#1527 fixed concurrent region decoder pool access

CHANGELOG.md

@@ -13,6 +13,10 @@ All notable changes to this project will be documented in this file.
 
 - upgraded Flutter to stable v3.29.3
 
+### Fixed
+
+- region decoding failing to access decoder pool
+
 ## <a id="v1.12.9"></a>[v1.12.9] - 2025-04-06
 
 ### Added

android/app/src/main/kotlin/deckers/thibault/aves/channel/calls/fetchers/RegionFetcher.kt

@@ -20,6 +20,8 @@ import deckers.thibault.aves.utils.MemoryUtils
 import deckers.thibault.aves.utils.MimeTypes
 import deckers.thibault.aves.utils.StorageUtils
 import io.flutter.plugin.common.MethodChannel
+import java.util.concurrent.locks.ReentrantLock
+import kotlin.concurrent.withLock
 import kotlin.math.max
 import kotlin.math.roundToInt
 
@@ -60,7 +62,7 @@ class RegionFetcher internal constructor(
         }
 
         try {
-            val decoder = getOrCreateDecoder(uri, requestKey)
+            val decoder = getOrCreateDecoder(context, uri, requestKey)
             if (decoder == null) {
                 result.error("fetch-read-null", "failed to open file for mimeType=$mimeType uri=$uri regionRect=$regionRect", null)
                 return
@@ -143,26 +145,6 @@ class RegionFetcher internal constructor(
         }
     }
 
-    private fun getOrCreateDecoder(uri: Uri, requestKey: Pair<Uri, Int?>): BitmapRegionDecoder? {
-        var decoderRef = decoderPool.firstOrNull { it.requestKey == requestKey }
-        if (decoderRef == null) {
-            val newDecoder = StorageUtils.openInputStream(context, uri)?.use { input ->
-                BitmapRegionDecoderCompat.newInstance(input)
-            }
-            if (newDecoder == null) {
-                return null
-            }
-            decoderRef = DecoderRef(requestKey, newDecoder)
-        } else {
-            decoderPool.remove(decoderRef)
-        }
-        decoderPool.add(0, decoderRef)
-        while (decoderPool.size > DECODER_POOL_SIZE) {
-            decoderPool.removeAt(decoderPool.size - 1)
-        }
-        return decoderRef.decoder
-    }
-
     private fun createTemporaryJpegExport(uri: Uri, mimeType: String, pageId: Int?): Uri {
         Log.d(LOG_TAG, "create JPEG export for uri=$uri mimeType=$mimeType pageId=$pageId")
         val target = Glide.with(context)
@@ -195,5 +177,29 @@ class RegionFetcher internal constructor(
         private const val DECODER_POOL_SIZE = 3
         private val decoderPool = ArrayList<DecoderRef>()
         private val exportUris = HashMap<Pair<Uri, Int?>, Uri>()
+
+        private val poolLock = ReentrantLock()
+
+        private fun getOrCreateDecoder(context: Context, uri: Uri, requestKey: Pair<Uri, Int?>): BitmapRegionDecoder? {
+            poolLock.withLock {
+                var decoderRef = decoderPool.firstOrNull { it.requestKey == requestKey }
+                if (decoderRef == null) {
+                    val newDecoder = StorageUtils.openInputStream(context, uri)?.use { input ->
+                        BitmapRegionDecoderCompat.newInstance(input)
+                    }
+                    if (newDecoder == null) {
+                        return null
+                    }
+                    decoderRef = DecoderRef(requestKey, newDecoder)
+                } else {
+                    decoderPool.remove(decoderRef)
+                }
+                decoderPool.add(0, decoderRef)
+                while (decoderPool.size > DECODER_POOL_SIZE) {
+                    decoderPool.removeAt(decoderPool.size - 1)
+                }
+                return decoderRef.decoder
+            }
+        }
     }
 }

android/app/src/main/kotlin/deckers/thibault/aves/channel/calls/fetchers/SvgRegionFetcher.kt

@@ -17,6 +17,8 @@ import deckers.thibault.aves.utils.BitmapUtils
 import deckers.thibault.aves.utils.MemoryUtils
 import deckers.thibault.aves.utils.StorageUtils
 import io.flutter.plugin.common.MethodChannel
+import java.util.concurrent.locks.ReentrantLock
+import kotlin.concurrent.withLock
 import kotlin.math.ceil
 
 class SvgRegionFetcher internal constructor(
@@ -38,7 +40,7 @@ class SvgRegionFetcher internal constructor(
         }
 
         try {
-            val svg = getOrCreateDecoder(uri)
+            val svg = getOrCreateDecoder(context, uri)
             if (svg == null) {
                 result.error("fetch-read-null", "failed to open file for uri=$uri regionRect=$regionRect", null)
                 return
@@ -95,7 +97,20 @@ class SvgRegionFetcher internal constructor(
         }
     }
 
-    private fun getOrCreateDecoder(uri: Uri): SVG? {
+    private data class DecoderRef(
+        val uri: Uri,
+        val decoder: SVG,
+    )
+
+    companion object {
+        private val PREFERRED_CONFIG = Bitmap.Config.ARGB_8888
+        private const val DECODER_POOL_SIZE = 3
+        private val decoderPool = ArrayList<DecoderRef>()
+
+        private val poolLock = ReentrantLock()
+
+        private fun getOrCreateDecoder(context: Context, uri: Uri): SVG? {
+            poolLock.withLock {
                 var decoderRef = decoderPool.firstOrNull { it.uri == uri }
                 if (decoderRef == null) {
                     val newDecoder = StorageUtils.openInputStream(context, uri)?.use { input ->
@@ -115,15 +130,6 @@ class SvgRegionFetcher internal constructor(
                 }
                 return decoderRef.decoder
             }
-
+        }
-    private data class DecoderRef(
-        val uri: Uri,
-        val decoder: SVG,
-    )
-
-    companion object {
-        private val PREFERRED_CONFIG = Bitmap.Config.ARGB_8888
-        private const val DECODER_POOL_SIZE = 3
-        private val decoderPool = ArrayList<DecoderRef>()
     }
 }