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b28858bf65
This patch updates the external diff interface engine for the change to store the symbolic links in the cache, recently done by Kay Sievers. The main thing it does is when comparing with the work tree, it prepares the counterpart to the blob being compared by doing a readlink followed by sending that result to a temporary file to be diffed. Signed-off-by: Junio C Hamano <junkio@cox.net>
407 lines
10 KiB
C
407 lines
10 KiB
C
/*
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* Copyright (C) 2005 Junio C Hamano
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*/
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <signal.h>
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#include "cache.h"
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#include "diff.h"
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static char *diff_opts = "-pu";
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static const char *external_diff(void)
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{
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static char *external_diff_cmd = NULL;
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static int done_preparing = 0;
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if (done_preparing)
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return external_diff_cmd;
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/*
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* Default values above are meant to match the
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* Linux kernel development style. Examples of
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* alternative styles you can specify via environment
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* variables are:
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*
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* GIT_DIFF_OPTS="-c";
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*/
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if (getenv("GIT_EXTERNAL_DIFF"))
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external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
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/* In case external diff fails... */
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diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts;
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done_preparing = 1;
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return external_diff_cmd;
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}
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/* Help to copy the thing properly quoted for the shell safety.
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* any single quote is replaced with '\'', and the caller is
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* expected to enclose the result within a single quote pair.
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*
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* E.g.
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* original sq_expand result
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* name ==> name ==> 'name'
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* a b ==> a b ==> 'a b'
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* a'b ==> a'\''b ==> 'a'\''b'
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*/
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static char *sq_expand(const char *src)
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{
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static char *buf = NULL;
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int cnt, c;
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const char *cp;
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char *bp;
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/* count bytes needed to store the quoted string. */
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for (cnt = 1, cp = src; *cp; cnt++, cp++)
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if (*cp == '\'')
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cnt += 3;
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buf = xmalloc(cnt);
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bp = buf;
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while ((c = *src++)) {
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if (c != '\'')
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*bp++ = c;
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else {
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bp = strcpy(bp, "'\\''");
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bp += 4;
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}
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}
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*bp = 0;
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return buf;
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}
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static struct diff_tempfile {
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const char *name;
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char hex[41];
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char mode[10];
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char tmp_path[50];
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} diff_temp[2];
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static void builtin_diff(const char *name,
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struct diff_tempfile *temp)
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{
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int i, next_at;
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const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
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const char *diff_arg = "'%s' '%s'||:"; /* "||:" is to return 0 */
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const char *input_name_sq[2];
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const char *path0[2];
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const char *path1[2];
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const char *name_sq = sq_expand(name);
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char *cmd;
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/* diff_cmd and diff_arg have 6 %s in total which makes
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* the sum of these strings 12 bytes larger than required.
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* we use 2 spaces around diff-opts, and we need to count
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* terminating NUL, so we subtract 9 here.
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*/
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int cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
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strlen(diff_arg) - 9);
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for (i = 0; i < 2; i++) {
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input_name_sq[i] = sq_expand(temp[i].name);
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if (!strcmp(temp[i].name, "/dev/null")) {
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path0[i] = "/dev/null";
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path1[i] = "";
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} else {
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path0[i] = i ? "b/" : "a/";
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path1[i] = name_sq;
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}
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cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
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strlen(input_name_sq[i]));
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}
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cmd = xmalloc(cmd_size);
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next_at = 0;
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next_at += snprintf(cmd+next_at, cmd_size-next_at,
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diff_cmd,
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path0[0], path1[0], path0[1], path1[1]);
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next_at += snprintf(cmd+next_at, cmd_size-next_at,
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" %s ", diff_opts);
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next_at += snprintf(cmd+next_at, cmd_size-next_at,
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diff_arg, input_name_sq[0], input_name_sq[1]);
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if (!path1[0][0])
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printf("Created: %s (mode:%s)\n", name, temp[1].mode);
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else if (!path1[1][0])
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printf("Deleted: %s\n", name);
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else if (strcmp(temp[0].mode, temp[1].mode)) {
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printf("Mode changed: %s (%s->%s)\n", name,
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temp[0].mode, temp[1].mode);
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/* Be careful. We do not want to diff between
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* symlink and a file.
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*/
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if (strncmp(temp[0].mode, "120", 3) !=
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strncmp(temp[1].mode, "120", 3))
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exit(0);
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}
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fflush(NULL);
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execlp("/bin/sh","sh", "-c", cmd, NULL);
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}
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/*
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* Given a name and sha1 pair, if the dircache tells us the file in
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* the work tree has that object contents, return true, so that
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* prepare_temp_file() does not have to inflate and extract.
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*/
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static int work_tree_matches(const char *name, const unsigned char *sha1)
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{
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struct cache_entry *ce;
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struct stat st;
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int pos, len;
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/* We do not read the cache ourselves here, because the
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* benchmark with my previous version that always reads cache
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* shows that it makes things worse for diff-tree comparing
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* two linux-2.6 kernel trees in an already checked out work
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* tree. This is because most diff-tree comparison deals with
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* only a small number of files, while reading the cache is
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* expensive for a large project, and its cost outweighs the
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* savings we get by not inflating the object to a temporary
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* file. Practically, this code only helps when we are used
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* by diff-cache --cached, which does read the cache before
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* calling us.
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*/
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if (!active_cache)
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return 0;
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len = strlen(name);
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pos = cache_name_pos(name, len);
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if (pos < 0)
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return 0;
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ce = active_cache[pos];
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if ((lstat(name, &st) < 0) ||
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!S_ISREG(st.st_mode) ||
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cache_match_stat(ce, &st) ||
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memcmp(sha1, ce->sha1, 20))
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return 0;
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return 1;
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}
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static void prep_temp_blob(struct diff_tempfile *temp,
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void *blob,
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unsigned long size,
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unsigned char *sha1,
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int mode)
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{
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int fd;
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strcpy(temp->tmp_path, ".diff_XXXXXX");
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fd = mkstemp(temp->tmp_path);
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if (fd < 0)
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die("unable to create temp-file");
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if (write(fd, blob, size) != size)
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die("unable to write temp-file");
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close(fd);
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temp->name = temp->tmp_path;
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strcpy(temp->hex, sha1_to_hex(sha1));
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temp->hex[40] = 0;
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sprintf(temp->mode, "%06o", mode);
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}
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static void prepare_temp_file(const char *name,
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struct diff_tempfile *temp,
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struct diff_spec *one)
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{
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static unsigned char null_sha1[20] = { 0, };
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int use_work_tree = 0;
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if (!one->file_valid) {
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not_a_valid_file:
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/* A '-' entry produces this for file-2, and
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* a '+' entry produces this for file-1.
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*/
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temp->name = "/dev/null";
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strcpy(temp->hex, ".");
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strcpy(temp->mode, ".");
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return;
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}
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if (one->sha1_valid &&
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(!memcmp(one->blob_sha1, null_sha1, sizeof(null_sha1)) ||
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work_tree_matches(name, one->blob_sha1)))
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use_work_tree = 1;
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if (!one->sha1_valid || use_work_tree) {
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struct stat st;
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temp->name = name;
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if (lstat(temp->name, &st) < 0) {
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if (errno == ENOENT)
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goto not_a_valid_file;
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die("stat(%s): %s", temp->name, strerror(errno));
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}
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if (S_ISLNK(st.st_mode)) {
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int ret;
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char *buf, buf_[1024];
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buf = ((sizeof(buf_) < st.st_size) ?
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xmalloc(st.st_size) : buf_);
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ret = readlink(name, buf, st.st_size);
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if (ret < 0)
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die("readlink(%s)", name);
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prep_temp_blob(temp, buf, st.st_size,
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(one->sha1_valid ?
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one->blob_sha1 : null_sha1),
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(one->sha1_valid ?
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one->mode : S_IFLNK));
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}
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else {
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if (!one->sha1_valid)
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strcpy(temp->hex, sha1_to_hex(null_sha1));
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else
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strcpy(temp->hex, sha1_to_hex(one->blob_sha1));
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sprintf(temp->mode, "%06o",
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S_IFREG |ce_permissions(st.st_mode));
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}
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return;
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}
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else {
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void *blob;
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char type[20];
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unsigned long size;
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blob = read_sha1_file(one->blob_sha1, type, &size);
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if (!blob || strcmp(type, "blob"))
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die("unable to read blob object for %s (%s)",
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name, sha1_to_hex(one->blob_sha1));
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prep_temp_blob(temp, blob, size, one->blob_sha1, one->mode);
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free(blob);
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}
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}
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static void remove_tempfile(void)
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{
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int i;
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for (i = 0; i < 2; i++)
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if (diff_temp[i].name == diff_temp[i].tmp_path) {
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unlink(diff_temp[i].name);
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diff_temp[i].name = NULL;
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}
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}
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static void remove_tempfile_on_signal(int signo)
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{
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remove_tempfile();
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}
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/* An external diff command takes:
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*
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* diff-cmd name infile1 infile1-sha1 infile1-mode \
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* infile2 infile2-sha1 infile2-mode.
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*
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*/
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void run_external_diff(const char *name,
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struct diff_spec *one,
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struct diff_spec *two)
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{
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struct diff_tempfile *temp = diff_temp;
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pid_t pid;
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int status;
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static int atexit_asked = 0;
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if (one && two) {
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prepare_temp_file(name, &temp[0], one);
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prepare_temp_file(name, &temp[1], two);
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if (! atexit_asked &&
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(temp[0].name == temp[0].tmp_path ||
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temp[1].name == temp[1].tmp_path)) {
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atexit_asked = 1;
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atexit(remove_tempfile);
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}
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signal(SIGINT, remove_tempfile_on_signal);
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}
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fflush(NULL);
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pid = fork();
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if (pid < 0)
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die("unable to fork");
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if (!pid) {
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const char *pgm = external_diff();
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if (pgm) {
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if (one && two)
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execlp(pgm, pgm,
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name,
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temp[0].name, temp[0].hex, temp[0].mode,
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temp[1].name, temp[1].hex, temp[1].mode,
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NULL);
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else
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execlp(pgm, pgm, name, NULL);
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}
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/*
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* otherwise we use the built-in one.
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*/
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if (one && two)
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builtin_diff(name, temp);
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else
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printf("* Unmerged path %s\n", name);
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exit(0);
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}
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if (waitpid(pid, &status, 0) < 0 ||
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!WIFEXITED(status) || WEXITSTATUS(status)) {
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/* Earlier we did not check the exit status because
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* diff exits non-zero if files are different, and
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* we are not interested in knowing that. It was a
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* mistake which made it harder to quit a diff-*
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* session that uses the git-apply-patch-script as
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* the GIT_EXTERNAL_DIFF. A custom GIT_EXTERNAL_DIFF
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* should also exit non-zero only when it wants to
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* abort the entire diff-* session.
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*/
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remove_tempfile();
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fprintf(stderr, "external diff died, stopping at %s.\n", name);
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exit(1);
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}
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remove_tempfile();
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}
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void diff_addremove(int addremove, unsigned mode,
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const unsigned char *sha1,
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const char *base, const char *path)
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{
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char concatpath[PATH_MAX];
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struct diff_spec spec[2], *one, *two;
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memcpy(spec[0].blob_sha1, sha1, 20);
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spec[0].mode = mode;
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spec[0].sha1_valid = spec[0].file_valid = 1;
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spec[1].file_valid = 0;
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if (addremove == '+') {
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one = spec + 1; two = spec;
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} else {
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one = spec; two = one + 1;
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}
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if (path) {
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strcpy(concatpath, base);
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strcat(concatpath, path);
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}
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run_external_diff(path ? concatpath : base, one, two);
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}
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void diff_change(unsigned old_mode, unsigned new_mode,
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const unsigned char *old_sha1,
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const unsigned char *new_sha1,
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const char *base, const char *path) {
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char concatpath[PATH_MAX];
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struct diff_spec spec[2];
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memcpy(spec[0].blob_sha1, old_sha1, 20);
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spec[0].mode = old_mode;
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memcpy(spec[1].blob_sha1, new_sha1, 20);
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spec[1].mode = new_mode;
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spec[0].sha1_valid = spec[0].file_valid = 1;
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spec[1].sha1_valid = spec[1].file_valid = 1;
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if (path) {
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strcpy(concatpath, base);
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strcat(concatpath, path);
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}
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run_external_diff(path ? concatpath : base, &spec[0], &spec[1]);
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}
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void diff_unmerge(const char *path)
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{
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run_external_diff(path, NULL, NULL);
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}
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