From 4789576e0e5364dcd3916ef583b2ea61bef23f24 Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Mon, 18 Apr 2005 15:07:24 -0700
Subject: [PATCH] [PATCH] show-diff.c: -R option for reverse diff.
This adds -R option to obtain reverse diff.
It may be useful in the merge workflow. After the base of the working
directory is merged and commited, in the working directory:
$ read-tree <tree-id-of-merged-tree>
$ show-diff -R
to re-validate if upstream changes make sense, and/or revert or
conflict with local changes you have in the working files.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
show-diff.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
diff --git a/show-diff.c b/show-diff.c
index 42359339bd..4456230a56 100644
--- a/show-diff.c
+++ b/show-diff.c
@@ -7,6 +7,8 @@
static char *diff_cmd = "diff -L 'a/%s' -L 'b/%s' ";
static char *diff_opts = "-p -u";
+static char *diff_arg_forward = " - '%s'";
+static char *diff_arg_reverse = " '%s' -";
static void prepare_diff_cmd(void)
{
@@ -63,12 +65,12 @@ static char *sq_expand(char *src)
}
static void show_differences(char *name, char *label, void *old_contents,
- unsigned long long old_size)
+ unsigned long long old_size, int reverse)
{
- static char *diff_arg = " - '%s'";
FILE *f;
char *name_sq = sq_expand(name);
char *label_sq = (name != label) ? sq_expand(label) : name_sq;
+ char *diff_arg = reverse ? diff_arg_reverse : diff_arg_forward;
int cmd_size = strlen(name_sq) + strlen(label_sq) * 2 +
strlen(diff_cmd) + strlen(diff_opts) + strlen(diff_arg);
char *cmd = malloc(cmd_size);
@@ -88,7 +90,7 @@ static void show_differences(char *name, char *label, void *old_contents,
free(cmd);
}
-static void show_diff_empty(struct cache_entry *ce)
+static void show_diff_empty(struct cache_entry *ce, int reverse)
{
char *old;
unsigned long int size;
@@ -100,7 +102,7 @@ static void show_diff_empty(struct cache_entry *ce)
sha1_to_hex(ce->sha1));
return;
}
- show_differences("/dev/null", ce->name, old, size);
+ show_differences("/dev/null", ce->name, old, size, reverse);
}
static const char *show_diff_usage = "show-diff [-q] [-s] [-z] [paths...]";
@@ -125,11 +127,14 @@ int main(int argc, char **argv)
int silent = 0;
int silent_on_nonexisting_files = 0;
int machine_readable = 0;
+ int reverse = 0;
int entries = read_cache();
int i;
while (1 < argc && argv[1][0] == '-') {
- if (!strcmp(argv[1], "-s"))
+ if (!strcmp(argv[1], "-R"))
+ reverse = 1;
+ else if (!strcmp(argv[1], "-s"))
silent_on_nonexisting_files = silent = 1;
else if (!strcmp(argv[1], "-q"))
silent_on_nonexisting_files = 1;
@@ -181,7 +186,7 @@ int main(int argc, char **argv)
else {
printf("%s: %s\n", ce->name, strerror(errno));
if (errno == ENOENT)
- show_diff_empty(ce);
+ show_diff_empty(ce, reverse);
}
continue;
}
@@ -202,7 +207,8 @@ int main(int argc, char **argv)
error("unable to read blob object for %s (%s)",
ce->name, sha1_to_hex(ce->sha1));
else
- show_differences(ce->name, ce->name, old, size);
+ show_differences(ce->name, ce->name, old, size,
+ reverse);
free(old);
}
return 0;