| /* |
| * Copyright (C) 2009, Google Inc. |
| * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org> and others |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Distribution License v. 1.0 which is available at |
| * https://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| |
| 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) { |
| super(w.isFirstParent()); |
| 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) { |
| return null; |
| } |
| |
| final boolean produce; |
| if ((c.flags & UNINTERESTING) != 0) |
| produce = false; |
| else { |
| if (filter.requiresCommitBody()) |
| c.parseBody(walker); |
| produce = filter.include(walker, c); |
| } |
| |
| int parentCount = c.getParentCount(); |
| for (int i = 0; i < parentCount; i++) { |
| RevCommit p = c.getParent(i); |
| // If the commit is uninteresting, don't try to prune |
| // parents because we want the maximal uninteresting set. |
| if (firstParent && i > 0 && (c.flags & UNINTERESTING) == 0) { |
| continue; |
| } |
| 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) { |
| pending.clear(); |
| return null; |
| } |
| } |
| } |