[mutter/wip/carlosg/xwayland-on-demand: 3/32] x11: Add X11 MetaSelectionSource implementation

[Carlos Garnacho <carlosg src gnome org>]

commit 882bec80ebdb7d6abb84f90dff3ae73ee94ed519
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon Nov 19 17:16:37 2018 +0100

    x11: Add X11 MetaSelectionSource implementation
    
    This object represents the selection ownership from an X11 client. The
    list of supported targets is queried upfront, so its initialization is
    asynchronous. Requests to read contents from the selection will hand
    a MetaX11SelectionInputStream.

 src/Makefile.am                             |   2 +
 src/meson.build                             |   2 +
 src/x11/meta-x11-selection-source-private.h |  44 +++++
 src/x11/meta-x11-selection-source.c         | 267 ++++++++++++++++++++++++++++
 4 files changed, 315 insertions(+)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index d74b6a5d4..8225b1dc3 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -356,6 +356,8 @@ libmutter_@LIBMUTTER_API_VERSION@_la_SOURCES =      \
        x11/meta-x11-selection-input-stream-private.h   \
        x11/meta-x11-selection-output-stream.c  \
        x11/meta-x11-selection-output-stream-private.h  \
+       x11/meta-x11-selection-source.c         \
+       x11/meta-x11-selection-source-private.h \
        x11/events.c                            \
        x11/events.h                            \
        x11/group-private.h                     \
diff --git a/src/meson.build b/src/meson.build
index 0ae8b5e30..642e2ed27 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -377,6 +377,8 @@ mutter_sources = [
   'x11/meta-x11-selection-input-stream-private.h',
   'x11/meta-x11-selection-output-stream.c',
   'x11/meta-x11-selection-output-stream-private.h',
+  'x11/meta-x11-selection-source.c',
+  'x11/meta-x11-selection-source-private.h',
   'x11/mutter-Xatomtype.h',
   'x11/session.c',
   'x11/session.h',
diff --git a/src/x11/meta-x11-selection-source-private.h b/src/x11/meta-x11-selection-source-private.h
new file mode 100644
index 000000000..95348a674
--- /dev/null
+++ b/src/x11/meta-x11-selection-source-private.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2018 Red Hat
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ * Author: Carlos Garnacho <carlosg gnome org>
+ */
+
+#ifndef META_X11_SELECTION_SOURCE_H
+#define META_X11_SELECTION_SOURCE_H
+
+#include "core/meta-selection-source.h"
+#include "x11/meta-x11-display-private.h"
+
+#define META_TYPE_X11_SELECTION_SOURCE (meta_x11_selection_source_get_type ())
+G_DECLARE_FINAL_TYPE (MetaX11SelectionSource,
+                      meta_x11_selection_source,
+                      META, X11_SELECTION_SOURCE,
+                      MetaSelectionSource)
+
+void                  meta_x11_selection_source_new_async  (MetaX11Display      *display,
+                                                            Window               owner,
+                                                            uint32_t             timestamp,
+                                                            Atom                 xselection,
+                                                            GCancellable        *cancellable,
+                                                            GAsyncReadyCallback  callback,
+                                                            gpointer             user_data);
+MetaSelectionSource * meta_x11_selection_source_new_finish (GAsyncResult  *result,
+                                                            GError       **error);
+
+#endif /* META_X11_SELECTION_SOURCE_H */
diff --git a/src/x11/meta-x11-selection-source.c b/src/x11/meta-x11-selection-source.c
new file mode 100644
index 000000000..e4b14f130
--- /dev/null
+++ b/src/x11/meta-x11-selection-source.c
@@ -0,0 +1,267 @@
+/*
+ * Copyright (C) 2018 Red Hat
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ * Author: Carlos Garnacho <carlosg gnome org>
+ */
+#include "config.h"
+
+#include <gdk/gdkx.h>
+
+#include "x11/meta-x11-selection-input-stream-private.h"
+#include "x11/meta-x11-selection-source-private.h"
+
+#define MAX_MIMETYPE_SIZE 4096
+
+struct _MetaX11SelectionSource
+{
+  MetaSelectionSource parent_instance;
+  MetaX11Display *display;
+  GList *mimetypes;
+  Window owner;
+  uint32_t timestamp;
+};
+
+G_DEFINE_TYPE (MetaX11SelectionSource, meta_x11_selection_source,
+               META_TYPE_SELECTION_SOURCE)
+
+static Atom
+selection_to_atom (MetaSelectionType  type,
+                   Display           *xdisplay)
+{
+  Atom atom;
+
+  switch (type)
+    {
+    case META_SELECTION_PRIMARY:
+      atom = XInternAtom (xdisplay, "PRIMARY", False);
+      break;
+    case META_SELECTION_CLIPBOARD:
+      atom = XInternAtom (xdisplay, "CLIPBOARD", False);
+      break;
+    case META_SELECTION_DND:
+      atom = XInternAtom (xdisplay, "XdndSelection", False);
+      break;
+    default:
+      g_warn_if_reached ();
+      atom = None;
+      break;
+    }
+
+  return atom;
+}
+
+static void
+stream_new_cb (GObject      *source,
+               GAsyncResult *res,
+               GTask        *task)
+{
+  GInputStream *stream;
+  GError *error = NULL;
+
+  stream = meta_x11_selection_input_stream_new_finish (res, NULL, NULL, &error);
+
+  if (stream)
+    g_task_return_pointer (task, stream, g_object_unref);
+  else
+    g_task_return_error (task, error);
+
+  g_object_unref (task);
+}
+
+static void
+meta_x11_selection_source_read_async (MetaSelectionSource *source,
+                                      const gchar         *mimetype,
+                                      GCancellable        *cancellable,
+                                      GAsyncReadyCallback  callback,
+                                      gpointer             user_data)
+{
+  MetaX11SelectionSource *source_x11 = META_X11_SELECTION_SOURCE (source);
+  MetaSelectionType selection;
+  Atom selection_atom;
+  GTask *task;
+
+  task = g_task_new (source, cancellable, callback, user_data);
+  g_task_set_source_tag (task, meta_x11_selection_source_read_async);
+
+  meta_selection_source_get_selection (source, &selection);
+  selection_atom = selection_to_atom (selection, source_x11->display->xdisplay);
+
+  meta_x11_selection_input_stream_new_async (source_x11->display,
+                                             source_x11->display->selection.window,
+                                             gdk_x11_get_xatom_name (selection_atom),
+                                             mimetype,
+                                             source_x11->timestamp,
+                                             G_PRIORITY_DEFAULT,
+                                             cancellable,
+                                             (GAsyncReadyCallback) stream_new_cb,
+                                             task);
+}
+
+static GInputStream *
+meta_x11_selection_source_read_finish (MetaSelectionSource  *source,
+                                       GAsyncResult         *result,
+                                       GError              **error)
+{
+  g_return_val_if_fail (g_task_is_valid (result, source), NULL);
+  g_return_val_if_fail (g_task_get_source_tag (G_TASK (result)) ==
+                        meta_x11_selection_source_read_async, NULL);
+
+  return g_task_propagate_pointer (G_TASK (result), error);
+}
+
+static GList *
+meta_x11_selection_source_get_mimetypes (MetaSelectionSource  *source)
+{
+  MetaX11SelectionSource *source_x11 = META_X11_SELECTION_SOURCE (source);
+
+  return g_list_copy_deep (source_x11->mimetypes, (GCopyFunc) g_strdup, NULL);
+}
+
+
+static void
+meta_x11_selection_source_class_init (MetaX11SelectionSourceClass *klass)
+{
+  MetaSelectionSourceClass *source_class = META_SELECTION_SOURCE_CLASS (klass);
+
+  source_class->read_async = meta_x11_selection_source_read_async;
+  source_class->read_finish = meta_x11_selection_source_read_finish;
+  source_class->get_mimetypes = meta_x11_selection_source_get_mimetypes;
+}
+
+static void
+meta_x11_selection_source_init (MetaX11SelectionSource *source)
+{
+}
+
+static GList *
+atoms_to_mimetypes (MetaX11Display *display,
+                    GBytes         *bytes)
+{
+  GList *mimetypes = NULL;
+  const Atom *atoms;
+  gsize size;
+  guint i, n_atoms;
+
+  atoms = g_bytes_get_data (bytes, &size);
+  n_atoms = size / sizeof (Atom);
+
+  for (i = 0; i < n_atoms; i++)
+    {
+      const gchar *mimetype;
+
+      mimetype = gdk_x11_get_xatom_name (atoms[i]);
+      mimetypes = g_list_prepend (mimetypes, g_strdup (mimetype));
+    }
+
+  return mimetypes;
+}
+
+static void
+read_mimetypes_cb (GInputStream *stream,
+                   GAsyncResult *res,
+                   GTask        *task)
+{
+  MetaX11SelectionSource *source_x11 = g_task_get_task_data (task);
+  GError *error = NULL;
+  GBytes *bytes;
+
+  bytes = g_input_stream_read_bytes_finish (stream, res, &error);
+  if (error)
+    {
+      g_task_return_error (task, error);
+      g_object_unref (task);
+      return;
+    }
+
+  source_x11->mimetypes = atoms_to_mimetypes (source_x11->display, bytes);
+  g_bytes_unref (bytes);
+
+  g_task_return_pointer (task,
+                         g_object_ref (g_task_get_task_data (task)),
+                         g_object_unref);
+  g_object_unref (task);
+}
+
+static void
+get_mimetypes_cb (GObject      *source,
+                  GAsyncResult *res,
+                  GTask        *task)
+{
+  GInputStream *stream;
+  GError *error = NULL;
+
+  stream = meta_x11_selection_input_stream_new_finish (res, NULL, NULL, &error);
+  if (error)
+    {
+      g_task_return_error (task, error);
+      g_object_unref (task);
+      return;
+    }
+
+  g_input_stream_read_bytes_async (stream,
+                                   MAX_MIMETYPE_SIZE,
+                                   G_PRIORITY_DEFAULT,
+                                   g_task_get_cancellable (task),
+                                   (GAsyncReadyCallback) read_mimetypes_cb,
+                                   task);
+}
+
+void
+meta_x11_selection_source_new_async (MetaX11Display      *display,
+                                     Window               owner,
+                                     uint32_t             timestamp,
+                                     Atom                 xselection,
+                                     GCancellable        *cancellable,
+                                     GAsyncReadyCallback  callback,
+                                     gpointer             user_data)
+{
+  MetaX11SelectionSource *source;
+  GTask *task;
+
+  source = g_object_new (META_TYPE_X11_SELECTION_SOURCE, NULL);
+  source->display = display;
+  source->owner = owner;
+  source->timestamp = timestamp;
+
+  task = g_task_new (NULL, cancellable, callback, user_data);
+  g_task_set_source_tag (task, meta_x11_selection_source_new_async);
+  g_task_set_task_data (task, source, g_object_unref);
+
+  meta_x11_selection_input_stream_new_async (display,
+                                             display->selection.window,
+                                             gdk_x11_get_xatom_name (xselection),
+                                             "TARGETS",
+                                             timestamp,
+                                             G_PRIORITY_DEFAULT,
+                                             cancellable,
+                                             (GAsyncReadyCallback) get_mimetypes_cb,
+                                             task);
+}
+
+MetaSelectionSource *
+meta_x11_selection_source_new_finish (GAsyncResult  *result,
+                                      GError       **error)
+{
+  GTask *task = G_TASK (result);
+
+  g_return_val_if_fail (g_task_is_valid (task, NULL), NULL);
+  g_return_val_if_fail (g_task_get_source_tag (task) ==
+                        meta_x11_selection_source_new_async, NULL);
+
+  return g_task_propagate_pointer (task, error);
+}