git/xdiff-interface.h, branch v2.40.2

xdiff-interface: replace discard_hunk_line() with a flag

2021-05-11T03:47:31Z

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 Signed-off-by: Junio C Hamano

pickaxe -G: terminate early on matching lines

2021-05-11T03:47:31Z

Solve a long-standing item for "git log -Grx" of us e.g. finding "+ str" in the diff context and noting that we had a "hit", but xdiff diligently continuing to generate and spew the rest of the diff at us. This makes use of a new "early return" xdiff interface added by preceding commits. The TODO item (or, the NEEDSWORK comment) has been there since "git log -G" was implemented. See f506b8e8b5f (git log/diff: add -G that greps in the patch text, 2010-08-23). But now with the support added in the preceding changes to the xdiff-interface we can return early. Let's assert the behavior of that new early-return xdiff-interface by having a BUG() call here to die if it ever starts handing us needless work again. Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano

xdiff-interface: allow early return from xdiff_emit_line_fn

2021-05-11T03:47:31Z

Finish the change started in the preceding commit and allow an early return from "xdiff_emit_line_fn" callbacks, this will allows diffcore-pickaxe.c to save itself redundant work. Our xdiff interface also had the limitation of not being able to abort early since the beginning, see d9ea73e0564 (combine-diff: refactor built-in xdiff interface., 2006-04-05). Although at that time "xdiff_emit_line_fn" was called "xdiff_emit_consume_fn", and "xdiff_emit_hunk_fn" didn't exist yet. There was some work in this area of xdiff-interface.[ch] recently with 3b40a090fd4 (diff: avoid generating unused hunk header lines, 2018-11-02) and 7c61e25fbf1 (diff: use hunk callback for word-diff, 2018-11-02). In combination those two changes allow us to not do any work on the hunks and diff at all, but didn't change the status quo with regards to consumers that e.g. want the diff lines, but might want to abort early. Whereas now we can abort e.g. on the first "-line" of a 1000 line diff if that's all we needed. This interface is rather scary as noted in the comment to xdiff-interface.h being added here, as noted there a future change could add more exit codes, and hack xdl_emit_diff() and friends to ignore or skip things more selectively as a result. I did not see an inherent reason for why xdl_emit_{diffrec,record}() could not be changed to ferry the "xdiff_emit_line_fn" error code upwards instead of returning -1 on all "ret < 0". But doing so would require corresponding changes in xdl_emit_diff(), xdl_diff(). I didn't see any issue with narrowly doing that to accomplish what I needed here, but it would leave xdiff's own return values in an inconsistent state. Instead I've left it at returning a more conventional (for git's own codebase) 1 for an early return, and translating it (or rather, all non-zero) to -1 for xdiff's consumption. The reason for most of the "stop" complexity in xdiff_outf() is because we want to be able to abort early, but do so in a way that doesn't skip the appropriate strbuf_reset() invocations. Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano

xdiff-interface: prepare for allowing early return

2021-05-11T03:47:31Z

Change the function prototype of xdiff_emit_line_fn to return an "int" instead of "void". Change all of those functions to "return 0", nothing checks those return values yet, and no behavior is being changed. In subsequent commits the interface will be changed to allow early return via this new return value. Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Junio C Hamano

Fix spelling errors in code comments

2019-11-10T07:00:54Z

Reported-by: Jens Schleusener Signed-off-by: Elijah Newren Signed-off-by: Junio C Hamano

*.[ch]: manually align parameter lists

2019-05-05T06:20:10Z

In previous patches, extern was mechanically removed from function declarations without care to formatting, causing parameter lists to be misaligned. Manually format changed sections such that the parameter lists should be realigned. Viewing this patch with 'git diff -w' should produce no output. Signed-off-by: Denton Liu Signed-off-by: Junio C Hamano

*.[ch]: remove extern from function declarations using spatch

2019-05-05T06:20:06Z

There has been a push to remove extern from function declarations. Remove some instances of "extern" for function declarations which are caught by Coccinelle. Note that Coccinelle has some difficulty with processing functions with `__attribute__` or varargs so some `extern` declarations are left behind to be dealt with in a future patch. This was the Coccinelle patch used: @@ type T; identifier f; @@ - extern T f(...); and it was run with: $ git ls-files \*.{c,h} | grep -v ^compat/ | xargs spatch --sp-file contrib/coccinelle/noextern.cocci --in-place Files under `compat/` are intentionally excluded as some are directly copied from external sources and we should avoid churning them as much as possible. Signed-off-by: Denton Liu Signed-off-by: Junio C Hamano

xdiff-interface: drop parse_hunk_header()

2018-11-05T04:14:35Z

This function was used only for parsing the hunk headers generated by xdiff. Now that we can use hunk callbacks to get that information directly, it has outlived its usefulness. Note to anyone who wants to resurrect it: the "len" parameter was totally unused, meaning that the function could read past the end of the "line" array. In practice this never happened, because we only used it to parse xdiff's generated header lines. But it would be dangerous to use it for other cases without fixing this defect. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

diff: avoid generating unused hunk header lines

2018-11-05T04:14:35Z

Some callers of xdi_diff_outf() do not look at the generated hunk header lines at all. By plugging in a no-op hunk callback, this tells xdiff not to even bother formatting them. This patch introduces a stock no-op callback and uses it with a few callers whose line callbacks explicitly ignore hunk headers (because they look only for +/- lines). Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

xdiff-interface: provide a separate consume callback for hunks

2018-11-02T11:43:02Z

The previous commit taught xdiff to optionally provide the hunk header data to a specialized callback. But most users of xdiff actually use our more convenient xdi_diff_outf() helper, which ensures that our callbacks are always fed whole lines. Let's plumb the special hunk-callback through this interface, too. It will follow the same rule as xdiff when the hunk callback is NULL (i.e., continue to pass a stringified hunk header to the line callback). Since we add NULL to each caller, there should be no behavior change yet. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano