1 /******************************************************************************* 2 * Copyright (c) 2000, 2005 IBM Corporation and others. 3 * 4 * This program and the accompanying materials 5 * are made available under the terms of the Eclipse Public License 2.0 6 * which accompanies this distribution, and is available at 7 * https://www.eclipse.org/legal/epl-2.0/ 8 * 9 * SPDX-License-Identifier: EPL-2.0 10 * 11 * Contributors: 12 * IBM Corporation - initial API and implementation 13 *******************************************************************************/ 14 package org.eclipse.team.core.variants; 15 16 import org.eclipse.core.resources.IResource; 17 import org.eclipse.core.resources.IWorkspaceRunnable; 18 import org.eclipse.core.runtime.CoreException; 19 import org.eclipse.core.runtime.IProgressMonitor; 20 import org.eclipse.core.runtime.OperationCanceledException; 21 import org.eclipse.team.core.TeamException; 22 23 /** 24 * The purpose of a <code>ResourceVariantByteStore</code> is to support the caching of 25 * the synchronization bytes for the resource variants that represent 26 * a resource line-up of interest such as a version, baseline or branch. The 27 * cache stores bytes in order to minimize the memory footprint of the tree. It is the 28 * responsibility of the client of this API to cache enough bytes to meaningfully identify 29 * a resource variant (and possibly create an {@link IResourceVariant} handle from them). 30 * <p> 31 * The bytes for a resource variant are accessed using the local <code>IResource</code> handle 32 * that corresponds to the resource variant (using the <code>getBytes</code> method). 33 * The potential children of a resource variant are also accessed 34 * by using the local handle that corresponds to the resource variant 35 * (using the <code>members</code> method). 36 * 37 * @since 3.0 38 */ 39 public abstract class ResourceVariantByteStore { 40 41 /** 42 * Dispose of any cached sync bytes when this cache is no longer needed. 43 */ dispose()44 public abstract void dispose(); 45 46 /** 47 * Return the bytes for the variant corresponding the given local resource. 48 * A return value of <code>null</code> means that no bytes have been stored 49 * for the resource variant. It is up to the client to determine whether 50 * this means that the resource variant does not exist or that it has not been 51 * fetched or otherwise determined yet. 52 * @param resource the local resource 53 * @return the bytes that represent the resource's variant 54 * @throws TeamException if an error occurs 55 */ getBytes(IResource resource)56 public abstract byte[] getBytes(IResource resource) throws TeamException; 57 58 /** 59 * Set the bytes for the variant corresponding the given local resource. 60 * The bytes should never be <code>null</code>. If it is known that the remote 61 * does not exist, <code>deleteBytes(IResource)</code> should be used instead. 62 * If the sync bytes for the remote are stale and should be removed, 63 * <code>flushBytes(IResouce, int)</code> should be called. 64 * @param resource the local resource 65 * @param bytes the bytes that represent the resource's variant 66 * @return <code>true</code> if the bytes changed 67 * @throws TeamException if an error occurs 68 */ setBytes(IResource resource, byte[] bytes)69 public abstract boolean setBytes(IResource resource, byte[] bytes) throws TeamException; 70 71 /** 72 * Remove the bytes from the tree for the resource variants corresponding to the 73 * given local resource and its descendants to the given depth. 74 * After the bytes are removed, <code>getBytes(resource)</code> will 75 * return <code>null</code> for the affected resources. 76 * @param resource the local resource 77 * @param depth the depth of the operation (one of <code>IResource.DEPTH_ZERO</code>, 78 * <code>IResource.DEPTH_ONE</code>, or <code>IResource.DEPTH_INFINITE</code>) 79 * @return <code>true</code> if there were bytes present which were removed 80 * @throws TeamException if an error occurs 81 */ flushBytes(IResource resource, int depth)82 public abstract boolean flushBytes(IResource resource, int depth) throws TeamException; 83 84 /** 85 * Method called to indicate that it is known that there is no variant associated 86 * with the local resource. Subclasses may handle this information in different ways. 87 * The <code>flush(IResource, int)</code> method should be used in the cases 88 * where a client wishes to remove bytes for other reason. 89 * @param resource the local resource 90 * @return <code>true</code> if this changes the bytes for the variant 91 */ deleteBytes(IResource resource)92 public abstract boolean deleteBytes(IResource resource) throws TeamException; 93 94 /** 95 * Return the children of the given resource that have resource variants in this tree. 96 * @param resource the parent resource 97 * @return the members who have resource variants in this tree. 98 */ members(IResource resource)99 public abstract IResource[] members(IResource resource) throws TeamException; 100 101 /** 102 * Helper method to compare two byte arrays for equality 103 * @param syncBytes1 the first byte array or <code>null</code> 104 * @param syncBytes2 the second byte array or <code>null</code> 105 * @return whether the two arrays are equal (i.e. same content) 106 */ equals(byte[] syncBytes1, byte[] syncBytes2)107 protected boolean equals(byte[] syncBytes1, byte[] syncBytes2) { 108 if (syncBytes1 == null) { 109 return syncBytes2 == null; 110 } else if (syncBytes2 == null) { 111 return false; 112 } 113 if (syncBytes1.length != syncBytes2.length) return false; 114 for (int i = 0; i < syncBytes1.length; i++) { 115 if (syncBytes1[i] != syncBytes2[i]) return false; 116 } 117 return true; 118 } 119 120 /** 121 * Run the given action which may contain multiple modifications 122 * to the byte store. By default, the action is run. Subclasses 123 * may override to obtain scheduling rules or batch deltas (if 124 * the byte store modifies workspace resources). 125 * @param root the root resource for all modifications 126 * @param runnable the action to perform 127 * @param monitor a progress monitor. 128 * @exception TeamException if the operation failed. 129 * @exception OperationCanceledException if the operation is canceled. 130 */ run(IResource root, IWorkspaceRunnable runnable, IProgressMonitor monitor)131 public void run(IResource root, IWorkspaceRunnable runnable, IProgressMonitor monitor) throws TeamException { 132 try { 133 runnable.run(monitor); 134 } catch (CoreException e) { 135 throw TeamException.asTeamException(e); 136 } 137 } 138 } 139