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      1 // Copyright (c) 2011 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 CHROME_BROWSER_EXTENSIONS_EXTENSION_FUNCTION_DISPATCHER_H_
      6 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_FUNCTION_DISPATCHER_H_
      7 #pragma once
      8 
      9 #include <string>
     10 #include <vector>
     11 
     12 #include "base/memory/ref_counted.h"
     13 #include "googleurl/src/gurl.h"
     14 #include "ui/gfx/native_widget_types.h"
     15 
     16 class Browser;
     17 class Extension;
     18 class ExtensionFunction;
     19 class ListValue;
     20 class Profile;
     21 class RenderViewHost;
     22 class TabContents;
     23 struct ExtensionHostMsg_DomMessage_Params;
     24 
     25 // A factory function for creating new ExtensionFunction instances.
     26 typedef ExtensionFunction* (*ExtensionFunctionFactory)();
     27 
     28 // ExtensionFunctionDispatcher receives requests to execute functions from
     29 // Chromium extensions running in a RenderViewHost and dispatches them to the
     30 // appropriate handler. It lives entirely on the UI thread.
     31 class ExtensionFunctionDispatcher {
     32  public:
     33   class Delegate {
     34    public:
     35     // Returns the browser that this delegate is associated with, if any.
     36     // Returns NULL otherwise.
     37     virtual Browser* GetBrowser() = 0;
     38 
     39     // Returns the native view for this extension view, if any. This may be NULL
     40     // if the view is not visible.
     41     virtual gfx::NativeView GetNativeViewOfHost() = 0;
     42 
     43     // Asks the delegate for any relevant TabContents associated with this
     44     // context. For example, the TabContents in which an infobar or
     45     // chrome-extension://<id> URL are being shown. Callers must check for a
     46     // NULL return value (as in the case of a background page).
     47     virtual TabContents* associated_tab_contents() const = 0;
     48 
     49    protected:
     50     virtual ~Delegate() {}
     51   };
     52 
     53   // The peer object allows us to notify ExtensionFunctions when we are
     54   // destroyed.
     55   // TODO: this should use WeakPtr
     56   struct Peer : public base::RefCounted<Peer> {
     57     explicit Peer(ExtensionFunctionDispatcher* dispatcher)
     58         : dispatcher_(dispatcher) {}
     59     ExtensionFunctionDispatcher* dispatcher_;
     60 
     61    private:
     62     friend class base::RefCounted<Peer>;
     63 
     64     ~Peer() {}
     65   };
     66 
     67   // Gets a list of all known extension function names.
     68   static void GetAllFunctionNames(std::vector<std::string>* names);
     69 
     70   // Override a previously registered function. Returns true if successful,
     71   // false if no such function was registered.
     72   static bool OverrideFunction(const std::string& name,
     73                                ExtensionFunctionFactory factory);
     74 
     75   // Resets all functions to their initial implementation.
     76   static void ResetFunctions();
     77 
     78   // Creates an instance for the specified RenderViewHost and URL. If the URL
     79   // does not contain a valid extension, returns NULL.
     80   static ExtensionFunctionDispatcher* Create(RenderViewHost* render_view_host,
     81                                              Delegate* delegate,
     82                                              const GURL& url);
     83 
     84   ~ExtensionFunctionDispatcher();
     85 
     86   Delegate* delegate() { return delegate_; }
     87 
     88   // Handle a request to execute an extension function.
     89   void HandleRequest(const ExtensionHostMsg_DomMessage_Params& params);
     90 
     91   // Send a response to a function.
     92   void SendResponse(ExtensionFunction* api, bool success);
     93 
     94   // Returns the current browser. Callers should generally prefer
     95   // ExtensionFunction::GetCurrentBrowser() over this method, as that one
     96   // provides the correct value for |include_incognito|.
     97   //
     98   // See the comments for ExtensionFunction::GetCurrentBrowser() for more
     99   // details.
    100   Browser* GetCurrentBrowser(bool include_incognito);
    101 
    102   // Handle a malformed message.  Possibly the result of an attack, so kill
    103   // the renderer.
    104   void HandleBadMessage(ExtensionFunction* api);
    105 
    106   // Gets the URL for the view we're displaying.
    107   const GURL& url() { return url_; }
    108 
    109   // Gets the ID for this extension.
    110   const std::string extension_id() { return extension_id_; }
    111 
    112   // The profile that this dispatcher is associated with.
    113   Profile* profile();
    114 
    115   // The RenderViewHost this dispatcher is associated with.
    116   RenderViewHost* render_view_host() { return render_view_host_; }
    117 
    118  private:
    119   ExtensionFunctionDispatcher(RenderViewHost* render_view_host,
    120                               Delegate* delegate,
    121                               const Extension* extension,
    122                               const GURL& url);
    123 
    124   // We need to keep a pointer to the profile because we use it in the dtor
    125   // in sending EXTENSION_FUNCTION_DISPATCHER_DESTROYED, but by that point
    126   // the render_view_host_ has been deleted.
    127   Profile* profile_;
    128 
    129   RenderViewHost* render_view_host_;
    130 
    131   Delegate* delegate_;
    132 
    133   GURL url_;
    134 
    135   std::string extension_id_;
    136 
    137   scoped_refptr<Peer> peer_;
    138 };
    139 
    140 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_FUNCTION_DISPATCHER_H_
    141