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-rw-r--r--tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/memoryleak/Test_Memory_Leak.java64
1 files changed, 64 insertions, 0 deletions
diff --git a/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/memoryleak/Test_Memory_Leak.java b/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/memoryleak/Test_Memory_Leak.java
new file mode 100644
index 0000000000..b6a0acf69b
--- /dev/null
+++ b/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/memoryleak/Test_Memory_Leak.java
@@ -0,0 +1,64 @@
+package org.eclipse.swt.tests.junit.memoryleak;
+
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.browser.Browser;
+import org.eclipse.swt.layout.FillLayout;
+import org.eclipse.swt.widgets.Display;
+import org.eclipse.swt.widgets.Shell;
+import org.junit.Test;
+
+/**
+ * Test Widgets for memory leaks. Used when updating dispose logic.
+ *
+ * Due to lack of better alternative, the current mechanism creates & disposes a widget in a loop.
+ * If the test makes it to the end without crashing your system, then you have no (major?) leaks.
+ *
+ * Run these on demand if updating dispose logic of a particular widget.
+ *
+ * Note:
+ * - The tests are a bit long, so they're not part of the main test suite.
+ * - Note, JNI != Java memory leaks. JNI leaks are not detected by Java profilers as they occur *outside* of the heap.
+ * Finding JNI leaks is not a trivial matter as typical C memory tools see the JVM as a memory leak itself.
+ * It's possible thou. Have not tried myself but see:
+ * https://stackoverflow.com/questions/33334126/how-to-find-memory-leaks-in-java-jni-c-process
+ * https://gdstechnology.blog.gov.uk/2015/12/11/using-jemalloc-to-get-to-the-bottom-of-a-memory-leak/
+ */
+public class Test_Memory_Leak {
+
+ static int COUNT_PRINT_PER_ROW = 50;
+
+ /**
+ * Create and dispose Browser instances.
+ *
+ * If this test runs at linear speed and passes, then it's fairly safe to say you have no memory leaks.
+ * A typical run will take 5 minutes.
+ *
+ * If you have a memory leak in the dispoal logic, then the loop eventually slows down and the test crashes.
+ * You would see 'memory pressure' errors. The Java process of the jUnit would grow significantly (100's of mbs)
+ * On my machine with Intel i7 & 16 GB of ram, this occurs at the ~420th iteration.
+ * (although with my testing, without memory leaks, it grows a little bit (by 100mb by end of test)).
+ */
+ @Test
+ public void test_Browser() {
+ Display display = new Display ();
+ Shell shell = new Shell(display);
+ shell.setLayout(new FillLayout());
+ shell.open ();
+
+ Browser browser;
+ int count = 50_000;
+
+ for (int i = 1; i <= count; i++) {
+ browser = new Browser(shell, SWT.None);
+ browser.setUrl("http://www.google.com");
+ while (display.readAndDispatch()) {
+ // This loop is needed because some disposal is delayed and done asynchronously in main loop.
+ // This loop typically performs ~12 iterations.
+ }
+ if (i != count) browser.dispose();
+ if (i % (COUNT_PRINT_PER_ROW) == 0) System.out.println();
+ System.out.print(i+ " ");
+ }
+ System.out.println();
+ }
+}

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