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/files/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
14namespace base {
15
16typedef HMODULE (WINAPI* LoadLibraryFunction)(const wchar_t* file_name);
17
18namespace {
19
20NativeLibrary 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
52std::string NativeLibraryLoadError::ToString() const {
53  return StringPrintf("%u", code);
54}
55
56// static
57NativeLibrary LoadNativeLibrary(const FilePath& library_path,
58                                NativeLibraryLoadError* error) {
59  return LoadNativeLibraryHelper(library_path, LoadLibraryW, error);
60}
61
62NativeLibrary 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
73void UnloadNativeLibrary(NativeLibrary library) {
74  FreeLibrary(library);
75}
76
77// static
78void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
79                                          const char* name) {
80  return GetProcAddress(library, name);
81}
82
83// static
84string16 GetNativeLibraryName(const string16& name) {
85  return name + ASCIIToUTF16(".dll");
86}
87
88}  // namespace base
89