DirCacheBuilder: Speed up reading from trees
Recursively copying a tree into a DirCache is a bottleneck for some
algorithms like the in memory merge code in Gerrit Code Review. Drop
a layer down in the stack and use CanonicalTreeParser directly as the
addition logic only processes 1 tree at a time and does not need the
merge sorting feature (or overhead) of TreeWalk.
Combined with 761814fe9c ("DirCacheEntry: Speed up creation by
avoiding string cast") tree loading 38,900 entries nearly halves
in running time from 70ms to 36ms on some platforms.
Change-Id: If1490ca25de0679a71cf508f59b486f9cc816165
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheBuilder.java b/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheBuilder.java
index 73405cb..cfebe2d 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheBuilder.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheBuilder.java
@@ -44,6 +44,9 @@
package org.eclipse.jgit.dircache;
+import static org.eclipse.jgit.lib.FileMode.TYPE_MASK;
+import static org.eclipse.jgit.lib.FileMode.TYPE_TREE;
+
import java.io.IOException;
import java.text.MessageFormat;
import java.util.Arrays;
@@ -51,9 +54,7 @@
import org.eclipse.jgit.internal.JGitText;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.ObjectReader;
-import org.eclipse.jgit.treewalk.AbstractTreeIterator;
import org.eclipse.jgit.treewalk.CanonicalTreeParser;
-import org.eclipse.jgit.treewalk.TreeWalk;
/**
* Updates a {@link DirCache} by adding individual {@link DirCacheEntry}s.
@@ -163,27 +164,56 @@ public void keep(final int pos, int cnt) {
* @throws IOException
* a tree cannot be read to iterate through its entries.
*/
- public void addTree(final byte[] pathPrefix, final int stage,
- final ObjectReader reader, final AnyObjectId tree) throws IOException {
- final TreeWalk tw = new TreeWalk(reader);
- tw.addTree(new CanonicalTreeParser(pathPrefix, reader, tree
- .toObjectId()));
- tw.setRecursive(true);
- if (tw.next()) {
- final DirCacheEntry newEntry = toEntry(stage, tw);
- beforeAdd(newEntry);
- fastAdd(newEntry);
- while (tw.next())
- fastAdd(toEntry(stage, tw));
+ public void addTree(byte[] pathPrefix, int stage, ObjectReader reader,
+ AnyObjectId tree) throws IOException {
+ CanonicalTreeParser p = createTreeParser(pathPrefix, reader, tree);
+ while (!p.eof()) {
+ if (isTree(p)) {
+ p = enterTree(p, reader);
+ continue;
+ }
+
+ DirCacheEntry first = toEntry(stage, p);
+ beforeAdd(first);
+ fastAdd(first);
+ p = p.next();
+ break;
+ }
+
+ // Rest of tree entries are correctly sorted; use fastAdd().
+ while (!p.eof()) {
+ if (isTree(p)) {
+ p = enterTree(p, reader);
+ } else {
+ fastAdd(toEntry(stage, p));
+ p = p.next();
+ }
}
}
- private DirCacheEntry toEntry(final int stage, final TreeWalk tw) {
- final DirCacheEntry e = new DirCacheEntry(tw.getRawPath(), stage);
- final AbstractTreeIterator i;
+ private static CanonicalTreeParser createTreeParser(byte[] pathPrefix,
+ ObjectReader reader, AnyObjectId tree) throws IOException {
+ return new CanonicalTreeParser(pathPrefix, reader, tree);
+ }
- i = tw.getTree(0, AbstractTreeIterator.class);
- e.setFileMode(tw.getFileMode(0));
+ private static boolean isTree(CanonicalTreeParser p) {
+ return (p.getEntryRawMode() & TYPE_MASK) == TYPE_TREE;
+ }
+
+ private static CanonicalTreeParser enterTree(CanonicalTreeParser p,
+ ObjectReader reader) throws IOException {
+ p = p.createSubtreeIterator(reader);
+ return p.eof() ? p.next() : p;
+ }
+
+ private static DirCacheEntry toEntry(int stage, CanonicalTreeParser i) {
+ byte[] buf = i.getEntryPathBuffer();
+ int len = i.getEntryPathLength();
+ byte[] path = new byte[len];
+ System.arraycopy(buf, 0, path, 0, len);
+
+ DirCacheEntry e = new DirCacheEntry(path, stage);
+ e.setFileMode(i.getEntryRawMode());
e.setObjectIdFromRaw(i.idBuffer(), i.idOffset());
return e;
}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheEntry.java b/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheEntry.java
index 22c32ff..c8bc096 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheEntry.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheEntry.java
@@ -505,6 +505,10 @@ public void setFileMode(final FileMode mode) {
NB.encodeInt32(info, infoOffset + P_MODE, mode.getBits());
}
+ void setFileMode(int mode) {
+ NB.encodeInt32(info, infoOffset + P_MODE, mode);
+ }
+
/**
* Get the cached creation time of this file, in milliseconds.
*
