read-cache.c: move index_has_changes() from merge.c

Since index_has_change() is an index-related function, move it to
read-cache.c, only modifying it to avoid uses of the active_cache and
active_nr macros.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

merge.c

@@ -17,37 +17,6 @@ static const char *merge_argument(struct commit *commit)
 		return EMPTY_TREE_SHA1_HEX;
 }
 
-int index_has_changes(struct strbuf *sb)
-{
-	struct object_id head;
-	int i;
-
-	if (!get_oid_tree("HEAD", &head)) {
-		struct diff_options opt;
-
-		diff_setup(&opt);
-		opt.flags.exit_with_status = 1;
-		if (!sb)
-			opt.flags.quick = 1;
-		do_diff_cache(&head, &opt);
-		diffcore_std(&opt);
-		for (i = 0; sb && i < diff_queued_diff.nr; i++) {
-			if (i)
-				strbuf_addch(sb, ' ');
-			strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
-		}
-		diff_flush(&opt);
-		return opt.flags.has_changes != 0;
-	} else {
-		for (i = 0; sb && i < active_nr; i++) {
-			if (i)
-				strbuf_addch(sb, ' ');
-			strbuf_addstr(sb, active_cache[i]->name);
-		}
-		return !!active_nr;
-	}
-}
-
 int try_merge_command(const char *strategy, size_t xopts_nr,
 		      const char **xopts, struct commit_list *common,
 		      const char *head_arg, struct commit_list *remotes)

read-cache.c

@@ -6,6 +6,8 @@
 #define NO_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
 #include "config.h"
+#include "diff.h"
+#include "diffcore.h"
 #include "tempfile.h"
 #include "lockfile.h"
 #include "cache-tree.h"
@@ -1984,6 +1986,37 @@ int unmerged_index(const struct index_state *istate)
 	return 0;
 }
 
+int index_has_changes(struct strbuf *sb)
+{
+	struct object_id head;
+	int i;
+
+	if (!get_oid_tree("HEAD", &head)) {
+		struct diff_options opt;
+
+		diff_setup(&opt);
+		opt.flags.exit_with_status = 1;
+		if (!sb)
+			opt.flags.quick = 1;
+		do_diff_cache(&head, &opt);
+		diffcore_std(&opt);
+		for (i = 0; sb && i < diff_queued_diff.nr; i++) {
+			if (i)
+				strbuf_addch(sb, ' ');
+			strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
+		}
+		diff_flush(&opt);
+		return opt.flags.has_changes != 0;
+	} else {
+		for (i = 0; sb && i < the_index.cache_nr; i++) {
+			if (i)
+				strbuf_addch(sb, ' ');
+			strbuf_addstr(sb, the_index.cache[i]->name);
+		}
+		return !!the_index.cache_nr;
+	}
+}
+
 #define WRITE_BUFFER_SIZE 8192
 static unsigned char write_buffer[WRITE_BUFFER_SIZE];
 static unsigned long write_buffer_len;