Rename RewriteTreeFilter to TreeRevFilter and make it public

The current behavior of passing a TreeFilter to RevWalk has limited
usefulness, since the RevFilter derived from the TreeFilter is always
ANDed together with any other RevFilters. It is also tied fairly
tightly to the parent rewriting mechanism.

Make TreeRevFilter a generic RevFilter that matches modified paths
against any TreeFilter. This allows for more complex logic like
(modified this path OR authored by this person).

Leave the rewrite flag logic in this class, since it's closely tied to
the parent comparison code, but hidden behind a protected constructor.

Change-Id: Ia72ef591a99415e6f340c5f64583a49c91f1b82f

org.eclipse.jgit.test/tst/org/eclipse/jgit/revwalk/TreeRevFilterTest.java

@@ -0,0 +1,188 @@
+/*
+ * Copyright (C) 2014, 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.revwalk;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+import java.util.Collections;
+
+import org.eclipse.jgit.revwalk.filter.OrRevFilter;
+import org.eclipse.jgit.revwalk.filter.RevFilter;
+import org.eclipse.jgit.revwalk.filter.SkipRevFilter;
+import org.eclipse.jgit.treewalk.filter.AndTreeFilter;
+import org.eclipse.jgit.treewalk.filter.PathFilterGroup;
+import org.eclipse.jgit.treewalk.filter.TreeFilter;
+import org.junit.Test;
+
+public class TreeRevFilterTest extends RevWalkTestCase {
+	private RevFilter treeRevFilter(String path) {
+		return new TreeRevFilter(rw, treeFilter(path));
+	}
+
+	private static TreeFilter treeFilter(String path) {
+		return AndTreeFilter.create(
+				PathFilterGroup.createFromStrings(Collections.singleton(path)),
+				TreeFilter.ANY_DIFF);
+	}
+
+	@Test
+	public void testStringOfPearls_FilePath1()
+			throws Exception {
+		RevCommit a = commit(tree(file("d/f", blob("a"))));
+		RevCommit b = commit(tree(file("d/f", blob("a"))), a);
+		RevCommit c = commit(tree(file("d/f", blob("b"))), b);
+		rw.setRevFilter(treeRevFilter("d/f"));
+		markStart(c);
+
+		assertCommit(c, rw.next());
+		assertEquals(1, c.getParentCount());
+		assertCommit(b, c.getParent(0));
+
+		assertCommit(a, rw.next()); // b was skipped
+		assertEquals(0, a.getParentCount());
+		assertNull(rw.next());
+	}
+
+	@Test
+	public void testStringOfPearls_FilePath2() throws Exception {
+		RevCommit a = commit(tree(file("d/f", blob("a"))));
+		RevCommit b = commit(tree(file("d/f", blob("a"))), a);
+		RevCommit c = commit(tree(file("d/f", blob("b"))), b);
+		RevCommit d = commit(tree(file("d/f", blob("b"))), c);
+		rw.setRevFilter(treeRevFilter("d/f"));
+		markStart(d);
+
+		// d was skipped
+		assertCommit(c, rw.next());
+		assertEquals(1, c.getParentCount());
+		assertCommit(b, c.getParent(0));
+
+		// b was skipped
+		assertCommit(a, rw.next());
+		assertEquals(0, a.getParentCount());
+		assertNull(rw.next());
+	}
+
+	@Test
+	public void testStringOfPearls_DirPath2() throws Exception {
+		RevCommit a = commit(tree(file("d/f", blob("a"))));
+		RevCommit b = commit(tree(file("d/f", blob("a"))), a);
+		RevCommit c = commit(tree(file("d/f", blob("b"))), b);
+		RevCommit d = commit(tree(file("d/f", blob("b"))), c);
+		rw.setRevFilter(treeRevFilter("d"));
+		markStart(d);
+
+		// d was skipped
+		assertCommit(c, rw.next());
+		assertEquals(1, c.getParentCount());
+		assertCommit(b, c.getParent(0));
+
+		// b was skipped
+		assertCommit(a, rw.next());
+		assertEquals(0, a.getParentCount());
+		assertNull(rw.next());
+	}
+
+	@Test
+	public void testStringOfPearls_FilePath3() throws Exception {
+		RevCommit a = commit(tree(file("d/f", blob("a"))));
+		RevCommit b = commit(tree(file("d/f", blob("a"))), a);
+		RevCommit c = commit(tree(file("d/f", blob("b"))), b);
+		RevCommit d = commit(tree(file("d/f", blob("b"))), c);
+		RevCommit e = commit(tree(file("d/f", blob("b"))), d);
+		RevCommit f = commit(tree(file("d/f", blob("b"))), e);
+		RevCommit g = commit(tree(file("d/f", blob("b"))), f);
+		RevCommit h = commit(tree(file("d/f", blob("b"))), g);
+		RevCommit i = commit(tree(file("d/f", blob("c"))), h);
+		rw.setRevFilter(treeRevFilter("d/f"));
+		markStart(i);
+
+		assertCommit(i, rw.next());
+		assertEquals(1, i.getParentCount());
+		assertCommit(h, i.getParent(0));
+
+		// h..d was skipped
+		assertCommit(c, rw.next());
+		assertEquals(1, c.getParentCount());
+		assertCommit(b, c.getParent(0));
+
+		// b was skipped
+		assertCommit(a, rw.next());
+		assertEquals(0, a.getParentCount());
+		assertNull(rw.next());
+	}
+
+	@Test
+	public void testPathFilterOrOtherFilter() throws Exception {
+		RevFilter pathFilter = treeRevFilter("d/f");
+		RevFilter skipFilter = SkipRevFilter.create(1);
+		RevFilter orFilter = OrRevFilter.create(skipFilter, pathFilter);
+
+		RevCommit a = parseBody(commit(5, tree(file("d/f", blob("a")))));
+		RevCommit b = parseBody(commit(5, tree(file("d/f", blob("a"))), a));
+		RevCommit c = parseBody(commit(5, tree(file("d/f", blob("b"))), b));
+
+		// Path filter matches c, a.
+		rw.setRevFilter(pathFilter);
+		markStart(c);
+		assertCommit(c, rw.next());
+		assertCommit(a, rw.next());
+
+		// Skip filter matches b, a.
+		rw.reset();
+		rw.setRevFilter(skipFilter);
+		markStart(c);
+		assertCommit(b, rw.next());
+		assertCommit(a, rw.next());
+
+		// (Path OR Skip) matches c, b, a.
+		rw.reset();
+		rw.setRevFilter(orFilter);
+		markStart(c);
+		assertCommit(c, rw.next());
+		assertCommit(b, rw.next());
+		assertCommit(a, rw.next());
+	}
+}

org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RewriteGenerator.java

@@ -57,7 +57,7 @@ import org.eclipse.jgit.errors.MissingObjectException;
  * commit that matched the revision walker's filters.
  * <p>
  * This generator is the second phase of a path limited revision walk and
- * assumes it is receiving RevCommits from {@link RewriteTreeFilter},
+ * assumes it is receiving RevCommits from {@link TreeRevFilter},
  * after they have been fully buffered by {@link AbstractRevQueue}. The full
  * buffering is necessary to allow the simple loop used within our own
  * {@link #rewrite(RevCommit)} to pull completely through a strand of
@@ -66,7 +66,7 @@ import org.eclipse.jgit.errors.MissingObjectException;
  * this loop to abort early, due to commits not being parsed and colored
  * correctly.
  *
- * @see RewriteTreeFilter
+ * @see TreeRevFilter
  */
 class RewriteGenerator extends Generator {
 	private static final int REWRITE = RevWalk.REWRITE;

org.eclipse.jgit/src/org/eclipse/jgit/revwalk/StartGenerator.java

@@ -127,7 +127,8 @@ class StartGenerator extends Generator {
 		else
 			pending = new DateRevQueue(q);
 		if (tf != TreeFilter.ALL) {
-			rf = AndRevFilter.create(new RewriteTreeFilter(w, tf), rf);
+			rf = AndRevFilter.create(
+					new TreeRevFilter(w, tf, RevWalk.REWRITE), rf);
 			pendingOutputType |= HAS_REWRITE;
 			if (w.getRewriteParents())
 				pendingOutputType |= NEEDS_REWRITE;

org.eclipse.jgit/src/org/eclipse/jgit/revwalk/TreeRevFilter.java

@@ -60,32 +60,65 @@ import org.eclipse.jgit.treewalk.TreeWalk;
 import org.eclipse.jgit.treewalk.filter.TreeFilter;
 
 /**
- * First phase of a path limited revision walk.
+ * Filter applying a {@link TreeFilter} against changed paths in each commit.
- * <p>
- * This filter is ANDed to evaluate after all other filters and ties the
- * configured {@link TreeFilter} into the revision walking process.
  * <p>
  * Each commit is differenced concurrently against all of its parents to look
- * for tree entries that are interesting to the TreeFilter. If none are found
+ * for tree entries that are interesting to the {@link TreeFilter}.
- * the commit is colored with {@link RevWalk#REWRITE}, allowing a later pass
- * implemented by {@link RewriteGenerator} to remove those colored commits from
- * the DAG.
  *
- * @see RewriteGenerator
+ * @since 3.5
  */
-class RewriteTreeFilter extends RevFilter {
+public class TreeRevFilter extends RevFilter {
 	private static final int PARSED = RevWalk.PARSED;
 
 	private static final int UNINTERESTING = RevWalk.UNINTERESTING;
 
-	private static final int REWRITE = RevWalk.REWRITE;
+	private final int rewriteFlag;
-
 	private final TreeWalk pathFilter;
 
-	RewriteTreeFilter(final RevWalk walker, final TreeFilter t) {
+	/**
+	 * Create a {@link RevFilter} from a {@link TreeFilter}.
+	 *
+	 * @param walker
+	 *            walker used for reading trees.
+	 * @param t
+	 *            filter to compare against any changed paths in each commit. If a
+	 *            {@link FollowFilter}, will be replaced with a new filter
+	 *            following new paths after a rename.
+	 * @since 3.5
+	 */
+	public TreeRevFilter(final RevWalk walker, final TreeFilter t) {
+		this(walker, t, 0);
+	}
+
+
+	/**
+	 * Create a filter for the first phase of a parent-rewriting limited revision
+	 * walk.
+	 * <p>
+	 * This filter is ANDed to evaluate before all other filters and ties the
+	 * configured {@link TreeFilter} into the revision walking process.
+	 * <p>
+	 * If no interesting tree entries are found the commit is colored with
+	 * {@code rewriteFlag}, allowing a later pass implemented by
+	 * {@link RewriteGenerator} to remove those colored commits from the DAG.
+	 *
+	 * @see RewriteGenerator
+	 *
+	 * @param walker
+	 *            walker used for reading trees.
+	 * @param t
+	 *            filter to compare against any changed paths in each commit. If a
+	 *            {@link FollowFilter}, will be replaced with a new filter
+	 *            following new paths after a rename.
+	 * @param rewriteFlag
+	 *            flag to color commits to be removed from the simplified DAT.
+	 */
+	TreeRevFilter(final RevWalk walker, final TreeFilter t,
+			final int rewriteFlag) {
 		pathFilter = new TreeWalk(walker.reader);
 		pathFilter.setFilter(t);
 		pathFilter.setRecursive(t.shouldBeRecursive());
+		this.rewriteFlag = rewriteFlag;
 	}
 
 	@Override
@@ -128,7 +161,7 @@ class RewriteTreeFilter extends RevFilter {
 				// No changes, so our tree is effectively the same as
 				// our parent tree. We pass the buck to our parent.
 				//
-				c.flags |= REWRITE;
+				c.flags |= rewriteFlag;
 				return false;
 			} else {
 				// We have interesting items, but neither of the special
@@ -149,7 +182,7 @@ class RewriteTreeFilter extends RevFilter {
 			//
 			if (tw.next())
 				return true;
-			c.flags |= REWRITE;
+			c.flags |= rewriteFlag;
 			return false;
 		}
 
@@ -192,7 +225,7 @@ class RewriteTreeFilter extends RevFilter {
 					continue;
 				}
 
-				c.flags |= REWRITE;
+				c.flags |= rewriteFlag;
 				c.parents = new RevCommit[] { p };
 				return false;
 			}
@@ -223,7 +256,7 @@ class RewriteTreeFilter extends RevFilter {
 		// as they are and allow those parents to flow into pending
 		// for further scanning.
 		//
-		c.flags |= REWRITE;
+		c.flags |= rewriteFlag;
 		return false;
 	}