1//=== FileOutputBuffer.h - File Output Buffer -------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// Utility for creating a in-memory buffer that will be written to a file. 11// 12//===----------------------------------------------------------------------===// 13 14#ifndef LLVM_SUPPORT_FILEOUTPUTBUFFER_H 15#define LLVM_SUPPORT_FILEOUTPUTBUFFER_H 16 17#include "llvm/ADT/OwningPtr.h" 18#include "llvm/ADT/SmallString.h" 19#include "llvm/ADT/StringRef.h" 20#include "llvm/Support/DataTypes.h" 21#include "llvm/Support/FileSystem.h" 22 23namespace llvm { 24class error_code; 25 26/// FileOutputBuffer - This interface provides simple way to create an in-memory 27/// buffer which will be written to a file. During the lifetime of these 28/// objects, the content or existence of the specified file is undefined. That 29/// is, creating an OutputBuffer for a file may immediately remove the file. 30/// If the FileOutputBuffer is committed, the target file's content will become 31/// the buffer content at the time of the commit. If the FileOutputBuffer is 32/// not committed, the file will be deleted in the FileOutputBuffer destructor. 33class FileOutputBuffer { 34public: 35 36 enum { 37 F_executable = 1 /// set the 'x' bit on the resulting file 38 }; 39 40 /// Factory method to create an OutputBuffer object which manages a read/write 41 /// buffer of the specified size. When committed, the buffer will be written 42 /// to the file at the specified path. 43 static error_code create(StringRef FilePath, size_t Size, 44 OwningPtr<FileOutputBuffer> &Result, 45 unsigned Flags = 0); 46 47 /// Returns a pointer to the start of the buffer. 48 uint8_t *getBufferStart() { 49 return (uint8_t*)Region->data(); 50 } 51 52 /// Returns a pointer to the end of the buffer. 53 uint8_t *getBufferEnd() { 54 return (uint8_t*)Region->data() + Region->size(); 55 } 56 57 /// Returns size of the buffer. 58 size_t getBufferSize() const { 59 return Region->size(); 60 } 61 62 /// Returns path where file will show up if buffer is committed. 63 StringRef getPath() const { 64 return FinalPath; 65 } 66 67 /// Flushes the content of the buffer to its file and deallocates the 68 /// buffer. If commit() is not called before this object's destructor 69 /// is called, the file is deleted in the destructor. The optional parameter 70 /// is used if it turns out you want the file size to be smaller than 71 /// initially requested. 72 error_code commit(int64_t NewSmallerSize = -1); 73 74 /// If this object was previously committed, the destructor just deletes 75 /// this object. If this object was not committed, the destructor 76 /// deallocates the buffer and the target file is never written. 77 ~FileOutputBuffer(); 78 79private: 80 FileOutputBuffer(const FileOutputBuffer &) LLVM_DELETED_FUNCTION; 81 FileOutputBuffer &operator=(const FileOutputBuffer &) LLVM_DELETED_FUNCTION; 82 83 FileOutputBuffer(llvm::sys::fs::mapped_file_region *R, 84 StringRef Path, StringRef TempPath); 85 86 OwningPtr<llvm::sys::fs::mapped_file_region> Region; 87 SmallString<128> FinalPath; 88 SmallString<128> TempPath; 89}; 90} // end namespace llvm 91 92#endif 93