// Copyright 2012 Google Inc. All Rights Reserved.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

package com.google.gitiles;

import static com.google.common.base.MoreObjects.toStringHelper;

import static com.google.common.base.Preconditions.checkArgument;

import static java.util.Objects.hash;

import static org.eclipse.jgit.lib.Constants.OBJ_BAD;

import static org.eclipse.jgit.lib.Constants.OBJ_TAG;

import com.google.common.annotations.VisibleForTesting;

import java.io.IOException;

import java.util.Objects;

import org.eclipse.jgit.errors.MissingObjectException;

import org.eclipse.jgit.lib.AbbreviatedObjectId;

import org.eclipse.jgit.lib.Constants;

import org.eclipse.jgit.lib.ObjectId;

import org.eclipse.jgit.revwalk.RevObject;

import org.eclipse.jgit.revwalk.RevWalk;

/**

* Object encapsulating a single revision as seen by Gitiles.

*

* <p>A single revision consists of a name, an ID, and a type. Name parsing is done once per request

* by {@link RevisionParser}.

*/

public class Revision {

/** Sentinel indicating a missing or empty revision. */

public static final Revision NULL = peeled("", ObjectId.zeroId(), OBJ_BAD);

/** Common default branch given to clients. */

public static final Revision HEAD = named("HEAD");

public static Revision normalizeParentExpressions(Revision rev) {

if (rev == null || (rev.name.indexOf('~') < 0 && rev.name.indexOf('^') < 0)) {

return rev;

}

return new Revision(rev.id.name(), rev.id, rev.type, rev.peeledId, rev.peeledType);

}

private final String name;

private final ObjectId id;

private final int type;

private final ObjectId peeledId;

private final int peeledType;

public static Revision peeled(String name, RevObject obj) {

return peeled(name, obj, obj.getType());

}

public static Revision unpeeled(String name, ObjectId id) {

return peeled(name, id, OBJ_BAD);

}

public static Revision named(String name) {

return peeled(name, null, OBJ_BAD);

}

public static Revision peel(String name, RevObject obj, RevWalk walk)

throws MissingObjectException, IOException {

RevObject peeled = walk.peel(obj);

return new Revision(name, obj, obj.getType(), peeled, peeled.getType());

}

private static Revision peeled(String name, ObjectId id, int type) {

checkArgument(type != OBJ_TAG, "expected non-tag for %s/%s", name, id);

return new Revision(name, id, type, id, type);

}

@VisibleForTesting

Revision(String name, ObjectId id, int type, ObjectId peeledId, int peeledType) {

this.name = name;

this.id = id;

this.type = type;

this.peeledId = peeledId;

this.peeledType = peeledType;

}

@SuppressWarnings("ReferenceEquality")

public static boolean isNull(Revision r) {

return r == NULL;

}

public String getName() {

return name;

}

public int getType() {

return type;

}

public ObjectId getId() {

return id;

}

public ObjectId getPeeledId() {

return peeledId;

}

public int getPeeledType() {

return peeledType;

}

public boolean matches(ObjectId other) {

return id.equals(other) || nameEqualsAbbreviated(other);

}

public boolean nameIsId() {

return nameEqualsAbbreviated(id);

}

@Override

public boolean equals(Object o) {

if (o instanceof Revision) {

Revision r = (Revision) o;

return Objects.equals(name, r.name)

&& Objects.equals(id, r.id)

&& type == r.type

&& Objects.equals(peeledId, r.peeledId)

&& peeledType == r.peeledType;

}

return false;

}

@Override

public int hashCode() {

return hash(name, id, type, peeledId, peeledType);

}

@Override

public String toString() {

return toStringHelper(this)

.omitNullValues()

.add("name", name)

.add("id", id != null ? id.getName() : null)

.add("type", type > 0 ? Constants.typeString(type) : null)

.add("peeledId", peeledId != null ? peeledId.getName() : null)

.add("peeledType", type > 0 ? Constants.typeString(peeledType) : null)

.toString();

}

private boolean nameEqualsAbbreviated(ObjectId other) {

return AbbreviatedObjectId.isId(name)

&& AbbreviatedObjectId.fromString(name).prefixCompare(other) == 0;

}

}