diff mbox series

[v3,05/10] diff-lib: accept option flags in run_diff_index()

Message ID 496908ac10152edb9cbcfdb75c43b1d00e163e3c.1600328335.git.liu.denton@gmail.com (mailing list archive)
State Superseded
Headers show
Series builtin/diff: learn --merge-base | expand

Commit Message

Denton Liu Sept. 17, 2020, 7:44 a.m. UTC 
In a future commit, we will teach run_diff_index() to accept more
options via flag bits. For now, change `cached` into a flag in the
`option` bitfield. The behaviour should remain exactly the same.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
---
 builtin/diff-index.c | 8 ++++----
 builtin/diff.c       | 8 ++++----
 diff-lib.c           | 6 +++---
 diff.h               | 3 ++-
 4 files changed, 13 insertions(+), 12 deletions(-)

Comments

Junio C Hamano Sept. 17, 2020, 5 p.m. UTC | #1 
Denton Liu <liu.denton@gmail.com> writes:

> diff --git a/diff-lib.c b/diff-lib.c
> index 50521e2093..0a0e69113c 100644
> --- a/diff-lib.c
> +++ b/diff-lib.c
> @@ -518,7 +518,7 @@ static int diff_cache(struct rev_info *revs,
>  	return unpack_trees(1, &t, &opts);
>  }
>  
> -int run_diff_index(struct rev_info *revs, int cached)
> +int run_diff_index(struct rev_info *revs, unsigned int option)
>  {
>  	struct object_array_entry *ent;

If we introduce

	int cached = !!(option & DIFF_INDEX_CACHED);

we do not have to touch the remainder of the function, and it makes
it easier to read the place(s) where 'cached' is used.  At that
point, the fact that we were instructed by a bit in the option flag
word is much much less important than we were instructed to compare
the tree-ish with the index and not the working tree files.

The same technique is used with DIFF_RACY_IS_MODIFIED flag in
run_diff_files().

> diff --git a/diff.h b/diff.h
> index e0c0af6286..0cc874f2d5 100644
> --- a/diff.h
> +++ b/diff.h
> @@ -585,7 +585,8 @@ const char *diff_aligned_abbrev(const struct object_id *sha1, int);
>  /* report racily-clean paths as modified */
>  #define DIFF_RACY_IS_MODIFIED 02
>  int run_diff_files(struct rev_info *revs, unsigned int option);
> -int run_diff_index(struct rev_info *revs, int cached);
> +#define DIFF_INDEX_CACHED 01
> +int run_diff_index(struct rev_info *revs, unsigned int option);

It is unclear from the above if the option word for run_diff_files()
and run_diff_index() share the same bit assignment.  After reading
the series through to the end, I know they are independent set of
bits and never shared, but I wonder if we can make it more obvious
here.

Perhaps an extra blank line before this new #define is sufficient to
make it clear?
diff mbox series

Patch

diff --git a/builtin/diff-index.c b/builtin/diff-index.c
index 93ec642423..c3878f7ad6 100644
--- a/builtin/diff-index.c
+++ b/builtin/diff-index.c
@@ -15,7 +15,7 @@  COMMON_DIFF_OPTIONS_HELP;
 int cmd_diff_index(int argc, const char **argv, const char *prefix)
 {
 	struct rev_info rev;
-	int cached = 0;
+	unsigned int option = 0;
 	int i;
 	int result;
 
@@ -32,7 +32,7 @@  int cmd_diff_index(int argc, const char **argv, const char *prefix)
 		const char *arg = argv[i];
 
 		if (!strcmp(arg, "--cached"))
-			cached = 1;
+			option |= DIFF_INDEX_CACHED;
 		else
 			usage(diff_cache_usage);
 	}
@@ -46,7 +46,7 @@  int cmd_diff_index(int argc, const char **argv, const char *prefix)
 	if (rev.pending.nr != 1 ||
 	    rev.max_count != -1 || rev.min_age != -1 || rev.max_age != -1)
 		usage(diff_cache_usage);
-	if (!cached) {
+	if (!(option & DIFF_INDEX_CACHED)) {
 		setup_work_tree();
 		if (read_cache_preload(&rev.diffopt.pathspec) < 0) {
 			perror("read_cache_preload");
@@ -56,7 +56,7 @@  int cmd_diff_index(int argc, const char **argv, const char *prefix)
 		perror("read_cache");
 		return -1;
 	}
-	result = run_diff_index(&rev, cached);
+	result = run_diff_index(&rev, option);
 	UNLEAK(rev);
 	return diff_result_code(&rev.diffopt, result);
 }
diff --git a/builtin/diff.c b/builtin/diff.c
index cb98811c21..e45e19e37e 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -134,11 +134,11 @@  static int builtin_diff_blobs(struct rev_info *revs,
 static int builtin_diff_index(struct rev_info *revs,
 			      int argc, const char **argv)
 {
-	int cached = 0;
+	unsigned int option = 0;
 	while (1 < argc) {
 		const char *arg = argv[1];
 		if (!strcmp(arg, "--cached") || !strcmp(arg, "--staged"))
-			cached = 1;
+			option |= DIFF_INDEX_CACHED;
 		else
 			usage(builtin_diff_usage);
 		argv++; argc--;
@@ -151,7 +151,7 @@  static int builtin_diff_index(struct rev_info *revs,
 	    revs->max_count != -1 || revs->min_age != -1 ||
 	    revs->max_age != -1)
 		usage(builtin_diff_usage);
-	if (!cached) {
+	if (!(option & DIFF_INDEX_CACHED)) {
 		setup_work_tree();
 		if (read_cache_preload(&revs->diffopt.pathspec) < 0) {
 			perror("read_cache_preload");
@@ -161,7 +161,7 @@  static int builtin_diff_index(struct rev_info *revs,
 		perror("read_cache");
 		return -1;
 	}
-	return run_diff_index(revs, cached);
+	return run_diff_index(revs, option);
 }
 
 static int builtin_diff_tree(struct rev_info *revs,
diff --git a/diff-lib.c b/diff-lib.c
index 50521e2093..0a0e69113c 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -518,7 +518,7 @@  static int diff_cache(struct rev_info *revs,
 	return unpack_trees(1, &t, &opts);
 }
 
-int run_diff_index(struct rev_info *revs, int cached)
+int run_diff_index(struct rev_info *revs, unsigned int option)
 {
 	struct object_array_entry *ent;
 
@@ -527,10 +527,10 @@  int run_diff_index(struct rev_info *revs, int cached)
 
 	trace_performance_enter();
 	ent = revs->pending.objects;
-	if (diff_cache(revs, &ent->item->oid, ent->name, cached))
+	if (diff_cache(revs, &ent->item->oid, ent->name, !!(option & DIFF_INDEX_CACHED)))
 		exit(128);
 
-	diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
+	diff_set_mnemonic_prefix(&revs->diffopt, "c/", (option & DIFF_INDEX_CACHED) ? "i/" : "w/");
 	diffcore_fix_diff_index();
 	diffcore_std(&revs->diffopt);
 	diff_flush(&revs->diffopt);
diff --git a/diff.h b/diff.h
index e0c0af6286..0cc874f2d5 100644
--- a/diff.h
+++ b/diff.h
@@ -585,7 +585,8 @@  const char *diff_aligned_abbrev(const struct object_id *sha1, int);
 /* report racily-clean paths as modified */
 #define DIFF_RACY_IS_MODIFIED 02
 int run_diff_files(struct rev_info *revs, unsigned int option);
-int run_diff_index(struct rev_info *revs, int cached);
+#define DIFF_INDEX_CACHED 01
+int run_diff_index(struct rev_info *revs, unsigned int option);
 
 int do_diff_cache(const struct object_id *, struct diff_options *);
 int diff_flush_patch_id(struct diff_options *, struct object_id *, int, int);