return map;
}
-/*
- * There used to be a second loose object header format which
- * was meant to mimic the in-pack format, allowing for direct
- * copy of the object data. This format turned up not to be
- * really worth it and we no longer write loose objects in that
- * format.
- */
-static int experimental_loose_object(unsigned char *map)
-{
- unsigned int word;
-
- /*
- * We must determine if the buffer contains the standard
- * zlib-deflated stream or the experimental format based
- * on the in-pack object format. Compare the header byte
- * for each format:
- *
- * RFC1950 zlib w/ deflate : 0www1000 : 0 <= www <= 7
- * Experimental pack-based : Stttssss : ttt = 1,2,3,4
- *
- * If bit 7 is clear and bits 0-3 equal 8, the buffer MUST be
- * in standard loose-object format, UNLESS it is a Git-pack
- * format object *exactly* 8 bytes in size when inflated.
- *
- * However, RFC1950 also specifies that the 1st 16-bit word
- * must be divisible by 31 - this checksum tells us our buffer
- * is in the standard format, giving a false positive only if
- * the 1st word of the Git-pack format object happens to be
- * divisible by 31, ie:
- * ((byte0 * 256) + byte1) % 31 = 0
- * => 0ttt10000www1000 % 31 = 0
- *
- * As it happens, this case can only arise for www=3 & ttt=1
- * - ie, a Commit object, which would have to be 8 bytes in
- * size. As no Commit can be that small, we find that the
- * combination of these two criteria (bitmask & checksum)
- * can always correctly determine the buffer format.
- */
- word = (map[0] << 8) + map[1];
- if ((map[0] & 0x8F) == 0x08 && !(word % 31))
- return 0;
- else
- return 1;
-}
-
unsigned long unpack_object_header_buffer(const unsigned char *buf,
unsigned long len, enum object_type *type, unsigned long *sizep)
{
int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
{
- unsigned long size, used;
- static const char valid_loose_object_type[8] = {
- 0, /* OBJ_EXT */
- 1, 1, 1, 1, /* "commit", "tree", "blob", "tag" */
- 0, /* "delta" and others are invalid in a loose object */
- };
- enum object_type type;
-
/* Get the data stream */
memset(stream, 0, sizeof(*stream));
stream->next_in = map;
stream->next_out = buffer;
stream->avail_out = bufsiz;
- if (experimental_loose_object(map)) {
- /*
- * The old experimental format we no longer produce;
- * we can still read it.
- */
- used = unpack_object_header_buffer(map, mapsize, &type, &size);
- if (!used || !valid_loose_object_type[type])
- return -1;
- map += used;
- mapsize -= used;
-
- /* Set up the stream for the rest.. */
- stream->next_in = map;
- stream->avail_in = mapsize;
- git_inflate_init(stream);
-
- /* And generate the fake traditional header */
- stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu",
- typename(type), size);
- return 0;
- }
git_inflate_init(stream);
return git_inflate(stream, 0);
}
+++ /dev/null
-#!/bin/sh
-#
-# Copyright (c) 2011 Roberto Tyley
-#
-
-test_description='Correctly identify and parse loose object headers
-
-There are two file formats for loose objects - the original standard
-format, and the experimental format introduced with Git v1.4.3, later
-deprecated with v1.5.3. Although Git no longer writes the
-experimental format, objects in both formats must be read, with the
-format for a given file being determined by the header.
-
-Detecting file format based on header is not entirely trivial, not
-least because the first byte of a zlib-deflated stream will vary
-depending on how much memory was allocated for the deflation window
-buffer when the object was written out (for example 4KB on Android,
-rather that 32KB on a normal PC).
-
-The loose objects used as test vectors have been generated with the
-following Git versions:
-
-standard format: Git v1.7.4.1
-experimental format: Git v1.4.3 (legacyheaders=false)
-standard format, deflated with 4KB window size: Agit/JGit on Android
-'
-
-. ./test-lib.sh
-
-assert_blob_equals() {
- printf "%s" "$2" >expected &&
- git cat-file -p "$1" >actual &&
- test_cmp expected actual
-}
-
-test_expect_success setup '
- cp -R "$TEST_DIRECTORY/t1013/objects" .git/ &&
- git --version
-'
-
-test_expect_success 'read standard-format loose objects' '
- git cat-file tag 8d4e360d6c70fbd72411991c02a09c442cf7a9fa &&
- git cat-file commit 6baee0540ea990d9761a3eb9ab183003a71c3696 &&
- git ls-tree 7a37b887a73791d12d26c0d3e39568a8fb0fa6e8 &&
- assert_blob_equals "257cc5642cb1a054f08cc83f2d943e56fd3ebe99" "foo$LF"
-'
-
-test_expect_success 'read experimental-format loose objects' '
- git cat-file tag 76e7fa9941f4d5f97f64fea65a2cba436bc79cbb &&
- git cat-file commit 7875c6237d3fcdd0ac2f0decc7d3fa6a50b66c09 &&
- git ls-tree 95b1625de3ba8b2214d1e0d0591138aea733f64f &&
- assert_blob_equals "2e65efe2a145dda7ee51d1741299f848e5bf752e" "a" &&
- assert_blob_equals "9ae9e86b7bd6cb1472d9373702d8249973da0832" "ab" &&
- assert_blob_equals "85df50785d62d3b05ab03d9cbf7e4a0b49449730" "abcd" &&
- assert_blob_equals "1656f9233d999f61ef23ef390b9c71d75399f435" "abcdefgh" &&
- assert_blob_equals "1e72a6b2c4a577ab0338860fa9fe87f761fc9bbd" "abcdefghi" &&
- assert_blob_equals "70e6a83d8dcb26fc8bc0cf702e2ddeb6adca18fd" "abcdefghijklmnop" &&
- assert_blob_equals "bd15045f6ce8ff75747562173640456a394412c8" "abcdefghijklmnopqrstuvwx"
-'
-
-test_expect_success 'read standard-format objects deflated with smaller window buffer' '
- git cat-file tag f816d5255855ac160652ee5253b06cd8ee14165a &&
- git cat-file tag 149cedb5c46929d18e0f118e9fa31927487af3b6
-'
-
-test_done
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