[PATCH v5 3/4] argv-array: return the pushed string from argv_push*()

[Martin Ågren]

From: Junio C Hamano <gits...@pobox.com>

Such an API change allows us to use an argv_array this way:

        struct argv_array to_free = ARGV_ARRAY_INIT;
        const char *msg;

        if (some condition) {
                msg = "constant string message";
                ... other logic ...
        } else {
                msg = argv_pushf(&to_free, "format %s", var);
        }
        ... use "msg" ...
        ... do other things ...
        argv_clear(&to_free);

Note that argv_array_pushl() and argv_array_pushv() are used to push
one or more strings with a single call, so we do not return any one
of these strings from these two functions in order to reduce the
chance to misuse the API.

Signed-off-by: Junio C Hamano <gits...@pobox.com>
Signed-off-by: Martin Ågren <martin.ag...@gmail.com>
---
 argv-array.h | 4 ++--
 argv-array.c | 6 ++++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/argv-array.h b/argv-array.h
index 29056e49a1..715c93b246 100644
--- a/argv-array.h
+++ b/argv-array.h
@@ -12,9 +12,9 @@ struct argv_array {
 #define ARGV_ARRAY_INIT { empty_argv, 0, 0 }
 
 void argv_array_init(struct argv_array *);
-void argv_array_push(struct argv_array *, const char *);
+const char *argv_array_push(struct argv_array *, const char *);
 __attribute__((format (printf,2,3)))
-void argv_array_pushf(struct argv_array *, const char *fmt, ...);
+const char *argv_array_pushf(struct argv_array *, const char *fmt, ...);
 LAST_ARG_MUST_BE_NULL
 void argv_array_pushl(struct argv_array *, ...);
 void argv_array_pushv(struct argv_array *, const char **);
diff --git a/argv-array.c b/argv-array.c
index 5d370fa336..449dfc105a 100644
--- a/argv-array.c
+++ b/argv-array.c
@@ -21,12 +21,13 @@ static void argv_array_push_nodup(struct argv_array *array, 
const char *value)
        array->argv[array->argc] = NULL;
 }
 
-void argv_array_push(struct argv_array *array, const char *value)
+const char *argv_array_push(struct argv_array *array, const char *value)
 {
        argv_array_push_nodup(array, xstrdup(value));
+       return array->argv[array->argc - 1];
 }
 
-void argv_array_pushf(struct argv_array *array, const char *fmt, ...)
+const char *argv_array_pushf(struct argv_array *array, const char *fmt, ...)
 {
        va_list ap;
        struct strbuf v = STRBUF_INIT;
@@ -36,6 +37,7 @@ void argv_array_pushf(struct argv_array *array, const char 
*fmt, ...)
        va_end(ap);
 
        argv_array_push_nodup(array, strbuf_detach(&v, NULL));
+       return array->argv[array->argc - 1];
 }
 
 void argv_array_pushl(struct argv_array *array, ...)
-- 
2.17.0.840.g5d83f92caf