quote: provide sq_dequote_to_argv_array

This is similar to sq_dequote_to_argv, but more convenient
if you have an argv_array. It's tempting to just feed the
components of the argv_array to sq_dequote_to_argv instead,
but:

  1. It wouldn't maintain the NULL-termination invariant
     of argv_array.

  2. It doesn't match the memory ownership policy of
     argv_array (in which each component is free-able, not a
     pointer into a separate buffer).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

quote.c

@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "quote.h"
+#include "argv-array.h"
 
 int quote_path_fully = 1;
 
@@ -120,7 +121,9 @@ char *sq_dequote(char *arg)
 	return sq_dequote_step(arg, NULL);
 }
 
-int sq_dequote_to_argv(char *arg, const char ***argv, int *nr, int *alloc)
+static int sq_dequote_to_argv_internal(char *arg,
+				       const char ***argv, int *nr, int *alloc,
+				       struct argv_array *array)
 {
 	char *next = arg;
 
@@ -130,13 +133,27 @@ int sq_dequote_to_argv(char *arg, const char ***argv, int *nr, int *alloc)
 		char *dequoted = sq_dequote_step(next, &next);
 		if (!dequoted)
 			return -1;
-		ALLOC_GROW(*argv, *nr + 1, *alloc);
-		(*argv)[(*nr)++] = dequoted;
+		if (argv) {
+			ALLOC_GROW(*argv, *nr + 1, *alloc);
+			(*argv)[(*nr)++] = dequoted;
+		}
+		if (array)
+			argv_array_push(array, dequoted);
 	} while (next);
 
 	return 0;
 }
 
+int sq_dequote_to_argv(char *arg, const char ***argv, int *nr, int *alloc)
+{
+	return sq_dequote_to_argv_internal(arg, argv, nr, alloc, NULL);
+}
+
+int sq_dequote_to_argv_array(char *arg, struct argv_array *array)
+{
+	return sq_dequote_to_argv_internal(arg, NULL, NULL, NULL, array);
+}
+
 /* 1 means: quote as octal
  * 0 means: quote as octal if (quote_path_fully)
  * -1 means: never quote

quote.h

@@ -45,6 +45,14 @@ extern char *sq_dequote(char *);
  */
 extern int sq_dequote_to_argv(char *arg, const char ***argv, int *nr, int *alloc);
 
+/*
+ * Same as above, but store the unquoted strings in an argv_array. We will
+ * still modify arg in place, but unlike sq_dequote_to_argv, the argv_array
+ * will duplicate and take ownership of the strings.
+ */
+struct argv_array;
+extern int sq_dequote_to_argv_array(char *arg, struct argv_array *);
+
 extern int unquote_c_style(struct strbuf *, const char *quoted, const char **endp);
 extern size_t quote_c_style(const char *name, struct strbuf *, FILE *, int no_dq);
 extern void quote_two_c_style(struct strbuf *, const char *, const char *, int);