When we are appending onto a thin pack we need to make sure the whole
object we wrote into the pack is what is there when we re-read the
pack to compute the final footer.
Nicolas Pitre pointed out the need to perform this sort of compare
in C Git. We missed it in my first round of index-pack improvements.
We also now take advantage of "roughly" block aligned reads during
the fixup operation. 4k is a popular filesystem block size and by
arranging the code a little differently we can always perform reads
on 4k alignments within the file. This should make it easier for
the OS to move data to us.
Signed-off-by: Shawn O. Pearce <spearce@xxxxxxxxxxx>
---
.../src/org/spearce/jgit/transport/IndexPack.java | 47 ++++++++++++++-----
1 files changed, 34 insertions(+), 13 deletions(-)
diff --git a/org.spearce.jgit/src/org/spearce/jgit/transport/IndexPack.java b/org.spearce.jgit/src/org/spearce/jgit/transport/IndexPack.java
index 7b1f7ee..d8e6548 100644
--- a/org.spearce.jgit/src/org/spearce/jgit/transport/IndexPack.java
+++ b/org.spearce.jgit/src/org/spearce/jgit/transport/IndexPack.java
@@ -76,7 +76,7 @@
/** Progress message when computing names of delta compressed objects. */
public static final String PROGRESS_RESOLVE_DELTA = "Resolving deltas";
- private static final int BUFFER_SIZE = 2048;
+ private static final int BUFFER_SIZE = 4096;
/**
* Create an index pack instance to load a new pack into a repository.
@@ -403,6 +403,7 @@ while (bi < b.size()) {
private void fixThinPack(final ProgressMonitor progress) throws IOException {
growEntries();
+ packDigest.reset();
originalEOF = packOut.length() - 20;
final Deflater def = new Deflater(Deflater.DEFAULT_COMPRESSION, false);
long end = originalEOF;
@@ -432,7 +433,7 @@ if (!baseById.isEmpty()) {
throw new MissingObjectException(need, "delta base");
}
- fixHeaderFooter();
+ fixHeaderFooter(packcsum, packDigest.digest());
}
private void writeWhole(final Deflater def, final int typeCode,
@@ -446,6 +447,7 @@ while (sz > 0) {
buf[hdrlen++] = (byte) (sz & 0x7f);
sz >>>= 7;
}
+ packDigest.update(buf, 0, hdrlen);
crc.update(buf, 0, hdrlen);
packOut.write(buf, 0, hdrlen);
def.reset();
@@ -453,37 +455,56 @@ while (sz > 0) {
def.finish();
while (!def.finished()) {
final int datlen = def.deflate(buf);
+ packDigest.update(buf, 0, datlen);
crc.update(buf, 0, datlen);
packOut.write(buf, 0, datlen);
}
}
- private void fixHeaderFooter() throws IOException {
+ private void fixHeaderFooter(final byte[] origcsum, final byte[] tailcsum)
+ throws IOException {
final MessageDigest origDigest = Constants.newMessageDigest();
- long origRemaining = originalEOF - 12;
+ final MessageDigest tailDigest = Constants.newMessageDigest();
+ long origRemaining = originalEOF;
packOut.seek(0);
- if (packOut.read(buf, 0, 12) != 12)
- throw new IOException("Cannot re-read pack header to fix count");
- origDigest.update(buf, 0, 12);
+ bAvail = 0;
+ bOffset = 0;
+ fillFromFile(12);
+
+ {
+ final int origCnt = (int) Math.min(bAvail, origRemaining);
+ origDigest.update(buf, 0, origCnt);
+ origRemaining -= origCnt;
+ if (origRemaining == 0)
+ tailDigest.update(buf, origCnt, bAvail - origCnt);
+ }
+
NB.encodeInt32(buf, 8, entryCount);
packOut.seek(0);
packOut.write(buf, 0, 12);
+ packOut.seek(bAvail);
packDigest.reset();
- packDigest.update(buf, 0, 12);
+ packDigest.update(buf, 0, bAvail);
for (;;) {
final int n = packOut.read(buf);
if (n < 0)
break;
- if (origRemaining > 0) {
- origDigest.update(buf, 0, (int) Math.min(n, origRemaining));
- origRemaining -= n;
- }
+ if (origRemaining != 0) {
+ final int origCnt = (int) Math.min(n, origRemaining);
+ origDigest.update(buf, 0, origCnt);
+ origRemaining -= origCnt;
+ if (origRemaining == 0)
+ tailDigest.update(buf, origCnt, n - origCnt);
+ } else
+ tailDigest.update(buf, 0, n);
+
packDigest.update(buf, 0, n);
}
- if (!Arrays.equals(origDigest.digest(), packcsum))
+ if (!Arrays.equals(origDigest.digest(), origcsum)
+ || !Arrays.equals(tailDigest.digest(), tailcsum))
throw new IOException("Pack corrupted while writing to filesystem");
packcsum = packDigest.digest();
--
1.6.0.272.g9ab4
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