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- /*
- * 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.util;
-
- import java.util.AbstractMap;
- import java.util.AbstractSet;
- import java.util.Iterator;
- import java.util.Map;
- import java.util.NoSuchElementException;
- import java.util.Set;
-
- import org.eclipse.jgit.lib.AnyObjectId;
- import org.eclipse.jgit.lib.ObjectId;
- import org.eclipse.jgit.lib.Ref;
- import org.eclipse.jgit.lib.RefComparator;
-
- /**
- * Specialized Map to present a {@code RefDatabase} namespace.
- * <p>
- * Although not declared as a {@link java.util.SortedMap}, iterators from this
- * map's projections always return references in {@link RefComparator} ordering.
- * The map's internal representation is a sorted array of {@link Ref} objects,
- * which means lookup and replacement is O(log N), while insertion and removal
- * can be as expensive as O(N + log N) while the list expands or contracts.
- * Since this is not a general map implementation, all entries must be keyed by
- * the reference name.
- * <p>
- * This class is really intended as a helper for {@code RefDatabase}, which
- * needs to perform a merge-join of three sorted {@link RefList}s in order to
- * present the unified namespace of the packed-refs file, the loose refs/
- * directory tree, and the resolved form of any symbolic references.
- */
- public class RefMap extends AbstractMap<String, Ref> {
- /**
- * Prefix denoting the reference subspace this map contains.
- * <p>
- * All reference names in this map must start with this prefix. If the
- * prefix is not the empty string, it must end with a '/'.
- */
- private final String prefix;
-
- /** Immutable collection of the packed references at construction time. */
- private RefList<Ref> packed;
-
- /**
- * Immutable collection of the loose references at construction time.
- * <p>
- * If an entry appears here and in {@link #packed}, this entry must take
- * precedence, as its more current. Symbolic references in this collection
- * are typically unresolved, so they only tell us who their target is, but
- * not the current value of the target.
- */
- private RefList<Ref> loose;
-
- /**
- * Immutable collection of resolved symbolic references.
- * <p>
- * This collection contains only the symbolic references we were able to
- * resolve at map construction time. Other loose references must be read
- * from {@link #loose}. Every entry in this list must be matched by an entry
- * in {@code loose}, otherwise it might be omitted by the map.
- */
- private RefList<Ref> resolved;
-
- private int size;
-
- private boolean sizeIsValid;
-
- private Set<Entry<String, Ref>> entrySet;
-
- /** Construct an empty map with a small initial capacity. */
- public RefMap() {
- prefix = "";
- packed = RefList.emptyList();
- loose = RefList.emptyList();
- resolved = RefList.emptyList();
- }
-
- /**
- * Construct a map to merge 3 collections together.
- *
- * @param prefix
- * prefix used to slice the lists down. Only references whose
- * names start with this prefix will appear to reside in the map.
- * Must not be null, use {@code ""} (the empty string) to select
- * all list items.
- * @param packed
- * items from the packed reference list, this is the last list
- * searched.
- * @param loose
- * items from the loose reference list, this list overrides
- * {@code packed} if a name appears in both.
- * @param resolved
- * resolved symbolic references. This list overrides the prior
- * list {@code loose}, if an item appears in both. Items in this
- * list <b>must</b> also appear in {@code loose}.
- */
- public RefMap(String prefix, RefList<Ref> packed, RefList<Ref> loose,
- RefList<Ref> resolved) {
- this.prefix = prefix;
- this.packed = packed;
- this.loose = loose;
- this.resolved = resolved;
- }
-
- @Override
- public boolean containsKey(Object name) {
- return get(name) != null;
- }
-
- @Override
- public Ref get(Object key) {
- String name = toRefName((String) key);
- Ref ref = resolved.get(name);
- if (ref == null)
- ref = loose.get(name);
- if (ref == null)
- ref = packed.get(name);
- return ref;
- }
-
- @Override
- public Ref put(final String keyName, Ref value) {
- String name = toRefName(keyName);
-
- if (!name.equals(value.getName()))
- throw new IllegalArgumentException();
-
- if (!resolved.isEmpty()) {
- // Collapse the resolved list into the loose list so we
- // can discard it and stop joining the two together.
- for (Ref ref : resolved)
- loose = loose.put(ref);
- resolved = RefList.emptyList();
- }
-
- int idx = loose.find(name);
- if (0 <= idx) {
- Ref prior = loose.get(name);
- loose = loose.set(idx, value);
- return prior;
- } else {
- Ref prior = get(keyName);
- loose = loose.add(idx, value);
- sizeIsValid = false;
- return prior;
- }
- }
-
- @Override
- public Ref remove(Object key) {
- String name = toRefName((String) key);
- Ref res = null;
- int idx;
- if (0 <= (idx = packed.find(name))) {
- res = packed.get(name);
- packed = packed.remove(idx);
- sizeIsValid = false;
- }
- if (0 <= (idx = loose.find(name))) {
- res = loose.get(name);
- loose = loose.remove(idx);
- sizeIsValid = false;
- }
- if (0 <= (idx = resolved.find(name))) {
- res = resolved.get(name);
- resolved = resolved.remove(idx);
- sizeIsValid = false;
- }
- return res;
- }
-
- @Override
- public boolean isEmpty() {
- return entrySet().isEmpty();
- }
-
- @Override
- public Set<Entry<String, Ref>> entrySet() {
- if (entrySet == null) {
- entrySet = new AbstractSet<Entry<String, Ref>>() {
- @Override
- public Iterator<Entry<String, Ref>> iterator() {
- return new SetIterator();
- }
-
- @Override
- public int size() {
- if (!sizeIsValid) {
- size = 0;
- Iterator<?> i = entrySet().iterator();
- for (; i.hasNext(); i.next())
- size++;
- sizeIsValid = true;
- }
- return size;
- }
-
- @Override
- public boolean isEmpty() {
- if (sizeIsValid)
- return 0 == size;
- return !iterator().hasNext();
- }
-
- @Override
- public void clear() {
- packed = RefList.emptyList();
- loose = RefList.emptyList();
- resolved = RefList.emptyList();
- size = 0;
- sizeIsValid = true;
- }
- };
- }
- return entrySet;
- }
-
- @Override
- public String toString() {
- StringBuilder r = new StringBuilder();
- boolean first = true;
- r.append('[');
- for (Ref ref : values()) {
- if (first)
- first = false;
- else
- r.append(", ");
- r.append(ref);
- }
- r.append(']');
- return r.toString();
- }
-
- private String toRefName(String name) {
- if (0 < prefix.length())
- name = prefix + name;
- return name;
- }
-
- private String toMapKey(Ref ref) {
- String name = ref.getName();
- if (0 < prefix.length())
- name = name.substring(prefix.length());
- return name;
- }
-
- private class SetIterator implements Iterator<Entry<String, Ref>> {
- private int packedIdx;
-
- private int looseIdx;
-
- private int resolvedIdx;
-
- private Entry<String, Ref> next;
-
- SetIterator() {
- if (0 < prefix.length()) {
- packedIdx = -(packed.find(prefix) + 1);
- looseIdx = -(loose.find(prefix) + 1);
- resolvedIdx = -(resolved.find(prefix) + 1);
- }
- }
-
- public boolean hasNext() {
- if (next == null)
- next = peek();
- return next != null;
- }
-
- public Entry<String, Ref> next() {
- if (hasNext()) {
- Entry<String, Ref> r = next;
- next = peek();
- return r;
- }
- throw new NoSuchElementException();
- }
-
- public Entry<String, Ref> peek() {
- if (packedIdx < packed.size() && looseIdx < loose.size()) {
- Ref p = packed.get(packedIdx);
- Ref l = loose.get(looseIdx);
- int cmp = RefComparator.compareTo(p, l);
- if (cmp < 0) {
- packedIdx++;
- return toEntry(p);
- }
-
- if (cmp == 0)
- packedIdx++;
- looseIdx++;
- return toEntry(resolveLoose(l));
- }
-
- if (looseIdx < loose.size())
- return toEntry(resolveLoose(loose.get(looseIdx++)));
- if (packedIdx < packed.size())
- return toEntry(packed.get(packedIdx++));
- return null;
- }
-
- private Ref resolveLoose(final Ref l) {
- if (resolvedIdx < resolved.size()) {
- Ref r = resolved.get(resolvedIdx);
- int cmp = RefComparator.compareTo(l, r);
- if (cmp == 0) {
- resolvedIdx++;
- return r;
- } else if (cmp > 0) {
- // WTF, we have a symbolic entry but no match
- // in the loose collection. That's an error.
- throw new IllegalStateException();
- }
- }
- return l;
- }
-
- private Ent toEntry(Ref p) {
- if (p.getName().startsWith(prefix))
- return new Ent(p);
- packedIdx = packed.size();
- looseIdx = loose.size();
- resolvedIdx = resolved.size();
- return null;
- }
-
- public void remove() {
- throw new UnsupportedOperationException();
- }
- }
-
- private class Ent implements Entry<String, Ref> {
- private Ref ref;
-
- Ent(Ref ref) {
- this.ref = ref;
- }
-
- public String getKey() {
- return toMapKey(ref);
- }
-
- public Ref getValue() {
- return ref;
- }
-
- public Ref setValue(Ref value) {
- Ref prior = put(getKey(), value);
- ref = value;
- return prior;
- }
-
- @Override
- public int hashCode() {
- return getKey().hashCode();
- }
-
- @Override
- public boolean equals(Object obj) {
- if (obj instanceof Map.Entry) {
- final Object key = ((Map.Entry) obj).getKey();
- final Object val = ((Map.Entry) obj).getValue();
- if (key instanceof String && val instanceof Ref) {
- final Ref r = (Ref) val;
- if (r.getName().equals(ref.getName())) {
- final ObjectId a = r.getObjectId();
- final ObjectId b = ref.getObjectId();
- if (a != null && b != null && AnyObjectId.equals(a, b))
- return true;
- }
- }
- }
- return false;
- }
-
- @Override
- public String toString() {
- return ref.toString();
- }
- }
- }
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