initial version of auto VK switching.

chrome/browser/chromeos/input_method/virtual_keyboard_selector.h

Index: chrome/browser/chromeos/input_method/virtual_keyboard_selector.h
diff --git a/chrome/browser/chromeos/input_method/virtual_keyboard_selector.h b/chrome/browser/chromeos/input_method/virtual_keyboard_selector.h
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+// Copyright (c) 2011 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_CHROMEOS_INPUT_METHOD_VIRTUAL_KEYBOARD_SELECTOR_H_
+#define CHROME_BROWSER_CHROMEOS_INPUT_METHOD_VIRTUAL_KEYBOARD_SELECTOR_H_
+#pragma once
+
+#include <list>
+#include <set>
+#include <string>
+
+#include "base/basictypes.h"
+#include "googleurl/src/gurl.h"
+
+namespace chromeos {
+namespace input_method {
+
+// A class which represents a virtual keyboard extension. One virtual keyboard
+// extension can support more than one keyboard layout.
+class VirtualKeyboard {
+ public:
+  VirtualKeyboard(const GURL& url,
+                  const std::set<std::string>& supported_layouts,
+                  bool is_system)
+      : url_(url),
+        supported_layouts_(supported_layouts),
+        is_system_(is_system) {}
+
+  // Returns URL for displaying the keyboard UI specified by |layout|.
+  // For example, when |url_| is "http://adcfj..kjhil/" and |layout| is "us",
+  // the function would return "http://adcfj..kjhil/index.html#us". When
+  // |layout| is empty, it returns |url_| as-is, which is "http://adcfj..kjhil/"
+  // in this case.
+  GURL GetURLForLayout(const std::string& layout) const;
+
+  const GURL& url() const { return url_; }
+  const std::set<std::string>& supported_layouts() const {
+    return supported_layouts_;
+  }
+  bool is_system() const { return is_system_; }
+
+ private:
+  const GURL url_;
+  const std::set<std::string> supported_layouts_;
+  const bool is_system_;
+
+  DISALLOW_COPY_AND_ASSIGN(VirtualKeyboard);
+};
+
+// A class which holds all available virtual keyboard extensions.
+class VirtualKeyboardSelector {
+ public:
+  VirtualKeyboardSelector();
+  ~VirtualKeyboardSelector();
+
+  // Adds a new virtual keyboard extension. If |keyboard.is_system_| is true,
+  // the virtual keyboard extension will initially have lower priority than non-
+  // system keyboard extensions.
+  // TODO(yusukes): Add RemoveVirtualKeyboard() as well.
+  void AddVirtualKeyboard(const GURL& url,
+                          const std::set<std::string>& supported_layouts,
+                          bool is_system);
+
+  // Selects and returns the most suitable virtual keyboard extension for the
+  // |layout|. Returns NULL if no virtual keyboard extension for the layout
+  // is found. If |current_|, which is the virtual keyboard extension currently
+  // in use, supports the |layout|, the current one will be returned. Otherwise
+  // the function scans the lists of |keyboards_| and |system_keyboards_|,
+  // respectively.
+  //
+  // Checking the |current_| keyboard is important for the following use case:
+  // - If I have installed a VK extension that provides a US and an FR layout
+  //   and I switch from the US layout of the extension (+ English IME) to the
+  //   French IME, then I would like to use the FR layout of the extension I am
+  //   currently using.
+  const VirtualKeyboard* SelectVirtualKeyboard(const std::string& layout);
+
+  // TODO(yusukes): Add a function something like
+  //   void SetUserPreference(const std::string& layout,
+  //                          const VirtualKeyboard& keyboard);
+  // so that users could use a specific virtual keyboard extension for the
+  // |layout|.
+
+ protected:
+  // This function neither checks |current_| nor updates the variable. The
+  // function is protected for testability.
+  const VirtualKeyboard* SelectVirtualKeyboardInternal(
+      const std::string& layout);
+
+ private:
+  // A list of 3rd party virtual keyboard extensions.
+  std::list<const VirtualKeyboard*> keyboards_;
+  // A list of system virtual keyboard extensions.
+  std::list<const VirtualKeyboard*> system_keyboards_;
+
+  // The virtual keyboard currently in use.
+  const VirtualKeyboard* current_;
+
+  DISALLOW_COPY_AND_ASSIGN(VirtualKeyboardSelector);
+};
+
+}  // namespace input_method
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_INPUT_METHOD_VIRTUAL_KEYBOARD_SELECTOR_H_