GSubprocess: New class for spawning child processes

There are a number of nice things this class brings:

0) Has a race-free termination API on all platforms (on UNIX, calls to
   kill() and waitpid() are coordinated as not to cause problems).
1) Operates in terms of G{Input,Output}Stream, not file descriptors
2) Standard GIO-style async API for wait() with cancellation
3) Makes some simple cases easy, like synchronously spawning a
   process with an argument list
4) Makes hard cases possible, like asynchronously running a process
   with stdout/stderr merged, output directly to a file path

Much rewriting and code review from Ryan Lortie <desrt@desrt.ca>

https://bugzilla.gnome.org/show_bug.cgi?id=672102

1 files changed, 27 insertions, 54 deletions

diff --git a/gio/glib-compile-resources.c b/gio/glib-compile-resources.c
index 6ec3076f4..d7dd58014 100644
--- a/gio/glib-compile-resources.c
+++ b/gio/glib-compile-resources.c
@@ -297,9 +297,8 @@ end_element (GMarkupParseContext  *context,
 
           if (xml_stripblanks && xmllint != NULL)
             {
-              gchar *argv[8];
-              int status, fd, argc;
-              gchar *stderr_child = NULL;
+              int fd;
+	      GSubprocess *proc;
 
               tmp_file = g_strdup ("resource-XXXXXXXX");
               if ((fd = g_mkstemp (tmp_file)) == -1)
@@ -315,43 +314,29 @@ end_element (GMarkupParseContext  *context,
                 }
               close (fd);
 
-              argc = 0;
-              argv[argc++] = (gchar *) xmllint;
-              argv[argc++] = "--nonet";
-              argv[argc++] = "--noblanks";
-              argv[argc++] = "--output";
-              argv[argc++] = tmp_file;
-              argv[argc++] = real_file;
-              argv[argc++] = NULL;
-              g_assert (argc <= G_N_ELEMENTS (argv));
-
-              if (!g_spawn_sync (NULL /* cwd */, argv, NULL /* envv */,
-                                 G_SPAWN_STDOUT_TO_DEV_NULL,
-                                 NULL, NULL, NULL, &stderr_child, &status, &my_error))
-                {
-                  g_propagate_error (error, my_error);
-                  goto cleanup;
-                }
-	      
-	      /* Ugly...we shoud probably just let stderr be inherited */
-	      if (!g_spawn_check_exit_status (status, NULL))
-                {
-                  g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
-                               _("Error processing input file with xmllint:\n%s"), stderr_child);
-                  g_free (stderr_child);
+              proc = g_subprocess_new (G_SUBPROCESS_FLAGS_STDOUT_SILENCE, error,
+                                       xmllint, "--nonet", "--noblanks", "--output", tmp_file, real_file, NULL);
+              g_free (real_file);
+	      real_file = NULL;
+
+	      if (!proc)
+		goto cleanup;
+
+	      if (!g_subprocess_wait_check (proc, NULL, error))
+		{
+		  g_object_unref (proc);
                   goto cleanup;
                 }
 
-              g_free (stderr_child);
-              g_free (real_file);
+	      g_object_unref (proc);
+
               real_file = g_strdup (tmp_file);
             }
 
           if (to_pixdata)
             {
-              gchar *argv[4];
-              gchar *stderr_child = NULL;
-              int status, fd, argc;
+              int fd;
+	      GSubprocess *proc;
 
               if (gdk_pixbuf_pixdata == NULL)
                 {
@@ -375,31 +360,19 @@ end_element (GMarkupParseContext  *context,
                 }
               close (fd);
 
-              argc = 0;
-              argv[argc++] = (gchar *) gdk_pixbuf_pixdata;
-              argv[argc++] = real_file;
-              argv[argc++] = tmp_file2;
-              argv[argc++] = NULL;
-              g_assert (argc <= G_N_ELEMENTS (argv));
+              proc = g_subprocess_new (G_SUBPROCESS_FLAGS_STDOUT_SILENCE, error,
+                                       gdk_pixbuf_pixdata, real_file, tmp_file2, NULL);
+              g_free (real_file);
+              real_file = NULL;
 
-              if (!g_spawn_sync (NULL /* cwd */, argv, NULL /* envv */,
-                                 G_SPAWN_STDOUT_TO_DEV_NULL,
-                                 NULL, NULL, NULL, &stderr_child, &status, &my_error))
-                {
-                  g_propagate_error (error, my_error);
-                  goto cleanup;
-                }
-	      
-	      if (!g_spawn_check_exit_status (status, NULL))
-                {
-                  g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
-			       _("Error processing input file with to-pixdata:\n%s"), stderr_child);
-                  g_free (stderr_child);
+	      if (!g_subprocess_wait_check (proc, NULL, error))
+		{
+		  g_object_unref (proc);
                   goto cleanup;
-                }
+		}
+
+	      g_object_unref (proc);
 
-              g_free (stderr_child);
-              g_free (real_file);
               real_file = g_strdup (tmp_file2);
             }
 	}