base/scoped_native_library.h

   1 // Copyright 2011 The Chromium Authors
   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/native_library.h"
  10 #include "base/scoped_generic.h"
  11
  12 namespace base {
  13
  14 class FilePath;
  15
  16 struct BASE_EXPORT NativeLibraryTraits {
  17   // It's assumed that this is a fast inline function with little-to-no
  18   // penalty for duplicate calls. This must be a static function even
  19   // for stateful traits.
  20   static NativeLibrary InvalidValue() { return nullptr; }
  21
  22   // This free function will not be called if library == InvalidValue()!
  23   static void Free(NativeLibrary library);
  24 };
  25
  26 // A class which encapsulates a base::NativeLibrary object available only in a
  27 // scope.
  28 // This class automatically unloads the loaded library in its destructor.
  29 class BASE_EXPORT ScopedNativeLibrary
  30     : public ScopedGeneric<NativeLibrary, NativeLibraryTraits> {
  31  public:
  32   // Initializes with a NULL library.
  33   ScopedNativeLibrary();
  34
  35   // Takes ownership of the given library handle.
  36   explicit ScopedNativeLibrary(NativeLibrary library);
  37
  38   // Opens the given library and manages its lifetime.
  39   explicit ScopedNativeLibrary(const FilePath& library_path);
  40
  41   // Move constructor. Takes ownership of handle stored in |scoped_library|
  42   ScopedNativeLibrary(ScopedNativeLibrary&& scoped_library);
  43
  44   // Move assignment operator. Takes ownership of handle stored in
  45   // |scoped_library|.
  46   ScopedNativeLibrary& operator=(ScopedNativeLibrary&& scoped_library) =
  47       default;
  48
  49   ScopedNativeLibrary(const ScopedNativeLibrary&) = delete;
  50   ScopedNativeLibrary& operator=(const ScopedNativeLibrary&) = delete;
  51
  52   ~ScopedNativeLibrary() override;
  53
  54   void* GetFunctionPointer(const char* function_name) const;
  55
  56   const NativeLibraryLoadError* GetError() const;
  57
  58  private:
  59   NativeLibraryLoadError error_;
  60 };
  61
  62 }  // namespace base
  63
  64 #endif  // BASE_SCOPED_NATIVE_LIBRARY_H_