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 23 namespace llvm { 24 class 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. 33 class FileOutputBuffer { 34 public: 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 79 private: 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