[glib/glib-2-36] g_file_set_contents(): don't allocate display name

[Matthias Clasen <matthiasc src gnome org>]

commit 75c0593a268b5ceb0cc7ac84d52e23a93a3f2e9d
Author: Ryan Lortie <desrt desrt ca>
Date:   Mon Jun 3 16:16:25 2013 -0400

    g_file_set_contents(): don't allocate display name
    
    g_file_set_contents() sets a GError in the event of various failures
    that count occur.  It uses g_filename_display_name() in order to get the
    filename to include in the messages.
    
    Factor out the error handling to make it easier to allocate the display
    name only when we need it (instead of allocating it every time).
    
    https://bugzilla.gnome.org/show_bug.cgi?id=701560

 glib/gfileutils.c |  124 ++++++++++++++++++++---------------------------------
 1 files changed, 46 insertions(+), 78 deletions(-)
---
diff --git a/glib/gfileutils.c b/glib/gfileutils.c
index 2350643..938bd97 100644
--- a/glib/gfileutils.c
+++ b/glib/gfileutils.c
@@ -1004,6 +1004,27 @@ rename_file (const char  *old_name,
   return TRUE;
 }
 
+/* format string must have two '%s':
+ *
+ *   - the place for the filename
+ *   - the place for the strerror
+ */
+static void
+format_error_message (GError      **error,
+                      const gchar  *filename,
+                      const gchar  *format_string)
+{
+  gint saved_errno = errno;
+  gchar *display_name;
+
+  display_name = g_filename_display_name (filename);
+
+  g_set_error (error, G_FILE_ERROR, g_file_error_from_errno (saved_errno),
+               format_string, display_name, g_strerror (saved_errno));
+
+  g_free (display_name);
+}
+
 static gchar *
 write_to_temp_file (const gchar  *contents,
                    gssize        length,
@@ -1011,30 +1032,20 @@ write_to_temp_file (const gchar  *contents,
                    GError      **err)
 {
   gchar *tmp_name;
-  gchar *display_name;
   gchar *retval;
   FILE *file;
   gint fd;
-  int save_errno;
 
   retval = NULL;
-  
+
   tmp_name = g_strdup_printf ("%s.XXXXXX", dest_file);
 
   errno = 0;
   fd = g_mkstemp_full (tmp_name, O_RDWR | O_BINARY, 0666);
-  save_errno = errno;
 
-  display_name = g_filename_display_name (tmp_name);
-      
   if (fd == -1)
     {
-      g_set_error (err,
-                  G_FILE_ERROR,
-                  g_file_error_from_errno (save_errno),
-                  _("Failed to create file '%s': %s"),
-                  display_name, g_strerror (save_errno));
-      
+      format_error_message (err, tmp_name, _("Failed to create file '%s': %s"));
       goto out;
     }
 
@@ -1042,17 +1053,10 @@ write_to_temp_file (const gchar  *contents,
   file = fdopen (fd, "wb");
   if (!file)
     {
-      save_errno = errno;
-      g_set_error (err,
-                  G_FILE_ERROR,
-                  g_file_error_from_errno (save_errno),
-                  _("Failed to open file '%s' for writing: fdopen() failed: %s"),
-                  display_name,
-                  g_strerror (save_errno));
-
+      format_error_message (err, tmp_name, _("Failed to open file '%s' for writing: fdopen() failed: %s"));
       close (fd);
       g_unlink (tmp_name);
-      
+
       goto out;
     }
 
@@ -1066,44 +1070,27 @@ write_to_temp_file (const gchar  *contents,
        */
       (void) posix_fallocate (fd, 0, length);
 #endif
-      
+
       errno = 0;
 
       n_written = fwrite (contents, 1, length, file);
 
       if (n_written < length)
-       {
-         save_errno = errno;
-      
-         g_set_error (err,
-                      G_FILE_ERROR,
-                      g_file_error_from_errno (save_errno),
-                      _("Failed to write file '%s': fwrite() failed: %s"),
-                      display_name,
-                      g_strerror (save_errno));
-
-         fclose (file);
-         g_unlink (tmp_name);
-         
-         goto out;
-       }
+        {
+          format_error_message (err, tmp_name, _("Failed to write file '%s': fwrite() failed: %s"));
+          fclose (file);
+          g_unlink (tmp_name);
+          goto out;
+        }
     }
 
   errno = 0;
   if (fflush (file) != 0)
-    { 
-      save_errno = errno;
-      
-      g_set_error (err,
-                  G_FILE_ERROR,
-                  g_file_error_from_errno (save_errno),
-                  _("Failed to write file '%s': fflush() failed: %s"),
-                  display_name, 
-                  g_strerror (save_errno));
-
+    {
+      format_error_message (err, tmp_name, _("Failed to write file '%s': fflush() failed: %s"));
       fclose (file);
       g_unlink (tmp_name);
-      
+
       goto out;
     }
 
@@ -1120,7 +1107,7 @@ write_to_temp_file (const gchar  *contents,
       goto no_fsync;
   }
 #endif
-  
+
 #ifdef HAVE_FSYNC
   {
     struct stat statbuf;
@@ -1132,23 +1119,13 @@ write_to_temp_file (const gchar  *contents,
      * the new and the old file on some filesystems. (I.E. those that don't
      * guarantee the data is written to the disk before the metadata.)
      */
-    if (g_lstat (dest_file, &statbuf) == 0 &&
-       statbuf.st_size > 0 &&
-       fsync (fileno (file)) != 0)
+    if (g_lstat (dest_file, &statbuf) == 0 && statbuf.st_size > 0 && fsync (fileno (file)) != 0)
       {
-       save_errno = errno;
-
-       g_set_error (err,
-                    G_FILE_ERROR,
-                    g_file_error_from_errno (save_errno),
-                    _("Failed to write file '%s': fsync() failed: %s"),
-                    display_name,
-                    g_strerror (save_errno));
-
+        format_error_message (err, tmp_name, _("Failed to write file '%s': fsync() failed: %s"));
         fclose (file);
-       g_unlink (tmp_name);
+        g_unlink (tmp_name);
 
-       goto out;
+        goto out;
       }
   }
 #endif
@@ -1156,30 +1133,21 @@ write_to_temp_file (const gchar  *contents,
 #ifdef BTRFS_SUPER_MAGIC
  no_fsync:
 #endif
-  
+
   errno = 0;
   if (fclose (file) == EOF)
-    { 
-      save_errno = errno;
-      
-      g_set_error (err,
-                  G_FILE_ERROR,
-                  g_file_error_from_errno (save_errno),
-                  _("Failed to close file '%s': fclose() failed: %s"),
-                  display_name, 
-                  g_strerror (save_errno));
-
+    {
+      format_error_message (err, tmp_name, _("Failed to close file '%s': fclose() failed: %s"));
       g_unlink (tmp_name);
-      
+
       goto out;
     }
 
   retval = g_strdup (tmp_name);
-  
+
  out:
   g_free (tmp_name);
-  g_free (display_name);
-  
+
   return retval;
 }