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Diffstat (limited to 'Documentation/technical/index-format.txt')
| -rw-r--r-- | Documentation/technical/index-format.txt | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/Documentation/technical/index-format.txt b/Documentation/technical/index-format.txt index 8930b3fabc..f352a9b22e 100644 --- a/Documentation/technical/index-format.txt +++ b/Documentation/technical/index-format.txt @@ -1,7 +1,7 @@ -GIT index format +Git index format ================ -= The git index file has the following format +== The Git index file has the following format All binary numbers are in network byte order. Version 2 is described here unless stated otherwise. @@ -12,7 +12,7 @@ GIT index format The signature is { 'D', 'I', 'R', 'C' } (stands for "dircache") 4-byte version number: - The current supported versions are 2 and 3. + The current supported versions are 2, 3 and 4. 32-bit number of index entries. @@ -21,9 +21,9 @@ GIT index format - Extensions Extensions are identified by signature. Optional extensions can - be ignored if GIT does not understand them. + be ignored if Git does not understand them. - GIT currently supports cached tree and resolve undo extensions. + Git currently supports cached tree and resolve undo extensions. 4-byte extension signature. If the first byte is 'A'..'Z' the extension is optional and can be ignored. @@ -93,8 +93,8 @@ GIT index format 12-bit name length if the length is less than 0xFFF; otherwise 0xFFF is stored in this field. - (Version 3) A 16-bit field, only applicable if the "extended flag" - above is 1, split into (high to low bits). + (Version 3 or later) A 16-bit field, only applicable if the + "extended flag" above is 1, split into (high to low bits). 1-bit reserved for future @@ -113,9 +113,22 @@ GIT index format are encoded in 7-bit ASCII and the encoding cannot contain a NUL byte (iow, this is a UNIX pathname). + (Version 4) In version 4, the entry path name is prefix-compressed + relative to the path name for the previous entry (the very first + entry is encoded as if the path name for the previous entry is an + empty string). At the beginning of an entry, an integer N in the + variable width encoding (the same encoding as the offset is encoded + for OFS_DELTA pack entries; see pack-format.txt) is stored, followed + by a NUL-terminated string S. Removing N bytes from the end of the + path name for the previous entry, and replacing it with the string S + yields the path name for this entry. + 1-8 nul bytes as necessary to pad the entry to a multiple of eight bytes while keeping the name NUL-terminated. + (Version 4) In version 4, the padding after the pathname does not + exist. + == Extensions === Cached tree @@ -148,8 +161,9 @@ GIT index format this span of index as a tree. An entry can be in an invalidated state and is represented by having - -1 in the entry_count field. In this case, there is no object name - and the next entry starts immediately after the newline. + a negative number in the entry_count field. In this case, there is no + object name and the next entry starts immediately after the newline. + When writing an invalid entry, -1 should always be used as entry_count. The entries are written out in the top-down, depth-first order. The first entry represents the root level of the repository, followed by the @@ -161,7 +175,7 @@ GIT index format A conflict is represented in the index as a set of higher stage entries. When a conflict is resolved (e.g. with "git add path"), these higher - stage entries will be removed and a stage-0 entry with proper resoluton + stage entries will be removed and a stage-0 entry with proper resolution is added. When these higher stage entries are removed, they are saved in the |