| /* |
| * Copyright (C) 2010, 2013 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.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| import org.eclipse.jgit.annotations.NonNull; |
| import org.eclipse.jgit.annotations.Nullable; |
| |
| /** |
| * Abstraction of name to {@link org.eclipse.jgit.lib.ObjectId} mapping. |
| * <p> |
| * A reference database stores a mapping of reference names to |
| * {@link org.eclipse.jgit.lib.ObjectId}. Every |
| * {@link org.eclipse.jgit.lib.Repository} has a single reference database, |
| * mapping names to the tips of the object graph contained by the |
| * {@link org.eclipse.jgit.lib.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. |
| * |
| * @since 4.2 |
| */ |
| public 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 java.io.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 java.io.IOException |
| * the database could not be read to check for conflicts. |
| * @see #getConflictingNames(String) |
| */ |
| public abstract boolean isNameConflicting(String name) throws IOException; |
| |
| /** |
| * Determine if a proposed reference cannot coexist with existing ones. If |
| * the passed name already exists, it's not considered a conflict. |
| * |
| * @param name |
| * proposed name to check for conflicts against |
| * @return a collection of full names of existing refs which would conflict |
| * with the passed ref name; empty collection when there are no |
| * conflicts |
| * @throws java.io.IOException |
| * @since 2.3 |
| * @see #isNameConflicting(String) |
| */ |
| @NonNull |
| public Collection<String> getConflictingNames(String name) |
| throws IOException { |
| Map<String, Ref> allRefs = getRefs(ALL); |
| // Cannot be nested within an existing reference. |
| int lastSlash = name.lastIndexOf('/'); |
| while (0 < lastSlash) { |
| String needle = name.substring(0, lastSlash); |
| if (allRefs.containsKey(needle)) |
| return Collections.singletonList(needle); |
| lastSlash = name.lastIndexOf('/', lastSlash - 1); |
| } |
| |
| List<String> conflicting = new ArrayList<>(); |
| // Cannot be the container of an existing reference. |
| String prefix = name + '/'; |
| for (String existing : allRefs.keySet()) |
| if (existing.startsWith(prefix)) |
| conflicting.add(existing); |
| |
| return conflicting; |
| } |
| |
| /** |
| * 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 org.eclipse.jgit.lib.SymbolicRef}, the update will |
| * replace it with an {@link org.eclipse.jgit.lib.ObjectIdRef}. |
| * Otherwise, the update will recursively traverse |
| * {@link org.eclipse.jgit.lib.SymbolicRef}s and operate on the |
| * leaf {@link org.eclipse.jgit.lib.ObjectIdRef}. |
| * @return a new update for the requested name; never null. |
| * @throws java.io.IOException |
| * the reference space cannot be accessed. |
| */ |
| @NonNull |
| 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 java.io.IOException |
| * the reference space cannot be accessed. |
| */ |
| @NonNull |
| public abstract RefRename newRename(String fromName, String toName) |
| throws IOException; |
| |
| /** |
| * Create a new batch update to attempt on this database. |
| * <p> |
| * The default implementation performs a sequential update of each command. |
| * |
| * @return a new batch update object. |
| */ |
| @NonNull |
| public BatchRefUpdate newBatchUpdate() { |
| return new BatchRefUpdate(this); |
| } |
| |
| /** |
| * Whether the database is capable of performing batch updates as atomic |
| * transactions. |
| * <p> |
| * If true, by default {@link org.eclipse.jgit.lib.BatchRefUpdate} instances |
| * will perform updates atomically, meaning either all updates will succeed, |
| * or all updates will fail. It is still possible to turn off this behavior |
| * on a per-batch basis by calling {@code update.setAtomic(false)}. |
| * <p> |
| * If false, {@link org.eclipse.jgit.lib.BatchRefUpdate} instances will |
| * never perform updates atomically, and calling |
| * {@code update.setAtomic(true)} will cause the entire batch to fail with |
| * {@code REJECTED_OTHER_REASON}. |
| * <p> |
| * This definition of atomicity is stronger than what is provided by |
| * {@link org.eclipse.jgit.transport.ReceivePack}. {@code ReceivePack} will |
| * attempt to reject all commands if it knows in advance some commands may |
| * fail, even if the storage layer does not support atomic transactions. |
| * Here, atomicity applies even in the case of unforeseeable errors. |
| * |
| * @return whether transactions are atomic by default. |
| * @since 3.6 |
| */ |
| public boolean performsAtomicTransactions() { |
| return false; |
| } |
| |
| /** |
| * 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)}. |
| * <p> |
| * To read a specific reference without using @{link #SEARCH_PATH}, see |
| * {@link #exactRef(String)}. |
| * |
| * @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 java.io.IOException |
| * the reference space cannot be accessed. |
| */ |
| @Nullable |
| public abstract Ref getRef(String name) throws IOException; |
| |
| /** |
| * Read a single reference. |
| * <p> |
| * Unlike {@link #getRef}, this method expects an unshortened reference |
| * name and does not search using the standard {@link #SEARCH_PATH}. |
| * |
| * @param name |
| * the unabbreviated name of the reference. |
| * @return the reference (if it exists); else {@code null}. |
| * @throws java.io.IOException |
| * the reference space cannot be accessed. |
| * @since 4.1 |
| */ |
| @Nullable |
| public Ref exactRef(String name) throws IOException { |
| Ref ref = getRef(name); |
| if (ref == null || !name.equals(ref.getName())) { |
| return null; |
| } |
| return ref; |
| } |
| |
| /** |
| * Read the specified references. |
| * <p> |
| * This method expects a list of unshortened reference names and returns |
| * a map from reference names to refs. Any named references that do not |
| * exist will not be included in the returned map. |
| * |
| * @param refs |
| * the unabbreviated names of references to look up. |
| * @return modifiable map describing any refs that exist among the ref |
| * ref names supplied. The map can be an unsorted map. |
| * @throws java.io.IOException |
| * the reference space cannot be accessed. |
| * @since 4.1 |
| */ |
| @NonNull |
| public Map<String, Ref> exactRef(String... refs) throws IOException { |
| Map<String, Ref> result = new HashMap<>(refs.length); |
| for (String name : refs) { |
| Ref ref = exactRef(name); |
| if (ref != null) { |
| result.put(name, ref); |
| } |
| } |
| return result; |
| } |
| |
| /** |
| * Find the first named reference. |
| * <p> |
| * This method expects a list of unshortened reference names and returns |
| * the first that exists. |
| * |
| * @param refs |
| * the unabbreviated names of references to look up. |
| * @return the first named reference that exists (if any); else {@code null}. |
| * @throws java.io.IOException |
| * the reference space cannot be accessed. |
| * @since 4.1 |
| */ |
| @Nullable |
| public Ref firstExactRef(String... refs) throws IOException { |
| for (String name : refs) { |
| Ref ref = exactRef(name); |
| if (ref != null) { |
| return ref; |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * 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 java.io.IOException |
| * the reference space cannot be accessed. |
| */ |
| @NonNull |
| public abstract Map<String, Ref> getRefs(String prefix) throws IOException; |
| |
| /** |
| * Get the additional reference-like entities from the repository. |
| * <p> |
| * The result list includes non-ref items such as MERGE_HEAD and |
| * FETCH_RESULT cast to be refs. The names of these refs are not returned by |
| * <code>getRefs(ALL)</code> but are accepted by {@link #getRef(String)} |
| * and {@link #exactRef(String)}. |
| * |
| * @return a list of additional refs |
| * @throws java.io.IOException |
| * the reference space cannot be accessed. |
| */ |
| @NonNull |
| public abstract List<Ref> getAdditionalRefs() 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 org.eclipse.jgit.lib.Ref#isPeeled()} will be true. |
| * <p> |
| * Implementors should check {@link org.eclipse.jgit.lib.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 {@code null}). |
| * @throws java.io.IOException |
| * the reference space or object space cannot be accessed. |
| */ |
| @NonNull |
| public abstract Ref peel(Ref ref) throws IOException; |
| |
| /** |
| * Triggers a refresh of all internal data structures. |
| * <p> |
| * In case the RefDatabase implementation has internal caches this method |
| * will trigger that all these caches are cleared. |
| * <p> |
| * Implementors should overwrite this method if they use any kind of caches. |
| */ |
| public void refresh() { |
| // nothing |
| } |
| |
| /** |
| * Try to find the specified name in the ref map using {@link #SEARCH_PATH}. |
| * |
| * @param map |
| * map of refs to search within. Names should be fully qualified, |
| * e.g. "refs/heads/master". |
| * @param name |
| * short name of ref to find, e.g. "master" to find |
| * "refs/heads/master" in map. |
| * @return The first ref matching the name, or {@code null} if not found. |
| * @since 3.4 |
| */ |
| @Nullable |
| public static Ref findRef(Map<String, Ref> map, String name) { |
| for (String prefix : SEARCH_PATH) { |
| String fullname = prefix + name; |
| Ref ref = map.get(fullname); |
| if (ref != null) |
| return ref; |
| } |
| return null; |
| } |
| } |