base/scoped_native_library.h

   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 BASE_SCOPED_NATIVE_LIBRARY_H_
   6 #define BASE_SCOPED_NATIVE_LIBRARY_H_
   7
   8 #include "base/base_export.h"
   9 #include "base/macros.h"
  10 #include "base/native_library.h"
  11 #include "base/scoped_generic.h"
  12
  13 namespace base {
  14
  15 class FilePath;
  16
  17 struct BASE_EXPORT NativeLibraryTraits {
  18   // It's assumed that this is a fast inline function with little-to-no
  19   // penalty for duplicate calls. This must be a static function even
  20   // for stateful traits.
  21   static NativeLibrary InvalidValue() { return nullptr; }
  22
  23   // This free function will not be called if library == InvalidValue()!
  24   static void Free(NativeLibrary library);
  25 };
  26
  27 // A class which encapsulates a base::NativeLibrary object available only in a
  28 // scope.
  29 // This class automatically unloads the loaded library in its destructor.
  30 class BASE_EXPORT ScopedNativeLibrary
  31     : public ScopedGeneric<NativeLibrary, NativeLibraryTraits> {
  32  public:
  33   // Initializes with a NULL library.
  34   ScopedNativeLibrary();
  35
  36   ~ScopedNativeLibrary() override;
  37
  38   // Takes ownership of the given library handle.
  39   explicit ScopedNativeLibrary(NativeLibrary library);
  40
  41   // Opens the given library and manages its lifetime.
  42   explicit ScopedNativeLibrary(const FilePath& library_path);
  43
  44   // Move constructor. Takes ownership of handle stored in |scoped_library|
  45   ScopedNativeLibrary(ScopedNativeLibrary&& scoped_library);
  46
  47   // Move assignment operator. Takes ownership of handle stored in
  48   // |scoped_library|.
  49   ScopedNativeLibrary& operator=(ScopedNativeLibrary&& scoped_library) =
  50       default;
  51
  52   void* GetFunctionPointer(const char* function_name) const;
  53
  54   const NativeLibraryLoadError* GetError() const;
  55
  56  private:
  57   NativeLibraryLoadError error_;
  58
  59   DISALLOW_COPY_AND_ASSIGN(ScopedNativeLibrary);
  60 };
  61
  62 }  // namespace base
  63
  64 #endif  // BASE_SCOPED_NATIVE_LIBRARY_H_