A 3-way merge (2 trees, and one common ancestor) is a specialized
type of merge which has a tighter restriction on its inputs. This
change refactors the merge API slightly to introduce this special
type, so we can add 3-way specific operations on the API.
Signed-off-by: Shawn O. Pearce <spearce@xxxxxxxxxxx>
---
This is a quick two patch series to teach JGit enough to enable an
application to perform simple cherry-picks, much like we already
support doing simple merges.
I'm already using it in Gerrit Code Review to enable projects to
have a more "format-patch | am" style workflow over a "push; pull"
style of workflow, if they choose to do that.
.../src/org/spearce/jgit/merge/MergeStrategy.java | 2 +-
.../src/org/spearce/jgit/merge/Merger.java | 2 +-
.../jgit/merge/StrategySimpleTwoWayInCore.java | 11 +--
.../spearce/jgit/merge/ThreeWayMergeStrategy.java | 46 ++++++++++
.../src/org/spearce/jgit/merge/ThreeWayMerger.java | 89 ++++++++++++++++++++
5 files changed, 141 insertions(+), 9 deletions(-)
create mode 100644 org.spearce.jgit/src/org/spearce/jgit/merge/ThreeWayMergeStrategy.java
create mode 100644 org.spearce.jgit/src/org/spearce/jgit/merge/ThreeWayMerger.java
diff --git a/org.spearce.jgit/src/org/spearce/jgit/merge/MergeStrategy.java b/org.spearce.jgit/src/org/spearce/jgit/merge/MergeStrategy.java
index 66bd86c..5439e5c 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/merge/MergeStrategy.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/merge/MergeStrategy.java
@@ -55,7 +55,7 @@
public static final MergeStrategy THEIRS = new StrategyOneSided("theirs", 1);
/** Simple strategy to merge paths, without simultaneous edits. */
- public static final MergeStrategy SIMPLE_TWO_WAY_IN_CORE = StrategySimpleTwoWayInCore.INSTANCE;
+ public static final ThreeWayMergeStrategy SIMPLE_TWO_WAY_IN_CORE = StrategySimpleTwoWayInCore.INSTANCE;
private static final HashMap<String, MergeStrategy> STRATEGIES = new HashMap<String, MergeStrategy>();
diff --git a/org.spearce.jgit/src/org/spearce/jgit/merge/Merger.java b/org.spearce.jgit/src/org/spearce/jgit/merge/Merger.java
index 100cc38..db3e329 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/merge/Merger.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/merge/Merger.java
@@ -122,7 +122,7 @@ public ObjectWriter getObjectWriter() {
* one or more sources could not be read, or outputs could not
* be written to the Repository.
*/
- public final boolean merge(final AnyObjectId[] tips) throws IOException {
+ public boolean merge(final AnyObjectId[] tips) throws IOException {
sourceObjects = new RevObject[tips.length];
for (int i = 0; i < tips.length; i++)
sourceObjects[i] = walk.parseAny(tips[i]);
diff --git a/org.spearce.jgit/src/org/spearce/jgit/merge/StrategySimpleTwoWayInCore.java b/org.spearce.jgit/src/org/spearce/jgit/merge/StrategySimpleTwoWayInCore.java
index 3ebe397..9807644 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/merge/StrategySimpleTwoWayInCore.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/merge/StrategySimpleTwoWayInCore.java
@@ -60,8 +60,8 @@
* trees will cause a merge conflict, as this strategy does not attempt to merge
* file contents.
*/
-public class StrategySimpleTwoWayInCore extends MergeStrategy {
- static final MergeStrategy INSTANCE = new StrategySimpleTwoWayInCore();
+public class StrategySimpleTwoWayInCore extends ThreeWayMergeStrategy {
+ static final ThreeWayMergeStrategy INSTANCE = new StrategySimpleTwoWayInCore();
/** Create a new instance of the strategy. */
protected StrategySimpleTwoWayInCore() {
@@ -74,11 +74,11 @@ public String getName() {
}
@Override
- public Merger newMerger(final Repository db) {
+ public ThreeWayMerger newMerger(final Repository db) {
return new InCoreMerger(db);
}
- private static class InCoreMerger extends Merger {
+ private static class InCoreMerger extends ThreeWayMerger {
private static final int T_BASE = 0;
private static final int T_OURS = 1;
@@ -101,9 +101,6 @@ InCoreMerger(final Repository local) {
@Override
protected boolean mergeImpl() throws IOException {
- if (sourceTrees.length != 2)
- return false;
-
tw.reset();
tw.addTree(mergeBase(0, 1));
tw.addTree(sourceTrees[0]);
diff --git a/org.spearce.jgit/src/org/spearce/jgit/merge/ThreeWayMergeStrategy.java b/org.spearce.jgit/src/org/spearce/jgit/merge/ThreeWayMergeStrategy.java
new file mode 100644
index 0000000..848e80b
--- /dev/null
+++ b/org.spearce.jgit/src/org/spearce/jgit/merge/ThreeWayMergeStrategy.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2009, Google Inc.
+ *
+ * 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 Git Development Community 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.spearce.jgit.merge;
+
+import org.spearce.jgit.lib.Repository;
+
+/** A merge strategy to merge 2 trees, using a common base ancestor tree. */
+public abstract class ThreeWayMergeStrategy extends MergeStrategy {
+ @Override
+ public abstract ThreeWayMerger newMerger(Repository db);
+}
diff --git a/org.spearce.jgit/src/org/spearce/jgit/merge/ThreeWayMerger.java b/org.spearce.jgit/src/org/spearce/jgit/merge/ThreeWayMerger.java
new file mode 100644
index 0000000..9d1621d
--- /dev/null
+++ b/org.spearce.jgit/src/org/spearce/jgit/merge/ThreeWayMerger.java
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2009, Google Inc.
+ *
+ * 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 Git Development Community 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.spearce.jgit.merge;
+
+import java.io.IOException;
+
+import org.spearce.jgit.errors.IncorrectObjectTypeException;
+import org.spearce.jgit.lib.AnyObjectId;
+import org.spearce.jgit.lib.Repository;
+
+/** A merge of 2 trees, using a common base ancestor tree. */
+public abstract class ThreeWayMerger extends Merger {
+ /**
+ * Create a new merge instance for a repository.
+ *
+ * @param local
+ * the repository this merger will read and write data on.
+ */
+ protected ThreeWayMerger(final Repository local) {
+ super(local);
+ }
+
+ /**
+ * Merge together two tree-ish objects.
+ * <p>
+ * Any tree-ish may be supplied as inputs. Commits and/or tags pointing at
+ * trees or commits may be passed as input objects.
+ *
+ * @param a
+ * source tree to be combined together.
+ * @param b
+ * source tree to be combined together.
+ * @return true if the merge was completed without conflicts; false if the
+ * merge strategy cannot handle this merge or there were conflicts
+ * preventing it from automatically resolving all paths.
+ * @throws IncorrectObjectTypeException
+ * one of the input objects is not a commit, but the strategy
+ * requires it to be a commit.
+ * @throws IOException
+ * one or more sources could not be read, or outputs could not
+ * be written to the Repository.
+ */
+ public boolean merge(final AnyObjectId a, final AnyObjectId b)
+ throws IOException {
+ return merge(new AnyObjectId[] { a, b });
+ }
+
+ @Override
+ public boolean merge(final AnyObjectId[] tips) throws IOException {
+ if (tips.length != 2)
+ return false;
+ return super.merge(tips);
+ }
+}
--
1.6.2.1.471.g682837
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