// Copyright 2014 Google Inc. All rights reserved. // // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file or at // https://developers.google.com/open-source/licenses/bsd #ifndef PACKAGER_FILE_FILE_H_ #define PACKAGER_FILE_FILE_H_ #include #include #include "packager/base/macros.h" namespace edash_packager { namespace media { extern const char* kLocalFilePrefix; /// Define an abstract file interface. class File { public: /// Open the specified file. /// This is a file factory method, it opens a proper file automatically /// based on prefix, e.g. "file://" for LocalFile. /// @param file_name contains the name of the file to be accessed. /// @param mode contains file access mode. Implementation dependent. /// @return A File pointer on success, false otherwise. static File* Open(const char* file_name, const char* mode); /// Delete the specified file. /// @param file_name contains the path of the file to be deleted. /// @return true if successful, false otherwise. static bool Delete(const char* file_name); /// Flush() and de-allocate resources associated with this file, and /// delete this File object. THIS IS THE ONE TRUE WAY TO DEALLOCATE /// THIS OBJECT. /// @return true on success. For writable files, returning false MAY /// INDICATE DATA LOSS. virtual bool Close() = 0; /// Read data and return it in buffer. /// @param[out] buffer points to a block of memory with a size of at least /// @a length bytes. /// @param length indicates number of bytes to be read. /// @return Number of bytes read, or a value < 0 on error. /// Zero on end-of-file, or if 'length' is zero. virtual int64_t Read(void* buffer, uint64_t length) = 0; /// Write block of data. /// @param buffer points to a block of memory with at least @a length bytes. /// @param length indicates number of bytes to write. /// @return Number of bytes written, or a value < 0 on error. virtual int64_t Write(const void* buffer, uint64_t length) = 0; /// @return Size of the file in bytes. A return value less than zero /// indicates a problem getting the size. virtual int64_t Size() = 0; /// Flush the file so that recently written data will survive an /// application crash (but not necessarily an OS crash). For /// instance, in LocalFile the data is flushed into the OS but not /// necessarily to disk. /// @return true on success, false otherwise. virtual bool Flush() = 0; /// @return The file name. const std::string& file_name() const { return file_name_; } // ************************************************************ // * Static Methods: File-on-the-filesystem status // ************************************************************ /// @return The size of a file in bytes on success, a value < 0 otherwise. /// The file will be opened and closed in the process. static int64_t GetFileSize(const char* file_name); /// Read the file into string. /// @param file_name is the file to be read. It should be a valid file. /// @param contents[out] points to the output string. Should not be NULL. /// @return true on success, false otherwise. static bool ReadFileToString(const char* file_name, std::string* contents); protected: explicit File(const std::string& file_name) : file_name_(file_name) {} /// Do *not* call the destructor directly (with the "delete" keyword) /// nor use scoped_ptr; instead use Close(). virtual ~File() {} /// Internal open. Should not be used directly. virtual bool Open() = 0; private: friend class ThreadedIoFile; // This is a file factory method, it creates a proper file, e.g. // LocalFile, MemFile based on prefix. static File* Create(const char* file_name, const char* mode); std::string file_name_; DISALLOW_COPY_AND_ASSIGN(File); }; } // namespace media } // namespace edash_packager #endif // PACKAGER_FILE_FILE_H_