1adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik//===- FileOutputBuffer.cpp - File Output Buffer ----------------*- C++ -*-===// 2adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik// 3adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik// The LLVM Compiler Infrastructure 4adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik// 5adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik// This file is distributed under the University of Illinois Open Source 6adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik// License. See LICENSE.TXT for details. 7adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik// 8adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik//===----------------------------------------------------------------------===// 9adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik// 10adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik// Utility for creating a in-memory buffer that will be written to a file. 11adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik// 12adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik//===----------------------------------------------------------------------===// 13adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 14ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines#include "llvm/Support/FileOutputBuffer.h" 154c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar#include "llvm/ADT/STLExtras.h" 164c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar#include "llvm/ADT/SmallString.h" 174c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar#include "llvm/Support/Errc.h" 18c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines#include <system_error> 19adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 20ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines#if !defined(_MSC_VER) && !defined(__MINGW32__) 21ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines#include <unistd.h> 22ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines#else 23ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines#include <io.h> 24ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines#endif 25ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines 266bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencerusing llvm::sys::fs::mapped_file_region; 27adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 28adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledziknamespace llvm { 2937ed9c199ca639565f6ce88105f9e39e898d82d0Stephen HinesFileOutputBuffer::FileOutputBuffer(std::unique_ptr<mapped_file_region> R, 306bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer StringRef Path, StringRef TmpPath) 3137ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines : Region(std::move(R)), FinalPath(Path), TempPath(TmpPath) {} 32adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 33adfe2637b839efe041165f27c9ad57e3befb2be0Nick KledzikFileOutputBuffer::~FileOutputBuffer() { 3436b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines sys::fs::remove(Twine(TempPath)); 35adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik} 36adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 37c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hinesstd::error_code 38c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen HinesFileOutputBuffer::create(StringRef FilePath, size_t Size, 39c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines std::unique_ptr<FileOutputBuffer> &Result, 40c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines unsigned Flags) { 41adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // If file already exists, it must be a regular file (to be mappable). 42adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik sys::fs::file_status Stat; 43c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines std::error_code EC = sys::fs::status(FilePath, Stat); 44adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik switch (Stat.type()) { 45adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik case sys::fs::file_type::file_not_found: 46adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // If file does not exist, we'll create one. 47adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik break; 48adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik case sys::fs::file_type::regular_file: { 49adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // If file is not currently writable, error out. 50adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // FIXME: There is no sys::fs:: api for checking this. 51adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // FIXME: In posix, you use the access() call to check this. 52adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik } 53adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik break; 54adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik default: 55adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik if (EC) 56adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik return EC; 57adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik else 58adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik return make_error_code(errc::operation_not_permitted); 59adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik } 60adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 61adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // Delete target file. 6236b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines EC = sys::fs::remove(FilePath); 63adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik if (EC) 64adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik return EC; 656bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer 6673e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola unsigned Mode = sys::fs::all_read | sys::fs::all_write; 6773e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola // If requested, make the output file executable. 6873e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola if (Flags & F_executable) 6973e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola Mode |= sys::fs::all_exe; 7073e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola 71adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // Create new file in same directory but with random name. 72adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik SmallString<128> TempFilePath; 73adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik int FD; 7473e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola EC = sys::fs::createUniqueFile(Twine(FilePath) + ".tmp%%%%%%%", FD, 7573e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola TempFilePath, Mode); 76adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik if (EC) 77adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik return EC; 786bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer 794c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar#ifndef LLVM_ON_WIN32 804c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar // On Windows, CreateFileMapping (the mmap function on Windows) 814c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar // automatically extends the underlying file. We don't need to 824c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar // extend the file beforehand. _chsize (ftruncate on Windows) is 834c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar // pretty slow just like it writes specified amount of bytes, 844c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar // so we should avoid calling that. 85ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines EC = sys::fs::resize_file(FD, Size); 86ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines if (EC) 87ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines return EC; 884c5e43da7792f75567b693105cc53e3f1992ad98Pirama Arumuga Nainar#endif 89ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines 9037ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines auto MappedFile = llvm::make_unique<mapped_file_region>( 91ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines FD, mapped_file_region::readwrite, Size, 0, EC); 92ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines int Ret = close(FD); 93adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik if (EC) 94adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik return EC; 95ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines if (Ret) 96ebe69fe11e48d322045d5949c83283927a0d790bStephen Hines return std::error_code(errno, std::generic_category()); 976bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer 9837ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines Result.reset( 9937ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines new FileOutputBuffer(std::move(MappedFile), FilePath, TempFilePath)); 100adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 101c6a4f5e819217e1e12c458aed8e7b122e23a3a58Stephen Hines return std::error_code(); 1026bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer} 103adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 104ebe69fe11e48d322045d5949c83283927a0d790bStephen Hinesstd::error_code FileOutputBuffer::commit() { 105adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // Unmap buffer, letting OS flush dirty pages to file on disk. 10637ed9c199ca639565f6ce88105f9e39e898d82d0Stephen Hines Region.reset(); 1076bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer 1086bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer 109adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // Rename file to final name. 110adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik return sys::fs::rename(Twine(TempPath), Twine(FinalPath)); 111adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik} 112adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik} // namespace 113