| /* |
| * Copyright (C) 2010, Google Inc. |
| * and other copyright owners as documented in the project's IP log. |
| * |
| * This program and the accompanying materials are made available |
| * under the terms of the Eclipse Distribution License v1.0 which |
| * accompanies this distribution, is reproduced below, and is |
| * available at http://www.eclipse.org/org/documents/edl-v10.php |
| * |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or |
| * without modification, are permitted provided that the following |
| * conditions are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * - Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following |
| * disclaimer in the documentation and/or other materials provided |
| * with the distribution. |
| * |
| * - Neither the name of the Eclipse Foundation, Inc. nor the |
| * names of its contributors may be used to endorse or promote |
| * products derived from this software without specific prior |
| * written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND |
| * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, |
| * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| package org.eclipse.jgit.lib; |
| |
| import java.io.IOException; |
| import java.util.Map; |
| |
| /** |
| * Abstraction of name to {@link ObjectId} mapping. |
| * <p> |
| * A reference database stores a mapping of reference names to {@link ObjectId}. |
| * Every {@link Repository} has a single reference database, mapping names to |
| * the tips of the object graph contained by the {@link ObjectDatabase}. |
| */ |
| public abstract class RefDatabase { |
| /** |
| * Order of prefixes to search when using non-absolute references. |
| * <p> |
| * The implementation's {@link #getRef(String)} method must take this search |
| * space into consideration when locating a reference by name. The first |
| * entry in the path is always {@code ""}, ensuring that absolute references |
| * are resolved without further mangling. |
| */ |
| protected static final String[] SEARCH_PATH = { "", //$NON-NLS-1$ |
| Constants.R_REFS, // |
| Constants.R_TAGS, // |
| Constants.R_HEADS, // |
| Constants.R_REMOTES // |
| }; |
| |
| /** |
| * Maximum number of times a {@link SymbolicRef} can be traversed. |
| * <p> |
| * If the reference is nested deeper than this depth, the implementation |
| * should either fail, or at least claim the reference does not exist. |
| */ |
| protected static final int MAX_SYMBOLIC_REF_DEPTH = 5; |
| |
| /** Magic value for {@link #getRefs(String)} to return all references. */ |
| public static final String ALL = "";//$NON-NLS-1$ |
| |
| /** |
| * Initialize a new reference database at this location. |
| * |
| * @throws IOException |
| * the database could not be created. |
| */ |
| public abstract void create() throws IOException; |
| |
| /** Close any resources held by this database. */ |
| public abstract void close(); |
| |
| /** |
| * Determine if a proposed reference name overlaps with an existing one. |
| * <p> |
| * Reference names use '/' as a component separator, and may be stored in a |
| * hierarchical storage such as a directory on the local filesystem. |
| * <p> |
| * If the reference "refs/heads/foo" exists then "refs/heads/foo/bar" must |
| * not exist, as a reference cannot have a value and also be a container for |
| * other references at the same time. |
| * <p> |
| * If the reference "refs/heads/foo/bar" exists than the reference |
| * "refs/heads/foo" cannot exist, for the same reason. |
| * |
| * @param name |
| * proposed name. |
| * @return true if the name overlaps with an existing reference; false if |
| * using this name right now would be safe. |
| * @throws IOException |
| * the database could not be read to check for conflicts. |
| */ |
| public abstract boolean isNameConflicting(String name) throws IOException; |
| |
| /** |
| * Create a new update command to create, modify or delete a reference. |
| * |
| * @param name |
| * the name of the reference. |
| * @param detach |
| * if {@code true} and {@code name} is currently a |
| * {@link SymbolicRef}, the update will replace it with an |
| * {@link ObjectIdRef}. Otherwise, the update will recursively |
| * traverse {@link SymbolicRef}s and operate on the leaf |
| * {@link ObjectIdRef}. |
| * @return a new update for the requested name; never null. |
| * @throws IOException |
| * the reference space cannot be accessed. |
| */ |
| public abstract RefUpdate newUpdate(String name, boolean detach) |
| throws IOException; |
| |
| /** |
| * Create a new update command to rename a reference. |
| * |
| * @param fromName |
| * name of reference to rename from |
| * @param toName |
| * name of reference to rename to |
| * @return an update command that knows how to rename a branch to another. |
| * @throws IOException |
| * the reference space cannot be accessed. |
| */ |
| public abstract RefRename newRename(String fromName, String toName) |
| throws IOException; |
| |
| /** |
| * Read a single reference. |
| * <p> |
| * Aside from taking advantage of {@link #SEARCH_PATH}, this method may be |
| * able to more quickly resolve a single reference name than obtaining the |
| * complete namespace by {@code getRefs(ALL).get(name)}. |
| * |
| * @param name |
| * the name of the reference. May be a short name which must be |
| * searched for using the standard {@link #SEARCH_PATH}. |
| * @return the reference (if it exists); else {@code null}. |
| * @throws IOException |
| * the reference space cannot be accessed. |
| */ |
| public abstract Ref getRef(String name) throws IOException; |
| |
| /** |
| * Get a section of the reference namespace. |
| * |
| * @param prefix |
| * prefix to search the namespace with; must end with {@code /}. |
| * If the empty string ({@link #ALL}), obtain a complete snapshot |
| * of all references. |
| * @return modifiable map that is a complete snapshot of the current |
| * reference namespace, with {@code prefix} removed from the start |
| * of each key. The map can be an unsorted map. |
| * @throws IOException |
| * the reference space cannot be accessed. |
| */ |
| public abstract Map<String, Ref> getRefs(String prefix) throws IOException; |
| |
| /** |
| * Peel a possibly unpeeled reference by traversing the annotated tags. |
| * <p> |
| * If the reference cannot be peeled (as it does not refer to an annotated |
| * tag) the peeled id stays null, but {@link Ref#isPeeled()} will be true. |
| * <p> |
| * Implementors should check {@link Ref#isPeeled()} before performing any |
| * additional work effort. |
| * |
| * @param ref |
| * The reference to peel |
| * @return {@code ref} if {@code ref.isPeeled()} is true; otherwise a new |
| * Ref object representing the same data as Ref, but isPeeled() will |
| * be true and getPeeledObjectId() will contain the peeled object |
| * (or null). |
| * @throws IOException |
| * the reference space or object space cannot be accessed. |
| */ |
| public abstract Ref peel(Ref ref) throws IOException; |
| } |