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- /*
- * Copyright (C) 2009, Google Inc.
- * 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;
- import org.eclipse.jgit.errors.StopWalkException;
- import org.eclipse.jgit.lib.ObjectId;
- import org.eclipse.jgit.revwalk.filter.RevFilter;
-
- /**
- * Default (and first pass) RevCommit Generator implementation for RevWalk.
- * <p>
- * This generator starts from a set of one or more commits and process them in
- * descending (newest to oldest) commit time order. Commits automatically cause
- * their parents to be enqueued for further processing, allowing the entire
- * commit graph to be walked. A {@link RevFilter} may be used to select a subset
- * of the commits and return them to the caller.
- */
- class PendingGenerator extends Generator {
- private static final int PARSED = RevWalk.PARSED;
-
- private static final int SEEN = RevWalk.SEEN;
-
- private static final int UNINTERESTING = RevWalk.UNINTERESTING;
-
- /**
- * Number of additional commits to scan after we think we are done.
- * <p>
- * This small buffer of commits is scanned to ensure we didn't miss anything
- * as a result of clock skew when the commits were made. We need to set our
- * constant to 1 additional commit due to the use of a pre-increment
- * operator when accessing the value.
- */
- static final int OVER_SCAN = 5 + 1;
-
- /** A commit near the end of time, to initialize {@link #last} with. */
- private static final RevCommit INIT_LAST;
-
- static {
- INIT_LAST = new RevCommit(ObjectId.zeroId());
- INIT_LAST.commitTime = Integer.MAX_VALUE;
- }
-
- private final RevWalk walker;
-
- private final DateRevQueue pending;
-
- private final RevFilter filter;
-
- private final int output;
-
- /** Last commit produced to the caller from {@link #next()}. */
- private RevCommit last = INIT_LAST;
-
- /**
- * Number of commits we have remaining in our over-scan allotment.
- * <p>
- * Only relevant if there are {@link #UNINTERESTING} commits in the
- * {@link #pending} queue.
- */
- private int overScan = OVER_SCAN;
-
- boolean canDispose;
-
- PendingGenerator(final RevWalk w, final DateRevQueue p,
- final RevFilter f, final int out) {
- walker = w;
- pending = p;
- filter = f;
- output = out;
- canDispose = true;
- }
-
- @Override
- int outputType() {
- return output | SORT_COMMIT_TIME_DESC;
- }
-
- @Override
- RevCommit next() throws MissingObjectException,
- IncorrectObjectTypeException, IOException {
- try {
- for (;;) {
- final RevCommit c = pending.next();
- if (c == null) {
- walker.reader.walkAdviceEnd();
- if (!(walker instanceof ObjectWalk))
- walker.reader.release();
- return null;
- }
-
- final boolean produce;
- if ((c.flags & UNINTERESTING) != 0)
- produce = false;
- else {
- c.parseBody(walker);
- produce = filter.include(walker, c);
- }
-
- for (final RevCommit p : c.parents) {
- if ((p.flags & SEEN) != 0)
- continue;
- if ((p.flags & PARSED) == 0)
- p.parseHeaders(walker);
- p.flags |= SEEN;
- pending.add(p);
- }
- walker.carryFlagsImpl(c);
-
- if ((c.flags & UNINTERESTING) != 0) {
- if (pending.everbodyHasFlag(UNINTERESTING)) {
- final RevCommit n = pending.peek();
- if (n != null && n.commitTime >= last.commitTime) {
- // This is too close to call. The next commit we
- // would pop is dated after the last one produced.
- // We have to keep going to ensure that we carry
- // flags as much as necessary.
- //
- overScan = OVER_SCAN;
- } else if (--overScan == 0)
- throw StopWalkException.INSTANCE;
- } else {
- overScan = OVER_SCAN;
- }
- if (canDispose)
- c.disposeBody();
- continue;
- }
-
- if (produce)
- return last = c;
- else if (canDispose)
- c.disposeBody();
- }
- } catch (StopWalkException swe) {
- walker.reader.walkAdviceEnd();
- walker.reader.release();
- pending.clear();
- return null;
- }
- }
- }
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