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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>
NewExtensionFunction()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>
RegisterFunction()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_
67