[PATCH/RFC/GSoC 10/17] rebase-common: implement cache_has_uncommitted_changes()

[Paul Tan <pyokagan@gmail.com>]

In the upcoming git-rebase-to-C rewrite, it is a common opertation to
check if the index has uncommitted changes, so that rebase can complain
that the index is dirty, or commit the uncommitted changes in the index.

builtin/pull.c already implements the function we want. Move it to
rebase-common.c so that it can be shared between all rebase backends and
git-pull.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/pull.c  | 22 +---------------------
 rebase-common.c | 17 +++++++++++++++++
 rebase-common.h |  5 +++++
 3 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/builtin/pull.c b/builtin/pull.c
index 9e65dc9..6be4213 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -307,26 +307,6 @@ static enum rebase_type config_get_rebase(void)
 }
 
 /**
- * Returns 1 if there are uncommitted changes, 0 otherwise.
- */
-static int has_uncommitted_changes(const char *prefix)
-{
-	struct rev_info rev_info;
-	int result;
-
-	if (is_cache_unborn())
-		return 0;
-
-	init_revisions(&rev_info, prefix);
-	DIFF_OPT_SET(&rev_info.diffopt, IGNORE_SUBMODULES);
-	DIFF_OPT_SET(&rev_info.diffopt, QUICK);
-	add_head_to_pending(&rev_info);
-	diff_setup_done(&rev_info.diffopt);
-	result = run_diff_index(&rev_info, 1);
-	return diff_result_code(&rev_info.diffopt, result);
-}
-
-/**
  * If the work tree has unstaged or uncommitted changes, dies with the
  * appropriate message.
  */
@@ -345,7 +325,7 @@ static void die_on_unclean_work_tree(const char *prefix)
 		do_die = 1;
 	}
 
-	if (has_uncommitted_changes(prefix)) {
+	if (cache_has_uncommitted_changes()) {
 		if (do_die)
 			error(_("Additionally, your index contains uncommitted changes."));
 		else
diff --git a/rebase-common.c b/rebase-common.c
index 61be8f1..94783a9 100644
--- a/rebase-common.c
+++ b/rebase-common.c
@@ -29,6 +29,23 @@ int cache_has_unstaged_changes(void)
 	return diff_result_code(&rev_info.diffopt, result);
 }
 
+int cache_has_uncommitted_changes(void)
+{
+	struct rev_info rev_info;
+	int result;
+
+	if (is_cache_unborn())
+		return 0;
+
+	init_revisions(&rev_info, NULL);
+	DIFF_OPT_SET(&rev_info.diffopt, IGNORE_SUBMODULES);
+	DIFF_OPT_SET(&rev_info.diffopt, QUICK);
+	add_head_to_pending(&rev_info);
+	diff_setup_done(&rev_info.diffopt);
+	result = run_diff_index(&rev_info, 1);
+	return diff_result_code(&rev_info.diffopt, result);
+}
+
 void rebase_options_init(struct rebase_options *opts)
 {
 	oidclr(&opts->onto);
diff --git a/rebase-common.h b/rebase-common.h
index 9d14e25..97d9a5b 100644
--- a/rebase-common.h
+++ b/rebase-common.h
@@ -11,6 +11,11 @@ void refresh_and_write_cache(unsigned int);
  */
 int cache_has_unstaged_changes(void);
 
+/**
+ * Returns 1 if there are uncommitted changes, 0 otherwise.
+ */
+int cache_has_uncommitted_changes(void);
+
 /* common rebase backend options */
 struct rebase_options {
 	struct object_id onto;
-- 
2.7.0