1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <windows.h> 18 19 #include "android-base/utf8.h" 20 21 #include <fcntl.h> 22 #include <stdio.h> 23 24 #include <algorithm> 25 #include <string> 26 27 #include "android-base/logging.h" 28 29 namespace android { 30 namespace base { 31 32 // Helper to set errno based on GetLastError() after WideCharToMultiByte()/MultiByteToWideChar(). 33 static void SetErrnoFromLastError() { 34 switch (GetLastError()) { 35 case ERROR_NO_UNICODE_TRANSLATION: 36 errno = EILSEQ; 37 break; 38 default: 39 errno = EINVAL; 40 break; 41 } 42 } 43 44 bool WideToUTF8(const wchar_t* utf16, const size_t size, std::string* utf8) { 45 utf8->clear(); 46 47 if (size == 0) { 48 return true; 49 } 50 51 // TODO: Consider using std::wstring_convert once libcxx is supported on 52 // Windows. 53 54 // Only Vista or later has this flag that causes WideCharToMultiByte() to 55 // return an error on invalid characters. 56 const DWORD flags = 57 #if (WINVER >= 0x0600) 58 WC_ERR_INVALID_CHARS; 59 #else 60 0; 61 #endif 62 63 const int chars_required = WideCharToMultiByte(CP_UTF8, flags, utf16, size, 64 NULL, 0, NULL, NULL); 65 if (chars_required <= 0) { 66 SetErrnoFromLastError(); 67 return false; 68 } 69 70 // This could potentially throw a std::bad_alloc exception. 71 utf8->resize(chars_required); 72 73 const int result = WideCharToMultiByte(CP_UTF8, flags, utf16, size, 74 &(*utf8)[0], chars_required, NULL, 75 NULL); 76 if (result != chars_required) { 77 SetErrnoFromLastError(); 78 CHECK_LE(result, chars_required) << "WideCharToMultiByte wrote " << result 79 << " chars to buffer of " << chars_required << " chars"; 80 utf8->clear(); 81 return false; 82 } 83 84 return true; 85 } 86 87 bool WideToUTF8(const wchar_t* utf16, std::string* utf8) { 88 // Compute string length of NULL-terminated string with wcslen(). 89 return WideToUTF8(utf16, wcslen(utf16), utf8); 90 } 91 92 bool WideToUTF8(const std::wstring& utf16, std::string* utf8) { 93 // Use the stored length of the string which allows embedded NULL characters 94 // to be converted. 95 return WideToUTF8(utf16.c_str(), utf16.length(), utf8); 96 } 97 98 // Internal helper function that takes MultiByteToWideChar() flags. 99 static bool UTF8ToWideWithFlags(const char* utf8, const size_t size, std::wstring* utf16, 100 const DWORD flags) { 101 utf16->clear(); 102 103 if (size == 0) { 104 return true; 105 } 106 107 // TODO: Consider using std::wstring_convert once libcxx is supported on 108 // Windows. 109 const int chars_required = MultiByteToWideChar(CP_UTF8, flags, utf8, size, 110 NULL, 0); 111 if (chars_required <= 0) { 112 SetErrnoFromLastError(); 113 return false; 114 } 115 116 // This could potentially throw a std::bad_alloc exception. 117 utf16->resize(chars_required); 118 119 const int result = MultiByteToWideChar(CP_UTF8, flags, utf8, size, 120 &(*utf16)[0], chars_required); 121 if (result != chars_required) { 122 SetErrnoFromLastError(); 123 CHECK_LE(result, chars_required) << "MultiByteToWideChar wrote " << result 124 << " chars to buffer of " << chars_required << " chars"; 125 utf16->clear(); 126 return false; 127 } 128 129 return true; 130 } 131 132 bool UTF8ToWide(const char* utf8, const size_t size, std::wstring* utf16) { 133 // If strictly interpreting as UTF-8 succeeds, return success. 134 if (UTF8ToWideWithFlags(utf8, size, utf16, MB_ERR_INVALID_CHARS)) { 135 return true; 136 } 137 138 const int saved_errno = errno; 139 140 // Fallback to non-strict interpretation, allowing invalid characters and 141 // converting as best as possible, and return false to signify a problem. 142 (void)UTF8ToWideWithFlags(utf8, size, utf16, 0); 143 errno = saved_errno; 144 return false; 145 } 146 147 bool UTF8ToWide(const char* utf8, std::wstring* utf16) { 148 // Compute string length of NULL-terminated string with strlen(). 149 return UTF8ToWide(utf8, strlen(utf8), utf16); 150 } 151 152 bool UTF8ToWide(const std::string& utf8, std::wstring* utf16) { 153 // Use the stored length of the string which allows embedded NULL characters 154 // to be converted. 155 return UTF8ToWide(utf8.c_str(), utf8.length(), utf16); 156 } 157 158 static bool isDriveLetter(wchar_t c) { 159 return (c >= L'a' && c <= L'z') || (c >= L'A' && c <= L'Z'); 160 } 161 162 bool UTF8PathToWindowsLongPath(const char* utf8, std::wstring* utf16) { 163 if (!UTF8ToWide(utf8, utf16)) { 164 return false; 165 } 166 // Note: Although most Win32 File I/O API are limited to MAX_PATH (260 167 // characters), the CreateDirectory API is limited to 248 characters. 168 if (utf16->length() >= 248) { 169 // If path is of the form "x:\" or "x:/" 170 if (isDriveLetter((*utf16)[0]) && (*utf16)[1] == L':' && 171 ((*utf16)[2] == L'\\' || (*utf16)[2] == L'/')) { 172 // Append long path prefix, and make sure there are no unix-style 173 // separators to ensure a fully compliant Win32 long path string. 174 utf16->insert(0, LR"(\\?\)"); 175 std::replace(utf16->begin(), utf16->end(), L'/', L'\\'); 176 } 177 } 178 return true; 179 } 180 181 // Versions of standard library APIs that support UTF-8 strings. 182 namespace utf8 { 183 184 FILE* fopen(const char* name, const char* mode) { 185 std::wstring name_utf16; 186 if (!UTF8PathToWindowsLongPath(name, &name_utf16)) { 187 return nullptr; 188 } 189 190 std::wstring mode_utf16; 191 if (!UTF8ToWide(mode, &mode_utf16)) { 192 return nullptr; 193 } 194 195 return _wfopen(name_utf16.c_str(), mode_utf16.c_str()); 196 } 197 198 int mkdir(const char* name, mode_t mode) { 199 std::wstring name_utf16; 200 if (!UTF8PathToWindowsLongPath(name, &name_utf16)) { 201 return -1; 202 } 203 204 return _wmkdir(name_utf16.c_str()); 205 } 206 207 int open(const char* name, int flags, ...) { 208 std::wstring name_utf16; 209 if (!UTF8PathToWindowsLongPath(name, &name_utf16)) { 210 return -1; 211 } 212 213 int mode = 0; 214 if ((flags & O_CREAT) != 0) { 215 va_list args; 216 va_start(args, flags); 217 mode = va_arg(args, int); 218 va_end(args); 219 } 220 221 return _wopen(name_utf16.c_str(), flags, mode); 222 } 223 224 int unlink(const char* name) { 225 std::wstring name_utf16; 226 if (!UTF8PathToWindowsLongPath(name, &name_utf16)) { 227 return -1; 228 } 229 230 return _wunlink(name_utf16.c_str()); 231 } 232 233 } // namespace utf8 234 } // namespace base 235 } // namespace android 236
