mozart: Initial commit of the view manager.

services/ui/view_manager/view_layout_request.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SERVICES_UI_VIEW_MANAGER_VIEW_LAYOUT_REQUEST_H_
+#define SERVICES_UI_VIEW_MANAGER_VIEW_LAYOUT_REQUEST_H_
+
+#include <memory>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "mojo/services/ui/views/interfaces/layouts.mojom.h"
+
+namespace view_manager {
+
+typedef base::Callback<void(mojo::ui::ViewLayoutInfoPtr)> ViewLayoutCallback;

[jamesr, 2015/10/27 23:13:10]

prefer 'using' for this sort of thing, it looks slightly saner (since it's like
other type / variable declarations)

[jeffbrown, 2015/10/28 01:37:29]

Done.

+
+// Describes a pending layout request for a view.
+class ViewLayoutRequest {
+ public:
+  ViewLayoutRequest(mojo::ui::ViewLayoutParamsPtr layout_params);

[jamesr, 2015/10/27 23:13:10]

explicit

[jeffbrown, 2015/10/28 01:37:29]

Done.

+
+  // Dispatches null layout info automatically if DispatchLayoutInfo was not

[jamesr, 2015/10/27 23:13:10]

hmm, side-effecty destructors on types that also do other things (i.e. aren't
pure RAII types) is iffy

[jeffbrown, 2015/10/28 01:37:29]

Agreed.  The side-effect could go at the point where the view is released
instead.  Going to leave this alone for now since this code will probably be
deleted in the next patch.

+  // called.
+  ~ViewLayoutRequest();
+
+  // Gets the layout parameters for this request.
+  // Does not confer ownership.
+  mojo::ui::ViewLayoutParams* layout_params() { return layout_params_.get(); }
+
+  // Gets the layout parameters for this request and takes ownership.
+  mojo::ui::ViewLayoutParamsPtr TakeLayoutParams() {
+    return layout_params_.Pass();
+  }
+
+  // Adds a callback to this layout request.
+  // Must be called before dispatching.
+  void AddCallback(const ViewLayoutCallback& callback);
+
+  // Returns true if the request has callbacks.
+  bool has_callbacks() { return !callbacks_.empty(); }
+
+  // Sends the layout information to each client.
+  // Must be invoked exactly once before destroying the request to prevent
+  // dangling callbacks.
+  void DispatchLayoutInfo(mojo::ui::ViewLayoutInfo* info);
+
+  // True if the request has been issued to the view.
+  // False if it is still pending in the queue.
+  bool issued;

[jamesr, 2015/10/27 23:13:10]

private, no public members on classes (add a getter if you need one, or split
mutable data members into a struct if you need that)

[jeffbrown, 2015/10/28 01:37:29]

Got it.  Skipping this one since this code is doomed.

+
+  mojo::ui::ViewLayoutParamsPtr layout_params_;

[jamesr, 2015/10/27 23:13:10]

trailing _ in particular should never be public

[jeffbrown, 2015/10/28 01:37:29]

Somewhere along the way I dropped the private: line

+  std::vector<ViewLayoutCallback> callbacks_;
+  bool was_dispatched_;
+
+  DISALLOW_COPY_AND_ASSIGN(ViewLayoutRequest);

[jamesr, 2015/10/27 23:13:10]

and this only makes sense in a private section

+};
+
+}  // namespace view_manager
+
+#endif  // SERVICES_UI_VIEW_MANAGER_VIEW_LAYOUT_REQUEST_H_