stash: call reflog_delete() in reflog.c

Now that cmd_reflog_delete has been libified an exported it into a new
reflog.c library so we can call it directly from builtin/stash.c. This
not only gives us a performance gain since we don't need to create a
subprocess, but it also allows us to use the ref transactions api in the
future.

Helped-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: John Cai <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: john-cai

builtin/stash.c

@@ -17,6 +17,7 @@
 #include "diffcore.h"
 #include "exec-cmd.h"
 #include "entry.h"
+#include "reflog.h"
 
 #define INCLUDE_ALL_FILES 2
 
@@ -634,20 +635,9 @@ static int reflog_is_empty(const char *refname)
 
 static int do_drop_stash(struct stash_info *info, int quiet)
 {
-	int ret;
-	struct child_process cp_reflog = CHILD_PROCESS_INIT;
-
-	/*
-	 * reflog does not provide a simple function for deleting refs. One will
-	 * need to be added to avoid implementing too much reflog code here
-	 */
-
-	cp_reflog.git_cmd = 1;
-	strvec_pushl(&cp_reflog.args, "reflog", "delete", "--updateref",
-		     "--rewrite", NULL);
-	strvec_push(&cp_reflog.args, info->revision.buf);
-	ret = run_command(&cp_reflog);
-	if (!ret) {
+	if (!reflog_delete(info->revision.buf,
+			   EXPIRE_REFLOGS_REWRITE | EXPIRE_REFLOGS_UPDATE_REF,
+			   0)) {
 		if (!quiet)
 			printf_ln(_("Dropped %s (%s)"), info->revision.buf,
 				  oid_to_hex(&info->w_commit));