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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 
14 namespace base {
15 
16 typedef HMODULE (WINAPI* LoadLibraryFunction)(const wchar_t* file_name);
17 
18 namespace {
19 
LoadNativeLibraryHelper(const FilePath & library_path,LoadLibraryFunction load_library_api,NativeLibraryLoadError * error)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 
ToString() const52 std::string NativeLibraryLoadError::ToString() const {
53   return StringPrintf("%u", code);
54 }
55 
56 // static
LoadNativeLibrary(const FilePath & library_path,NativeLibraryLoadError * error)57 NativeLibrary LoadNativeLibrary(const FilePath& library_path,
58                                 NativeLibraryLoadError* error) {
59   return LoadNativeLibraryHelper(library_path, LoadLibraryW, error);
60 }
61 
LoadNativeLibraryDynamically(const FilePath & library_path)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
UnloadNativeLibrary(NativeLibrary library)73 void UnloadNativeLibrary(NativeLibrary library) {
74   FreeLibrary(library);
75 }
76 
77 // static
GetFunctionPointerFromNativeLibrary(NativeLibrary library,const char * name)78 void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
79                                           const char* name) {
80   return GetProcAddress(library, name);
81 }
82 
83 // static
GetNativeLibraryName(const string16 & name)84 string16 GetNativeLibraryName(const string16& name) {
85   return name + ASCIIToUTF16(".dll");
86 }
87 
88 }  // namespace base
89