git/userdiff.h, branch v2.40.2

diff: teach diff to read algorithm from diff driver

2023-02-21T17:29:10Z

It can be useful to specify diff algorithms per file type. For example, one may want to use the minimal diff algorithm for .json files, another for .c files, etc. The diff machinery already checks attributes for a diff driver. Teach the diff driver parser a new type "algorithm" to look for in the config, which will be used if a driver has been specified through the attributes. Enforce precedence of the diff algorithm by favoring the command line option, then looking at the driver attributes & config combination, then finally the diff.algorithm config. To enforce precedence order, use a new `ignore_driver_algorithm` member during options parsing to indicate the diff algorithm was set via command line args. Signed-off-by: John Cai Signed-off-by: Junio C Hamano

userdiff: add and use for_each_userdiff_driver()

2021-04-08T19:19:10Z

Refactor the userdiff_find_by_namelen() function so that a new for_each_userdiff_driver() API function does most of the work. This will be useful for the same reason we've got other for_each_*() API functions as part of various APIs, and will be used in a follow-up commit. Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano

notes-cache.c: remove the_repository references

2018-11-12T05:50:06Z

Signed-off-by: Nguyễn Thái Ngọc Duy Signed-off-by: Junio C Hamano

userdiff.c: remove implicit dependency on the_index

2018-09-21T16:50:58Z

[jc: squashed in missing forward decl in userdiff.h found by Ramsay] Helped-by: Ramsay Jones Signed-off-by: Nguyễn Thái Ngọc Duy Signed-off-by: Junio C Hamano

diff: clarify textconv interface

2016-02-22T18:40:35Z

The memory allocation scheme for the textconv interface is a bit tricky, and not well documented. It was originally designed as an internal part of diff.c (matching fill_mmfile), but gradually was made public. Refactoring it is difficult, but we can at least improve the situation by documenting the intended flow and enforcing it with an in-code assertion. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

refactor get_textconv to not require diff_filespec

2011-05-23T22:46:02Z

This function actually does two things: 1. Load the userdiff driver for the filespec. 2. Decide whether the driver has a textconv component, and initialize the textconv cache if applicable. Only part (1) requires the filespec object, and some callers may not have a filespec at all. So let's split them it into two functions, and put part (2) with the userdiff code, which is a better fit. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

diff: cache textconv output

2010-04-02T07:05:31Z

Running a textconv filter can take a long time. It's particularly bad for a large file which needs to be spooled to disk, but even for small files, the fork+exec overhead can add up for something like "git log -p". This patch uses the notes-cache mechanism to keep a fast cache of textconv output. Caches are stored in refs/notes/textconv/$x, where $x is the userdiff driver defined in gitattributes. Caching is enabled only if diff.$x.cachetextconv is true. In my test repo, on a commit with 45 jpg and avi files changed and a textconv to show their exif tags: [before] $ time git show >/dev/null real 0m13.724s user 0m12.057s sys 0m1.624s [after, first run] $ git config diff.mfo.cachetextconv true $ time git show >/dev/null real 0m14.252s user 0m12.197s sys 0m1.800s [after, subsequent runs] $ time git show >/dev/null real 0m0.352s user 0m0.148s sys 0m0.200s So for a slight (3.8%) cost on the first run, we achieve an almost 40x speed up on subsequent runs. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

color-words: make regex configurable via attributes

2009-01-17T18:44:21Z

Make the --color-words splitting regular expression configurable via the diff driver's 'wordregex' attribute. The user can then set the driver on a file in .gitattributes. If a regex is given on the command line, it overrides the driver's setting. We also provide built-in regexes for the languages that already had funcname patterns, and add an appropriate diff driver entry for C/++. (The patterns are designed to run UTF-8 sequences into a single chunk to make sure they remain readable.) Signed-off-by: Thomas Rast Signed-off-by: Junio C Hamano

userdiff: require explicitly allowing textconv

2008-10-26T21:09:48Z

Diffs that have been produced with textconv almost certainly cannot be applied, so we want to be careful not to generate them in things like format-patch. This introduces a new diff options, ALLOW_TEXTCONV, which controls this behavior. It is off by default, but is explicitly turned on for the "log" family of commands, as well as the "diff" porcelain (but not diff-* plumbing). Because both text conversion and external diffing are controlled by these diff options, we can get rid of the "plumbing versus porcelain" distinction when reading the config. This was an attempt to control the same thing, but suffered from being too coarse-grained. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

diff: add filter for converting binary to text

2008-10-18T15:02:55Z

When diffing binary files, it is sometimes nice to see the differences of a canonical text form rather than either a binary patch or simply "binary files differ." Until now, the only option for doing this was to define an external diff command to perform the diff. This was a lot of work, since the external command needed to take care of doing the diff itself (including mode changes), and lost the benefit of git's colorization and other options. This patch adds a text conversion option, which converts a file to its canonical format before performing the diff. This is less flexible than an arbitrary external diff, but is much less work to set up. For example: $ echo '*.jpg diff=exif' >>.gitattributes $ git config diff.exif.textconv exiftool $ git config diff.exif.binary false allows one to see jpg diffs represented by the text output of exiftool. Signed-off-by: Jeff King Signed-off-by: Shawn O. Pearce