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