in a separate file. This extension records the changes to be made on
top of that to produce the final index.
- The signature for this extension is { 'l', 'i, 'n', 'k' }.
+ The signature for this extension is { 'l', 'i', 'n', 'k' }.
The extension consists of:
The remaining index entries after replaced ones will be added to the
final index. These added entries are also sorted by entry name then
stage.
+
+== Untracked cache
+
+ Untracked cache saves the untracked file list and necessary data to
+ verify the cache. The signature for this extension is { 'U', 'N',
+ 'T', 'R' }.
+
+ The extension starts with
+
+ - A sequence of NUL-terminated strings, preceded by the size of the
+ sequence in variable width encoding. Each string describes the
+ environment where the cache can be used.
+
+ - Stat data of $GIT_DIR/info/exclude. See "Index entry" section from
+ ctime field until "file size".
+
+ - Stat data of core.excludesfile
+
+ - 32-bit dir_flags (see struct dir_struct)
+
+ - 160-bit SHA-1 of $GIT_DIR/info/exclude. Null SHA-1 means the file
+ does not exist.
+
+ - 160-bit SHA-1 of core.excludesfile. Null SHA-1 means the file does
+ not exist.
+
+ - NUL-terminated string of per-dir exclude file name. This usually
+ is ".gitignore".
+
+ - The number of following directory blocks, variable width
+ encoding. If this number is zero, the extension ends here with a
+ following NUL.
+
+ - A number of directory blocks in depth-first-search order, each
+ consists of
+
+ - The number of untracked entries, variable width encoding.
+
+ - The number of sub-directory blocks, variable width encoding.
+
+ - The directory name terminated by NUL.
+
+ - A number of untracked file/dir names terminated by NUL.
+
+The remaining data of each directory block is grouped by type:
+
+ - An ewah bitmap, the n-th bit marks whether the n-th directory has
+ valid untracked cache entries.
+
+ - An ewah bitmap, the n-th bit records "check-only" bit of
+ read_directory_recursive() for the n-th directory.
+
+ - An ewah bitmap, the n-th bit indicates whether SHA-1 and stat data
+ is valid for the n-th directory and exists in the next data.
+
+ - An array of stat data. The n-th data corresponds with the n-th
+ "one" bit in the previous ewah bitmap.
+
+ - An array of SHA-1. The n-th SHA-1 corresponds with the n-th "one" bit
+ in the previous ewah bitmap.
+
+ - One NUL.
+
+== File System Monitor cache
+
+ The file system monitor cache tracks files for which the core.fsmonitor
+ hook has told us about changes. The signature for this extension is
+ { 'F', 'S', 'M', 'N' }.
+
+ The extension starts with
+
+ - 32-bit version number: the current supported version is 1.
+
+ - 64-bit time: the extension data reflects all changes through the given
+ time which is stored as the nanoseconds elapsed since midnight,
+ January 1, 1970.
+
+ - 32-bit bitmap size: the size of the CE_FSMONITOR_VALID bitmap.
+
+ - An ewah bitmap, the n-th bit indicates whether the n-th index entry
+ is not CE_FSMONITOR_VALID.
+
+== End of Index Entry
+
+ The End of Index Entry (EOIE) is used to locate the end of the variable
+ length index entries and the begining of the extensions. Code can take
+ advantage of this to quickly locate the index extensions without having
+ to parse through all of the index entries.
+
+ Because it must be able to be loaded before the variable length cache
+ entries and other index extensions, this extension must be written last.
+ The signature for this extension is { 'E', 'O', 'I', 'E' }.
+
+ The extension consists of:
+
+ - 32-bit offset to the end of the index entries
+
+ - 160-bit SHA-1 over the extension types and their sizes (but not
+ their contents). E.g. if we have "TREE" extension that is N-bytes
+ long, "REUC" extension that is M-bytes long, followed by "EOIE",
+ then the hash would be:
+
+ SHA-1("TREE" + <binary representation of N> +
+ "REUC" + <binary representation of M>)
+
+== Index Entry Offset Table
+
+ The Index Entry Offset Table (IEOT) is used to help address the CPU
+ cost of loading the index by enabling multi-threading the process of
+ converting cache entries from the on-disk format to the in-memory format.
+ The signature for this extension is { 'I', 'E', 'O', 'T' }.
+
+ The extension consists of:
+
+ - 32-bit version (currently 1)
+
+ - A number of index offset entries each consisting of:
+
+ - 32-bit offset from the begining of the file to the first cache entry
+ in this block of entries.
+
+ - 32-bit count of cache entries in this block