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// Copyright (c) 2006-2008 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 CHROME_BROWSER_CONTROLLER_H__
#define CHROME_BROWSER_CONTROLLER_H__
#include <vector>
#include "base/basictypes.h"
#include "base/hash_tables.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 base::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__
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