Generalize and libify index_is_dirty() to index_differs_from(...)

index_is_dirty() in builtin-revert.c checks if the index is dirty.
This patch generalizes this function to check if the index differs
from a revision, i.e. the former index_is_dirty() behavior can now be
achieved by index_differs_from("HEAD", 0).

The second argument "diff_flags" allows to set further diff option
flags like DIFF_OPT_IGNORE_SUBMODULES. See DIFF_OPT_* macros in diff.h
for a list.

index_differs_from() seems to be useful for more than builtin-revert.c,
so it is moved into diff-lib.c and also used in builtin-commit.c.

Yet to mention:

 - "rev.abbrev = 0;" can be safely removed.
   This has no impact on performance or functioning of neither
   setup_revisions() nor run_diff_index().

 - rev.pending.objects is free()d because this fixes a leak.
   (Also see 295dd2ad "Fix memory leak in traverse_commit_list")

Mentored-by: Daniel Barkalow <barkalow@iabervon.org>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-commit.c b/builtin-commit.c
index d6a3a62..46e649c 100644 (file)
--- a/builtin-commit.c
+++ b/builtin-commit.c
@@ -561,7 +561,6 @@ static int prepare_to_commit(const char *index_file, const char *prefix)
                commitable = run_status(fp, index_file, prefix, 1);
                wt_status_use_color = saved_color_setting;
        } else {
-               struct rev_info rev;
                unsigned char sha1[20];
                const char *parent = "HEAD";
 
@@ -573,16 +572,8 @@ static int prepare_to_commit(const char *index_file, const char *prefix)
 
                if (get_sha1(parent, sha1))
                        commitable = !!active_nr;
-               else {
-                       init_revisions(&rev, "");
-                       rev.abbrev = 0;
-                       setup_revisions(0, NULL, &rev, parent);
-                       DIFF_OPT_SET(&rev.diffopt, QUIET);
-                       DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
-                       run_diff_index(&rev, 1 /* cached */);
-
-                       commitable = !!DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES);
-               }
+               else
+                       commitable = index_differs_from(parent, 0);
        }
 
        fclose(fp);

diff --git a/builtin-revert.c b/builtin-revert.c
index d48313c..d210150 100644 (file)
--- a/builtin-revert.c
+++ b/builtin-revert.c
@@ -223,17 +223,6 @@ static char *help_msg(const unsigned char *sha1)
        return helpbuf;
 }
 
-static int index_is_dirty(void)
-{
-       struct rev_info rev;
-       init_revisions(&rev, NULL);
-       setup_revisions(0, NULL, &rev, "HEAD");
-       DIFF_OPT_SET(&rev.diffopt, QUIET);
-       DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
-       run_diff_index(&rev, 1);
-       return !!DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES);
-}
-
 static struct tree *empty_tree(void)
 {
        struct tree *tree = xcalloc(1, sizeof(struct tree));
@@ -279,7 +268,7 @@ static int revert_or_cherry_pick(int argc, const char **argv)
        } else {
                if (get_sha1("HEAD", head))
                        die ("You do not have a valid HEAD");
-               if (index_is_dirty())
+               if (index_differs_from("HEAD", 0))
                        die ("Dirty index: cannot %s", me);
        }
        discard_cache();

diff --git a/diff-lib.c b/diff-lib.c
index a41e1ec..79d0606 100644 (file)
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -513,3 +513,18 @@ int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
                exit(128);
        return 0;
 }
+
+int index_differs_from(const char *def, int diff_flags)
+{
+       struct rev_info rev;
+
+       init_revisions(&rev, NULL);
+       setup_revisions(0, NULL, &rev, def);
+       DIFF_OPT_SET(&rev.diffopt, QUIET);
+       DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
+       rev.diffopt.flags |= diff_flags;
+       run_diff_index(&rev, 1);
+       if (rev.pending.alloc)
+               free(rev.pending.objects);
+       return (DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES) != 0);
+}

diff --git a/diff.h b/diff.h
index 23cd90c..6703a4f 100644 (file)
--- a/diff.h
+++ b/diff.h
@@ -265,4 +265,6 @@ extern int diff_result_code(struct diff_options *, int);
 
 extern void diff_no_index(struct rev_info *, int, const char **, int, const char *);
 
+extern int index_differs_from(const char *def, int diff_flags);
+
 #endif /* DIFF_H */