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git/diff-helper.c
Junio C Hamano 52e9578985 [PATCH] Introducing software archaeologist's tool "pickaxe".
This steals the "pickaxe" feature from JIT and make it available
to the bare Plumbing layer.  From the command line, the user
gives a string he is intersted in.

Using the diff-core infrastructure previously introduced, it
filters the differences to limit the output only to the diffs
between <src> and <dst> where the string appears only in one but
not in the other.  For example:

 $ ./git-rev-list HEAD | ./git-diff-tree -Sdiff-tree-helper --stdin -M

would show the diffs that touch the string "diff-tree-helper".

In real software-archaeologist application, you would typically
look for a few to several lines of code and see where that code
came from.

The "pickaxe" module runs after "rename/copy detection" module,
so it even crosses the file rename boundary, as the above
example demonstrates.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-21 09:58:03 -07:00

148 lines
3.2 KiB
C

/*
* Copyright (C) 2005 Junio C Hamano
*/
#include <limits.h>
#include "cache.h"
#include "strbuf.h"
#include "diff.h"
static int detect_rename = 0;
static int diff_score_opt = 0;
static int generate_patch = 1;
static char *pickaxe = 0;
static int parse_oneside_change(const char *cp, int *mode,
unsigned char *sha1, char *path)
{
int ch, m;
m = 0;
while ((ch = *cp) && '0' <= ch && ch <= '7') {
m = (m << 3) | (ch - '0');
cp++;
}
*mode = m;
if (strncmp(cp, "\tblob\t", 6) && strncmp(cp, " blob ", 6) &&
strncmp(cp, "\ttree\t", 6) && strncmp(cp, " tree ", 6))
return -1;
cp += 6;
if (get_sha1_hex(cp, sha1))
return -1;
cp += 40;
if ((*cp != '\t') && *cp != ' ')
return -1;
strcpy(path, ++cp);
return 0;
}
static int parse_diff_raw_output(const char *buf)
{
char path[PATH_MAX];
unsigned char old_sha1[20], new_sha1[20];
const char *cp = buf;
int ch, old_mode, new_mode;
switch (*cp++) {
case 'U':
diff_unmerge(cp + 1);
break;
case '+':
if (parse_oneside_change(cp, &new_mode, new_sha1, path))
return -1;
diff_addremove('+', new_mode, new_sha1, path, NULL);
break;
case '-':
if (parse_oneside_change(cp, &old_mode, old_sha1, path))
return -1;
diff_addremove('-', old_mode, old_sha1, path, NULL);
break;
case '*':
old_mode = new_mode = 0;
while ((ch = *cp) && ('0' <= ch && ch <= '7')) {
old_mode = (old_mode << 3) | (ch - '0');
cp++;
}
if (strncmp(cp, "->", 2))
return -1;
cp += 2;
while ((ch = *cp) && ('0' <= ch && ch <= '7')) {
new_mode = (new_mode << 3) | (ch - '0');
cp++;
}
if (strncmp(cp, "\tblob\t", 6) && strncmp(cp, " blob ", 6) &&
strncmp(cp, "\ttree\t", 6) && strncmp(cp, " tree ", 6))
return -1;
cp += 6;
if (get_sha1_hex(cp, old_sha1))
return -1;
cp += 40;
if (strncmp(cp, "->", 2))
return -1;
cp += 2;
if (get_sha1_hex(cp, new_sha1))
return -1;
cp += 40;
if ((*cp != '\t') && *cp != ' ')
return -1;
strcpy(path, ++cp);
diff_change(old_mode, new_mode, old_sha1, new_sha1, path, NULL);
break;
default:
return -1;
}
return 0;
}
static const char *diff_helper_usage =
"git-diff-helper [-z] [-R] [-M] [-C] [-S<string>] paths...";
int main(int ac, const char **av) {
struct strbuf sb;
int reverse = 0;
int line_termination = '\n';
strbuf_init(&sb);
while (1 < ac && av[1][0] == '-') {
if (av[1][1] == 'R')
reverse = 1;
else if (av[1][1] == 'z')
line_termination = 0;
else if (av[1][1] == 'p') /* hidden from the help */
generate_patch = 0;
else if (av[1][1] == 'M') {
detect_rename = 1;
diff_score_opt = diff_scoreopt_parse(av[1]);
}
else if (av[1][1] == 'C') {
detect_rename = 2;
diff_score_opt = diff_scoreopt_parse(av[1]);
}
else if (av[1][1] == 'S') {
pickaxe = av[1] + 2;
}
else
usage(diff_helper_usage);
ac--; av++;
}
/* the remaining parameters are paths patterns */
diff_setup(detect_rename, diff_score_opt, pickaxe,
reverse, (generate_patch ? -1 : line_termination),
av+1, ac-1);
while (1) {
int status;
read_line(&sb, stdin, line_termination);
if (sb.eof)
break;
status = parse_diff_raw_output(sb.buf);
if (status) {
diff_flush();
printf("%s%c", sb.buf, line_termination);
}
}
diff_flush();
return 0;
}