From 0aae1bf0d2e6e03d91e3f180a060f545175737ac Mon Sep 17 00:00:00 2001
From: Ryan Lortie <desrt@desrt.ca>
Date: Tue, 29 Sep 2015 10:16:52 -0400
Subject: [PATCH] g_local_file_trash: write info file first

Recent changes to file monitors removed the delay before events were
reported.  Among other things, this caused the trash backend of gvfs to
notice trashed files sooner than before.

On noticing trashed files, the backend tries to read the info file to
discover (among other things) the original location of the file.

Unfortunately, g_local_file_trash() does a strange dance when trashing a
file.  It does a loop of open(O_EXCL) in order to file an empty filename
in the trash to write an info file to, trashes the file, and only then
writes the contents of the info file.  This means that at the time the
file is moved to the trash, the info file is an empty stub.

Change the order so that we write out the actual content of the info
file first.  If the actual trash files then we will unlink the info file
anyway.

https://bugzilla.gnome.org/show_bug.cgi?id=749314
---
 gio/glocalfile.c | 51 ++++++++++++++++++++++++++----------------------
 1 file changed, 28 insertions(+), 23 deletions(-)

diff --git a/gio/glocalfile.c b/gio/glocalfile.c
index 60b95609e..2ed6dff43 100644
--- a/gio/glocalfile.c
+++ b/gio/glocalfile.c
@@ -2099,6 +2099,34 @@ g_local_file_trash (GFile         *file,
 
   (void) g_close (fd, NULL);
 
+  /* Write the full content of the info file before trashing to make
+   * sure someone doesn't read an empty file.  See #749314
+   */
+
+  /* Use absolute names for homedir */
+  if (is_homedir_trash)
+    original_name = g_strdup (local->filename);
+  else
+    original_name = try_make_relative (local->filename, topdir);
+  original_name_escaped = g_uri_escape_string (original_name, "/", FALSE);
+  
+  g_free (original_name);
+  g_free (topdir);
+  
+  {
+    time_t t;
+    struct tm now;
+    t = time (NULL);
+    localtime_r (&t, &now);
+    delete_time[0] = 0;
+    strftime(delete_time, sizeof (delete_time), "%Y-%m-%dT%H:%M:%S", &now);
+  }
+
+  data = g_strdup_printf ("[Trash Info]\nPath=%s\nDeletionDate=%s\n",
+			  original_name_escaped, delete_time);
+
+  g_file_set_contents (infofile, data, -1, NULL);
+
   /* TODO: Maybe we should verify that you can delete the file from the trash
      before moving it? OTOH, that is hard, as it needs a recursive scan */
 
@@ -2142,29 +2170,6 @@ g_local_file_trash (GFile         *file,
 
   /* TODO: Do we need to update mtime/atime here after the move? */
 
-  /* Use absolute names for homedir */
-  if (is_homedir_trash)
-    original_name = g_strdup (local->filename);
-  else
-    original_name = try_make_relative (local->filename, topdir);
-  original_name_escaped = g_uri_escape_string (original_name, "/", FALSE);
-  
-  g_free (original_name);
-  g_free (topdir);
-  
-  {
-    time_t t;
-    struct tm now;
-    t = time (NULL);
-    localtime_r (&t, &now);
-    delete_time[0] = 0;
-    strftime(delete_time, sizeof (delete_time), "%Y-%m-%dT%H:%M:%S", &now);
-  }
-
-  data = g_strdup_printf ("[Trash Info]\nPath=%s\nDeletionDate=%s\n",
-			  original_name_escaped, delete_time);
-
-  g_file_set_contents (infofile, data, -1, NULL);
   g_free (infofile);
   g_free (data);