| /* |
| * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> |
| * 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 java.io.IOException; |
| |
| import org.eclipse.jgit.errors.IncorrectObjectTypeException; |
| import org.eclipse.jgit.errors.MissingObjectException; |
| |
| /** |
| * Replaces a RevCommit's parents until not colored with REWRITE. |
| * <p> |
| * Before a RevCommit is returned to the caller its parents are updated to |
| * create a dense DAG. Instead of reporting the actual parents as recorded when |
| * the commit was created the returned commit will reflect the next closest |
| * 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 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 |
| * {@link RevWalk#REWRITE} colored commits and come up with a simplification |
| * that makes the DAG dense. Not fully buffering the commits first would cause |
| * this loop to abort early, due to commits not being parsed and colored |
| * correctly. |
| * |
| * @see TreeRevFilter |
| */ |
| class RewriteGenerator extends Generator { |
| private static final int REWRITE = RevWalk.REWRITE; |
| |
| /** For {@link #cleanup(RevCommit[])} to remove duplicate parents. */ |
| private static final int DUPLICATE = RevWalk.TEMP_MARK; |
| |
| private final Generator source; |
| |
| RewriteGenerator(Generator s) { |
| super(s.firstParent); |
| source = s; |
| } |
| |
| @Override |
| void shareFreeList(BlockRevQueue q) { |
| source.shareFreeList(q); |
| } |
| |
| @Override |
| int outputType() { |
| return source.outputType() & ~NEEDS_REWRITE; |
| } |
| |
| @Override |
| RevCommit next() throws MissingObjectException, |
| IncorrectObjectTypeException, IOException { |
| final RevCommit c = source.next(); |
| if (c == null) { |
| return null; |
| } |
| boolean rewrote = false; |
| final RevCommit[] pList = c.parents; |
| final int nParents = pList.length; |
| for (int i = 0; i < nParents; i++) { |
| final RevCommit oldp = pList[i]; |
| final RevCommit newp = rewrite(oldp); |
| if (firstParent) { |
| if (newp == null) { |
| c.parents = RevCommit.NO_PARENTS; |
| } else { |
| c.parents = new RevCommit[] { newp }; |
| } |
| return c; |
| } |
| if (oldp != newp) { |
| pList[i] = newp; |
| rewrote = true; |
| } |
| } |
| if (rewrote) { |
| c.parents = cleanup(pList); |
| } |
| return c; |
| } |
| |
| private RevCommit rewrite(RevCommit p) { |
| for (;;) { |
| final RevCommit[] pList = p.parents; |
| if (pList.length > 1) { |
| // This parent is a merge, so keep it. |
| // |
| return p; |
| } |
| |
| if ((p.flags & RevWalk.UNINTERESTING) != 0) { |
| // Retain uninteresting parents. They show where the |
| // DAG was cut off because it wasn't interesting. |
| // |
| return p; |
| } |
| |
| if ((p.flags & REWRITE) == 0) { |
| // This parent was not eligible for rewriting. We |
| // need to keep it in the DAG. |
| // |
| return p; |
| } |
| |
| if (pList.length == 0) { |
| // We can't go back any further, other than to |
| // just delete the parent entirely. |
| // |
| return null; |
| } |
| |
| p = pList[0]; |
| } |
| } |
| |
| private RevCommit[] cleanup(RevCommit[] oldList) { |
| // Remove any duplicate parents caused due to rewrites (e.g. a merge |
| // with two sides that both simplified back into the merge base). |
| // We also may have deleted a parent by marking it null. |
| // |
| int newCnt = 0; |
| for (int o = 0; o < oldList.length; o++) { |
| final RevCommit p = oldList[o]; |
| if (p == null) |
| continue; |
| if ((p.flags & DUPLICATE) != 0) { |
| oldList[o] = null; |
| continue; |
| } |
| p.flags |= DUPLICATE; |
| newCnt++; |
| } |
| |
| if (newCnt == oldList.length) { |
| for (RevCommit p : oldList) |
| p.flags &= ~DUPLICATE; |
| return oldList; |
| } |
| |
| final RevCommit[] newList = new RevCommit[newCnt]; |
| newCnt = 0; |
| for (RevCommit p : oldList) { |
| if (p != null) { |
| newList[newCnt++] = p; |
| p.flags &= ~DUPLICATE; |
| } |
| } |
| |
| return newList; |
| } |
| } |