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- /*
- * Copyright (C) 2007-2009, Robin Rosenberg <robin.rosenberg@dewire.com>
- * Copyright (C) 2006-2008, Shawn O. Pearce <spearce@spearce.org>
- * 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 static org.eclipse.jgit.lib.Constants.R_TAGS;
-
- import java.io.BufferedReader;
- import java.io.File;
- import java.io.FileInputStream;
- import java.io.FileNotFoundException;
- import java.io.IOException;
- import java.io.InputStreamReader;
- import java.util.HashMap;
- import java.util.Map;
-
- import org.eclipse.jgit.errors.ObjectWritingException;
- import org.eclipse.jgit.lib.Ref.Storage;
- import org.eclipse.jgit.util.FS;
- import org.eclipse.jgit.util.IO;
- import org.eclipse.jgit.util.RawParseUtils;
-
- class RefDatabase {
- private static final String REFS_SLASH = "refs/";
-
- private static final String[] refSearchPaths = { "", REFS_SLASH,
- R_TAGS, Constants.R_HEADS, Constants.R_REMOTES };
-
- private final Repository db;
-
- private final File gitDir;
-
- private final File refsDir;
-
- private Map<String, Ref> looseRefs;
- private Map<String, Long> looseRefsMTime;
- private Map<String, String> looseSymRefs;
-
- private final File packedRefsFile;
-
- private Map<String, Ref> packedRefs;
-
- private long packedRefsLastModified;
-
- private long packedRefsLength;
-
- int lastRefModification;
-
- int lastNotifiedRefModification;
-
- private int refModificationCounter;
-
- RefDatabase(final Repository r) {
- db = r;
- gitDir = db.getDirectory();
- refsDir = FS.resolve(gitDir, "refs");
- packedRefsFile = FS.resolve(gitDir, Constants.PACKED_REFS);
- clearCache();
- }
-
- synchronized void clearCache() {
- looseRefs = new HashMap<String, Ref>();
- looseRefsMTime = new HashMap<String, Long>();
- packedRefs = new HashMap<String, Ref>();
- looseSymRefs = new HashMap<String, String>();
- packedRefsLastModified = 0;
- packedRefsLength = 0;
- }
-
- Repository getRepository() {
- return db;
- }
-
- void create() {
- refsDir.mkdir();
- new File(refsDir, "heads").mkdir();
- new File(refsDir, "tags").mkdir();
- }
-
- ObjectId idOf(final String name) throws IOException {
- refreshPackedRefs();
- final Ref r = readRefBasic(name, 0);
- return r != null ? r.getObjectId() : null;
- }
-
- /**
- * Create a command to update, create or delete a ref in this repository.
- *
- * @param name
- * name of the ref the caller wants to modify.
- * @return an update command. The caller must finish populating this command
- * and then invoke one of the update methods to actually make a
- * change.
- * @throws IOException
- * a symbolic ref was passed in and could not be resolved back
- * to the base ref, as the symbolic ref could not be read.
- */
- RefUpdate newUpdate(final String name) throws IOException {
- refreshPackedRefs();
- Ref r = readRefBasic(name, 0);
- if (r == null)
- r = new Ref(Ref.Storage.NEW, name, null);
- return new RefUpdate(this, r, fileForRef(r.getName()));
- }
-
- void stored(final String origName, final String name, final ObjectId id, final long time) {
- synchronized (this) {
- looseRefs.put(name, new Ref(Ref.Storage.LOOSE, name, name, id));
- looseRefsMTime.put(name, time);
- setModified();
- }
- db.fireRefsMaybeChanged();
- }
-
- /**
- * An set of update operations for renaming a ref
- *
- * @param fromRef Old ref name
- * @param toRef New ref name
- * @return a RefUpdate operation to rename a ref
- * @throws IOException
- */
- RefRename newRename(String fromRef, String toRef) throws IOException {
- refreshPackedRefs();
- Ref f = readRefBasic(fromRef, 0);
- Ref t = new Ref(Ref.Storage.NEW, toRef, null);
- RefUpdate refUpdateFrom = new RefUpdate(this, f, fileForRef(f.getName()));
- RefUpdate refUpdateTo = new RefUpdate(this, t, fileForRef(t.getName()));
- return new RefRename(refUpdateTo, refUpdateFrom);
- }
-
- /**
- * Writes a symref (e.g. HEAD) to disk
- *
- * @param name
- * symref name
- * @param target
- * pointed to ref
- * @throws IOException
- */
- void link(final String name, final String target) throws IOException {
- final byte[] content = Constants.encode("ref: " + target + "\n");
- lockAndWriteFile(fileForRef(name), content);
- synchronized (this) {
- looseSymRefs.remove(name);
- setModified();
- }
- db.fireRefsMaybeChanged();
- }
-
- void uncacheSymRef(String name) {
- synchronized(this) {
- looseSymRefs.remove(name);
- setModified();
- }
- }
-
- void uncacheRef(String name) {
- looseRefs.remove(name);
- looseRefsMTime.remove(name);
- packedRefs.remove(name);
- }
-
- private void setModified() {
- lastRefModification = refModificationCounter++;
- }
-
- Ref readRef(final String partialName) throws IOException {
- refreshPackedRefs();
- for (int k = 0; k < refSearchPaths.length; k++) {
- final Ref r = readRefBasic(refSearchPaths[k] + partialName, 0);
- if (r != null && r.getObjectId() != null)
- return r;
- }
- return null;
- }
-
- /**
- * @return all known refs (heads, tags, remotes).
- */
- Map<String, Ref> getAllRefs() {
- return readRefs();
- }
-
- /**
- * @return all tags; key is short tag name ("v1.0") and value of the entry
- * contains the ref with the full tag name ("refs/tags/v1.0").
- */
- Map<String, Ref> getTags() {
- final Map<String, Ref> tags = new HashMap<String, Ref>();
- for (final Ref r : readRefs().values()) {
- if (r.getName().startsWith(R_TAGS))
- tags.put(r.getName().substring(R_TAGS.length()), r);
- }
- return tags;
- }
-
- private Map<String, Ref> readRefs() {
- final HashMap<String, Ref> avail = new HashMap<String, Ref>();
- readPackedRefs(avail);
- readLooseRefs(avail, REFS_SLASH, refsDir);
- try {
- final Ref r = readRefBasic(Constants.HEAD, 0);
- if (r != null && r.getObjectId() != null)
- avail.put(Constants.HEAD, r);
- } catch (IOException e) {
- // ignore here
- }
- db.fireRefsMaybeChanged();
- return avail;
- }
-
- private synchronized void readPackedRefs(final Map<String, Ref> avail) {
- refreshPackedRefs();
- avail.putAll(packedRefs);
- }
-
- private void readLooseRefs(final Map<String, Ref> avail,
- final String prefix, final File dir) {
- final File[] entries = dir.listFiles();
- if (entries == null)
- return;
-
- for (final File ent : entries) {
- final String entName = ent.getName();
- if (".".equals(entName) || "..".equals(entName))
- continue;
- if (ent.isDirectory()) {
- readLooseRefs(avail, prefix + entName + "/", ent);
- } else {
- try {
- final Ref ref = readRefBasic(prefix + entName, 0);
- if (ref != null)
- avail.put(ref.getOrigName(), ref);
- } catch (IOException e) {
- continue;
- }
- }
- }
- }
-
- Ref peel(final Ref ref) {
- if (ref.isPeeled())
- return ref;
- ObjectId peeled = null;
- try {
- Object target = db.mapObject(ref.getObjectId(), ref.getName());
- while (target instanceof Tag) {
- final Tag tag = (Tag)target;
- peeled = tag.getObjId();
- if (Constants.TYPE_TAG.equals(tag.getType()))
- target = db.mapObject(tag.getObjId(), ref.getName());
- else
- break;
- }
- } catch (IOException e) {
- // Ignore a read error. Callers will also get the same error
- // if they try to use the result of getPeeledObjectId.
- }
- return new Ref(ref.getStorage(), ref.getName(), ref.getObjectId(), peeled, true);
-
- }
-
- private File fileForRef(final String name) {
- if (name.startsWith(REFS_SLASH))
- return new File(refsDir, name.substring(REFS_SLASH.length()));
- return new File(gitDir, name);
- }
-
- private Ref readRefBasic(final String name, final int depth) throws IOException {
- return readRefBasic(name, name, depth);
- }
-
- private synchronized Ref readRefBasic(final String origName,
- final String name, final int depth) throws IOException {
- // Prefer loose ref to packed ref as the loose
- // file can be more up-to-date than a packed one.
- //
- Ref ref = looseRefs.get(origName);
- final File loose = fileForRef(name);
- final long mtime = loose.lastModified();
- if (ref != null) {
- Long cachedlastModified = looseRefsMTime.get(name);
- if (cachedlastModified != null && cachedlastModified == mtime) {
- if (packedRefs.containsKey(origName))
- return new Ref(Storage.LOOSE_PACKED, origName, ref
- .getObjectId(), ref.getPeeledObjectId(), ref
- .isPeeled());
- else
- return ref;
- }
- looseRefs.remove(origName);
- looseRefsMTime.remove(origName);
- }
-
- if (mtime == 0) {
- // If last modified is 0 the file does not exist.
- // Try packed cache.
- //
- ref = packedRefs.get(name);
- if (ref != null)
- if (!ref.getOrigName().equals(origName))
- ref = new Ref(Storage.LOOSE_PACKED, origName, name, ref.getObjectId());
- return ref;
- }
-
- String line = null;
- try {
- Long cachedlastModified = looseRefsMTime.get(name);
- if (cachedlastModified != null && cachedlastModified == mtime) {
- line = looseSymRefs.get(name);
- }
- if (line == null) {
- line = readLine(loose);
- looseRefsMTime.put(name, mtime);
- looseSymRefs.put(name, line);
- }
- } catch (FileNotFoundException notLoose) {
- return packedRefs.get(name);
- }
-
- if (line == null || line.length() == 0) {
- looseRefs.remove(origName);
- looseRefsMTime.remove(origName);
- return new Ref(Ref.Storage.LOOSE, origName, name, null);
- }
-
- if (line.startsWith("ref: ")) {
- if (depth >= 5) {
- throw new IOException("Exceeded maximum ref depth of " + depth
- + " at " + name + ". Circular reference?");
- }
-
- final String target = line.substring("ref: ".length());
- Ref r = readRefBasic(target, target, depth + 1);
- Long cachedMtime = looseRefsMTime.get(name);
- if (cachedMtime != null && cachedMtime != mtime)
- setModified();
- looseRefsMTime.put(name, mtime);
- if (r == null)
- return new Ref(Ref.Storage.LOOSE, origName, target, null);
- if (!origName.equals(r.getName()))
- r = new Ref(Ref.Storage.LOOSE_PACKED, origName, r.getName(), r.getObjectId(), r.getPeeledObjectId(), true);
- return r;
- }
-
- setModified();
-
- final ObjectId id;
- try {
- id = ObjectId.fromString(line);
- } catch (IllegalArgumentException notRef) {
- throw new IOException("Not a ref: " + name + ": " + line);
- }
-
- Storage storage;
- if (packedRefs.containsKey(name))
- storage = Ref.Storage.LOOSE_PACKED;
- else
- storage = Ref.Storage.LOOSE;
- ref = new Ref(storage, name, id);
- looseRefs.put(name, ref);
- looseRefsMTime.put(name, mtime);
-
- if (!origName.equals(name)) {
- ref = new Ref(Ref.Storage.LOOSE, origName, name, id);
- looseRefs.put(origName, ref);
- }
-
- return ref;
- }
-
- private synchronized void refreshPackedRefs() {
- final long currTime = packedRefsFile.lastModified();
- final long currLen = currTime == 0 ? 0 : packedRefsFile.length();
- if (currTime == packedRefsLastModified && currLen == packedRefsLength)
- return;
- if (currTime == 0) {
- packedRefsLastModified = 0;
- packedRefsLength = 0;
- packedRefs = new HashMap<String, Ref>();
- return;
- }
-
- final Map<String, Ref> newPackedRefs = new HashMap<String, Ref>();
- try {
- final BufferedReader b = openReader(packedRefsFile);
- try {
- String p;
- Ref last = null;
- while ((p = b.readLine()) != null) {
- if (p.charAt(0) == '#')
- continue;
-
- if (p.charAt(0) == '^') {
- if (last == null)
- throw new IOException("Peeled line before ref.");
-
- final ObjectId id = ObjectId.fromString(p.substring(1));
- last = new Ref(Ref.Storage.PACKED, last.getName(), last
- .getName(), last.getObjectId(), id, true);
- newPackedRefs.put(last.getName(), last);
- continue;
- }
-
- final int sp = p.indexOf(' ');
- final ObjectId id = ObjectId.fromString(p.substring(0, sp));
- final String name = copy(p, sp + 1, p.length());
- last = new Ref(Ref.Storage.PACKED, name, name, id);
- newPackedRefs.put(last.getName(), last);
- }
- } finally {
- b.close();
- }
- packedRefsLastModified = currTime;
- packedRefsLength = currLen;
- packedRefs = newPackedRefs;
- setModified();
- } catch (FileNotFoundException noPackedRefs) {
- // Ignore it and leave the new map empty.
- //
- packedRefsLastModified = 0;
- packedRefsLength = 0;
- packedRefs = newPackedRefs;
- } catch (IOException e) {
- throw new RuntimeException("Cannot read packed refs", e);
- }
- }
-
- private static String copy(final String src, final int off, final int end) {
- return new StringBuilder(end - off).append(src, off, end).toString();
- }
-
- private void lockAndWriteFile(File file, byte[] content) throws IOException {
- String name = file.getName();
- final LockFile lck = new LockFile(file);
- if (!lck.lock())
- throw new ObjectWritingException("Unable to lock " + name);
- try {
- lck.write(content);
- } catch (IOException ioe) {
- throw new ObjectWritingException("Unable to write " + name, ioe);
- }
- if (!lck.commit())
- throw new ObjectWritingException("Unable to write " + name);
- }
-
- synchronized void removePackedRef(String name) throws IOException {
- packedRefs.remove(name);
- writePackedRefs();
- }
-
- private void writePackedRefs() throws IOException {
- new RefWriter(packedRefs.values()) {
- @Override
- protected void writeFile(String name, byte[] content) throws IOException {
- lockAndWriteFile(new File(db.getDirectory(), name), content);
- }
- }.writePackedRefs();
- }
-
- private static String readLine(final File file)
- throws FileNotFoundException, IOException {
- final byte[] buf = IO.readFully(file, 4096);
- int n = buf.length;
-
- // remove trailing whitespaces
- while (n > 0 && Character.isWhitespace(buf[n - 1]))
- n--;
-
- if (n == 0)
- return null;
- return RawParseUtils.decode(buf, 0, n);
- }
-
- private static BufferedReader openReader(final File fileLocation)
- throws FileNotFoundException {
- return new BufferedReader(new InputStreamReader(new FileInputStream(
- fileLocation), Constants.CHARSET));
- }
- }
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