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fix(android): make capture failure and late PixelCopy cleanup safe #681

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e38af66
fix(android): make capture failure and late PixelCopy cleanup safe
OskarEichler Aug 28, 2026
fd9705b
Complete source audit follow-up: fix(android): make capture failure a…
OskarEichler Aug 28, 2026
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7 changes: 5 additions & 2 deletions android/src/main/java/fr/greweb/reactnativeviewshot/RNViewShotModule.java
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,7 @@ public void releaseCapture(String uri) {
File file = new File(path);
if (!file.exists()) return;
File parent = file.getParentFile();
if (parent.equals(reactContext.getExternalCacheDir()) || parent.equals(reactContext.getCacheDir())) {
if (parent != null && (parent.equals(reactContext.getExternalCacheDir()) || parent.equals(reactContext.getCacheDir()))) {
file.delete();
}
}
Expand Down Expand Up @@ -87,8 +87,8 @@ public void captureRef(Double tagFromJs, ReadableMap options, Promise promise) {
final Boolean snapshotContentContainer = options.getBoolean("snapshotContentContainer");
final boolean handleGLSurfaceView = options.hasKey("handleGLSurfaceViewOnAndroid") && options.getBoolean("handleGLSurfaceViewOnAndroid");

File outputFile = null;
try {
File outputFile = null;
if (Results.TEMP_FILE.equals(resultStreamFormat)) {
outputFile = createTempFile(getReactApplicationContext(), extension, fileName);
}
Expand All @@ -111,6 +111,9 @@ public void captureRef(Double tagFromJs, ReadableMap options, Promise promise) {
uiManager.addUIBlock(uiBlock);
}
} catch (final Throwable ex) {
if (outputFile != null) {
outputFile.delete();
}
Log.e(NAME, "Failed to snapshot view tag " + tag, ex);
promise.reject(ViewShot.ERROR_UNABLE_TO_SNAPSHOT, "Failed to snapshot view tag " + tag);
}
Expand Down
130 changes: 93 additions & 37 deletions android/src/main/java/fr/greweb/reactnativeviewshot/ViewShot.java
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Original file line number Diff line number Diff line change
Expand Up @@ -48,7 +48,7 @@
import java.util.WeakHashMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
Expand Down Expand Up @@ -227,18 +227,17 @@ private void executeImpl(final NativeViewHierarchyManager nativeViewHierarchyMan
// UIManager queue.
Log.e(TAG, "Failed to resolve view for snapshot", ex);
final String detail = ex.getMessage() != null ? ex.getMessage() : ex.toString();
promise.reject(ERROR_UNABLE_TO_SNAPSHOT,
"Failed to resolve view for snapshot: " + detail, ex);
rejectCapture("Failed to resolve view for snapshot: " + detail, ex);
return;
}

if (view == null) {
Log.e(TAG, "No view found with reactTag: " + tag, new AssertionError());
promise.reject(ERROR_UNABLE_TO_SNAPSHOT, "No view found with reactTag: " + tag);
rejectCapture("No view found with reactTag: " + tag, null);
return;
}

executor.execute(new Runnable () {
final Runnable capture = new Runnable () {
@Override
public void run() {
try {
Expand All @@ -258,11 +257,20 @@ public void run() {
} catch (final Throwable ex) {
Log.e(TAG, "Failed to capture view snapshot", ex);
final String detail = ex.getMessage() != null ? ex.getMessage() : ex.toString();
promise.reject(ERROR_UNABLE_TO_SNAPSHOT,
"Failed to capture view snapshot: " + detail, ex);
rejectCapture("Failed to capture view snapshot: " + detail, ex);
}
}
});
};
try {
executor.execute(capture);
} catch (RejectedExecutionException ex) {
rejectCapture("Capture executor rejected the snapshot", ex);
}
}

private void rejectCapture(final String message, @Nullable final Throwable cause) {
if (output != null) output.delete();
promise.reject(ERROR_UNABLE_TO_SNAPSHOT, message, cause);
}

private void saveToTempFileOnDevice(@NonNull final View view) throws IOException {
Expand Down Expand Up @@ -715,6 +723,10 @@ public void run(@NonNull AtomicBoolean cancelled) {
}
}
} finally {
// Publish completion before the final cancellation read.
// Otherwise a timeout between this read and the wrapper's
// completion signal leaves neither thread owning cleanup.
uiTaskFinished.set(true);
// Only own the recycle when the caller has abandoned us
// (timed out): otherwise the caller is still alive and
// will keep using the bitmap for child overlays, scale
Expand Down Expand Up @@ -752,46 +764,40 @@ public void run(@NonNull AtomicBoolean cancelled) {
if (child.getVisibility() != VISIBLE) continue;

final TextureView tvChild = (TextureView) child;
tvChild.setOpaque(false); // <-- switch off background fill

final boolean wasOpaque = tvChild.isOpaque();
// NOTE (olku): get re-usable bitmap. TextureView should use bitmaps with matching size,
// otherwise content of the TextureView will be scaled to provided bitmap dimensions
final Bitmap childBitmapBuffer = tvChild.getBitmap(getExactBitmapForScreenshot(child.getWidth(), child.getHeight()));

final Bitmap childBitmapBuffer = getExactBitmapForScreenshot(child.getWidth(), child.getHeight());
final int countCanvasSave = c.save();
applyTransformations(c, view, child);

// due to re-use of bitmaps for screenshot, we can get bitmap that is bigger in size than requested
c.drawBitmap(childBitmapBuffer, 0, 0, paint);

c.restoreToCount(countCanvasSave);
recycleBitmap(childBitmapBuffer);
try {
tvChild.setOpaque(false); // switch off background fill only for this copy
tvChild.getBitmap(childBitmapBuffer);
applyTransformations(c, view, child);
c.drawBitmap(childBitmapBuffer, 0, 0, paint);
} finally {
tvChild.setOpaque(wasOpaque);
c.restoreToCount(countCanvasSave);
recycleBitmap(childBitmapBuffer);
}
} else if (child instanceof SurfaceView && handleGLSurfaceView) {
final SurfaceView svChild = (SurfaceView)child;
final CountDownLatch latch = new CountDownLatch(1);

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
final Bitmap childBitmapBuffer = getExactBitmapForScreenshot(child.getWidth(), child.getHeight());
try {
PixelCopy.request(svChild, childBitmapBuffer, new PixelCopy.OnPixelCopyFinishedListener() {
@Override
public void onPixelCopyFinished(int copyResult) {
final int countCanvasSave = c.save();
applyTransformations(c, view, child);
c.drawBitmap(childBitmapBuffer, 0, 0, paint);
c.restoreToCount(countCanvasSave);
recycleBitmap(childBitmapBuffer);
latch.countDown();
}
}, new Handler(Looper.getMainLooper()));
latch.await(SURFACE_VIEW_READ_PIXELS_TIMEOUT, TimeUnit.SECONDS);
} catch (Exception e) {
Log.e(TAG, "Cannot PixelCopy for " + svChild, e);
final Bitmap childBitmapBuffer = captureSurfaceView(svChild);
if (childBitmapBuffer != null) {
final int countCanvasSave = c.save();
try {
applyTransformations(c, view, child);
c.drawBitmap(childBitmapBuffer, 0, 0, paint);
} finally {
c.restoreToCount(countCanvasSave);
recycleBitmap(childBitmapBuffer);
}
}
} else {
Bitmap cache = svChild.getDrawingCache();
if (cache != null) {
c.drawBitmap(svChild.getDrawingCache(), 0, 0, paint);
c.drawBitmap(cache, 0, 0, paint);
}
}
}
Expand Down Expand Up @@ -840,6 +846,56 @@ public void onPixelCopyFinished(int copyResult) {
}
}

@Nullable
private Bitmap captureSurfaceView(@NonNull final SurfaceView view) {
if (view.getWidth() <= 0 || view.getHeight() <= 0) return null;

final Bitmap buffer = getExactBitmapForScreenshot(view.getWidth(), view.getHeight());
final AtomicReference<Bitmap> pending = new AtomicReference<>(buffer);
final AtomicBoolean abandoned = new AtomicBoolean(false);
final AtomicInteger result = new AtomicInteger(-1);
final CountDownLatch completed = new CountDownLatch(1);
try {
PixelCopy.request(view, buffer, new PixelCopy.OnPixelCopyFinishedListener() {
@Override
public void onPixelCopyFinished(int copyResult) {
result.set(copyResult);
completed.countDown();
// A timed-out capture must leave this buffer alone until
// PixelCopy finishes writing. Never touch its parent canvas
// here: that capture may already have returned to the pool.
if (abandoned.get()) {
final Bitmap unused = pending.getAndSet(null);
if (unused != null) recycleBitmap(unused);
}
}
}, new Handler(Looper.getMainLooper()));
} catch (IllegalArgumentException e) {
recycleBitmap(buffer);
Log.e(TAG, "Cannot PixelCopy for " + view, e);
return null;
}

try {
if (completed.await(SURFACE_VIEW_READ_PIXELS_TIMEOUT, TimeUnit.SECONDS)
&& result.get() == PixelCopy.SUCCESS) {
return pending.getAndSet(null);
}
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
Log.e(TAG, "Interrupted PixelCopy for " + view, e);
} finally {
abandoned.set(true);
// Covers completion immediately before abandonment. The callback
// covers completion after it; getAndSet gives exactly one owner.
if (completed.getCount() == 0) {
final Bitmap unused = pending.getAndSet(null);
if (unused != null) recycleBitmap(unused);
}
}
return null;
}

/**
* Walk the parent chain from {@code child} up to (but not including)
* {@code root}, returning the visited views in leaf-to-root order.
Expand Down
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