1 files changed, 102 insertions, 0 deletions
diff --git a/tests/org.eclipse.swt.tests.gtk/ManualTests/org/eclipse/swt/tests/gtk/snippets/Bug546274_StyledTextVMCrash.java b/tests/org.eclipse.swt.tests.gtk/ManualTests/org/eclipse/swt/tests/gtk/snippets/Bug546274_StyledTextVMCrash.java
new file mode 100644
index 0000000000..878da10e23
--- /dev/null
+++ b/tests/org.eclipse.swt.tests.gtk/ManualTests/org/eclipse/swt/tests/gtk/snippets/Bug546274_StyledTextVMCrash.java
@@ -0,0 +1,102 @@
+/*******************************************************************************
+ * Copyright (c) 2019 Syntevo and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Syntevo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.swt.tests.gtk.snippets;
+
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.custom.StyledText;
+import org.eclipse.swt.graphics.GC;
+import org.eclipse.swt.graphics.Image;
+import org.eclipse.swt.layout.FillLayout;
+import org.eclipse.swt.widgets.Composite;
+import org.eclipse.swt.widgets.Display;
+import org.eclipse.swt.widgets.Shell;
+
+public class Bug546274_StyledTextVMCrash {
+	private static class MyStyledText extends StyledText {
+		int 	cairoCacheSize = 16;	// see MAX_FREED_POOL_SIZE in cairo
+		Image 	tempImages[] = new Image[cairoCacheSize];
+		GC 		tempGCs[] = new GC[cairoCacheSize];
+
+		public MyStyledText(Composite parent, int style) {
+			super(parent, style);
+			allocTempGCs();
+		}
+
+		void allocTempGCs() {
+			for (int i = 0; i < cairoCacheSize; i++) {
+				tempImages[i] = new Image(this.getDisplay(), 1, 1);
+				tempGCs[i] = new GC(tempImages[i]);
+			}
+		}
+
+		@Override
+		public void scroll(int destX, int destY, int x, int y, int width, int height, boolean all) {
+			// Evaluate with debugger: (cachedCairo.handle == this.cachedCairo);
+			// This already shows that 'this.cachedCairo' can't be used.
+			Image tempImage = new Image(this.getDisplay(), 1, 1);
+			GC cachedCairo = new GC(tempImage);
+
+			// Evict 'cachedCairo' from Cairo's cache 'context_pool' by
+			// 1) Populating cache with free objects
+			// 2) Releasing 'cachedCairo' and it will be truly deleted
+			{
+				if (tempGCs != null) {
+					for (int i = 0; i < tempGCs.length; i++) {
+						tempGCs[i].dispose();
+						tempImages[i].dispose();
+					}
+				}
+
+				cachedCairo.dispose();
+				tempImage.dispose();
+			}
+
+			// Make sure the same malloc() block can't be used again
+			for (int i = 1; i < 1024; i++) {
+				// Intentional leak
+				org.eclipse.swt.internal.gtk.GTK.malloc(i);
+			}
+
+			super.scroll(destX, destY, x, y, width, height, all);
+
+			// Drain Cairo's cache 'context_pool' to force the next cairo to use malloc()
+			allocTempGCs();
+		}
+	}
+
+	public static void main(String[] args) {
+		final Display display = new Display();
+
+		final Shell shell = new Shell(display, SWT.SHELL_TRIM);
+		shell.setLayout(new FillLayout(SWT.VERTICAL));
+		shell.setSize(300, 200);
+
+		String hintText = "Try to horz scroll this StyledText\n" +
+						"\n" +
+						"Horz scrollbar is forced by this long line of text xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
+
+		final StyledText text = new MyStyledText(shell, SWT.BORDER | SWT.H_SCROLL);
+		text.setText(hintText);
+
+		shell.open();
+
+		while (!shell.isDisposed()) {
+			if (!display.readAndDispatch()) {
+				display.sleep();
+			}
+		}
+
+		display.dispose();
+	}
+}