[PATCH] Diff-tree-helper take two.
This reworks the diff-tree-helper and show-diff to further make external diff command interface simpler. These commands now honor GIT_EXTERNAL_DIFF environment variable which can point at an arbitrary program that takes 7 parameters: name file1 file1-sha1 file1-mode file2 file2-sha1 file2-mode The parameters for an external diff command are as follows: name this invocation of the command is to emit diff for the named cache/tree entry. file1 pathname that holds the contents of the first file. This can be a file inside the working tree, or a temporary file created from the blob object, or /dev/null. The command should not attempt to unlink it -- the temporary is unlinked by the caller. file1-sha1 sha1 hash if file1 is a blob object, or "." otherwise. file1-mode mode bits for file1, or "." for a deleted file. If GIT_EXTERNAL_DIFF environment variable is not set, the default is to invoke diff with the set of parameters old show-diff used to use. This built-in implementation honors the GIT_DIFF_CMD and GIT_DIFF_OPTS environment variables as before. Signed-off-by: Junio C Hamano <junkio@cox.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:

committed by
Linus Torvalds

parent
d1df574380
commit
be3cfa85f4
248
diff.c
248
diff.c
@ -1,13 +1,22 @@
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/*
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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 "cache.h"
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#include "diff.h"
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static char *diff_cmd = "diff -L 'k/%s' -L 'l/%s' ";
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static char *diff_opts = "-p -u";
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static char *diff_arg_forward = " - '%s'";
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static char *diff_arg_reverse = " '%s' -";
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static char *diff_cmd = "diff -L'k/%s' -L'l/%s'";
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static char *diff_opts = "-pu";
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void prepare_diff_cmd(void)
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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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@ -17,8 +26,15 @@ void prepare_diff_cmd(void)
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* GIT_DIFF_CMD="diff -L '%s' -L '%s'"
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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_cmd = getenv("GIT_DIFF_CMD") ? : diff_cmd;
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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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@ -58,49 +74,195 @@ static char *sq_expand(const char *src)
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return buf;
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}
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void show_differences(const char *name, /* filename on the filesystem */
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const char *label, /* diff label to use */
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void *old_contents, /* contents in core */
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unsigned long long old_size, /* size in core */
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int reverse /* 0: diff core file
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1: diff file core */)
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{
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FILE *f;
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char *name_sq = sq_expand(name);
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const char *label_sq = (name != label) ? sq_expand(label) : name_sq;
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char *diff_arg = reverse ? diff_arg_reverse : diff_arg_forward;
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int cmd_size = strlen(name_sq) + strlen(label_sq) * 2 +
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strlen(diff_cmd) + strlen(diff_opts) + strlen(diff_arg);
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char *cmd = malloc(cmd_size);
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int next_at;
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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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fflush(stdout);
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next_at = snprintf(cmd, cmd_size, diff_cmd, label_sq, label_sq);
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next_at += snprintf(cmd+next_at, cmd_size-next_at, "%s", diff_opts);
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next_at += snprintf(cmd+next_at, cmd_size-next_at, diff_arg, name_sq);
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f = popen(cmd, "w");
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if (old_size)
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fwrite(old_contents, old_size, 1, f);
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pclose(f);
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if (label_sq != name_sq)
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free((void*)label_sq); /* constness */
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free(name_sq);
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free(cmd);
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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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static char *diff_arg = "'%s' '%s'";
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const char *name_1_sq = sq_expand(temp[0].name);
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const char *name_2_sq = sq_expand(temp[1].name);
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const char *name_sq = sq_expand(name);
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/* diff_cmd and diff_arg have 4 %s in total which makes
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* the sum of these strings 8 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 5 here.
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*/
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int cmd_size = (strlen(diff_cmd) +
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strlen(name_sq) * 2 +
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strlen(diff_opts) +
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strlen(diff_arg) +
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strlen(name_1_sq) + strlen(name_2_sq)
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- 5);
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char *cmd = malloc(cmd_size);
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int next_at = 0;
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next_at += snprintf(cmd+next_at, cmd_size-next_at,
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diff_cmd, name_sq, name_sq);
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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, name_1_sq, name_2_sq);
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execlp("/bin/sh","sh", "-c", cmd, NULL);
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}
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void show_diff_empty(const unsigned char *sha1,
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const char *name,
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int reverse)
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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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char *old;
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unsigned long int size;
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unsigned char type[20];
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static unsigned char null_sha1[20] = { 0, };
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old = read_sha1_file(sha1, type, &size);
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if (! old) {
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error("unable to read blob object for %s (%s)", name,
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sha1_to_hex(sha1));
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if (!one->file_valid) {
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not_a_valid_file:
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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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show_differences("/dev/null", name, old, size, reverse);
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if (one->sha1_valid &&
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!memcmp(one->u.sha1, null_sha1, sizeof(null_sha1))) {
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one->sha1_valid = 0;
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one->u.name = name;
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}
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if (!one->sha1_valid) {
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struct stat st;
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temp->name = one->u.name;
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if (stat(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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strcpy(temp->hex, ".");
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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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else {
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int fd;
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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->u.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->u.sha1));
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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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free(blob);
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temp->name = temp->tmp_path;
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strcpy(temp->hex, sha1_to_hex(one->u.sha1));
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temp->hex[40] = 0;
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sprintf(temp->mode, "%06o", one->mode);
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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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/* 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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int pid, status;
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static int atexit_asked = 0;
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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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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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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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/*
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* otherwise we use the built-in one.
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*/
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builtin_diff(name, temp);
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exit(0);
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}
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if (waitpid(pid, &status, 0) < 0 || !WIFEXITED(status))
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die("diff program failed");
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remove_tempfile();
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}
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void show_diff_empty(const struct cache_entry *ce, int reverse)
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{
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struct diff_spec spec[2], *one, *two;
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memcpy(spec[0].u.sha1, ce->sha1, 20);
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spec[0].mode = ntohl(ce->ce_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 (reverse) {
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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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run_external_diff(ce->name, one, two);
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}
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void show_differences(const struct cache_entry *ce, int reverse)
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{
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struct diff_spec spec[2], *one, *two;
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memcpy(spec[0].u.sha1, ce->sha1, 20);
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spec[0].mode = ntohl(ce->ce_mode);
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spec[0].sha1_valid = spec[0].file_valid = 1;
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spec[1].u.name = ce->name; /* the name we stated */
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spec[1].sha1_valid = 0;
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spec[1].file_valid = 1;
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if (reverse) {
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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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run_external_diff(ce->name, one, two);
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}
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