xdp-utils: Allow passing an fd the to spawned child process

This allows to use the same spawn methods to be used also by the icon
validator, which in a future commit will use it and switch to using fds
instead of temp files.

src/xdp-utils.c

@@ -432,16 +432,18 @@ xdp_spawn (GError     **error,
   g_ptr_array_add (args, NULL);
   va_end (ap);
 
-  output = xdp_spawnv ((const gchar * const *) args->pdata, error);
+  output = xdp_spawn_full ((const gchar * const *) args->pdata, -1, -1, error);
 
   g_ptr_array_free (args, TRUE);
 
   return output;
 }
 
 gchar *
-xdp_spawnv (const gchar * const  *argv,
-            GError              **error)
+xdp_spawn_full (const gchar * const  *argv,
+                int                   source_fd,
+                int                   target_fd,
+                GError              **error)
 {
   g_autoptr(GSubprocessLauncher) launcher = NULL;
   g_autoptr(GSubprocess) subp = NULL;
@@ -453,6 +455,9 @@ xdp_spawnv (const gchar * const  *argv,
 
   launcher = g_subprocess_launcher_new (G_SUBPROCESS_FLAGS_STDOUT_PIPE);
 
+  if (source_fd != -1)
+    g_subprocess_launcher_take_fd (launcher, source_fd, target_fd);
+
   commandline = xdp_quote_argv ((const char **)argv);
   g_debug ("Running: %s", commandline);
 

src/xdp-utils.h

@@ -125,7 +125,9 @@ char *   xdp_quote_argv (const char           *argv[]);
 char *   xdp_spawn      (GError              **error,
                          const gchar          *argv0,
                          ...) G_GNUC_NULL_TERMINATED;
-char *   xdp_spawnv     (const gchar * const  *argv,
+char *   xdp_spawn_full (const gchar * const  *argv,
+                         int                   source_fd,
+                         int                   target_fd,
                          GError              **error);
 
 char * xdp_canonicalize_filename (const char *path);