// Copyright 2014 The Crashpad Authors. All rights reserved. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. #ifndef CRASHPAD_UTIL_FILE_FILE_WRITER_H_ #define CRASHPAD_UTIL_FILE_FILE_WRITER_H_ #include #include #include #include #include #include #include "base/basictypes.h" #include "base/files/file_path.h" #include "base/files/scoped_file.h" namespace crashpad { //! \brief A version of `iovec` with a `const` #iov_base field. //! //! This structure is intended to be used for write operations. // // Type compatibility with iovec is tested with static assertions in the // implementation file. struct WritableIoVec { //! \brief The base address of a memory region for output. const void* iov_base; //! \brief The size of the memory pointed to by #iov_base. size_t iov_len; }; //! \brief An interface to write to files and other file-like objects with POSIX //! semantics. class FileWriterInterface { public: //! \brief Wraps `write()` or provides an alternate implementation with //! identical semantics. This method will write the entire buffer, //! continuing after a short write or after being interrupted. //! //! \return `true` if the operation succeeded, `false` if it failed, with an //! error message logged. virtual bool Write(const void* data, size_t size) = 0; //! \brief Wraps `writev()` or provides an alternate implementation with //! identical semantics. This method will write the entire buffer, //! continuing after a short write or after being interrupted. //! //! \return `true` if the operation succeeded, `false` if it failed, with an //! error message logged. //! //! \note The contents of \a iovecs are undefined when this method returns. virtual bool WriteIoVec(std::vector* iovecs) = 0; //! \brief Wraps `lseek()` or provides an alternate implementation with //! identical semantics. //! //! \return The return value of `lseek()`. `-1` on failure, with an error //! message logged. virtual off_t Seek(off_t offset, int whence) = 0; protected: ~FileWriterInterface() {} }; //! \brief A file writer implementation that wraps traditional POSIX file //! operations on files accessed through the filesystem. class FileWriter : public FileWriterInterface { public: FileWriter(); ~FileWriter(); //! \brief Wraps `open()`. //! //! \return `true` if the operation succeeded, `false` if it failed, with an //! error message logged. //! //! \note After a successful call, this method cannot be called again until //! after Close(). bool Open(const base::FilePath& path, int oflag, mode_t mode); //! \brief Wraps `close().` //! //! \note It is only valid to call this method on an object that has had a //! successful Open() that has not yet been matched by a subsequent call //! to this method. void Close(); // FileWriterInterface: //! \copydoc FileWriterInterface::Write() //! //! \note It is only valid to call this method between a successful Open() and //! a Close(). bool Write(const void* data, size_t size) override; //! \copydoc FileWriterInterface::WriteIoVec() //! //! \note It is only valid to call this method between a successful Open() and //! a Close(). bool WriteIoVec(std::vector* iovecs) override; //! \copydoc FileWriterInterface::Seek() //! //! \note It is only valid to call this method between a successful Open() and //! a Close(). off_t Seek(off_t offset, int whence) override; private: base::ScopedFD fd_; DISALLOW_COPY_AND_ASSIGN(FileWriter); }; } // namespace crashpad #endif // CRASHPAD_UTIL_FILE_FILE_WRITER_H_