safer image streaming

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

@@ -12,6 +12,7 @@ import com.caverock.androidsvg.SVG
 import com.caverock.androidsvg.SVGParseException
 import deckers.thibault.aves.metadata.SvgHelper.normalizeSize
 import deckers.thibault.aves.utils.BitmapUtils.getBytes
+import deckers.thibault.aves.utils.MemoryUtils
 import deckers.thibault.aves.utils.StorageUtils
 import io.flutter.plugin.common.MethodChannel
 import kotlin.math.ceil
@@ -29,13 +30,10 @@ class SvgRegionFetcher internal constructor(
         imageHeight: Int,
         result: MethodChannel.Result,
     ) {
-        if (sizeBytes != null && sizeBytes > FILE_SIZE_DANGER_THRESHOLD) {
+        if (!MemoryUtils.canAllocate(sizeBytes)) {
-            val availableHeapSize = Runtime.getRuntime().let { it.maxMemory() - (it.totalMemory() - it.freeMemory()) }
+            // opening an SVG that large would yield an OOM during parsing from `com.caverock.androidsvg.SVGParser`
-            if (sizeBytes > availableHeapSize) {
+            result.error("fetch-read-large", "SVG too large at $sizeBytes bytes, for uri=$uri regionRect=$regionRect", null)
-                // opening an SVG that large would yield an OOM during parsing from `com.caverock.androidsvg.SVGParser`
+            return
-                result.error("fetch-read-large", "SVG too large at $sizeBytes bytes, with only $availableHeapSize free bytes, for uri=$uri regionRect=$regionRect", null)
-                return
-            }
         }
 
         var currentSvgRef = lastSvgRef
@@ -113,9 +111,4 @@ class SvgRegionFetcher internal constructor(
         val uri: Uri,
         val svg: SVG,
     )
-
-    companion object {
-        // arbitrary size to detect files that may yield an OOM
-        private const val FILE_SIZE_DANGER_THRESHOLD = 10 * (1 shl 20) // MB
-    }
 }

android/app/src/main/kotlin/deckers/thibault/aves/channel/streams/ImageByteStreamHandler.kt

@@ -15,6 +15,7 @@ import deckers.thibault.aves.decoder.VideoThumbnail
 import deckers.thibault.aves.utils.BitmapUtils.applyExifOrientation
 import deckers.thibault.aves.utils.BitmapUtils.getBytes
 import deckers.thibault.aves.utils.LogUtils
+import deckers.thibault.aves.utils.MemoryUtils
 import deckers.thibault.aves.utils.MimeTypes
 import deckers.thibault.aves.utils.MimeTypes.canDecodeWithFlutter
 import deckers.thibault.aves.utils.MimeTypes.isHeic
@@ -97,18 +98,23 @@ class ImageByteStreamHandler(private val context: Context, private val arguments
         }
 
         if (isVideo(mimeType)) {
-            streamVideoByGlide(uri, mimeType)
+            streamVideoByGlide(uri, mimeType, sizeBytes)
         } else if (!canDecodeWithFlutter(mimeType, rotationDegrees, isFlipped)) {
             // decode exotic format on platform side, then encode it in portable format for Flutter
             streamImageByGlide(uri, pageId, mimeType, sizeBytes, rotationDegrees, isFlipped)
         } else {
             // to be decoded by Flutter
-            streamImageAsIs(uri, mimeType)
+            streamImageAsIs(uri, mimeType, sizeBytes)
         }
         endOfStream()
     }
 
-    private fun streamImageAsIs(uri: Uri, mimeType: String) {
+    private fun streamImageAsIs(uri: Uri, mimeType: String, sizeBytes: Long?) {
+        if (!MemoryUtils.canAllocate(sizeBytes)) {
+            error("streamImage-image-read-large", "original image too large at $sizeBytes bytes, for mimeType=$mimeType uri=$uri", null)
+            return
+        }
+
         try {
             StorageUtils.openInputStream(context, uri)?.use { input -> streamBytes(input) }
         } catch (e: Exception) {
@@ -144,7 +150,12 @@ class ImageByteStreamHandler(private val context: Context, private val arguments
                 bitmap = applyExifOrientation(context, bitmap, rotationDegrees, isFlipped)
             }
             if (bitmap != null) {
-                success(bitmap.getBytes(MimeTypes.canHaveAlpha(mimeType), recycle = false))
+                val bytes = bitmap.getBytes(MimeTypes.canHaveAlpha(mimeType), recycle = false)
+                if (MemoryUtils.canAllocate(sizeBytes)) {
+                    success(bytes)
+                } else {
+                    error("streamImage-image-decode-large", "decoded image too large at $sizeBytes bytes, for mimeType=$mimeType uri=$uri", null)
+                }
             } else {
                 error("streamImage-image-decode-null", "failed to get image for mimeType=$mimeType uri=$uri", null)
             }
@@ -155,7 +166,7 @@ class ImageByteStreamHandler(private val context: Context, private val arguments
         }
     }
 
-    private suspend fun streamVideoByGlide(uri: Uri, mimeType: String) {
+    private suspend fun streamVideoByGlide(uri: Uri, mimeType: String, sizeBytes: Long?) {
         val target = Glide.with(context)
             .asBitmap()
             .apply(glideOptions)
@@ -165,7 +176,12 @@ class ImageByteStreamHandler(private val context: Context, private val arguments
             @Suppress("BlockingMethodInNonBlockingContext")
             val bitmap = target.get()
             if (bitmap != null) {
-                success(bitmap.getBytes(canHaveAlpha = false, recycle = false))
+                val bytes = bitmap.getBytes(canHaveAlpha = false, recycle = false)
+                if (MemoryUtils.canAllocate(sizeBytes)) {
+                    success(bytes)
+                } else {
+                    error("streamImage-video-large", "decoded image too large at $sizeBytes bytes, for mimeType=$mimeType uri=$uri", null)
+                }
             } else {
                 error("streamImage-video-null", "failed to get image for mimeType=$mimeType uri=$uri", null)
             }

android/app/src/main/kotlin/deckers/thibault/aves/utils/BitmapUtils.kt

@@ -15,7 +15,7 @@ object BitmapUtils {
     private const val INITIAL_BUFFER_SIZE = 2 shl 17 // 256kB
 
     // arbitrary size to detect buffer that may yield an OOM
-    private const val BUFFER_SIZE_DANGER_THRESHOLD = 10 * (1 shl 20) // MB
+    private const val BUFFER_SIZE_DANGER_THRESHOLD = 3 * (1 shl 20) // MB
 
     private val freeBaos = ArrayList<ByteArrayOutputStream>()
     private val mutex = Mutex()
@@ -44,11 +44,8 @@ object BitmapUtils {
             if (recycle) this.recycle()
 
             val bufferSize = stream.size()
-            if (bufferSize > BUFFER_SIZE_DANGER_THRESHOLD) {
+            if (bufferSize > BUFFER_SIZE_DANGER_THRESHOLD && !MemoryUtils.canAllocate(bufferSize)) {
-                val availableHeapSize = Runtime.getRuntime().let { it.maxMemory() - (it.totalMemory() - it.freeMemory()) }
+                throw Exception("bitmap compressed to $bufferSize bytes, which cannot be allocated to a new byte array")
-                if (bufferSize > availableHeapSize) {
-                    throw Exception("compressed bitmap to $bufferSize bytes, which cannot be allocated to a new byte array, with only $availableHeapSize free bytes")
-                }
             }
 
             val byteArray = stream.toByteArray()

android/app/src/main/kotlin/deckers/thibault/aves/utils/MemoryUtils.kt

@@ -0,0 +1,17 @@
+package deckers.thibault.aves.utils
+
+import android.util.Log
+
+object MemoryUtils {
+    private val LOG_TAG = LogUtils.createTag<MemoryUtils>()
+
+    fun canAllocate(byteSize: Number?): Boolean {
+        byteSize ?: return true
+        val availableHeapSize = Runtime.getRuntime().let { it.maxMemory() - (it.totalMemory() - it.freeMemory()) }
+        val danger = byteSize.toLong() > availableHeapSize
+        if (danger) {
+            Log.e(LOG_TAG, "trying to handle $byteSize bytes, with only $availableHeapSize free bytes")
+        }
+        return !danger
+    }
+}