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/strings/stringprintf.h"
  11 #include "base/strings/utf_string_conversions.h"
  12 #include "base/threading/thread_restrictions.h"
  13
  14 namespace base {
  15
  16 typedef HMODULE (WINAPI* LoadLibraryFunction)(const wchar_t* file_name);
  17
  18 namespace {
  19
  20 NativeLibrary LoadNativeLibraryHelper(const FilePath& library_path,
  21                                       LoadLibraryFunction load_library_api,
  22                                       NativeLibraryLoadError* error) {
  23   // LoadLibrary() opens the file off disk.
  24   ThreadRestrictions::AssertIOAllowed();
  25
  26   // Switch the current directory to the library directory as the library
  27   // may have dependencies on DLLs in this directory.
  28   bool restore_directory = false;
  29   FilePath current_directory;
  30   if (GetCurrentDirectory(&current_directory)) {
  31     FilePath plugin_path = library_path.DirName();
  32     if (!plugin_path.empty()) {
  33       SetCurrentDirectory(plugin_path);
  34       restore_directory = true;
  35     }
  36   }
  37
  38   HMODULE module = (*load_library_api)(library_path.value().c_str());
  39   if (!module && error) {
  40     // GetLastError() needs to be called immediately after |load_library_api|.
  41     error->code = GetLastError();
  42   }
  43
  44   if (restore_directory)
  45     SetCurrentDirectory(current_directory);
  46
  47   return module;
  48 }
  49
  50 }  // namespace
  51
  52 std::string NativeLibraryLoadError::ToString() const {
  53   return StringPrintf("%u", code);
  54 }
  55
  56 // static
  57 NativeLibrary LoadNativeLibrary(const FilePath& library_path,
  58                                 NativeLibraryLoadError* error) {
  59   return LoadNativeLibraryHelper(library_path, LoadLibraryW, error);
  60 }
  61
  62 NativeLibrary LoadNativeLibraryDynamically(const FilePath& library_path) {
  63   typedef HMODULE (WINAPI* LoadLibraryFunction)(const wchar_t* file_name);
  64
  65   LoadLibraryFunction load_library;
  66   load_library = reinterpret_cast<LoadLibraryFunction>(
  67       GetProcAddress(GetModuleHandle(L"kernel32.dll"), "LoadLibraryW"));
  68
  69   return LoadNativeLibraryHelper(library_path, load_library, NULL);
  70 }
  71
  72 // static
  73 void UnloadNativeLibrary(NativeLibrary library) {
  74   FreeLibrary(library);
  75 }
  76
  77 // static
  78 void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
  79                                           const char* name) {
  80   return GetProcAddress(library, name);
  81 }
  82
  83 // static
  84 string16 GetNativeLibraryName(const string16& name) {
  85   return name + ASCIIToUTF16(".dll");
  86 }
  87
  88 }  // namespace base