Bug 568042 - provide ILogicalStructureTypeDelegate3#releaseValue APIY20201025-1200Y20201024-1200Y20201023-1200I20201026-0840I20201026-0650I20201025-1800I20201025-0040I20201024-1800I20201023-1800I20201023-0250

Provide an API to allow logical structure type delegates to garbage
collect their logical structures once they're no longer displayed.

Change-Id: I25e78c4d5fb84d54d6e47a6b0f12998b6b8b4f37
Signed-off-by: Julian Honnen <julian.honnen@vector.com>

2 files changed, 45 insertions, 1 deletions

diff --git a/org.eclipse.debug.core/core/org/eclipse/debug/core/model/ILogicalStructureTypeDelegate3.java b/org.eclipse.debug.core/core/org/eclipse/debug/core/model/ILogicalStructureTypeDelegate3.java
new file mode 100644
index 000000000..8ba0d52e6
--- /dev/null
+++ b/org.eclipse.debug.core/core/org/eclipse/debug/core/model/ILogicalStructureTypeDelegate3.java
@@ -0,0 +1,35 @@
+/*******************************************************************************
+ *  Copyright (c) 2020 Julian Honnen
+ *
+ *  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:
+ *     Julian Honnen <julian.honnen@vector.com> - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.debug.core.model;
+
+/**
+ * Optional extension to <code>ILogicalStructureTypeDelegate</code> that allows
+ * a logical structure type delegate to garbage collect its logical structures
+ * once they're no longer displayed.
+ *
+ * @since 3.17
+ * @see ILogicalStructureTypeDelegate
+ */
+public interface ILogicalStructureTypeDelegate3 {
+
+	/**
+	 * Called when the logical structure returned from
+	 * {@link ILogicalStructureTypeDelegate#getLogicalStructure(IValue)} is no
+	 * longer used and can be discarded.
+	 *
+	 * @param logicalStructure the logical structure value to discard
+	 */
+	void releaseValue(IValue logicalStructure);
+
+}
diff --git a/org.eclipse.debug.core/core/org/eclipse/debug/internal/core/LogicalStructureType.java b/org.eclipse.debug.core/core/org/eclipse/debug/internal/core/LogicalStructureType.java
index 7fc9d1739..074fc67d7 100644
--- a/org.eclipse.debug.core/core/org/eclipse/debug/internal/core/LogicalStructureType.java
+++ b/org.eclipse.debug.core/core/org/eclipse/debug/internal/core/LogicalStructureType.java
@@ -23,6 +23,7 @@ import org.eclipse.debug.core.DebugPlugin;
 import org.eclipse.debug.core.ILogicalStructureType;
 import org.eclipse.debug.core.model.ILogicalStructureTypeDelegate;
 import org.eclipse.debug.core.model.ILogicalStructureTypeDelegate2;
+import org.eclipse.debug.core.model.ILogicalStructureTypeDelegate3;
 import org.eclipse.debug.core.model.IValue;
 
 /**
@@ -30,7 +31,7 @@ import org.eclipse.debug.core.model.IValue;
  *
  * @see IConfigurationElementConstants
  */
-public class LogicalStructureType implements ILogicalStructureType {
+public class LogicalStructureType implements ILogicalStructureType, ILogicalStructureTypeDelegate3 {
 
 	private IConfigurationElement fConfigurationElement;
 	private ILogicalStructureTypeDelegate fDelegate;
@@ -108,6 +109,14 @@ public class LogicalStructureType implements ILogicalStructureType {
 		return false;
 	}
 
+	@Override
+	public void releaseValue(IValue logicalStructure) {
+		ILogicalStructureTypeDelegate delegate = getDelegate();
+		if (delegate instanceof ILogicalStructureTypeDelegate3) {
+			((ILogicalStructureTypeDelegate3) delegate).releaseValue(logicalStructure);
+		}
+	}
+
 	/**
 	 * Returns the <code>ILogicalStructuresTypeDelegate</code> delegate
 	 * @return the delegate