extensions/browser/extension_function_registry.h

   1 // Copyright 2014 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 EXTENSIONS_BROWSER_EXTENSION_FUNCTION_REGISTRY_H_
   6 #define EXTENSIONS_BROWSER_EXTENSION_FUNCTION_REGISTRY_H_
   7
   8 #include <map>
   9 #include <string>
  10 #include <vector>
  11
  12 #include "extensions/browser/extension_function_histogram_value.h"
  13
  14 class ExtensionFunction;
  15
  16 // A factory function for creating new ExtensionFunction instances.
  17 typedef ExtensionFunction* (*ExtensionFunctionFactory)();
  18
  19 // Template for defining ExtensionFunctionFactory.
  20 template <class T>
  21 ExtensionFunction* NewExtensionFunction() {
  22   return new T();
  23 }
  24
  25 // Contains a list of all known extension functions and allows clients to
  26 // create instances of them.
  27 class ExtensionFunctionRegistry {
  28  public:
  29   static ExtensionFunctionRegistry* GetInstance();
  30   explicit ExtensionFunctionRegistry();
  31   virtual ~ExtensionFunctionRegistry();
  32
  33   // Adds all function names to 'names'.
  34   void GetAllNames(std::vector<std::string>* names);
  35
  36   // Allows overriding of specific functions (e.g. for testing).  Functions
  37   // must be previously registered.  Returns true if successful.
  38   bool OverrideFunction(const std::string& name,
  39                         ExtensionFunctionFactory factory);
  40
  41   // Factory method for the ExtensionFunction registered as 'name'.
  42   ExtensionFunction* NewFunction(const std::string& name);
  43
  44   template <class T>
  45   void RegisterFunction() {
  46     ExtensionFunctionFactory factory = &NewExtensionFunction<T>;
  47     factories_[T::function_name()] =
  48         FactoryEntry(factory, T::histogram_value());
  49   }
  50
  51   struct FactoryEntry {
  52    public:
  53     explicit FactoryEntry();
  54     explicit FactoryEntry(
  55         ExtensionFunctionFactory factory,
  56         extensions::functions::HistogramValue histogram_value);
  57
  58     ExtensionFunctionFactory factory_;
  59     extensions::functions::HistogramValue histogram_value_;
  60   };
  61
  62   typedef std::map<std::string, FactoryEntry> FactoryMap;
  63   FactoryMap factories_;
  64 };
  65
  66 #endif  // EXTENSIONS_BROWSER_EXTENSION_FUNCTION_REGISTRY_H_