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1 // Copyright (c) 2012 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 "net/disk_cache/file.h" | |
6 | |
7 #include "base/files/file_path.h" | |
8 #include "base/lazy_instance.h" | |
9 #include "base/message_loop/message_loop.h" | |
10 #include "net/base/net_errors.h" | |
11 #include "net/disk_cache/disk_cache.h" | |
12 | |
13 namespace { | |
14 | |
15 // Structure used for asynchronous operations. | |
16 struct MyOverlapped { | |
17 MyOverlapped(disk_cache::File* file, size_t offset, | |
18 disk_cache::FileIOCallback* callback); | |
19 ~MyOverlapped() {} | |
20 OVERLAPPED* overlapped() { | |
21 return &context_.overlapped; | |
22 } | |
23 | |
24 base::MessageLoopForIO::IOContext context_; | |
25 scoped_refptr<disk_cache::File> file_; | |
26 disk_cache::FileIOCallback* callback_; | |
27 }; | |
28 | |
29 COMPILE_ASSERT(!offsetof(MyOverlapped, context_), starts_with_overlapped); | |
30 | |
31 // Helper class to handle the IO completion notifications from the message loop. | |
32 class CompletionHandler : public base::MessageLoopForIO::IOHandler { | |
33 virtual void OnIOCompleted(base::MessageLoopForIO::IOContext* context, | |
34 DWORD actual_bytes, | |
35 DWORD error); | |
36 }; | |
37 | |
38 static base::LazyInstance<CompletionHandler> g_completion_handler = | |
39 LAZY_INSTANCE_INITIALIZER; | |
40 | |
41 void CompletionHandler::OnIOCompleted( | |
42 base::MessageLoopForIO::IOContext* context, | |
43 DWORD actual_bytes, | |
44 DWORD error) { | |
45 MyOverlapped* data = reinterpret_cast<MyOverlapped*>(context); | |
46 | |
47 if (error) { | |
48 DCHECK(!actual_bytes); | |
49 actual_bytes = static_cast<DWORD>(net::ERR_CACHE_READ_FAILURE); | |
50 NOTREACHED(); | |
51 } | |
52 | |
53 if (data->callback_) | |
54 data->callback_->OnFileIOComplete(static_cast<int>(actual_bytes)); | |
55 | |
56 delete data; | |
57 } | |
58 | |
59 MyOverlapped::MyOverlapped(disk_cache::File* file, size_t offset, | |
60 disk_cache::FileIOCallback* callback) { | |
61 memset(this, 0, sizeof(*this)); | |
62 context_.handler = g_completion_handler.Pointer(); | |
63 context_.overlapped.Offset = static_cast<DWORD>(offset); | |
64 file_ = file; | |
65 callback_ = callback; | |
66 } | |
67 | |
68 } // namespace | |
69 | |
70 namespace disk_cache { | |
71 | |
72 File::File(base::PlatformFile file) | |
73 : init_(true), mixed_(true), platform_file_(INVALID_HANDLE_VALUE), | |
74 sync_platform_file_(file) { | |
75 } | |
76 | |
77 bool File::Init(const base::FilePath& name) { | |
78 DCHECK(!init_); | |
79 if (init_) | |
80 return false; | |
81 | |
82 DWORD sharing = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE; | |
83 DWORD access = GENERIC_READ | GENERIC_WRITE | DELETE; | |
84 platform_file_ = CreateFile(name.value().c_str(), access, sharing, NULL, | |
85 OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL); | |
86 | |
87 if (INVALID_HANDLE_VALUE == platform_file_) | |
88 return false; | |
89 | |
90 base::MessageLoopForIO::current()->RegisterIOHandler( | |
91 platform_file_, g_completion_handler.Pointer()); | |
92 | |
93 init_ = true; | |
94 sync_platform_file_ = CreateFile(name.value().c_str(), access, sharing, NULL, | |
95 OPEN_EXISTING, 0, NULL); | |
96 | |
97 if (INVALID_HANDLE_VALUE == sync_platform_file_) | |
98 return false; | |
99 | |
100 return true; | |
101 } | |
102 | |
103 File::~File() { | |
104 if (!init_) | |
105 return; | |
106 | |
107 if (INVALID_HANDLE_VALUE != platform_file_) | |
108 CloseHandle(platform_file_); | |
109 if (INVALID_HANDLE_VALUE != sync_platform_file_) | |
110 CloseHandle(sync_platform_file_); | |
111 } | |
112 | |
113 base::PlatformFile File::platform_file() const { | |
114 DCHECK(init_); | |
115 return (INVALID_HANDLE_VALUE == platform_file_) ? sync_platform_file_ : | |
116 platform_file_; | |
117 } | |
118 | |
119 bool File::IsValid() const { | |
120 if (!init_) | |
121 return false; | |
122 return (INVALID_HANDLE_VALUE != platform_file_ || | |
123 INVALID_HANDLE_VALUE != sync_platform_file_); | |
124 } | |
125 | |
126 bool File::Read(void* buffer, size_t buffer_len, size_t offset) { | |
127 DCHECK(init_); | |
128 if (buffer_len > ULONG_MAX || offset > LONG_MAX) | |
129 return false; | |
130 | |
131 DWORD ret = SetFilePointer(sync_platform_file_, static_cast<LONG>(offset), | |
132 NULL, FILE_BEGIN); | |
133 if (INVALID_SET_FILE_POINTER == ret) | |
134 return false; | |
135 | |
136 DWORD actual; | |
137 DWORD size = static_cast<DWORD>(buffer_len); | |
138 if (!ReadFile(sync_platform_file_, buffer, size, &actual, NULL)) | |
139 return false; | |
140 return actual == size; | |
141 } | |
142 | |
143 bool File::Write(const void* buffer, size_t buffer_len, size_t offset) { | |
144 DCHECK(init_); | |
145 if (buffer_len > ULONG_MAX || offset > ULONG_MAX) | |
146 return false; | |
147 | |
148 DWORD ret = SetFilePointer(sync_platform_file_, static_cast<LONG>(offset), | |
149 NULL, FILE_BEGIN); | |
150 if (INVALID_SET_FILE_POINTER == ret) | |
151 return false; | |
152 | |
153 DWORD actual; | |
154 DWORD size = static_cast<DWORD>(buffer_len); | |
155 if (!WriteFile(sync_platform_file_, buffer, size, &actual, NULL)) | |
156 return false; | |
157 return actual == size; | |
158 } | |
159 | |
160 // We have to increase the ref counter of the file before performing the IO to | |
161 // prevent the completion to happen with an invalid handle (if the file is | |
162 // closed while the IO is in flight). | |
163 bool File::Read(void* buffer, size_t buffer_len, size_t offset, | |
164 FileIOCallback* callback, bool* completed) { | |
165 DCHECK(init_); | |
166 if (!callback) { | |
167 if (completed) | |
168 *completed = true; | |
169 return Read(buffer, buffer_len, offset); | |
170 } | |
171 | |
172 if (buffer_len > ULONG_MAX || offset > ULONG_MAX) | |
173 return false; | |
174 | |
175 MyOverlapped* data = new MyOverlapped(this, offset, callback); | |
176 DWORD size = static_cast<DWORD>(buffer_len); | |
177 | |
178 DWORD actual; | |
179 if (!ReadFile(platform_file_, buffer, size, &actual, data->overlapped())) { | |
180 *completed = false; | |
181 if (GetLastError() == ERROR_IO_PENDING) | |
182 return true; | |
183 delete data; | |
184 return false; | |
185 } | |
186 | |
187 // The operation completed already. We'll be called back anyway. | |
188 *completed = (actual == size); | |
189 DCHECK_EQ(size, actual); | |
190 data->callback_ = NULL; | |
191 data->file_ = NULL; // There is no reason to hold on to this anymore. | |
192 return *completed; | |
193 } | |
194 | |
195 bool File::Write(const void* buffer, size_t buffer_len, size_t offset, | |
196 FileIOCallback* callback, bool* completed) { | |
197 DCHECK(init_); | |
198 if (!callback) { | |
199 if (completed) | |
200 *completed = true; | |
201 return Write(buffer, buffer_len, offset); | |
202 } | |
203 | |
204 return AsyncWrite(buffer, buffer_len, offset, callback, completed); | |
205 } | |
206 | |
207 bool File::AsyncWrite(const void* buffer, size_t buffer_len, size_t offset, | |
208 FileIOCallback* callback, bool* completed) { | |
209 DCHECK(init_); | |
210 DCHECK(callback); | |
211 DCHECK(completed); | |
212 if (buffer_len > ULONG_MAX || offset > ULONG_MAX) | |
213 return false; | |
214 | |
215 MyOverlapped* data = new MyOverlapped(this, offset, callback); | |
216 DWORD size = static_cast<DWORD>(buffer_len); | |
217 | |
218 DWORD actual; | |
219 if (!WriteFile(platform_file_, buffer, size, &actual, data->overlapped())) { | |
220 *completed = false; | |
221 if (GetLastError() == ERROR_IO_PENDING) | |
222 return true; | |
223 delete data; | |
224 return false; | |
225 } | |
226 | |
227 // The operation completed already. We'll be called back anyway. | |
228 *completed = (actual == size); | |
229 DCHECK_EQ(size, actual); | |
230 data->callback_ = NULL; | |
231 data->file_ = NULL; // There is no reason to hold on to this anymore. | |
232 return *completed; | |
233 } | |
234 | |
235 bool File::SetLength(size_t length) { | |
236 DCHECK(init_); | |
237 if (length > ULONG_MAX) | |
238 return false; | |
239 | |
240 DWORD size = static_cast<DWORD>(length); | |
241 HANDLE file = platform_file(); | |
242 if (INVALID_SET_FILE_POINTER == SetFilePointer(file, size, NULL, FILE_BEGIN)) | |
243 return false; | |
244 | |
245 return TRUE == SetEndOfFile(file); | |
246 } | |
247 | |
248 size_t File::GetLength() { | |
249 DCHECK(init_); | |
250 LARGE_INTEGER size; | |
251 HANDLE file = platform_file(); | |
252 if (!GetFileSizeEx(file, &size)) | |
253 return 0; | |
254 if (size.HighPart) | |
255 return ULONG_MAX; | |
256 | |
257 return static_cast<size_t>(size.LowPart); | |
258 } | |
259 | |
260 // Static. | |
261 void File::WaitForPendingIO(int* num_pending_io) { | |
262 while (*num_pending_io) { | |
263 // Asynchronous IO operations may be in flight and the completion may end | |
264 // up calling us back so let's wait for them. | |
265 base::MessageLoopForIO::IOHandler* handler = g_completion_handler.Pointer(); | |
266 base::MessageLoopForIO::current()->WaitForIOCompletion(100, handler); | |
267 } | |
268 } | |
269 | |
270 // Static. | |
271 void File::DropPendingIO() { | |
272 } | |
273 | |
274 } // namespace disk_cache | |
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