check(!isDestroyed) { "TsAnalyeWorker has already been destroyed" }
+    analyzerJob = analyzerScope.launch {
       while (isActive) {
         processNextMessage()
       }
@@ -105,8 +125,8 @@ internal class TsAnalyzeWorker(
     }
   }
 
-  private suspend fun processNextMessage() {
-    val message = withContext(Dispatchers.IO) { messageChannel.take() }
+  private fun processNextMessage() {
+    val message = messageChannel.take()
 
     try {
       when (message) {

editor/src/main/java/com/itsaky/androidide/editor/schemes/IDEColorSchemeProvider.kt

@@ -50,6 +50,9 @@ object IDEColorSchemeProvider {
   private const val SCHEME_IS_DARK = "scheme.isDark"
   private const val SCHEME_FILE = "scheme.file"
 
+  private var isDefaultSchemeLoaded = false
+  private var isCurrentSchemeLoaded = false
+
   /**
    * The default color scheme.
    *
@@ -58,7 +61,10 @@ object IDEColorSchemeProvider {
    */
   private var defaultScheme: IDEColorScheme? = null
     get() {
-      return field ?: getColorScheme(DEFAULT_COLOR_SCHEME).also { field = it }
+      return field ?: getColorScheme(DEFAULT_COLOR_SCHEME).also { scheme ->
+        field = scheme
+        isDefaultSchemeLoaded = scheme != null
+      }
     }
 
   /**
@@ -69,7 +75,10 @@ object IDEColorSchemeProvider {
    */
   private var currentScheme: IDEColorScheme? = null
     get() {
-      return field ?: getColorScheme(colorScheme).also { field = it }
+      return field ?: getColorScheme(colorScheme).also { scheme ->
+        field = scheme
+        isCurrentSchemeLoaded = scheme != null
+      }
     }
 
   /**
@@ -179,9 +188,21 @@ object IDEColorSchemeProvider {
     context: Context,
     coroutineScope: CoroutineScope,
     type: String? = null,
-    callbackContext: CoroutineContext = Dispatchers.Main,
+    callbackContext: CoroutineContext = Dispatchers.Main.immediate,
     callback: (SchemeAndroidIDE?) -> Unit
   ) {
+
+    // If the scheme has already been loaded, do not bother to dispatch an IO coroutine
+    // simply invoke the callback on the requested context
+    if (isCurrentSchemeLoaded && isDefaultSchemeLoaded) {
+      coroutineScope.launch(callbackContext) {
+        callback(readScheme(context, type))
+      }
+      return
+    }
+
+    // scheme has not been loaded
+    // load the scheme using the IO dispatcher
     coroutineScope.launch(Dispatchers.IO) {
       val scheme = readScheme(context, type)
       withContext(callbackContext) {
@@ -252,7 +273,10 @@ object IDEColorSchemeProvider {
   fun destroy() {
     this.schemes.clear()
     this.currentScheme = null
+    this.isCurrentSchemeLoaded = false
+
     this.defaultScheme = null
+    this.isDefaultSchemeLoaded = false
   }
 
   @WorkerThread