| /* |
| * Copyright (C) 2011, 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.internal.storage.dfs; |
| |
| import static org.eclipse.jgit.lib.Ref.Storage.NEW; |
| |
| import java.io.IOException; |
| import java.util.Collections; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| import org.eclipse.jgit.errors.MissingObjectException; |
| import org.eclipse.jgit.lib.ObjectIdRef; |
| import org.eclipse.jgit.lib.Ref; |
| import org.eclipse.jgit.lib.RefDatabase; |
| import org.eclipse.jgit.lib.RefRename; |
| import org.eclipse.jgit.lib.RefUpdate; |
| import org.eclipse.jgit.lib.SymbolicRef; |
| import org.eclipse.jgit.revwalk.RevObject; |
| import org.eclipse.jgit.revwalk.RevTag; |
| import org.eclipse.jgit.revwalk.RevWalk; |
| import org.eclipse.jgit.util.RefList; |
| import org.eclipse.jgit.util.RefMap; |
| |
| /** |
| * Abstract DfsRefDatabase class. |
| * |
| */ |
| public abstract class DfsRefDatabase extends RefDatabase { |
| private final DfsRepository repository; |
| |
| private final AtomicReference<RefCache> cache; |
| |
| /** |
| * Initialize the reference database for a repository. |
| * |
| * @param repository |
| * the repository this database instance manages references for. |
| */ |
| protected DfsRefDatabase(DfsRepository repository) { |
| this.repository = repository; |
| this.cache = new AtomicReference<>(); |
| } |
| |
| /** |
| * Get the repository the database holds the references of. |
| * |
| * @return the repository the database holds the references of. |
| */ |
| protected DfsRepository getRepository() { |
| return repository; |
| } |
| |
| boolean exists() throws IOException { |
| return 0 < read().size(); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public Ref exactRef(String name) throws IOException { |
| RefCache curr = read(); |
| Ref ref = curr.ids.get(name); |
| return ref != null ? resolve(ref, 0, curr.ids) : null; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public List<Ref> getAdditionalRefs() { |
| return Collections.emptyList(); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public Map<String, Ref> getRefs(String prefix) throws IOException { |
| RefCache curr = read(); |
| RefList<Ref> packed = RefList.emptyList(); |
| RefList<Ref> loose = curr.ids; |
| RefList.Builder<Ref> sym = new RefList.Builder<>(curr.sym.size()); |
| |
| for (int idx = 0; idx < curr.sym.size(); idx++) { |
| Ref ref = curr.sym.get(idx); |
| String name = ref.getName(); |
| ref = resolve(ref, 0, loose); |
| if (ref != null && ref.getObjectId() != null) { |
| sym.add(ref); |
| } else { |
| // A broken symbolic reference, we have to drop it from the |
| // collections the client is about to receive. Should be a |
| // rare occurrence so pay a copy penalty. |
| int toRemove = loose.find(name); |
| if (0 <= toRemove) |
| loose = loose.remove(toRemove); |
| } |
| } |
| |
| return new RefMap(prefix, packed, loose, sym.toRefList()); |
| } |
| |
| private Ref resolve(Ref ref, int depth, RefList<Ref> loose) |
| throws IOException { |
| if (!ref.isSymbolic()) |
| return ref; |
| |
| Ref dst = ref.getTarget(); |
| |
| if (MAX_SYMBOLIC_REF_DEPTH <= depth) |
| return null; // claim it doesn't exist |
| |
| dst = loose.get(dst.getName()); |
| if (dst == null) |
| return ref; |
| |
| dst = resolve(dst, depth + 1, loose); |
| if (dst == null) |
| return null; |
| return new SymbolicRef(ref.getName(), dst); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public Ref peel(Ref ref) throws IOException { |
| final Ref oldLeaf = ref.getLeaf(); |
| if (oldLeaf.isPeeled() || oldLeaf.getObjectId() == null) |
| return ref; |
| |
| Ref newLeaf = doPeel(oldLeaf); |
| |
| RefCache cur = read(); |
| int idx = cur.ids.find(oldLeaf.getName()); |
| if (0 <= idx && cur.ids.get(idx) == oldLeaf) { |
| RefList<Ref> newList = cur.ids.set(idx, newLeaf); |
| cache.compareAndSet(cur, new RefCache(newList, cur)); |
| cachePeeledState(oldLeaf, newLeaf); |
| } |
| |
| return recreate(ref, newLeaf); |
| } |
| |
| Ref doPeel(Ref leaf) throws MissingObjectException, |
| IOException { |
| try (RevWalk rw = new RevWalk(repository)) { |
| RevObject obj = rw.parseAny(leaf.getObjectId()); |
| if (obj instanceof RevTag) { |
| return new ObjectIdRef.PeeledTag( |
| leaf.getStorage(), |
| leaf.getName(), |
| leaf.getObjectId(), |
| rw.peel(obj).copy()); |
| } else { |
| return new ObjectIdRef.PeeledNonTag( |
| leaf.getStorage(), |
| leaf.getName(), |
| leaf.getObjectId()); |
| } |
| } |
| } |
| |
| static Ref recreate(Ref old, Ref leaf) { |
| if (old.isSymbolic()) { |
| Ref dst = recreate(old.getTarget(), leaf); |
| return new SymbolicRef(old.getName(), dst); |
| } |
| return leaf; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public RefUpdate newUpdate(String refName, boolean detach) |
| throws IOException { |
| boolean detachingSymbolicRef = false; |
| Ref ref = exactRef(refName); |
| if (ref == null) |
| ref = new ObjectIdRef.Unpeeled(NEW, refName, null); |
| else |
| detachingSymbolicRef = detach && ref.isSymbolic(); |
| |
| DfsRefUpdate update = new DfsRefUpdate(this, ref); |
| if (detachingSymbolicRef) |
| update.setDetachingSymbolicRef(); |
| return update; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public RefRename newRename(String fromName, String toName) |
| throws IOException { |
| RefUpdate src = newUpdate(fromName, true); |
| RefUpdate dst = newUpdate(toName, true); |
| return new DfsRefRename(src, dst); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public boolean isNameConflicting(String refName) throws IOException { |
| RefList<Ref> all = read().ids; |
| |
| // Cannot be nested within an existing reference. |
| int lastSlash = refName.lastIndexOf('/'); |
| while (0 < lastSlash) { |
| String needle = refName.substring(0, lastSlash); |
| if (all.contains(needle)) |
| return true; |
| lastSlash = refName.lastIndexOf('/', lastSlash - 1); |
| } |
| |
| // Cannot be the container of an existing reference. |
| String prefix = refName + '/'; |
| int idx = -(all.find(prefix) + 1); |
| if (idx < all.size() && all.get(idx).getName().startsWith(prefix)) |
| return true; |
| return false; |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public void create() { |
| // Nothing to do. |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public void refresh() { |
| clearCache(); |
| } |
| |
| /** {@inheritDoc} */ |
| @Override |
| public void close() { |
| clearCache(); |
| } |
| |
| void clearCache() { |
| cache.set(null); |
| } |
| |
| void stored(Ref ref) { |
| RefCache oldCache, newCache; |
| do { |
| oldCache = cache.get(); |
| if (oldCache == null) |
| return; |
| newCache = oldCache.put(ref); |
| } while (!cache.compareAndSet(oldCache, newCache)); |
| } |
| |
| void removed(String refName) { |
| RefCache oldCache, newCache; |
| do { |
| oldCache = cache.get(); |
| if (oldCache == null) |
| return; |
| newCache = oldCache.remove(refName); |
| } while (!cache.compareAndSet(oldCache, newCache)); |
| } |
| |
| private RefCache read() throws IOException { |
| RefCache c = cache.get(); |
| if (c == null) { |
| c = scanAllRefs(); |
| cache.set(c); |
| } |
| return c; |
| } |
| |
| /** |
| * Read all known references in the repository. |
| * |
| * @return all current references of the repository. |
| * @throws java.io.IOException |
| * references cannot be accessed. |
| */ |
| protected abstract RefCache scanAllRefs() throws IOException; |
| |
| /** |
| * Compare a reference, and put if it matches. |
| * <p> |
| * Two reference match if and only if they satisfy the following: |
| * |
| * <ul> |
| * <li>If one reference is a symbolic ref, the other one should be a symbolic |
| * ref. |
| * <li>If both are symbolic refs, the target names should be same. |
| * <li>If both are object ID refs, the object IDs should be same. |
| * </ul> |
| * |
| * @param oldRef |
| * old value to compare to. If the reference is expected to not |
| * exist the old value has a storage of |
| * {@link org.eclipse.jgit.lib.Ref.Storage#NEW} and an ObjectId |
| * value of {@code null}. |
| * @param newRef |
| * new reference to store. |
| * @return true if the put was successful; false otherwise. |
| * @throws java.io.IOException |
| * the reference cannot be put due to a system error. |
| */ |
| protected abstract boolean compareAndPut(Ref oldRef, Ref newRef) |
| throws IOException; |
| |
| /** |
| * Compare a reference, and delete if it matches. |
| * |
| * @param oldRef |
| * the old reference information that was previously read. |
| * @return true if the remove was successful; false otherwise. |
| * @throws java.io.IOException |
| * the reference could not be removed due to a system error. |
| */ |
| protected abstract boolean compareAndRemove(Ref oldRef) throws IOException; |
| |
| /** |
| * Update the cached peeled state of a reference |
| * <p> |
| * The ref database invokes this method after it peels a reference that had |
| * not been peeled before. This allows the storage to cache the peel state |
| * of the reference, and if it is actually peelable, the target that it |
| * peels to, so that on-the-fly peeling doesn't have to happen on the next |
| * reference read. |
| * |
| * @param oldLeaf |
| * the old reference. |
| * @param newLeaf |
| * the new reference, with peel information. |
| */ |
| protected void cachePeeledState(Ref oldLeaf, Ref newLeaf) { |
| try { |
| compareAndPut(oldLeaf, newLeaf); |
| } catch (IOException e) { |
| // Ignore an exception during caching. |
| } |
| } |
| |
| /** Collection of references managed by this database. */ |
| public static class RefCache { |
| final RefList<Ref> ids; |
| |
| final RefList<Ref> sym; |
| |
| /** |
| * Initialize a new reference cache. |
| * <p> |
| * The two reference lists supplied must be sorted in correct order |
| * (string compare order) by name. |
| * |
| * @param ids |
| * references that carry an ObjectId, and all of {@code sym}. |
| * @param sym |
| * references that are symbolic references to others. |
| */ |
| public RefCache(RefList<Ref> ids, RefList<Ref> sym) { |
| this.ids = ids; |
| this.sym = sym; |
| } |
| |
| RefCache(RefList<Ref> ids, RefCache old) { |
| this(ids, old.sym); |
| } |
| |
| /** @return number of references in this cache. */ |
| public int size() { |
| return ids.size(); |
| } |
| |
| /** |
| * Find a reference by name. |
| * |
| * @param name |
| * full name of the reference. |
| * @return the reference, if it exists, otherwise null. |
| */ |
| public Ref get(String name) { |
| return ids.get(name); |
| } |
| |
| /** |
| * Obtain a modified copy of the cache with a ref stored. |
| * <p> |
| * This cache instance is not modified by this method. |
| * |
| * @param ref |
| * reference to add or replace. |
| * @return a copy of this cache, with the reference added or replaced. |
| */ |
| public RefCache put(Ref ref) { |
| RefList<Ref> newIds = this.ids.put(ref); |
| RefList<Ref> newSym = this.sym; |
| if (ref.isSymbolic()) { |
| newSym = newSym.put(ref); |
| } else { |
| int p = newSym.find(ref.getName()); |
| if (0 <= p) |
| newSym = newSym.remove(p); |
| } |
| return new RefCache(newIds, newSym); |
| } |
| |
| /** |
| * Obtain a modified copy of the cache with the ref removed. |
| * <p> |
| * This cache instance is not modified by this method. |
| * |
| * @param refName |
| * reference to remove, if it exists. |
| * @return a copy of this cache, with the reference removed. |
| */ |
| public RefCache remove(String refName) { |
| RefList<Ref> newIds = this.ids; |
| int p = newIds.find(refName); |
| if (0 <= p) |
| newIds = newIds.remove(p); |
| |
| RefList<Ref> newSym = this.sym; |
| p = newSym.find(refName); |
| if (0 <= p) |
| newSym = newSym.remove(p); |
| return new RefCache(newIds, newSym); |
| } |
| } |
| } |