content/public/browser/web_ui_message_handler.h

   1 // Copyright (c) 2012 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 CONTENT_PUBLIC_BROWSER_WEB_UI_MESSAGE_HANDLER_H_
   6 #define CONTENT_PUBLIC_BROWSER_WEB_UI_MESSAGE_HANDLER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/gtest_prod_util.h"
  10 #include "base/strings/string16.h"
  11 #include "content/common/content_export.h"
  12
  13 class GURL;
  14 class WebUIBrowserTest;
  15
  16 namespace base {
  17 class DictionaryValue;
  18 class ListValue;
  19 }
  20
  21 namespace content {
  22
  23 class WebUI;
  24 class WebUIImpl;
  25
  26 // Messages sent from the DOM are forwarded via the WebUI to handler
  27 // classes. These objects are owned by WebUI and destroyed when the
  28 // host is destroyed.
  29 class CONTENT_EXPORT WebUIMessageHandler {
  30  public:
  31   WebUIMessageHandler() : web_ui_(nullptr) {}
  32   virtual ~WebUIMessageHandler() {}
  33
  34  protected:
  35   FRIEND_TEST_ALL_PREFIXES(WebUIMessageHandlerTest, ExtractIntegerValue);
  36   FRIEND_TEST_ALL_PREFIXES(WebUIMessageHandlerTest, ExtractDoubleValue);
  37   FRIEND_TEST_ALL_PREFIXES(WebUIMessageHandlerTest, ExtractStringValue);
  38
  39   // Helper methods:
  40
  41   // Extract an integer value from a list Value.
  42   static bool ExtractIntegerValue(const base::ListValue* value, int* out_int);
  43
  44   // Extract a floating point (double) value from a list Value.
  45   static bool ExtractDoubleValue(const base::ListValue* value,
  46                                  double* out_value);
  47
  48   // Extract a string value from a list Value.
  49   static base::string16 ExtractStringValue(const base::ListValue* value);
  50
  51   // This is where subclasses specify which messages they'd like to handle and
  52   // perform any additional initialization.. At this point web_ui() will return
  53   // the associated WebUI object.
  54   virtual void RegisterMessages() = 0;
  55
  56   // Returns the attached WebUI for this handler.
  57   WebUI* web_ui() const { return web_ui_; }
  58
  59   // Sets the attached WebUI - exposed to subclasses for testing purposes.
  60   void set_web_ui(WebUI* web_ui) { web_ui_ = web_ui; }
  61
  62  private:
  63   // Provide external classes access to web_ui() and set_web_ui().
  64   friend class WebUIImpl;
  65   friend class ::WebUIBrowserTest;
  66
  67   WebUI* web_ui_;
  68 };
  69
  70 }  // namespace content
  71
  72 #endif  // CONTENT_PUBLIC_BROWSER_WEB_UI_MESSAGE_HANDLER_H_