base/native_library_win.cc

   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 #include "base/native_library.h"
   6
   7 #include <windows.h>
   8
   9 #include "base/file_util.h"
  10 #include "base/threading/thread_restrictions.h"
  11 #include "base/utf_string_conversions.h"
  12
  13 namespace base {
  14
  15 typedef HMODULE (WINAPI* LoadLibraryFunction)(const wchar_t* file_name);
  16
  17 NativeLibrary LoadNativeLibraryHelper(const FilePath& library_path,
  18                                       LoadLibraryFunction load_library_api) {
  19   // LoadLibrary() opens the file off disk.
  20   base::ThreadRestrictions::AssertIOAllowed();
  21
  22   // Switch the current directory to the library directory as the library
  23   // may have dependencies on DLLs in this directory.
  24   bool restore_directory = false;
  25   FilePath current_directory;
  26   if (file_util::GetCurrentDirectory(&current_directory)) {
  27     FilePath plugin_path = library_path.DirName();
  28     if (!plugin_path.empty()) {
  29       file_util::SetCurrentDirectory(plugin_path);
  30       restore_directory = true;
  31     }
  32   }
  33
  34   HMODULE module = (*load_library_api)(library_path.value().c_str());
  35   if (restore_directory)
  36     file_util::SetCurrentDirectory(current_directory);
  37
  38   return module;
  39 }
  40
  41 // static
  42 NativeLibrary LoadNativeLibrary(const FilePath& library_path,
  43                                 std::string* error) {
  44   return LoadNativeLibraryHelper(library_path, LoadLibraryW);
  45 }
  46
  47 NativeLibrary LoadNativeLibraryDynamically(const FilePath& library_path) {
  48   typedef HMODULE (WINAPI* LoadLibraryFunction)(const wchar_t* file_name);
  49
  50   LoadLibraryFunction load_library;
  51   load_library = reinterpret_cast<LoadLibraryFunction>(
  52       GetProcAddress(GetModuleHandle(L"kernel32.dll"), "LoadLibraryW"));
  53
  54   return LoadNativeLibraryHelper(library_path, load_library);
  55 }
  56
  57 // static
  58 void UnloadNativeLibrary(NativeLibrary library) {
  59   FreeLibrary(library);
  60 }
  61
  62 // static
  63 void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
  64                                           const char* name) {
  65   return GetProcAddress(library, name);
  66 }
  67
  68 // static
  69 string16 GetNativeLibraryName(const string16& name) {
  70   return name + ASCIIToUTF16(".dll");
  71 }
  72
  73 }  // namespace base