components/mus/public/cpp/view_tree_delegate.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_MUS_PUBLIC_CPP_VIEW_TREE_DELEGATE_H_
   6 #define COMPONENTS_MUS_PUBLIC_CPP_VIEW_TREE_DELEGATE_H_
   7
   8 #include <string>
   9
  10 #include "components/mus/public/interfaces/view_tree.mojom.h"
  11 #include "mojo/application/public/interfaces/service_provider.mojom.h"
  12 #include "mojo/services/network/public/interfaces/url_loader.mojom.h"
  13
  14 namespace mus {
  15
  16 class View;
  17 class ViewTreeConnection;
  18
  19 // Interface implemented by an application using the view manager.
  20 //
  21 // Each call to OnEmbed() results in a new ViewTreeConnection and new root View.
  22 // ViewTreeConnection is deleted by any of the following:
  23 // . If the root of the connection is destroyed. This happens if the owner
  24 //   of the root Embed()s another app in root, or the owner explicitly deletes
  25 //   root.
  26 // . The connection to the view manager is lost.
  27 // . Explicitly by way of calling delete.
  28 //
  29 // When the ViewTreeConnection is deleted all views are deleted (and observers
  30 // notified). This is followed by notifying the delegate by way of
  31 // OnConnectionLost().
  32 class ViewTreeDelegate {
  33  public:
  34   // Called when the application implementing this interface is embedded at
  35   // |root|.
  36   //
  37   // |services| exposes the services offered by the embedder to the delegate.
  38   //
  39   // |exposed_services| is an object that the delegate can add services to
  40   // expose to the embedder.
  41   //
  42   // Note that if a different application is subsequently embedded at |root|,
  43   // the pipes connecting |services| and |exposed_services| to the embedder and
  44   // any services obtained from them are not broken and will continue to be
  45   // valid.
  46   virtual void OnEmbed(View* root) = 0;
  47
  48   // Sent when another app is embedded in the same View as this connection.
  49   // Subsequently the root View and this object are destroyed (observers are
  50   // notified appropriately).
  51   virtual void OnUnembed();
  52
  53   // Called from the destructor of ViewTreeConnection after all the Views have
  54   // been destroyed. |connection| is no longer valid after this call.
  55   virtual void OnConnectionLost(ViewTreeConnection* connection) = 0;
  56
  57  protected:
  58   virtual ~ViewTreeDelegate() {}
  59 };
  60
  61 }  // namespace mus
  62
  63 #endif  // COMPONENTS_MUS_PUBLIC_CPP_VIEW_TREE_DELEGATE_H_