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Diffstat (limited to 'third_party/libwebrtc/rtc_base/system/file_wrapper.h')
-rw-r--r-- | third_party/libwebrtc/rtc_base/system/file_wrapper.h | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/third_party/libwebrtc/rtc_base/system/file_wrapper.h b/third_party/libwebrtc/rtc_base/system/file_wrapper.h new file mode 100644 index 0000000000..92a552cfd9 --- /dev/null +++ b/third_party/libwebrtc/rtc_base/system/file_wrapper.h @@ -0,0 +1,113 @@ +/* + * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. + * + * Use of this source code is governed by a BSD-style license + * that can be found in the LICENSE file in the root of the source + * tree. An additional intellectual property rights grant can be found + * in the file PATENTS. All contributing project authors may + * be found in the AUTHORS file in the root of the source tree. + */ + +#ifndef RTC_BASE_SYSTEM_FILE_WRAPPER_H_ +#define RTC_BASE_SYSTEM_FILE_WRAPPER_H_ + +#include <stddef.h> +#include <stdint.h> +#include <stdio.h> + +#include <string> + +#include "absl/strings/string_view.h" + +// Implementation that can read (exclusive) or write from/to a file. + +namespace webrtc { + +// This class is a thin wrapper around FILE*. It's main features are that it +// owns the FILE*, calling fclose on destruction, and that on windows, file +// names passed to the open methods are always treated as utf-8, regardless of +// system code page. + +// Most of the methods return only a success/fail indication. When needed, an +// optional argument |int* error| should be added to all methods, in the same +// way as for the OpenWriteOnly methods. +class FileWrapper final { + public: + // Opens a file, in read or write mode. Use the is_open() method on the + // returned object to check if the open operation was successful. On failure, + // and if `error` is non-null, the system errno value is stored at |*error|. + // The file is closed by the destructor. + static FileWrapper OpenReadOnly(absl::string_view file_name_utf8); + static FileWrapper OpenWriteOnly(absl::string_view file_name_utf8, + int* error = nullptr); + + FileWrapper() = default; + + // Takes over ownership of `file`, closing it on destruction. Calling with + // null `file` is allowed, and results in a FileWrapper with is_open() false. + explicit FileWrapper(FILE* file) : file_(file) {} + ~FileWrapper() { Close(); } + + // Copying is not supported. + FileWrapper(const FileWrapper&) = delete; + FileWrapper& operator=(const FileWrapper&) = delete; + + // Support for move semantics. + FileWrapper(FileWrapper&&); + FileWrapper& operator=(FileWrapper&&); + + // Returns true if a file has been opened. If the file is not open, no methods + // but is_open and Close may be called. + bool is_open() const { return file_ != nullptr; } + + // Closes the file, and implies Flush. Returns true on success, false if + // writing buffered data fails. On failure, the file is nevertheless closed. + // Calling Close on an already closed file does nothing and returns success. + bool Close(); + + // Releases and returns the wrapped file without closing it. This call passes + // the ownership of the file to the caller, and the wrapper is no longer + // responsible for closing it. Similarly the previously wrapped file is no + // longer available for the wrapper to use in any aspect. + FILE* Release(); + + // Write any buffered data to the underlying file. Returns true on success, + // false on write error. Note: Flushing when closing, is not required. + bool Flush(); + + // Seeks to the beginning of file. Returns true on success, false on failure, + // e.g., if the underlying file isn't seekable. + bool Rewind() { return SeekTo(0); } + // TODO(nisse): The seek functions are used only by the WavReader. If that + // code is demoted to test code, seek functions can be deleted from this + // utility. + // Seek relative to current file position. + bool SeekRelative(int64_t offset); + // Seek to given position. + bool SeekTo(int64_t position); + + // Returns the file size or -1 if a size could not be determined. + // (A file size might not exists for non-seekable files or file-like + // objects, for example /dev/tty on unix.) + long FileSize(); + + // Returns number of bytes read. Short count indicates EOF or error. + size_t Read(void* buf, size_t length); + + // If the most recent Read() returned a short count, this methods returns true + // if the short count was due to EOF, and false it it was due to some i/o + // error. + bool ReadEof() const; + + // Returns true if all data was successfully written (or buffered), or false + // if there was an error. Writing buffered data can fail later, and is + // reported with return value from Flush or Close. + bool Write(const void* buf, size_t length); + + private: + FILE* file_ = nullptr; +}; + +} // namespace webrtc + +#endif // RTC_BASE_SYSTEM_FILE_WRAPPER_H_ |