зеркало из https://github.com/microsoft/git.git
408 строки
10 KiB
C
408 строки
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 <limits.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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