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Implemented Double-Checked Locking in ImagehandleManager #2905

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Merged
HeikoKlare merged 1 commit into from
Jan 20, 2026
Merged

Implemented Double-Checked Locking in ImagehandleManager #2905

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74 changes: 38 additions & 36 deletions bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/Image.java
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,8 @@

import java.io.*;
import java.util.*;
import java.util.Map.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import java.util.function.*;
import java.util.stream.*;

Expand Down Expand Up @@ -138,7 +139,7 @@ public final class Image extends Resource implements Drawable {
private final ImageHandleManager imageHandleManager = new ImageHandleManager();

private class ImageHandleManager {
private Map<Integer, DestroyableImageHandle> zoomLevelToImageHandle = new HashMap<>();
private Map<Integer, DestroyableImageHandle> zoomLevelToImageHandle = new ConcurrentHashMap<>();

InternalImageHandle get(int zoom) {
final DestroyableImageHandle imageHandle = zoomLevelToImageHandle.get(zoom);
Expand All @@ -153,15 +154,7 @@ InternalImageHandle getOrCreate(int zoom, Supplier<DestroyableImageHandle> creat
if (zoom == -1) {
return null;
}

DestroyableImageHandle imageHandle = (DestroyableImageHandle) get(zoom);
if (imageHandle != null) {
return imageHandle;
}

imageHandle = creator.get();
zoomLevelToImageHandle.put(zoom, imageHandle);
return imageHandle;
return zoomLevelToImageHandle.computeIfAbsent(zoom, __ -> creator.get());
}

boolean contains(int zoom) {
Expand All @@ -181,16 +174,23 @@ Set<Integer> getAllZooms() {
}

void destroyHandles(Predicate<Integer> filter) {
Iterator<Entry<Integer, DestroyableImageHandle>> it = zoomLevelToImageHandle.entrySet().iterator();
while (it.hasNext()) {
Entry<Integer, DestroyableImageHandle> zoomToHandle = it.next();
if (filter.test(zoomToHandle.getKey())) {
DestroyableImageHandle imageHandle = zoomToHandle.getValue();
it.remove();
zoomLevelToImageHandle.remove(imageHandle.zoom(), imageHandle);
imageHandle.destroy();
}
}
zoomLevelToImageHandle.entrySet().removeIf(entry -> {
if (filter.test(entry.getKey())) {
entry.getValue().destroy();
return true;
}
return false;
});
}

<R> R executeOnHandle(int zoom, Function<AtomicReference<DestroyableImageHandle>,R> executable) {
AtomicReference<R> computedValue = new AtomicReference<>();
zoomLevelToImageHandle.compute(zoom, (key, value) -> {
AtomicReference<DestroyableImageHandle> handleReference = new AtomicReference<>(value);
computedValue.set(executable.apply(handleReference));
return handleReference.get();
});
return computedValue.get();
}

@Override
Expand Down Expand Up @@ -1304,12 +1304,13 @@ public Rectangle getBounds() {

Rectangle getBounds(int zoom) {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
if (imageHandleManager.contains(zoom)) {
InternalImageHandle imageMetadata = imageHandleManager.get(zoom);
Rectangle rectangle = new Rectangle(0, 0, imageMetadata.width(), imageMetadata.height());
return Win32DPIUtils.scaleBounds(rectangle, zoom, imageMetadata.zoom());
}
return this.imageProvider.getBounds(zoom);
return imageHandleManager.executeOnHandle(zoom, imageHandle -> {
if (imageHandle.get() != null) {
Rectangle rectangle = new Rectangle(0, 0, imageHandle.get().width(), imageHandle.get().height());
return Win32DPIUtils.scaleBounds(rectangle, zoom, imageHandle.get().zoom());
}
return this.imageProvider.getBounds(zoom);
});
}

/**
Expand Down Expand Up @@ -1383,15 +1384,16 @@ public ImageData getImageData() {
*/
public ImageData getImageData (int zoom) {
if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
InternalImageHandle imageHandle = imageHandleManager.get(zoom);
if (imageHandle != null) {
return imageHandle.getImageData();
}

if (this.imageProvider.isPersistentImageHandleRequriedForImageData()) {
return imageHandleManager.getOrCreate(zoom, () -> imageProvider.newImageHandle(new ZoomContext(zoom))).getImageData();
}
return this.imageProvider.newImageData(zoom);
return imageHandleManager.executeOnHandle(zoom, imageHandle -> {
if (imageHandle.get() != null) {
return imageHandle.get().getImageData();
}
if (this.imageProvider.isPersistentImageHandleRequriedForImageData()) {
imageHandle.set(imageProvider.newImageHandle(new ZoomContext(zoom)));
return imageHandle.get().getImageData();
}
return this.imageProvider.newImageData(zoom);
});
}

/**
Expand Down
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