git/xdiff-interface.c
Patrick Steinhardt e7da938570 global: introduce USE_THE_REPOSITORY_VARIABLE macro
Use of the `the_repository` variable is deprecated nowadays, and we
slowly but steadily convert the codebase to not use it anymore. Instead,
callers should be passing down the repository to work on via parameters.

It is hard though to prove that a given code unit does not use this
variable anymore. The most trivial case, merely demonstrating that there
is no direct use of `the_repository`, is already a bit of a pain during
code reviews as the reviewer needs to manually verify claims made by the
patch author. The bigger problem though is that we have many interfaces
that implicitly rely on `the_repository`.

Introduce a new `USE_THE_REPOSITORY_VARIABLE` macro that allows code
units to opt into usage of `the_repository`. The intent of this macro is
to demonstrate that a certain code unit does not use this variable
anymore, and to keep it from new dependencies on it in future changes,
be it explicit or implicit

For now, the macro only guards `the_repository` itself as well as
`the_hash_algo`. There are many more known interfaces where we have an
implicit dependency on `the_repository`, but those are not guarded at
the current point in time. Over time though, we should start to add
guards as required (or even better, just remove them).

Define the macro as required in our code units. As expected, most of our
code still relies on the global variable. Nearly all of our builtins
rely on the variable as there is no way yet to pass `the_repository` to
their entry point. For now, declare the macro in "biultin.h" to keep the
required changes at least a little bit more contained.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-14 10:26:33 -07:00

342 lines
7.8 KiB
C

#define USE_THE_REPOSITORY_VARIABLE
#include "git-compat-util.h"
#include "gettext.h"
#include "config.h"
#include "hex.h"
#include "object-store-ll.h"
#include "strbuf.h"
#include "xdiff-interface.h"
#include "xdiff/xtypes.h"
#include "xdiff/xdiffi.h"
#include "xdiff/xutils.h"
struct xdiff_emit_state {
xdiff_emit_hunk_fn hunk_fn;
xdiff_emit_line_fn line_fn;
void *consume_callback_data;
struct strbuf remainder;
};
static int xdiff_out_hunk(void *priv_,
long old_begin, long old_nr,
long new_begin, long new_nr,
const char *func, long funclen)
{
struct xdiff_emit_state *priv = priv_;
if (priv->remainder.len)
BUG("xdiff emitted hunk in the middle of a line");
priv->hunk_fn(priv->consume_callback_data,
old_begin, old_nr, new_begin, new_nr,
func, funclen);
return 0;
}
static int consume_one(void *priv_, char *s, unsigned long size)
{
struct xdiff_emit_state *priv = priv_;
char *ep;
while (size) {
unsigned long this_size;
int ret;
ep = memchr(s, '\n', size);
this_size = (ep == NULL) ? size : (ep - s + 1);
ret = priv->line_fn(priv->consume_callback_data, s, this_size);
if (ret)
return ret;
size -= this_size;
s += this_size;
}
return 0;
}
static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
{
struct xdiff_emit_state *priv = priv_;
int i;
int stop = 0;
if (!priv->line_fn)
return 0;
for (i = 0; i < nbuf; i++) {
if (stop)
return 1;
if (mb[i].ptr[mb[i].size-1] != '\n') {
/* Incomplete line */
strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
continue;
}
/* we have a complete line */
if (!priv->remainder.len) {
stop = consume_one(priv, mb[i].ptr, mb[i].size);
continue;
}
strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
strbuf_reset(&priv->remainder);
}
if (stop)
return -1;
if (priv->remainder.len) {
stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
strbuf_reset(&priv->remainder);
}
if (stop)
return -1;
return 0;
}
/*
* Trim down common substring at the end of the buffers,
* but end on a complete line.
*/
static void trim_common_tail(mmfile_t *a, mmfile_t *b)
{
const int blk = 1024;
long trimmed = 0, recovered = 0;
char *ap = a->size ? a->ptr + a->size : a->ptr;
char *bp = b->size ? b->ptr + b->size : b->ptr;
long smaller = (a->size < b->size) ? a->size : b->size;
while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
trimmed += blk;
ap -= blk;
bp -= blk;
}
while (recovered < trimmed)
if (ap[recovered++] == '\n')
break;
a->size -= trimmed - recovered;
b->size -= trimmed - recovered;
}
int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *xecb)
{
mmfile_t a = *mf1;
mmfile_t b = *mf2;
if (mf1->size > MAX_XDIFF_SIZE || mf2->size > MAX_XDIFF_SIZE)
return -1;
if (!xecfg->ctxlen && !(xecfg->flags & XDL_EMIT_FUNCCONTEXT))
trim_common_tail(&a, &b);
return xdl_diff(&a, &b, xpp, xecfg, xecb);
}
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 ret;
struct xdiff_emit_state state;
xdemitcb_t ecb;
memset(&state, 0, sizeof(state));
state.hunk_fn = hunk_fn;
state.line_fn = line_fn;
state.consume_callback_data = consume_callback_data;
memset(&ecb, 0, sizeof(ecb));
if (hunk_fn)
ecb.out_hunk = xdiff_out_hunk;
ecb.out_line = xdiff_outf;
ecb.priv = &state;
strbuf_init(&state.remainder, 0);
ret = xdi_diff(mf1, mf2, xpp, xecfg, &ecb);
strbuf_release(&state.remainder);
return ret;
}
int read_mmfile(mmfile_t *ptr, const char *filename)
{
struct stat st;
FILE *f;
size_t sz;
if (stat(filename, &st))
return error_errno("Could not stat %s", filename);
if (!(f = fopen(filename, "rb")))
return error_errno("Could not open %s", filename);
sz = xsize_t(st.st_size);
ptr->ptr = xmalloc(sz ? sz : 1);
if (sz && fread(ptr->ptr, sz, 1, f) != 1) {
fclose(f);
return error("Could not read %s", filename);
}
fclose(f);
ptr->size = sz;
return 0;
}
void read_mmblob(mmfile_t *ptr, const struct object_id *oid)
{
unsigned long size;
enum object_type type;
if (oideq(oid, null_oid())) {
ptr->ptr = xstrdup("");
ptr->size = 0;
return;
}
ptr->ptr = repo_read_object_file(the_repository, oid, &type, &size);
if (!ptr->ptr || type != OBJ_BLOB)
die("unable to read blob object %s", oid_to_hex(oid));
ptr->size = size;
}
#define FIRST_FEW_BYTES 8000
int buffer_is_binary(const char *ptr, unsigned long size)
{
if (FIRST_FEW_BYTES < size)
size = FIRST_FEW_BYTES;
return !!memchr(ptr, 0, size);
}
struct ff_regs {
int nr;
struct ff_reg {
regex_t re;
int negate;
} *array;
};
static long ff_regexp(const char *line, long len,
char *buffer, long buffer_size, void *priv)
{
struct ff_regs *regs = priv;
regmatch_t pmatch[2];
int i;
int result;
/* Exclude terminating newline (and cr) from matching */
if (len > 0 && line[len-1] == '\n') {
if (len > 1 && line[len-2] == '\r')
len -= 2;
else
len--;
}
for (i = 0; i < regs->nr; i++) {
struct ff_reg *reg = regs->array + i;
if (!regexec_buf(&reg->re, line, len, 2, pmatch, 0)) {
if (reg->negate)
return -1;
break;
}
}
if (regs->nr <= i)
return -1;
i = pmatch[1].rm_so >= 0 ? 1 : 0;
line += pmatch[i].rm_so;
result = pmatch[i].rm_eo - pmatch[i].rm_so;
if (result > buffer_size)
result = buffer_size;
while (result > 0 && (isspace(line[result - 1])))
result--;
memcpy(buffer, line, result);
return result;
}
void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
{
int i;
struct ff_regs *regs;
xecfg->find_func = ff_regexp;
regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
for (i = 0, regs->nr = 1; value[i]; i++)
if (value[i] == '\n')
regs->nr++;
ALLOC_ARRAY(regs->array, regs->nr);
for (i = 0; i < regs->nr; i++) {
struct ff_reg *reg = regs->array + i;
const char *ep, *expression;
char *buffer = NULL;
if (!value)
BUG("mismatch between line count and parsing");
ep = strchr(value, '\n');
reg->negate = (*value == '!');
if (reg->negate && i == regs->nr - 1)
die("Last expression must not be negated: %s", value);
if (*value == '!')
value++;
if (ep)
expression = buffer = xstrndup(value, ep - value);
else
expression = value;
if (regcomp(&reg->re, expression, cflags))
die("Invalid regexp to look for hunk header: %s", expression);
free(buffer);
value = ep ? ep + 1 : NULL;
}
}
void xdiff_clear_find_func(xdemitconf_t *xecfg)
{
if (xecfg->find_func) {
int i;
struct ff_regs *regs = xecfg->find_func_priv;
for (i = 0; i < regs->nr; i++)
regfree(&regs->array[i].re);
free(regs->array);
free(regs);
xecfg->find_func = NULL;
xecfg->find_func_priv = NULL;
}
}
unsigned long xdiff_hash_string(const char *s, size_t len, long flags)
{
return xdl_hash_record(&s, s + len, flags);
}
int xdiff_compare_lines(const char *l1, long s1,
const char *l2, long s2, long flags)
{
return xdl_recmatch(l1, s1, l2, s2, flags);
}
int parse_conflict_style_name(const char *value)
{
if (!strcmp(value, "diff3"))
return XDL_MERGE_DIFF3;
else if (!strcmp(value, "zdiff3"))
return XDL_MERGE_ZEALOUS_DIFF3;
else if (!strcmp(value, "merge"))
return 0;
/*
* Please update _git_checkout() in git-completion.bash when
* you add new merge config
*/
else
return -1;
}
int git_xmerge_style = -1;
int git_xmerge_config(const char *var, const char *value,
const struct config_context *ctx, void *cb)
{
if (!strcmp(var, "merge.conflictstyle")) {
if (!value)
return config_error_nonbool(var);
git_xmerge_style = parse_conflict_style_name(value);
if (git_xmerge_style == -1)
return error(_("unknown style '%s' given for '%s'"),
value, var);
return 0;
}
return git_default_config(var, value, ctx, cb);
}