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2021-05-11xdiff-interface: replace discard_hunk_line() with a flagLibravatar Ævar Arnfjörð Bjarmason1-1/+2
Remove the dummy discard_hunk_line() function added in 3b40a090fd4 (diff: avoid generating unused hunk header lines, 2018-11-02) in favor of having a new XDL_EMIT_NO_HUNK_HDR flag, for use along with the two existing and similar XDL_EMIT_* flags. Unlike the recently amended xdiff_emit_line_fn interface which'll be called in a loop in xdl_emit_diff(), the hunk header is only emitted once. It makes more sense to pass this as a flag than provide a dummy callback because that function may be able to skip doing certain work if it knows the caller is doing nothing with the hunk header. It would be possible to do so in the case of -U0 now, but the benefit of doing so is so small that I haven't bothered. But this leaves the door open to that, and more importantly makes the API use more intuitive. The reason we're putting a flag in the gap between 1<<0 and 1<<2 is that the old 1<<1 flag was removed in 907681e940d (xdiff: drop XDL_EMIT_COMMON, 2016-02-23) without re-ordering the remaining flags. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-05xdiff: unignore changes in function contextLibravatar René Scharfe1-0/+17
Changes involving only blank lines are hidden with --ignore-blank-lines, unless they appear in the context lines of other changes. This is handled by xdl_get_hunk() for context added by --inter-hunk-context, -u and -U. Function context for -W and --function-context added by xdl_emit_diff() doesn't pay attention to such ignored changes; it relies fully on xdl_get_hunk() and shows just the post-image of ignored changes appearing in function context. That's inconsistent and confusing. Improve the result of using --ignore-blank-lines and --function-context together by fully showing ignored changes if they happen to fall within function context. Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-07-23xdiff: clamp function context indices in post-imageLibravatar Jeff King1-2/+2
After finding a function line for --function-context in the pre-image, xdl_emit_diff() calculates the equivalent line in the post-image. It assumes that the lines between changes are the same on both sides. If the option --ignore-blank-lines was also given then this is not necessarily true. Clamp the calculation results for start and end of the function context to prevent out-of-bounds array accesses. Note that this _just_ fixes the case where our mismatch sends us off the beginning of the file. There are likely other cases where our assumption causes us to go to the wrong line within the file. Nobody has developed a test case yet, and the ultimate fix is likely more complicated than this patch. But this at least prevents a segfault in the meantime. Credit for finding the bug goes to "Liu Wei of Tencent Security Xuanwu Lab". Reported-by: 刘炜 <lw17qhdz@gmail.com> Helped-by: René Scharfe <l.s.r@web.de> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-21xdiff: show non-empty lines before functions with -WLibravatar René Scharfe1-0/+3
Non-empty lines before a function definition are most likely comments for that function and thus relevant. Include them in function context. Such a non-empty line might also belong to the preceeding function if there is no separating blank line. Stop extending the context upwards also at the next function line to make sure only one extra function body is shown at most. Original-patch-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-21xdiff: factor out is_func_rec()Libravatar René Scharfe1-3/+7
Add a helper for checking if a given record is a function line. It frees callers from having to deal with the buffer arguments of match_func_rec(). Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-09Replace Free Software Foundation address in license noticesLibravatar Todd Zullinger1-2/+2
The mailing address for the FSF has changed over the years. Rather than updating the address across all files, refer readers to gnu.org, as the GNU GPL documentation now suggests for license notices. The mailing address is retained in the full license files (COPYING and LGPL-2.1). The old address is still present in t/diff-lib/COPYING. This is intentional, as the file is used in tests and the contents are not expected to change. Signed-off-by: Todd Zullinger <tmz@pobox.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-01-15xdiff -W: relax end-of-file function detectionLibravatar Vegard Nossum1-8/+6
When adding a new function to the end of a file, it's enough to know that 1) the addition is at the end of the file; and 2) there is a function _somewhere_ in there. If we had simply been changing the end of an existing function, then we would also be deleting something from the old version. This fixes the case where we add e.g. // Begin of dummy static int dummy(void) { } to the end of the file. Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Acked-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-21Merge branch 'rs/xdiff-merge-overlapping-hunks-for-W-context'Libravatar Junio C Hamano1-1/+1
"git diff -W" output needs to extend the context backward to include the header line of the current function and also forward to include the body of the entire current function up to the header line of the next one. This process may have to merge to adjacent hunks, but the code forgot to do so in some cases. * rs/xdiff-merge-overlapping-hunks-for-W-context: xdiff: fix merging of hunks with -W context and -u context
2016-09-14xdiff: fix merging of hunks with -W context and -u contextLibravatar René Scharfe1-1/+1
If the function context for a hunk (with -W) reaches the beginning of the next hunk then we need to merge these two -- otherwise we'd show some lines twice, which looks strange and even confuses git apply. We already do this checking and merging in xdl_emit_diff(), but forget to consider regular context (with -u or -U). Fix that by merging hunks already if function context of the first one touches or overlaps regular context of the second one. Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-07xdiff: remove unneeded declarationsLibravatar Stefan Beller1-9/+0
Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-09xdiff: fix merging of appended hunk with -WLibravatar René Scharfe1-1/+2
When -W is given we search the lines between the end of the current context and the next change for a function line. If there is none then we merge those two hunks as they must be part of the same function. If the next change is an appended chunk we abort the search early in get_func_line(), however, because its line number is out of range. Fix that by searching from the end of the pre-image in that case instead. Reported-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-05-31xdiff: -W: don't include common trailing empty lines in contextLibravatar René Scharfe1-0/+2
Empty lines between functions are shown by diff -W, as it considers them to be part of the function preceding them. They are not interesting in most languages. The previous patch stopped showing them in the special case of a function added at the end of a file. Stop extending context to those empty lines by skipping back over them from the start of the next function. Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-05-31xdiff: ignore empty lines before added functions with -WLibravatar René Scharfe1-2/+20
If a new function and a preceding empty line is appended, diff -W shows the previous function in full in order to provide context for that empty line. In most languages empty lines between sections are not interesting in and off themselves and showing a whole extra function for them is not what we want. Skip empty lines when checking of the appended chunk starts with a function line, thereby avoiding to extend the context just for them. Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-05-31xdiff: handle appended chunks better with -WLibravatar René Scharfe1-3/+24
If lines are added at the end of a file, diff -W shows the whole file. That's because get_func_line() only considers the pre-image and gives up if it sees a record index beyond its end. Consider the post-image as well to see if the added lines already make up a full function. If it doesn't then search for the previous function line by starting from the bottom of the pre-image, thereby avoiding to confuse get_func_line(). Reuse the existing label called "again", as it's exactly where we need to jump to when we're done handling the pre-context, but rename it to "post_context_calculation" in order to document its new purpose better. Reported-by: Junio C Hamano <gitster@pobox.com> Initial-patch-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-05-31xdiff: factor out match_func_rec()Libravatar René Scharfe1-4/+11
Add match_func_rec(), a helper that wraps accessing a record and calling the appropriate function for checking if it contains a function line. Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-22xdiff: drop XDL_EMIT_COMMONLibravatar Jeff King1-18/+0
There are no more callers that use this mode, and none likely to be added (as our xdl_merge() eliminates the common use of it for generating 3-way merge bases). This is effectively a revert of a9ed376 (xdiff: generate "anti-diffs" aka what is common to two files, 2006-06-28), though of course trying to revert that ancient commit directly produces many textual conflicts. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-10-16C: have space around && and || operatorsLibravatar Junio C Hamano1-1/+1
Correct all hits from git grep -e '\(&&\|||\)[^ ]' -e '[^ ]\(&&\|||\)' -- '*.c' i.e. && or || operators that are followed by anything but a SP, or that follow something other than a SP or a HT, so that these operators have a SP around it when necessary. We usually refrain from making this kind of a tree-wide change in order to avoid unnecessary conflicts with other "real work" patches, but in this case, the end result does not have a potentially cumbersome tree-wide impact, while this is a tree-wide cleanup. Fixes to compat/regex/regcomp.c and xdiff/xemit.c are to replace a HT immediately after && with a SP. This is based on Felipe's patch to bultin/symbolic-ref.c; I did all the finding out what other files in the whole tree need to be fixed and did the fix and also the log message while reviewing that single liner, so any screw-ups in this version are mine. Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-06-19diff: add --ignore-blank-lines optionLibravatar Antoine Pelisse1-6/+43
The goal of the patch is to introduce the GNU diff -B/--ignore-blank-lines as closely as possible. The short option is not available because it's already used for "break-rewrites". When this option is used, git-diff will not create hunks that simply add or remove empty lines, but will still show empty lines addition/suppression if they are close enough to "valuable" changes. There are two differences between this option and GNU diff -B option: - GNU diff doesn't have "--inter-hunk-context", so this must be handled - The following sequence looks like a bug (context is displayed twice): $ seq 5 >file1 $ cat <<EOF >file2 change 1 2 3 4 5 change EOF $ diff -u -B file1 file2 --- file1 2013-06-08 22:13:04.471517834 +0200 +++ file2 2013-06-08 22:13:23.275517855 +0200 @@ -1,5 +1,7 @@ +change 1 2 + 3 4 5 @@ -3,3 +5,4 @@ 3 4 5 +change So here is a more thorough description of the option: - real changes are interesting - blank lines that are close enough (less than context size) to interesting changes are considered interesting (recursive definition) - "context" lines are used around each hunk of interesting changes - If two hunks are separated by less than "inter-hunk-context", they will be merged into one. The implementation does the "interesting changes selection" in a single pass. Signed-off-by: Antoine Pelisse <apelisse@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-01-29Merge branch 'rs/diff-postimage-in-context'Libravatar Junio C Hamano1-6/+6
* rs/diff-postimage-in-context: xdiff: print post-image for common records instead of pre-image
2012-01-06xdiff: print post-image for common records instead of pre-imageLibravatar René Scharfe1-6/+6
Normally it doesn't matter if we show the pre-image or th post-image for the common parts of a diff because they are the same. If white-space changes are ignored they can differ, though. The new text after applying the diff is more interesting in that case, so show that instead of the old contents. Note: GNU diff shows the pre-image. Suggested-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-10-10diff: add option to show whole functions as contextLibravatar René Scharfe1-6/+48
Add the option -W/--function-context to git diff. It is similar to the same option of git grep and expands the context of change hunks so that the whole surrounding function is shown. This "natural" context can allow changes to be understood better. Note: GNU patch doesn't like diffs generated with the new option; it seems to expect context lines to be the same before and after changes. git apply doesn't complain. This implementation has the same shortcoming as the one in grep, namely that there is no way to explicitly find the end of a function. That means that a few lines of extra context are shown, right up to the next recognized function begins. It's already useful in its current form, though. The function get_func_line() in xdiff/xemit.c is extended to work forward as well as backward to find post-context as well as pre-context. It returns the position of the first found matching line. The func_line parameter is made optional, as we don't need it for -W. The enhanced function is then used in xdl_emit_diff() to extend the context as needed. If the added context overlaps with the next change, it is merged into the current hunk. Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-10-10xdiff: factor out get_func_line()Libravatar René Scharfe1-16/+27
Move the code to search for a function line to be shown in the hunk header into its own function and to make returning the length-limited result string easier, introduce struct func_line. Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-09-30diff: avoid repeated scanning while looking for funcnameLibravatar René Scharfe1-24/+14
For each hunk, xdl_find_func searches the preimage for a function name until the beginning of the file. If the file does not contain any function names, this search has complexity O(n^2) in the number of hunks n. Instead, inline xdl_find_func() and keep track of up to which line we have scanned already and the contents of the last funcname line that we have found. Noticed and a different approach proposed by Clemens Buchacher. This alternative solution was done by René Scharfe. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-03-15Fix various dead stores found by the clang static analyzerLibravatar Benjamin Kramer1-1/+1
http-push.c::finish_request(): request is initialized by the for loop index-pack.c::free_base_data(): b is initialized by the for loop merge-recursive.c::process_renames(): move compare to narrower scope, and remove unused assignments to it remove unused variable renames2 xdiff/xdiffi.c::xdl_recs_cmp(): remove unused variable ec xdiff/xemit.c::xdl_emit_diff(): xche is always overwritten Signed-off-by: Benjamin Kramer <benny.kra@googlemail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-12-29diff: add option to show context between close hunksLibravatar René Scharfe1-1/+2
Merge two hunks if there is only the specified number of otherwise unshown context between them. For --inter-hunk-context=1, the resulting patch has the same number of lines but shows uninterrupted context instead of a context header line in between. Patches generated with this option are easier to read but are also more likely to conflict if the file to be patched contains other changes. This patch keeps the default for this option at 0. It is intended to just make the feature available in order to see its advantages and downsides. Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-10-25Allow alternate "low-level" emit function from xdl_diffLibravatar Brian Downing1-2/+1
For some users (e.g. git blame), getting textual patch output is just extra work, as they can get all the information they need from the low- level diff structures. Allow for an alternate low-level emit function to be defined to allow bypassing the textual patch generation; set xemitconf_t's emit_func member to enable this. The (void (*)()) type is pretty ugly, but the alternative would be to include most of the private xdiff headers in xdiff.h to get the types required for the "proper" function prototype. Also, a (void *) won't work, as ANSI C doesn't allow a function pointer to be cast to an object pointer. Signed-off-by: Brian Downing <bdowning@lavos.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-07-06Per-path attribute based hunk header selection.Libravatar Junio C Hamano1-14/+23
This makes"diff -p" hunk headers customizable via gitattributes mechanism. It is based on Johannes's earlier patch that allowed to define a single regexp to be used for everything. The mechanism to arrive at the regexp that is used to define hunk header is the same as other use of gitattributes. You assign an attribute, funcname (because "diff -p" typically uses the name of the function the patch is about as the hunk header), a simple string value. This can be one of the names of built-in pattern (currently, "java" is defined) or a custom pattern name, to be looked up from the configuration file. (in .gitattributes) *.java funcname=java *.perl funcname=perl (in .git/config) [funcname] java = ... # ugly and complicated regexp to override the built-in one. perl = ... # another ugly and complicated regexp to define a new one. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-06-08Missing statics.Libravatar Pierre Habouzit1-2/+2
Signed-off-by: Pierre Habouzit <madcoder@debian.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-06-07War on whitespaceLibravatar Junio C Hamano1-1/+0
This uses "git-apply --whitespace=strip" to fix whitespace errors that have crept in to our source files over time. There are a few files that need to have trailing whitespaces (most notably, test vectors). The results still passes the test, and build result in Documentation/ area is unchanged. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2006-11-23Increase length of function name bufferLibravatar Andy Parkins1-1/+1
In xemit.c:xdl_emit_diff() a buffer for showing the function name as commentary is allocated; this buffer was 40 characters. This is a bit small; particularly for C++ function names where there is often an identical prefix (like void LongNamespace::LongClassName) on multiple functions, which makes the context the same everywhere. In other words the context is useless. This patch increases that buffer to 80 characters - which may still not be enough, but is better Signed-off-by: Andy Parkins <andyparkins@gmail.com> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-10-25xdiff: Match GNU diff behaviour when deciding hunk comment worthiness of linesLibravatar Petr Baudis1-2/+1
This removes the '#' and '(' tests and adds a '$' test instead although I have no idea what it is actually good for - but hey, if that's what GNU diff does... Pasky only went and did as Junio sayeth. Signed-off-by: Petr Baudis <pasky@suse.cz> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-10-23xdiff/xemit.c (xdl_find_func): Elide trailing white space in a context header.Libravatar Jim Meyering1-1/+1
This removes trailing blanks from git-generated diff headers the same way a similar patch did that for GNU diff: http://article.gmane.org/gmane.comp.gnu.utils.bugs/13839 That is, it removes trailing blanks on the hunk header line that shows the function name. Signed-off-by: Jim Meyering <jim@meyering.net> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-06-28xdiff: generate "anti-diffs" aka what is common to two filesLibravatar Linus Torvalds1-0/+18
This fairly trivial patch adds a new XDL_EMIT_xxx flag to tell libxdiff that we don't want to generate the _diff_ between two files, we want to see the lines that are _common_ to two files. So when you set XDL_EMIT_COMMON, xdl_diff() will do everything exactly like it used to do, but the output records it generates just contain the lines that aren't part of the diff. This is for doing things like generating the common base case for a file that was added in both branches. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-27xdiff: Show function names in hunk headers.Libravatar Mark Wooding1-1/+40
The speed of the built-in diff generator is nice; but the function names shown by `diff -p' are /really/ nice. And I hate having to choose. So, we hack xdiff to find the function names and print them. xdiff has grown a flag to say whether to dig up the function names. The builtin_diff function passes this flag unconditionally. I suppose it could parse GIT_DIFF_OPTS, but it doesn't at the moment. I've also reintroduced the `function name' into the test suite, from which it was removed in commit 3ce8f089. The function names are parsed by a particularly stupid algorithm at the moment: it just tries to find a line in the `old' file, from before the start of the hunk, whose first character looks plausible. Still, it's most definitely a start. Signed-off-by: Mark Wooding <mdw@distorted.org.uk> Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-25Use a *real* built-in diff generatorLibravatar Linus Torvalds1-0/+141
This uses a simplified libxdiff setup to generate unified diffs _without_ doing fork/execve of GNU "diff". This has several huge advantages, for example: Before: [torvalds@g5 linux]$ time git diff v2.6.16.. > /dev/null real 0m24.818s user 0m13.332s sys 0m8.664s After: [torvalds@g5 linux]$ time git diff v2.6.16.. > /dev/null real 0m4.563s user 0m2.944s sys 0m1.580s and the fact that this should be a lot more portable (ie we can ignore all the issues with doing fork/execve under Windows). Perhaps even more importantly, this allows us to do diffs without actually ever writing out the git file contents to a temporary file (and without any of the shell quoting issues on filenames etc etc). NOTE! THIS PATCH DOES NOT DO THAT OPTIMIZATION YET! I was lazy, and the current "diff-core" code actually will always write the temp-files, because it used to be something that you simply had to do. So this current one actually writes a temp-file like before, and then reads it into memory again just to do the diff. Stupid. But if this basic infrastructure is accepted, we can start switching over diff-core to not write temp-files, which should speed things up even further, especially when doing big tree-to-tree diffs. Now, in the interest of full disclosure, I should also point out a few downsides: - the libxdiff algorithm is different, and I bet GNU diff has gotten a lot more testing. And the thing is, generating a diff is not an exact science - you can get two different diffs (and you will), and they can both be perfectly valid. So it's not possible to "validate" the libxdiff output by just comparing it against GNU diff. - GNU diff does some nice eye-candy, like trying to figure out what the last function was, and adding that information to the "@@ .." line. libxdiff doesn't do that. - The libxdiff thing has some known deficiencies. In particular, it gets the "\No newline at end of file" case wrong. So this is currently for the experimental branch only. I hope Davide will help fix it. That said, I think the huge performance advantage, and the fact that it integrates better is definitely worth it. But it should go into a development branch at least due to the missing newline issue. Technical note: this is based on libxdiff-0.17, but I did some surgery to get rid of the extraneous fat - stuff that git doesn't need, and seriously cutting down on mmfile_t, which had much more capabilities than the diff algorithm either needed or used. In this version, "mmfile_t" is just a trivial <pointer,length> tuple. That said, I tried to keep the differences to simple removals, so that you can do a diff between this and the libxdiff origin, and you'll basically see just things getting deleted. Even the mmfile_t simplifications are left in a state where the diffs should be readable. Apologies to Davide, whom I'd love to get feedback on this all from (I wrote my own "fill_mmfile()" for the new simpler mmfile_t format: the old complex format had a helper function for that, but I did my surgery with the goal in mind that eventually we _should_ just do mmfile_t mf; buf = read_sha1_file(sha1, type, &size); mf->ptr = buf; mf->size = size; .. use "mf" directly .. which was really a nightmare with the old "helpful" mmfile_t, and really is that easy with the new cut-down interfaces). [ Btw, as any hawk-eye can see from the diff, this was actually generated with itself, so it is "self-hosting". That's about all the testing it has gotten, along with the above kernel diff, which eye-balls correctly, but shows the newline issue when you double-check it with "git-apply" ] Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>