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git/xdiff-interface.c
Johannes Schindelin 381b851c9b merge-file: handle empty files gracefully
Earlier, it would error out while trying to read and/or writing them.
Now, calling merge-file with empty files is neither interesting nor
useful, but it is a bug that needed fixing.

Noticed by Clemens Buchacher.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2008-03-13 23:43:56 -07:00

240 lines
5.4 KiB
C

#include "cache.h"
#include "xdiff-interface.h"
static int parse_num(char **cp_p, int *num_p)
{
char *cp = *cp_p;
int num = 0;
int read_some;
while ('0' <= *cp && *cp <= '9')
num = num * 10 + *cp++ - '0';
if (!(read_some = cp - *cp_p))
return -1;
*cp_p = cp;
*num_p = num;
return 0;
}
int parse_hunk_header(char *line, int len,
int *ob, int *on,
int *nb, int *nn)
{
char *cp;
cp = line + 4;
if (parse_num(&cp, ob)) {
bad_line:
return error("malformed diff output: %s", line);
}
if (*cp == ',') {
cp++;
if (parse_num(&cp, on))
goto bad_line;
}
else
*on = 1;
if (*cp++ != ' ' || *cp++ != '+')
goto bad_line;
if (parse_num(&cp, nb))
goto bad_line;
if (*cp == ',') {
cp++;
if (parse_num(&cp, nn))
goto bad_line;
}
else
*nn = 1;
return -!!memcmp(cp, " @@", 3);
}
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->consume(priv, s, this_size);
size -= this_size;
s += this_size;
}
}
int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
{
struct xdiff_emit_state *priv = priv_;
int i;
for (i = 0; i < nbuf; i++) {
if (mb[i].ptr[mb[i].size-1] != '\n') {
/* Incomplete line */
priv->remainder = xrealloc(priv->remainder,
priv->remainder_size +
mb[i].size);
memcpy(priv->remainder + priv->remainder_size,
mb[i].ptr, mb[i].size);
priv->remainder_size += mb[i].size;
continue;
}
/* we have a complete line */
if (!priv->remainder) {
consume_one(priv, mb[i].ptr, mb[i].size);
continue;
}
priv->remainder = xrealloc(priv->remainder,
priv->remainder_size +
mb[i].size);
memcpy(priv->remainder + priv->remainder_size,
mb[i].ptr, mb[i].size);
consume_one(priv, priv->remainder,
priv->remainder_size + mb[i].size);
free(priv->remainder);
priv->remainder = NULL;
priv->remainder_size = 0;
}
if (priv->remainder) {
consume_one(priv, priv->remainder, priv->remainder_size);
free(priv->remainder);
priv->remainder = NULL;
priv->remainder_size = 0;
}
return 0;
}
/*
* Trim down common substring at the end of the buffers,
* but leave at least ctx lines at the end.
*/
static void trim_common_tail(mmfile_t *a, mmfile_t *b, long ctx)
{
const int blk = 1024;
long trimmed = 0, recovered = 0;
char *ap = a->ptr + a->size;
char *bp = b->ptr + b->size;
long smaller = (a->size < b->size) ? a->size : b->size;
if (ctx)
return;
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;
trim_common_tail(&a, &b, xecfg->ctxlen);
return xdl_diff(&a, &b, xpp, xecfg, xecb);
}
int read_mmfile(mmfile_t *ptr, const char *filename)
{
struct stat st;
FILE *f;
size_t sz;
if (stat(filename, &st))
return error("Could not stat %s", filename);
if ((f = fopen(filename, "rb")) == NULL)
return error("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)
return error("Could not read %s", filename);
fclose(f);
ptr->size = sz;
return 0;
}
#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)
{
char *line_buffer = xstrndup(line, len); /* make NUL terminated */
struct ff_regs *regs = priv;
regmatch_t pmatch[2];
int result = 0, i;
for (i = 0; i < regs->nr; i++) {
struct ff_reg *reg = regs->array + i;
if (reg->negate ^ !!regexec(&reg->re,
line_buffer, 2, pmatch, 0)) {
free(line_buffer);
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;
else
while (result > 0 && (isspace(line[result - 1]) ||
line[result - 1] == '\n'))
result--;
memcpy(buffer, line, result);
free(line_buffer);
return result;
}
void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value)
{
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++;
regs->array = xmalloc(regs->nr * sizeof(struct ff_reg));
for (i = 0; i < regs->nr; i++) {
struct ff_reg *reg = regs->array + i;
const char *ep = strchr(value, '\n'), *expression;
char *buffer = NULL;
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, 0))
die("Invalid regexp to look for hunk header: %s", expression);
if (buffer)
free(buffer);
value = ep + 1;
}
}