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IllegalArgumentException when painting image while running out of handles

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評価

難易度
4/5
見積もり時間
3〜5日
初心者へのやさしさ
55/100
issue の種類
バグ
明瞭さ
おおむね明確
活発さ
静か
技術スタック
java
領域
backend

調査の方向性

Start in Image.java at the GetDIBits call cited in the issue, then trace how its return value reaches DestroyableImageHandle.getImageData and image painting. Reproduce on Windows with the supplied program or a focused test that exhausts handles. Done means handle exhaustion reports an SWT error such as “No more handles,” rather than an IllegalArgumentException.

索引モデルが issue の本文から書いたものです。

説明

Windows

Describe the bug

Trying to paint an image while all available handles have been consumed fails with an IllegalArgumentException instead of an SWTError.

To Reproduce

package gef;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class DrawGC2 {

	public static void main(String[] args) {
		Shell shell = new Shell();
		Display display = shell.getDisplay();

		int width = 310;
		int height = 310;

		List<Image> images = new ArrayList<>();
		for (int i = 0; i < 8000; ++i) {
			Image image = new Image(display, width, height);
			GC gc = new GC(image);
			gc.dispose();
			images.add(image);
		}

		shell.addPaintListener(event -> {
			for (Image image : images) {
				event.gc.drawImage(image, 0, 0, width, height, 0, 0, 100, 100);
			}
		});

		shell.open();

		while (!shell.isDisposed()) {
			if (!display.readAndDispatch()) {
				display.sleep();
			}
		}

		images.forEach(Image::dispose);
	}
}

Stacktrace:

Exception in thread "main" java.lang.IllegalArgumentException: Argument not valid
	at org.eclipse.swt.SWT.error(SWT.java:4915)
	at org.eclipse.swt.SWT.error(SWT.java:4849)
	at org.eclipse.swt.SWT.error(SWT.java:4820)
	at org.eclipse.swt.graphics.ImageData.<init>(ImageData.java:439)
	at org.eclipse.swt.graphics.ImageData.<init>(ImageData.java:287)
	at org.eclipse.swt.graphics.Image$DestroyableImageHandle.getImageData(Image.java:3305)
	at org.eclipse.swt.graphics.Image$AbstractImageProviderWrapper.getClosestAvailableImageData(Image.java:2106)
	at org.eclipse.swt.graphics.Image$PlainImageProviderWrapper.loadImageData(Image.java:2388)
	at org.eclipse.swt.graphics.Image$HandleAtSize.getOrCreateImageHandleAtClosestSize(Image.java:254)
	at org.eclipse.swt.graphics.Image$HandleAtSize.lambda$0(Image.java:225)
	at java.base/java.util.Optional.orElseGet(Optional.java:364)
	at org.eclipse.swt.graphics.Image$HandleAtSize.refresh(Image.java:225)
	at org.eclipse.swt.graphics.Image.executeOnImageHandleAtBestFittingSize(Image.java:968)
	at org.eclipse.swt.graphics.GC$DrawScalingImageToImageOperation.draw(GC.java:1240)
	at org.eclipse.swt.graphics.GC$DrawScalingImageToImageOperation.apply(GC.java:1222)
	at org.eclipse.swt.graphics.GC.storeAndApplyOperationForExistingHandle(GC.java:6136)
	at org.eclipse.swt.graphics.GC.drawImage(GC.java:1152)
	at gef.DrawGC2.lambda$0(DrawGC2.java:30)
	at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:272)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:91)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4363)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1217)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1241)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1226)
	at org.eclipse.swt.widgets.Composite.WM_PAINT(Composite.java:1627)
	at org.eclipse.swt.widgets.Control.windowProc(Control.java:5021)
	at org.eclipse.swt.widgets.Canvas.windowProc(Canvas.java:336)
	at org.eclipse.swt.widgets.Decorations.windowProc(Decorations.java:1490)
	at org.eclipse.swt.widgets.Shell.windowProc(Shell.java:2446)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:5131)
	at org.eclipse.swt.internal.win32.OS.UpdateWindow(Native Method)
	at org.eclipse.swt.widgets.Decorations.setVisible(Decorations.java:1322)
	at org.eclipse.swt.widgets.Shell.setVisible(Shell.java:2192)
	at org.eclipse.swt.widgets.Shell.open(Shell.java:1334)
	at gef.DrawGC2.main(DrawGC2.java:34)

Expected behavior

SWT should return a proper error message. Ideally an "No more handles" error.

Environment:

  1. Select the platform(s) on which the behavior is seen:
    • All OS
    • Windows
    • Linux
    • macOS

Version since
Only tested on master.

Additional information

I think the problem is that the return value is not validated when calling GetDIBits, for example here:

https://github.com/eclipse-platform/eclipse.platform.swt/blob/725c9485b9e37c3e9bc2993923db02fe15781aec/bundles/org.eclipse.swt/Eclipse%20SWT/win32/org/eclipse/swt/graphics/Image.java#L3254-L3257

From the documentation:

If the function fails, the return value is zero.

Which is the case here, resulting in an "empty" image data, causing the validation error.

主要言語
Java
スター
202
フォーク
206
平均マージ
20時間 20分
マージ済み PR（30日）
113

環境構築

はじめの一歩

  1. issue を最後まで読み、次にプロジェクトのコントリビューションガイドを読みます。
  2. 着手することを issue にコメントします — 二人が同じ作業をするのを防げます。
  3. リポジトリをフォークし、ブランチを切って変更します。
  4. issue 番号を参照したプルリクエストを送ります。

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