Add chrome to the repository.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@15 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 198 insertions, 0 deletions

diff --git a/chrome/browser/controller.h b/chrome/browser/controller.h
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+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CHROME_BROWSER_CONTROLLER_H__
+#define CHROME_BROWSER_CONTROLLER_H__
+
+#include <hash_map>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "chrome/views/button.h"
+#include "chrome/views/controller.h"
+
+class ButtonController;
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// CommandObserver interface
+//
+//   A component of the View portion of the MVC pattern implements the
+//   CommandObserver interface to update itself when the state of its command
+//   changes.
+//
+///////////////////////////////////////////////////////////////////////////////
+class CommandObserver {
+ public:
+  // Update the View because this command's enabled state has changed.
+  virtual void SetEnabled(bool enabled) = 0;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// CommandHandler interface
+//
+//   An object implementing the CommandHandler interface is responsible for
+//   actually executing specific commands.
+//
+//   This object is also responsible for producing contextual labels if needed.
+//
+///////////////////////////////////////////////////////////////////////////////
+class CommandHandler {
+ public:
+
+  // This method is called to give the command handler a chance to specify
+  // a contextual label for the provided command id. Returns true if a
+  // contextual label has been assigned or false if the default label should be
+  // used.
+  virtual bool GetContextualLabel(int id, std::wstring* out) const {
+    return false;
+  }
+
+  // Whether the specified command can be executed.
+  virtual bool IsCommandEnabled(int id) const { return true; }
+
+  // Execute a command, according to the command's state (currently binary!)
+  virtual void ExecuteCommand(int id) = 0;
+};
+
+typedef std::vector<CommandObserver*> CommandObserverList;
+
+// A piece of data about a command - whether or not it is enabled, and a list
+// of objects that observe the enabled state of this command.
+struct Command {
+  bool enabled;
+  CommandObserverList* observers;
+};
+typedef stdext::hash_map<int, Command*> CommandMap;
+
+
+///////////////////////////////////////////////////////////////////////////////
+//
+// Controller class
+//
+//   This is the Controller portion of a MVC pattern. It handles dispatching
+//   commands, maintaining enabled state, and updating the UI as that state
+//   changes. The purpose of using MVC and a controller like this is to
+//   maintain a clear separation between rendering, control logic and various
+//   data sources so that code is more maintainable.
+//
+///////////////////////////////////////////////////////////////////////////////
+class CommandController : public Controller {
+ public:
+  // The controller is constructed with an object implementing the
+  // CommandHandler interface, to which the Controller defers execution
+  // duties. This keeps the Controller fairly simple without requiring a
+  // lot of reworking of the command handlers. If there are significant
+  // groups of commands that require execution separated from this handler,
+  // then the Command object can be extended to provide a handler field that
+  // specifies a handler different to the default.
+  CommandController(CommandHandler* handler);
+  virtual ~CommandController();
+
+  // Add a button to the list of managed buttons. The button is synced with
+  // the provided command
+  void AddManagedButton(ChromeViews::Button* button, int command);
+
+  // Controller
+  virtual bool SupportsCommand(int id) const;
+  virtual bool IsCommandEnabled(int id) const;
+  virtual bool GetContextualLabel(int id, std::wstring* out) const;
+  virtual void ExecuteCommand(int id);
+
+
+  // Adds an observer to the state of a particular command. If the command does
+  // not exist, it is created, initialized to false.
+  void AddCommandObserver(int id, CommandObserver* observer);
+
+  // Removes an observer to the state of a particular command.
+  void RemoveCommandObserver(int id, CommandObserver* observer);
+
+  // Notify all observers of a particular command that the command has been
+  // enabled or disabled. If the command does not exist, it is created and
+  // initialized to |state|. This function is very lightweight if the command
+  // state has not changed.
+  void UpdateCommandEnabled(int id, bool state);
+
+ private:
+  ///////////////////////////////////////////////////////////////////////////////
+  //
+  // ButtonController
+  //
+  // An adapter class to use ChromeViews buttons with our controller
+  //
+  ///////////////////////////////////////////////////////////////////////////////
+  class ButtonController : public ChromeViews::BaseButton::ButtonListener,
+                           public CommandObserver {
+
+   public:
+
+    ButtonController(ChromeViews::Button* b,
+                     CommandController* controller,
+                     int command)
+        : button_(b),
+          controller_(controller) {
+      controller_->AddCommandObserver(command, this);
+      button_->SetListener(this, command);
+
+      // The button's initial state should be the current command state.
+      button_->SetEnabled(controller_->IsCommandEnabled(command));
+    }
+
+    virtual void SetEnabled(bool enabled) {
+      button_->SetEnabled(enabled);
+    }
+
+    virtual void ButtonPressed(ChromeViews::BaseButton* sender) {
+      controller_->ExecuteCommand(sender->GetTag());
+    }
+
+   private:
+    ChromeViews::Button* button_;
+    CommandController* controller_;
+  };
+
+  // Get a Command node for a given command ID, creating an entry if it doesn't
+  // exist if desired.
+  Command* GetCommand(int id, bool create);
+
+  // This is the default handler for all command execution
+  CommandHandler* handler_;
+
+  // This is a map of command IDs to states and observer lists
+  CommandMap commands_;
+
+  // vector of ButtonController for managed buttons
+  std::vector<ButtonController*> managed_button_controllers_;
+
+  CommandController();
+  DISALLOW_EVIL_CONSTRUCTORS(CommandController);
+};
+
+#endif // CHROME_BROWSER_CONTROLLER_H__