Implement truncate support for output streams

Backends receive a TRUNCATE message which contains a size parameter.
Truncation is signaled with a TRUNCATED message (which contains no other
useful information).

In more detail:
Add a new dbus method, OpenForWriteFlags, which has a flags parameter to
implement can_seek and can_truncate.  These flags are used in
GDaemonFileOutputStream.  Compatability with old clients is maintained.
Implement the can_truncate and truncate_fn GDaemonFileOutputStream
methods.
Add two new message types to the daemon socket protocol:
    G_VFS_DAEMON_SOCKET_PROTOCOL_REQUEST_TRUNCATE
    G_VFS_DAEMON_SOCKET_PROTOCOL_REPLY_TRUNCATED
Add a new job type, GVfsJobTruncate.
Add two new methods to GVfsBackend which backend classes can implement:
truncate and try_truncate

https://bugzilla.gnome.org/show_bug.cgi?id=573837

1 files changed, 63 insertions, 0 deletions

diff --git a/daemon/gvfsjobtruncate.h b/daemon/gvfsjobtruncate.h
new file mode 100644
index 00000000..9a3f0494
--- /dev/null
+++ b/daemon/gvfsjobtruncate.h
@@ -0,0 +1,63 @@
+/* GIO - GLib Input, Output and Streaming Library
+ * 
+ * Copyright (C) 2013 Ross Lagerwall
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __G_VFS_JOB_TRUNCATE_H__
+#define __G_VFS_JOB_TRUNCATE_H__
+
+#include <gvfsjob.h>
+#include <gvfsbackend.h>
+#include <gvfswritechannel.h>
+
+G_BEGIN_DECLS
+
+#define G_VFS_TYPE_JOB_TRUNCATE         (g_vfs_job_truncate_get_type ())
+#define G_VFS_JOB_TRUNCATE(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), G_VFS_TYPE_JOB_TRUNCATE, GVfsJobTruncate))
+#define G_VFS_JOB_TRUNCATE_CLASS(k)     (G_TYPE_CHECK_CLASS_CAST((k), G_VFS_TYPE_JOB_TRUNCATE, GVfsJobTruncateClass))
+#define G_VFS_IS_JOB_TRUNCATE(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), G_VFS_TYPE_JOB_TRUNCATE))
+#define G_VFS_IS_JOB_TRUNCATE_CLASS(k)  (G_TYPE_CHECK_CLASS_TYPE ((k), G_VFS_TYPE_JOB_TRUNCATE))
+#define G_VFS_JOB_TRUNCATE_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), G_VFS_TYPE_JOB_TRUNCATE, GVfsJobTruncateClass))
+
+typedef struct _GVfsJobTruncateClass   GVfsJobTruncateClass;
+
+struct _GVfsJobTruncate
+{
+  GVfsJob parent_instance;
+
+  GVfsWriteChannel *channel;
+  GVfsBackend *backend;
+  GVfsBackendHandle handle;
+  goffset size;
+};
+
+struct _GVfsJobTruncateClass
+{
+  GVfsJobClass parent_class;
+};
+
+GType g_vfs_job_truncate_get_type (void) G_GNUC_CONST;
+
+GVfsJob *g_vfs_job_truncate_new (GVfsWriteChannel  *channel,
+                                 GVfsBackendHandle  handle,
+                                 goffset            size,
+                                 GVfsBackend       *backend);
+
+G_END_DECLS
+
+#endif /* __G_VFS_JOB_TRUNCATE_H__ */