@Override
public Map<String, Ref> getRefs(String prefix) throws IOException {
final RefList<LooseRef> oldLoose = looseRefs.get();
LooseScanner scan = new LooseScanner(oldLoose);
scan.scan(prefix);
final RefList<Ref> packed = getPackedRefs();
RefList<LooseRef> loose;
if (scan.newLoose != null) {
scan.newLoose.sort();
loose = scan.newLoose.toRefList();
if (looseRefs.compareAndSet(oldLoose, loose)) modCnt.incrementAndGet();
} else loose = oldLoose;
fireRefsChanged();
RefList.Builder<Ref> symbolic = scan.symbolic;
for (int idx = 0; idx < symbolic.size(); ) {
final Ref symbolicRef = symbolic.get(idx);
final Ref resolvedRef = resolve(symbolicRef, 0, prefix, loose, packed);
if (resolvedRef != null && resolvedRef.getObjectId() != null) {
symbolic.set(idx, resolvedRef);
idx++;
} 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.
symbolic.remove(idx);
final int toRemove = loose.find(symbolicRef.getName());
if (0 <= toRemove) loose = loose.remove(toRemove);
}
}
symbolic.sort();
return new RefMap(prefix, packed, upcast(loose), symbolic.toRefList());
}
private Ref resolve(
final Ref ref, int depth, String prefix, RefList<LooseRef> loose, RefList<Ref> packed)
throws IOException {
if (ref.isSymbolic()) {
Ref dst = ref.getTarget();
if (MAX_SYMBOLIC_REF_DEPTH <= depth) return null; // claim it doesn't exist
// If the cached value can be assumed to be current due to a
// recent scan of the loose directory, use it.
if (loose != null && dst.getName().startsWith(prefix)) {
int idx;
if (0 <= (idx = loose.find(dst.getName()))) dst = loose.get(idx);
else if (0 <= (idx = packed.find(dst.getName()))) dst = packed.get(idx);
else return ref;
} else {
dst = readRef(dst.getName(), packed);
if (dst == null) return ref;
}
dst = resolve(dst, depth + 1, prefix, loose, packed);
if (dst == null) return null;
return new SymbolicRef(ref.getName(), dst);
}
return ref;
}
@Override
public boolean isNameConflicting(String name) throws IOException {
RefList<Ref> packed = getPackedRefs();
RefList<LooseRef> loose = getLooseRefs();
// Cannot be nested within an existing reference.
int lastSlash = name.lastIndexOf('/');
while (0 < lastSlash) {
String needle = name.substring(0, lastSlash);
if (loose.contains(needle) || packed.contains(needle)) return true;
lastSlash = name.lastIndexOf('/', lastSlash - 1);
}
// Cannot be the container of an existing reference.
String prefix = name + '/';
int idx;
idx = -(packed.find(prefix) + 1);
if (idx < packed.size() && packed.get(idx).getName().startsWith(prefix)) return true;
idx = -(loose.find(prefix) + 1);
if (idx < loose.size() && loose.get(idx).getName().startsWith(prefix)) return true;
return false;
}
private void putLooseRef(LooseRef ref) {
RefList<LooseRef> cList, nList;
do {
cList = looseRefs.get();
nList = cList.put(ref);
} while (!looseRefs.compareAndSet(cList, nList));
modCnt.incrementAndGet();
fireRefsChanged();
}
/**
* 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);
}
void scan(String prefix) {
if (ALL.equals(prefix)) {
scanOne(HEAD);
scanTree(R_REFS, refsDir);
// If any entries remain, they are deleted, drop them.
if (newLoose == null && curIdx < curLoose.size()) newLoose = curLoose.copy(curIdx);
} else if (prefix.startsWith(R_REFS) && prefix.endsWith("/")) { // $NON-NLS-1$
curIdx = -(curLoose.find(prefix) + 1);
File dir = new File(refsDir, prefix.substring(R_REFS.length()));
scanTree(prefix, dir);
// Skip over entries still within the prefix; these have
// been removed from the directory.
while (curIdx < curLoose.size()) {
if (!curLoose.get(curIdx).getName().startsWith(prefix)) break;
if (newLoose == null) newLoose = curLoose.copy(curIdx);
curIdx++;
}
// Keep any entries outside of the prefix space, we
// do not know anything about their status.
if (newLoose != null) {
while (curIdx < curLoose.size()) newLoose.add(curLoose.get(curIdx++));
}
}
}
private Ref readRef(String name, RefList<Ref> packed) throws IOException {
final RefList<LooseRef> curList = looseRefs.get();
final int idx = curList.find(name);
if (0 <= idx) {
final LooseRef o = curList.get(idx);
final LooseRef n = scanRef(o, name);
if (n == null) {
if (looseRefs.compareAndSet(curList, curList.remove(idx))) modCnt.incrementAndGet();
return packed.get(name);
}
if (o == n) return n;
if (looseRefs.compareAndSet(curList, curList.set(idx, n))) modCnt.incrementAndGet();
return n;
}
final LooseRef n = scanRef(null, name);
if (n == null) return packed.get(name);
// check whether the found new ref is the an additional ref. These refs
// should not go into looseRefs
for (int i = 0; i < additionalRefsNames.length; i++)
if (name.equals(additionalRefsNames[i])) return n;
if (looseRefs.compareAndSet(curList, curList.add(idx, n))) modCnt.incrementAndGet();
return n;
}
/**
* Adds a set of refs to the set of packed-refs. Only non-symbolic refs are added. If a ref with
* the given name already existed in packed-refs it is updated with the new value. Each loose ref
* which was added to the packed-ref file is deleted. If a given ref can't be locked it will not
* be added to the pack file.
*
* @param refs the refs to be added. Must be fully qualified.
* @throws IOException
*/
public void pack(List<String> refs) throws IOException {
if (refs.size() == 0) return;
FS fs = parent.getFS();
// Lock the packed refs file and read the content
LockFile lck = new LockFile(packedRefsFile);
if (!lck.lock())
throw new IOException(MessageFormat.format(JGitText.get().cannotLock, packedRefsFile));
try {
final PackedRefList packed = getPackedRefs();
RefList<Ref> cur = readPackedRefs();
// Iterate over all refs to be packed
for (String refName : refs) {
Ref ref = readRef(refName, cur);
if (ref.isSymbolic()) continue; // can't pack symbolic refs
// Add/Update it to packed-refs
int idx = cur.find(refName);
if (idx >= 0) cur = cur.set(idx, peeledPackedRef(ref));
else cur = cur.add(idx, peeledPackedRef(ref));
}
// The new content for packed-refs is collected. Persist it.
commitPackedRefs(lck, cur, packed);
// Now delete the loose refs which are now packed
for (String refName : refs) {
// Lock the loose ref
File refFile = fileFor(refName);
if (!fs.exists(refFile)) continue;
LockFile rLck = new LockFile(refFile);
if (!rLck.lock()) continue;
try {
LooseRef currentLooseRef = scanRef(null, refName);
if (currentLooseRef == null || currentLooseRef.isSymbolic()) continue;
Ref packedRef = cur.get(refName);
ObjectId clr_oid = currentLooseRef.getObjectId();
if (clr_oid != null && clr_oid.equals(packedRef.getObjectId())) {
RefList<LooseRef> curLoose, newLoose;
do {
curLoose = looseRefs.get();
int idx = curLoose.find(refName);
if (idx < 0) break;
newLoose = curLoose.remove(idx);
} while (!looseRefs.compareAndSet(curLoose, newLoose));
int levels = levelsIn(refName) - 2;
delete(refFile, levels, rLck);
}
} finally {
rLck.unlock();
}
}
// Don't fire refsChanged. The refs have not change, only their
// storage.
} finally {
lck.unlock();
}
}
@Override
public boolean isNameConflicting(String refName) throws IOException {
RefList<DhtRef> all = readRefs().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;
}
RefDirectory(final FileRepository db) {
final FS fs = db.getFS();
parent = db;
gitDir = db.getDirectory();
logWriter = new ReflogWriter(db);
refsDir = fs.resolve(gitDir, R_REFS);
packedRefsFile = fs.resolve(gitDir, PACKED_REFS);
looseRefs.set(RefList.<LooseRef>emptyList());
packedRefs.set(PackedRefList.NO_PACKED_REFS);
}
void stored(String refName, RefData newData) {
DhtRef ref = fromData(refName, newData);
RefCache oldCache, newCache;
do {
oldCache = cache.get();
if (oldCache == null) return;
RefList<DhtRef> ids = oldCache.ids.put(ref);
RefList<DhtRef> sym = oldCache.sym;
if (ref.isSymbolic()) {
sym = sym.put(ref);
} else {
int p = sym.find(refName);
if (0 <= p) sym = sym.remove(p);
}
newCache = new RefCache(ids, sym, oldCache.hints);
} while (!cache.compareAndSet(oldCache, newCache));
}
@Override
public Ref peel(final Ref ref) throws IOException {
final Ref leaf = ref.getLeaf();
if (leaf.isPeeled() || leaf.getObjectId() == null) return ref;
ObjectIdRef newLeaf = doPeel(leaf);
// Try to remember this peeling in the cache, so we don't have to do
// it again in the future, but only if the reference is unchanged.
if (leaf.getStorage().isLoose()) {
RefList<LooseRef> curList = looseRefs.get();
int idx = curList.find(leaf.getName());
if (0 <= idx && curList.get(idx) == leaf) {
LooseRef asPeeled = ((LooseRef) leaf).peel(newLeaf);
RefList<LooseRef> newList = curList.set(idx, asPeeled);
looseRefs.compareAndSet(curList, newList);
}
}
return recreate(ref, newLeaf);
}
void delete(RefDirectoryUpdate update) throws IOException {
Ref dst = update.getRef();
String name = dst.getName();
// Write the packed-refs file using an atomic update. We might
// wind up reading it twice, before and after the lock, to ensure
// we don't miss an edit made externally.
final PackedRefList packed = getPackedRefs();
if (packed.contains(name)) {
LockFile lck = new LockFile(packedRefsFile);
if (!lck.lock()) throw new LockFailedException(packedRefsFile);
try {
PackedRefList cur = readPackedRefs();
int idx = cur.find(name);
if (0 <= idx) commitPackedRefs(lck, cur.remove(idx), packed);
} finally {
lck.unlock();
}
}
RefList<LooseRef> curLoose, newLoose;
do {
curLoose = looseRefs.get();
int idx = curLoose.find(name);
if (idx < 0) break;
newLoose = curLoose.remove(idx);
} while (!looseRefs.compareAndSet(curLoose, newLoose));
int levels = levelsIn(name) - 2;
delete(logWriter.logFor(name), levels);
if (dst.getStorage().isLoose()) {
update.unlock();
delete(fileFor(name), levels);
}
modCnt.incrementAndGet();
fireRefsChanged();
}
private static class PackedRefList extends RefList<Ref> {
static final PackedRefList NO_PACKED_REFS =
new PackedRefList(RefList.emptyList(), FileSnapshot.MISSING_FILE, ObjectId.zeroId());
final FileSnapshot snapshot;
final ObjectId id;
PackedRefList(RefList<Ref> src, FileSnapshot s, ObjectId i) {
super(src);
snapshot = s;
id = i;
}
}
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);
}
@Override
public Map<String, Ref> getRefs(String prefix) throws IOException {
RefCache curr = readRefs();
RefList<DhtRef> packed = RefList.emptyList();
RefList<DhtRef> loose = curr.ids;
RefList.Builder<DhtRef> sym = new RefList.Builder<DhtRef>(curr.sym.size());
for (int idx = 0; idx < curr.sym.size(); idx++) {
DhtRef 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());
}
/**
* 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);
}
void removed(String refName) {
RefCache oldCache, newCache;
do {
oldCache = cache.get();
if (oldCache == null) return;
int p;
RefList<DhtRef> ids = oldCache.ids;
p = ids.find(refName);
if (0 <= p) ids = ids.remove(p);
RefList<DhtRef> sym = oldCache.sym;
p = sym.find(refName);
if (0 <= p) sym = sym.remove(p);
newCache = new RefCache(ids, sym, oldCache.hints);
} while (!cache.compareAndSet(oldCache, newCache));
}
private void scanOne(String name) {
LooseRef cur;
if (curIdx < curLoose.size()) {
do {
cur = curLoose.get(curIdx);
int cmp = RefComparator.compareTo(cur, name);
if (cmp < 0) {
// Reference is not loose anymore, its been deleted.
// Skip the name in the new result list.
if (newLoose == null) newLoose = curLoose.copy(curIdx);
curIdx++;
cur = null;
continue;
}
if (cmp > 0) // Newly discovered loose reference.
cur = null;
break;
} while (curIdx < curLoose.size());
} else cur = null; // Newly discovered loose reference.
LooseRef n;
try {
n = scanRef(cur, name);
} catch (IOException notValid) {
n = null;
}
if (n != null) {
if (cur != n && newLoose == null) newLoose = curLoose.copy(curIdx);
if (newLoose != null) newLoose.add(n);
if (n.isSymbolic()) symbolic.add(n);
} else if (cur != null) {
// Tragically, this file is no longer a loose reference.
// Kill our cached entry of it.
if (newLoose == null) newLoose = curLoose.copy(curIdx);
}
if (cur != null) curIdx++;
}
private void clearReferences() {
looseRefs.set(RefList.<LooseRef>emptyList());
packedRefs.set(PackedRefList.NO_PACKED_REFS);
}
/**
* 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);
}
/** @return number of references in this cache. */
public int size() {
return ids.size();
}
