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"
25 /// FileOutputBuffer - This interface provides simple way to create an in-memory
26 /// buffer which will be written to a file. During the lifetime of these
27 /// objects, the content or existence of the specified file is undefined. That
28 /// is, creating an OutputBuffer for a file may immediately remove the file.
29 /// If the FileOutputBuffer is committed, the target file's content will become
30 /// the buffer content at the time of the commit. If the FileOutputBuffer is
31 /// not committed, the file will be deleted in the FileOutputBuffer destructor.
32 class FileOutputBuffer {
36 F_executable = 1 /// set the 'x' bit on the resulting file
39 /// Factory method to create an OutputBuffer object which manages a read/write
40 /// buffer of the specified size. When committed, the buffer will be written
41 /// to the file at the specified path.
42 static error_code create(StringRef FilePath, size_t Size,
43 std::unique_ptr<FileOutputBuffer> &Result,
46 /// Returns a pointer to the start of the buffer.
47 uint8_t *getBufferStart() {
48 return (uint8_t*)Region->data();
51 /// Returns a pointer to the end of the buffer.
52 uint8_t *getBufferEnd() {
53 return (uint8_t*)Region->data() + Region->size();
56 /// Returns size of the buffer.
57 size_t getBufferSize() const {
58 return Region->size();
61 /// Returns path where file will show up if buffer is committed.
62 StringRef getPath() const {
66 /// Flushes the content of the buffer to its file and deallocates the
67 /// buffer. If commit() is not called before this object's destructor
68 /// is called, the file is deleted in the destructor. The optional parameter
69 /// is used if it turns out you want the file size to be smaller than
70 /// initially requested.
71 error_code commit(int64_t NewSmallerSize = -1);
73 /// If this object was previously committed, the destructor just deletes
74 /// this object. If this object was not committed, the destructor
75 /// deallocates the buffer and the target file is never written.
79 FileOutputBuffer(const FileOutputBuffer &) LLVM_DELETED_FUNCTION;
80 FileOutputBuffer &operator=(const FileOutputBuffer &) LLVM_DELETED_FUNCTION;
82 FileOutputBuffer(llvm::sys::fs::mapped_file_region *R,
83 StringRef Path, StringRef TempPath);
85 std::unique_ptr<llvm::sys::fs::mapped_file_region> Region;
86 SmallString<128> FinalPath;
87 SmallString<128> TempPath;
89 } // end namespace llvm