1 //===- FileOutputBuffer.cpp - 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 #include "llvm/Support/FileOutputBuffer.h"
15 #include "llvm/ADT/OwningPtr.h"
16 #include "llvm/ADT/SmallVector.h"
17 #include "llvm/Support/raw_ostream.h"
18 #include "llvm/Support/system_error.h"
20 using llvm::sys::fs::mapped_file_region;
23 FileOutputBuffer::FileOutputBuffer(mapped_file_region * R,
24 StringRef Path, StringRef TmpPath)
30 FileOutputBuffer::~FileOutputBuffer() {
32 sys::fs::remove(Twine(TempPath), Existed);
35 error_code FileOutputBuffer::create(StringRef FilePath,
37 OwningPtr<FileOutputBuffer> &Result,
39 // If file already exists, it must be a regular file (to be mappable).
40 sys::fs::file_status Stat;
41 error_code EC = sys::fs::status(FilePath, Stat);
42 switch (Stat.type()) {
43 case sys::fs::file_type::file_not_found:
44 // If file does not exist, we'll create one.
46 case sys::fs::file_type::regular_file: {
47 // If file is not currently writable, error out.
48 // FIXME: There is no sys::fs:: api for checking this.
49 // FIXME: In posix, you use the access() call to check this.
56 return make_error_code(errc::operation_not_permitted);
59 // Delete target file.
61 EC = sys::fs::remove(FilePath, Existed);
65 // Create new file in same directory but with random name.
66 SmallString<128> TempFilePath;
68 EC = sys::fs::unique_file(Twine(FilePath) + ".tmp%%%%%%%",
69 FD, TempFilePath, false, 0644);
73 OwningPtr<mapped_file_region> MappedFile(new mapped_file_region(
74 FD, true, mapped_file_region::readwrite, Size, 0, EC));
78 // If requested, make the output file executable.
79 if ( Flags & F_executable ) {
80 sys::fs::file_status Stat2;
81 EC = sys::fs::status(Twine(TempFilePath), Stat2);
85 sys::fs::perms new_perms = Stat2.permissions();
86 if ( new_perms & sys::fs::owner_read )
87 new_perms |= sys::fs::owner_exe;
88 if ( new_perms & sys::fs::group_read )
89 new_perms |= sys::fs::group_exe;
90 if ( new_perms & sys::fs::others_read )
91 new_perms |= sys::fs::others_exe;
92 new_perms |= sys::fs::add_perms;
93 EC = sys::fs::permissions(Twine(TempFilePath), new_perms);
98 Result.reset(new FileOutputBuffer(MappedFile.get(), FilePath, TempFilePath));
102 return error_code::success();
105 error_code FileOutputBuffer::commit(int64_t NewSmallerSize) {
106 // Unmap buffer, letting OS flush dirty pages to file on disk.
109 // If requested, resize file as part of commit.
110 if ( NewSmallerSize != -1 ) {
111 error_code EC = sys::fs::resize_file(Twine(TempPath), NewSmallerSize);
116 // Rename file to final name.
117 return sys::fs::rename(Twine(TempPath), Twine(FinalPath));