git/xdiff-interface.h
Ævar Arnfjörð Bjarmason 5d93460024 xdiff-interface: replace discard_hunk_line() with a flag
Remove the dummy discard_hunk_line() function added in
3b40a090fd (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 907681e940 (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>
2021-05-11 12:47:31 +09:00

72 lines
2.7 KiB
C

#ifndef XDIFF_INTERFACE_H
#define XDIFF_INTERFACE_H
#include "cache.h"
#include "xdiff/xdiff.h"
/*
* xdiff isn't equipped to handle content over a gigabyte;
* we make the cutoff 1GB - 1MB to give some breathing
* room for constant-sized additions (e.g., merge markers)
*/
#define MAX_XDIFF_SIZE (1024UL * 1024 * 1023)
/**
* The `xdiff_emit_line_fn` function can return 1 to abort early, or 0
* to continue processing. Note that doing so is an all-or-nothing
* affair, as returning 1 will return all the way to the top-level,
* e.g. the xdi_diff_outf() call to generate the diff.
*
* Thus returning 1 means you won't be getting any more diff lines. If
* you need something in-between those two options you'll to use
* `xdl_emit_hunk_consume_func_t` and implement your own version of
* xdl_emit_diff().
*
* We may extend the interface in the future to understand other more
* granular return values. While you should return 1 to exit early,
* doing so will currently make your early return indistinguishable
* from an error internal to xdiff, xdiff itself will see that
* non-zero return and translate it to -1.
*
* See "diff_grep" in diffcore-pickaxe.c for a trick to work around
* this, i.e. using the "consume_callback_data" to note the desired
* early return.
*/
typedef int (*xdiff_emit_line_fn)(void *, char *, unsigned long);
typedef void (*xdiff_emit_hunk_fn)(void *data,
long old_begin, long old_nr,
long new_begin, long new_nr,
const char *func, long funclen);
int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *ecb);
int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
xdiff_emit_hunk_fn hunk_fn,
xdiff_emit_line_fn line_fn,
void *consume_callback_data,
xpparam_t const *xpp, xdemitconf_t const *xecfg);
int read_mmfile(mmfile_t *ptr, const char *filename);
void read_mmblob(mmfile_t *ptr, const struct object_id *oid);
int buffer_is_binary(const char *ptr, unsigned long size);
void xdiff_set_find_func(xdemitconf_t *xecfg, const char *line, int cflags);
void xdiff_clear_find_func(xdemitconf_t *xecfg);
int git_xmerge_config(const char *var, const char *value, void *cb);
extern int git_xmerge_style;
/*
* Compare the strings l1 with l2 which are of size s1 and s2 respectively.
* Returns 1 if the strings are deemed equal, 0 otherwise.
* The `flags` given as XDF_WHITESPACE_FLAGS determine how white spaces
* are treated for the comparison.
*/
int xdiff_compare_lines(const char *l1, long s1,
const char *l2, long s2, long flags);
/*
* Returns a hash of the string s of length len.
* The `flags` given as XDF_WHITESPACE_FLAGS determine how white spaces
* are treated for the hash.
*/
unsigned long xdiff_hash_string(const char *s, size_t len, long flags);
#endif