From 903fb9c7395cc45b5e8c98948c3a627c0bcc01d9 Mon Sep 17 00:00:00 2001 From: Colby Ranger Date: Fri, 28 Jun 2013 14:02:26 -0700 Subject: [PATCH] Implement get nth offset in PackIndex. Currently, the offset can only be retrieved by ObjectId or iterating all of the entries. Add a method to lookup the offset by position in the index sorted by SHA1. Change-Id: I45e9ac8b752d1dab47b202753a1dcca7122b958e --- .../storage/file/PackIndexTestCase.java | 15 ++++++++++ .../jgit/internal/storage/file/PackIndex.java | 13 ++++++++ .../internal/storage/file/PackIndexV1.java | 27 +++++++++++++---- .../internal/storage/file/PackIndexV2.java | 30 +++++++++++++++---- 4 files changed, 73 insertions(+), 12 deletions(-) diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/PackIndexTestCase.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/PackIndexTestCase.java index aa3817e3a..7eeb0c0ea 100644 --- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/PackIndexTestCase.java +++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/PackIndexTestCase.java @@ -157,6 +157,21 @@ public void testCompareEntriesOffsetsWithFindOffsets() { } } + /** + * Compare offset from iterator entries with output of getOffset() method. + */ + @Test + public void testCompareEntriesOffsetsWithGetOffsets() { + int i = 0; + for (MutableEntry me : smallIdx) { + assertEquals(smallIdx.getOffset(i++), me.getOffset()); + } + int j = 0; + for (MutableEntry me : denseIdx) { + assertEquals(denseIdx.getOffset(j++), me.getOffset()); + } + } + /** * Test partial results of iterator comparing to content of well-known * (prepared) dense index, that may need multi-level indexing. diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackIndex.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackIndex.java index 44baeb190..0040aea71 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackIndex.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackIndex.java @@ -244,6 +244,19 @@ public final ObjectId getObjectId(final int nthPosition) { return getObjectId(((long) u31) << 1 | one); } + /** + * Get offset in a pack for the n-th object entry returned by + * {@link #iterator()}. + * + * @param nthPosition + * unsigned 32 bit position within the traversal of + * {@link #iterator()} for which the caller needs the offset. The + * first returned {@link MutableEntry} is 0, the second is 1, + * etc. Positions past 2**31-1 are negative, but still valid. + * @return the offset in a pack for the corresponding entry. + */ + abstract long getOffset(long nthPosition); + /** * Locate the file offset position for the requested object. * diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackIndexV1.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackIndexV1.java index 8c381fb83..2d574d80a 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackIndexV1.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackIndexV1.java @@ -113,15 +113,13 @@ public long getOffset64Count() { return n64; } - @Override - public ObjectId getObjectId(final long nthPosition) { + private int findLevelOne(final long nthPosition) { int levelOne = Arrays.binarySearch(idxHeader, nthPosition + 1); - long base; if (levelOne >= 0) { // If we hit the bucket exactly the item is in the bucket, or // any bucket before it which has the same object count. // - base = idxHeader[levelOne]; + long base = idxHeader[levelOne]; while (levelOne > 0 && base == idxHeader[levelOne - 1]) levelOne--; } else { @@ -129,13 +127,30 @@ public ObjectId getObjectId(final long nthPosition) { // levelOne = -(levelOne + 1); } + return levelOne; + } - base = levelOne > 0 ? idxHeader[levelOne - 1] : 0; - final int p = (int) (nthPosition - base); + private int getLevelTwo(final long nthPosition, final int levelOne) { + final long base = levelOne > 0 ? idxHeader[levelOne - 1] : 0; + return (int) (nthPosition - base); + } + + @Override + public ObjectId getObjectId(final long nthPosition) { + final int levelOne = findLevelOne(nthPosition); + final int p = getLevelTwo(nthPosition, levelOne); final int dataIdx = idOffset(p); return ObjectId.fromRaw(idxdata[levelOne], dataIdx); } + @Override + long getOffset(long nthPosition) { + final int levelOne = findLevelOne(nthPosition); + final int levelTwo = getLevelTwo(nthPosition, levelOne); + final int p = (4 + Constants.OBJECT_ID_LENGTH) * levelTwo; + return NB.decodeUInt32(idxdata[levelOne], p); + } + @Override public long findOffset(final AnyObjectId objId) { final int levelOne = objId.getFirstByte(); diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackIndexV2.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackIndexV2.java index 9b1a5f3ce..9d2caa2e8 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackIndexV2.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/PackIndexV2.java @@ -170,15 +170,13 @@ public long getOffset64Count() { return offset64.length / 8; } - @Override - public ObjectId getObjectId(final long nthPosition) { + private int findLevelOne(final long nthPosition) { int levelOne = Arrays.binarySearch(fanoutTable, nthPosition + 1); - long base; if (levelOne >= 0) { // If we hit the bucket exactly the item is in the bucket, or // any bucket before it which has the same object count. // - base = fanoutTable[levelOne]; + long base = fanoutTable[levelOne]; while (levelOne > 0 && base == fanoutTable[levelOne - 1]) levelOne--; } else { @@ -186,19 +184,39 @@ public ObjectId getObjectId(final long nthPosition) { // levelOne = -(levelOne + 1); } + return levelOne; + } - base = levelOne > 0 ? fanoutTable[levelOne - 1] : 0; - final int p = (int) (nthPosition - base); + private int getLevelTwo(final long nthPosition, final int levelOne) { + final long base = levelOne > 0 ? fanoutTable[levelOne - 1] : 0; + return (int) (nthPosition - base); + } + + @Override + public ObjectId getObjectId(final long nthPosition) { + final int levelOne = findLevelOne(nthPosition); + final int p = getLevelTwo(nthPosition, levelOne); final int p4 = p << 2; return ObjectId.fromRaw(names[levelOne], p4 + p); // p * 5 } + @Override + public long getOffset(final long nthPosition) { + final int levelOne = findLevelOne(nthPosition); + final int levelTwo = getLevelTwo(nthPosition, levelOne); + return getOffset(levelOne, levelTwo); + } + @Override public long findOffset(final AnyObjectId objId) { final int levelOne = objId.getFirstByte(); final int levelTwo = binarySearchLevelTwo(objId, levelOne); if (levelTwo == -1) return -1; + return getOffset(levelOne, levelTwo); + } + + private long getOffset(final int levelOne, final int levelTwo) { final long p = NB.decodeUInt32(offset32[levelOne], levelTwo << 2); if ((p & IS_O64) != 0) return NB.decodeUInt64(offset64, (8 * (int) (p & ~IS_O64)));