1 files changed, 111 insertions, 0 deletions
diff --git a/bundles/org.eclipse.team.core/src/org/eclipse/team/internal/core/subscribers/caches/ResourceVariantByteStore.java b/bundles/org.eclipse.team.core/src/org/eclipse/team/internal/core/subscribers/caches/ResourceVariantByteStore.java
new file mode 100644
index 000000000..bf51f5a6a
--- /dev/null
+++ b/bundles/org.eclipse.team.core/src/org/eclipse/team/internal/core/subscribers/caches/ResourceVariantByteStore.java
@@ -0,0 +1,111 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2003 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials 
+ * are made available under the terms of the Common Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/cpl-v10.html
+ * 
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.team.internal.core.subscribers.caches;
+
+import org.eclipse.core.resources.IResource;
+import org.eclipse.team.core.TeamException;
+
+/**
+ * The purpose of a <code>ResourceVariantByteStore</code> is to support the caching of
+ * the synchronization bytes for the resource variants that represent
+ * a resource line-up of interest such as a version, baseline or branch. The
+ * cache stores bytes in order to minimize the memory footprint of the tree. It is the
+ * reponsibility of the client of this API to cache enough bytes to meaningfully identify
+ * a resource variant (and possibly create an {@link IResourceVariant} handle from them).
+ * <p>
+ * The bytes for
+ * a resource variant are accessed using the local handle that corresponds to the 
+ * resource variant (using the <code>getSyncInfo</code> method). 
+ * The potential children of a resource variant are also accessed
+ * by using the local handle that corresponds to the resource variant 
+ * (using the <code>members</code> method).
+ */
+public abstract class ResourceVariantByteStore {
+
+	/**
+	 * Dispose of any cached sync bytes when this cache is no longer needed.
+	 */
+	public abstract void dispose();
+	
+	/**
+	 * Return the bytes for the variant corresponding the given local resource.
+	 * A return value of <code>null</code> means that no bytes have been stored
+	 * for the resource variant. It is up to the client to determine whether
+	 * this means that the resource variant does not exist or that it has not been
+	 * fetched or otherwise determined yet.
+	 * @param resource the local resource
+	 * @return the bytes that represent the resource's variant
+	 * @throws TeamException
+	 */
+	public abstract byte[] getBytes(IResource resource) throws TeamException;
+	
+	/**
+	 * Set the bytes for the variant corresponding the given local resource. 
+	 * The bytes should never be <code>null</code>. If it is known that the remote 
+	 * does not exist, <code>deleteBytes(IResource)</code> should be used instead. 
+	 * If the sync bytes for the remote are stale and should be removed, 
+	 * <code>flushBytes(IResouce, int)</code> should be called.
+	 * @param resource the local resource
+	 * @param bytes the bytes that represent the resource's variant
+	 * @return <code>true</code> if the bytes changed
+	 * @throws TeamException
+	 */
+	public abstract boolean setBytes(IResource resource, byte[] bytes) throws TeamException;
+	
+	/**
+	 * Remove the bytes from the tree for the resource variants corresponding to the 
+	 * given local resource and its descendants to the given depth.
+	 * After the bytes are removed, <code>getBytes(resource)</code> will 
+	 * return <code>null</code> for the affected resources.
+	 * @param resource the local resource
+	 * @param depth the depth of the operation (one of <code>IResource.DEPTH_ZERO</code>,
+	 * <code>IResource.DEPTH_ONE</code>, or <code>IResource.DEPTH_INFINITE</code>)
+	 * @return <code>true</code> if there were bytes present which were removed
+	 * @throws TeamException
+	 */
+	public abstract boolean flushBytes(IResource resource, int depth) throws TeamException;
+	
+	/**
+	 * Method called to indicate that it is known that there is no variant associated 
+	 * with the local resource. Subclasses may handle this information in different ways.
+	 * The <code>flush(IResource, int)</code> method should be used in the cases
+	 * where a client wishes to remove bytes for other reason.
+	 * @param resource the local resource
+	 * @return <code>true</code> if this changes the bytes for the variant
+	 */
+	public abstract boolean deleteBytes(IResource resource) throws TeamException;
+	
+	/**
+	 * Return the children of the given resource that have resource variants in this tree.
+	 * @param resource the parent resource
+	 * @return the members who have resource variants in this tree.
+	 */
+	public abstract IResource[] members(IResource resource) throws TeamException;
+	
+	/**
+	 * Helper method to compare two byte arrays for equality
+	 * @param syncBytes1 the first byte array or <code>null</code>
+	 * @param syncBytes2 the second byte array or <code>null</code>
+	 * @return whetehr the two arrays are equal (i.e. same content)
+	 */
+	protected boolean equals(byte[] syncBytes1, byte[] syncBytes2) {
+		if (syncBytes1 == null) {
+			return syncBytes2 == null;
+		} else if (syncBytes2 == null) {
+			return false;
+		}
+		if (syncBytes1.length != syncBytes2.length) return false;
+		for (int i = 0; i < syncBytes1.length; i++) {
+			if (syncBytes1[i] != syncBytes2[i]) return false;
+		}
+		return true;
+	}
+}