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 // See net/disk_cache/disk_cache.h for the public interface of the cache. 6 7 #ifndef NET_DISK_CACHE_FILE_H_ 8 #define NET_DISK_CACHE_FILE_H_ 9 10 #include "base/memory/ref_counted.h" 11 #include "base/platform_file.h" 12 #include "net/base/net_export.h" 13 14 namespace base { 15 class FilePath; 16 } 17 18 namespace disk_cache { 19 20 // This interface is used to support asynchronous ReadData and WriteData calls. 21 class FileIOCallback { 22 public: 23 // Notified of the actual number of bytes read or written. This value is 24 // negative if an error occurred. 25 virtual void OnFileIOComplete(int bytes_copied) = 0; 26 27 protected: 28 virtual ~FileIOCallback() {} 29 }; 30 31 // Simple wrapper around a file that allows asynchronous operations. 32 class NET_EXPORT_PRIVATE File : public base::RefCounted<File> { 33 friend class base::RefCounted<File>; 34 public: 35 File(); 36 // mixed_mode set to true enables regular synchronous operations for the file. 37 explicit File(bool mixed_mode); 38 39 // Initializes the object to use the passed in file instead of opening it with 40 // the Init() call. No asynchronous operations can be performed with this 41 // object. 42 explicit File(base::PlatformFile file); 43 44 // Initializes the object to point to a given file. The file must aready exist 45 // on disk, and allow shared read and write. 46 bool Init(const base::FilePath& name); 47 48 // Returns the handle or file descriptor. 49 base::PlatformFile platform_file() const; 50 51 // Returns true if the file was opened properly. 52 bool IsValid() const; 53 54 // Performs synchronous IO. 55 bool Read(void* buffer, size_t buffer_len, size_t offset); 56 bool Write(const void* buffer, size_t buffer_len, size_t offset); 57 58 // Performs asynchronous IO. callback will be called when the IO completes, 59 // as an APC on the thread that queued the operation. 60 bool Read(void* buffer, size_t buffer_len, size_t offset, 61 FileIOCallback* callback, bool* completed); 62 bool Write(const void* buffer, size_t buffer_len, size_t offset, 63 FileIOCallback* callback, bool* completed); 64 65 // Sets the file's length. The file is truncated or extended with zeros to 66 // the new length. 67 bool SetLength(size_t length); 68 size_t GetLength(); 69 70 // Blocks until |num_pending_io| IO operations complete. 71 static void WaitForPendingIO(int* num_pending_io); 72 73 // Drops current pending operations without waiting for them to complete. 74 static void DropPendingIO(); 75 76 protected: 77 virtual ~File(); 78 79 // Performs the actual asynchronous write. If notify is set and there is no 80 // callback, the call will be re-synchronized. 81 bool AsyncWrite(const void* buffer, size_t buffer_len, size_t offset, 82 FileIOCallback* callback, bool* completed); 83 84 private: 85 bool init_; 86 bool mixed_; 87 base::PlatformFile platform_file_; // Regular, asynchronous IO handle. 88 base::PlatformFile sync_platform_file_; // Synchronous IO handle. 89 90 DISALLOW_COPY_AND_ASSIGN(File); 91 }; 92 93 } // namespace disk_cache 94 95 #endif // NET_DISK_CACHE_FILE_H_ 96
