git/xdiff-interface.c
brian m. carlson 14228447c9 hash: provide per-algorithm null OIDs
Up until recently, object IDs did not have an algorithm member, only a
hash.  Consequently, it was possible to share one null (all-zeros)
object ID among all hash algorithms.  Now that we're going to be
handling objects from multiple hash algorithms, it's important to make
sure that all object IDs have a correct algorithm field.

Introduce a per-algorithm null OID, and add it to struct hash_algo.
Introduce a wrapper function as well, and use it everywhere we used to
use the null_oid constant.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-27 16:31:39 +09:00

324 lines
7.5 KiB
C

#include "cache.h"
#include "config.h"
#include "object-store.h"
#include "xdiff-interface.h"
#include "xdiff/xtypes.h"
#include "xdiff/xdiffi.h"
#include "xdiff/xemit.h"
#include "xdiff/xmacros.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 void consume_one(void *priv_, char *s, unsigned long size)
{
struct xdiff_emit_state *priv = priv_;
char *ep;
while (size) {
unsigned long this_size;
ep = memchr(s, '\n', size);
this_size = (ep == NULL) ? size : (ep - s + 1);
priv->line_fn(priv->consume_callback_data, s, this_size);
size -= this_size;
s += this_size;
}
}
static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
{
struct xdiff_emit_state *priv = priv_;
int i;
if (!priv->line_fn)
return 0;
for (i = 0; i < nbuf; i++) {
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) {
consume_one(priv, mb[i].ptr, mb[i].size);
continue;
}
strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
consume_one(priv, priv->remainder.buf, priv->remainder.len);
strbuf_reset(&priv->remainder);
}
if (priv->remainder.len) {
consume_one(priv, priv->remainder.buf, priv->remainder.len);
strbuf_reset(&priv->remainder);
}
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);
}
void discard_hunk_line(void *priv,
long ob, long on, long nb, long nn,
const char *func, long funclen)
{
}
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")) == NULL)
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 = read_object_file(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 git_xmerge_style = -1;
int git_xmerge_config(const char *var, const char *value, void *cb)
{
if (!strcmp(var, "merge.conflictstyle")) {
if (!value)
die("'%s' is not a boolean", var);
if (!strcmp(value, "diff3"))
git_xmerge_style = XDL_MERGE_DIFF3;
else if (!strcmp(value, "merge"))
git_xmerge_style = 0;
/*
* Please update _git_checkout() in
* git-completion.bash when you add new merge config
*/
else
die("unknown style '%s' given for '%s'",
value, var);
return 0;
}
return git_default_config(var, value, cb);
}