[resources] Check cached deferreds and drop them if they are cancelled. (#4819)

Before the fix we could cancel a coroutine and the cancelled deferred
was saved in cache.

## Release Notes
### Fixes - Resources
- _(prerelease fix)_ Fix a cached empty resource on a Compose for Web if
the resource loading was canceled during progress

components/resources/library/src/commonMain/kotlin/org/jetbrains/compose/resources/AsyncCache.kt

@@ -0,0 +1,31 @@
+package org.jetbrains.compose.resources
+
+import kotlinx.coroutines.CoroutineStart
+import kotlinx.coroutines.Deferred
+import kotlinx.coroutines.async
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+
+internal class AsyncCache<K, V> {
+    private val mutex = Mutex()
+    private val cache = mutableMapOf<K, Deferred<V>>()
+
+    suspend fun getOrLoad(key: K, load: suspend () -> V): V = coroutineScope {
+        val deferred = mutex.withLock {
+            var cached = cache[key]
+            if (cached == null || cached.isCancelled) {
+                //LAZY - to free the mutex lock as fast as possible
+                cached = async(start = CoroutineStart.LAZY) { load() }
+                cache[key] = cached
+            }
+            cached
+        }
+        deferred.await()
+    }
+
+    //@TestOnly
+    fun clear() {
+        cache.clear()
+    }
+}

components/resources/library/src/commonMain/kotlin/org/jetbrains/compose/resources/ImageResources.kt

@@ -1,6 +1,9 @@
 package org.jetbrains.compose.resources
 
-import androidx.compose.runtime.*
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Immutable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
 import androidx.compose.ui.graphics.ImageBitmap
 import androidx.compose.ui.graphics.painter.BitmapPainter
 import androidx.compose.ui.graphics.painter.Painter
@@ -9,9 +12,6 @@ import androidx.compose.ui.graphics.vector.rememberVectorPainter
 import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.unit.Density
 import androidx.compose.ui.unit.dp
-import kotlinx.coroutines.*
-import kotlinx.coroutines.sync.Mutex
-import kotlinx.coroutines.sync.withLock
 import org.jetbrains.compose.resources.vector.toImageVector
 import org.jetbrains.compose.resources.vector.xmldom.Element
 
@@ -91,6 +91,7 @@ fun vectorResource(resource: DrawableResource): ImageVector {
 }
 
 internal expect class SvgElement
+
 internal expect fun SvgElement.toSvgPainter(density: Density): Painter
 
 private val emptySvgPainter: Painter by lazy { BitmapPainter(emptyImageBitmap) }
@@ -135,8 +136,7 @@ private sealed interface ImageCache {
     class Svg(val painter: Painter) : ImageCache
 }
 
-private val imageCacheMutex = Mutex()
-private val imageCache = mutableMapOf<String, Deferred<ImageCache>>()
+private val imageCache = AsyncCache<String, ImageCache>()
 
 //@TestOnly
 internal fun dropImageCache() {
@@ -147,14 +147,4 @@ private suspend fun loadImage(
     path: String,
     resourceReader: ResourceReader,
     decode: (ByteArray) -> ImageCache
-): ImageCache = coroutineScope {
-    val deferred = imageCacheMutex.withLock {
-        imageCache.getOrPut(path) {
-            //LAZY - to free the mutex lock as fast as possible
-            async(start = CoroutineStart.LAZY) {
-                decode(resourceReader.read(path))
-            }
-        }
-    }
-    deferred.await()
-}
+): ImageCache = imageCache.getOrLoad(path) { decode(resourceReader.read(path)) }

components/resources/library/src/commonMain/kotlin/org/jetbrains/compose/resources/StringResourcesUtils.kt

@@ -1,11 +1,6 @@
 package org.jetbrains.compose.resources
 
-import kotlinx.coroutines.*
-import kotlinx.coroutines.sync.Mutex
-import kotlinx.coroutines.sync.withLock
 import org.jetbrains.compose.resources.plural.PluralCategory
-import org.jetbrains.compose.resources.vector.xmldom.Element
-import org.jetbrains.compose.resources.vector.xmldom.NodeList
 import kotlin.io.encoding.Base64
 import kotlin.io.encoding.ExperimentalEncodingApi
 
@@ -20,8 +15,7 @@ internal sealed interface StringItem {
     data class Array(val items: List<String>) : StringItem
 }
 
-private val stringsCacheMutex = Mutex()
-private val stringItemsCache = mutableMapOf<String, Deferred<StringItem>>()
+private val stringItemsCache = AsyncCache<String, StringItem>()
 //@TestOnly
 internal fun dropStringItemsCache() {
     stringItemsCache.clear()
@@ -30,28 +24,22 @@ internal fun dropStringItemsCache() {
 internal suspend fun getStringItem(
     resourceItem: ResourceItem,
     resourceReader: ResourceReader
-): StringItem = coroutineScope {
-    val deferred = stringsCacheMutex.withLock {
-        stringItemsCache.getOrPut("${resourceItem.path}/${resourceItem.offset}-${resourceItem.size}") {
-            //LAZY - to free the mutex lock as fast as possible
-            async(start = CoroutineStart.LAZY) {
-                val record = resourceReader.readPart(
-                    resourceItem.path,
-                    resourceItem.offset,
-                    resourceItem.size
-                ).decodeToString()
-                val recordItems = record.split('|')
-                val recordType = recordItems.first()
-                val recordData = recordItems.last()
-                when (recordType) {
-                    "plurals" -> recordData.decodeAsPlural()
-                    "string-array" -> recordData.decodeAsArray()
-                    else -> recordData.decodeAsString()
-                }
-            }
-        }
+): StringItem = stringItemsCache.getOrLoad(
+    key = "${resourceItem.path}/${resourceItem.offset}-${resourceItem.size}"
+) {
+    val record = resourceReader.readPart(
+        resourceItem.path,
+        resourceItem.offset,
+        resourceItem.size
+    ).decodeToString()
+    val recordItems = record.split('|')
+    val recordType = recordItems.first()
+    val recordData = recordItems.last()
+    when (recordType) {
+        "plurals" -> recordData.decodeAsPlural()
+        "string-array" -> recordData.decodeAsArray()
+        else -> recordData.decodeAsString()
     }
-    deferred.await()
 }
 
 @OptIn(ExperimentalEncodingApi::class)

components/resources/library/src/commonMain/kotlin/org/jetbrains/compose/resources/plural/PluralRuleList.kt

@@ -5,12 +5,7 @@
 
 package org.jetbrains.compose.resources.plural
 
-import kotlinx.coroutines.CoroutineStart
-import kotlinx.coroutines.Deferred
-import kotlinx.coroutines.async
-import kotlinx.coroutines.coroutineScope
-import kotlinx.coroutines.sync.Mutex
-import kotlinx.coroutines.sync.withLock
+import org.jetbrains.compose.resources.AsyncCache
 import org.jetbrains.compose.resources.InternalResourceApi
 import org.jetbrains.compose.resources.LanguageQualifier
 import org.jetbrains.compose.resources.RegionQualifier
@@ -21,8 +16,7 @@ internal class PluralRuleList(private val rules: Array<PluralRule>) {
     }
 
     companion object {
-        private val cacheMutex = Mutex()
-        private val cache = Array<Deferred<PluralRuleList>?>(cldrPluralRuleLists.size) { null }
+        private val cache = AsyncCache<Int, PluralRuleList>()
         private val emptyList = PluralRuleList(emptyArray())
 
         @OptIn(InternalResourceApi::class)
@@ -36,17 +30,7 @@ internal class PluralRuleList(private val rules: Array<PluralRule>) {
 
         suspend fun getInstance(cldrLocaleName: String): PluralRuleList {
             val listIndex = cldrPluralRuleListIndexByLocale[cldrLocaleName]!!
-            return coroutineScope {
-                val deferred = cacheMutex.withLock {
-                    if (cache[listIndex] == null) {
-                        cache[listIndex] = async(start = CoroutineStart.LAZY) {
-                            createInstance(listIndex)
-                        }
-                    }
-                    cache[listIndex]!!
-                }
-                deferred.await()
-            }
+            return cache.getOrLoad(listIndex) { createInstance(listIndex) }
         }
 
         @OptIn(InternalResourceApi::class)