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 14cd81d94322a39503e4a3e87b6ee03d4fcb3465fbStephen Hines#include "llvm/Support/Errc.h" 15adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik#include "llvm/Support/FileOutputBuffer.h" 16adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik#include "llvm/ADT/SmallVector.h" 17adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik#include "llvm/Support/raw_ostream.h" 18cd81d94322a39503e4a3e87b6ee03d4fcb3465fbStephen Hines#include <system_error> 19adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 206bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencerusing llvm::sys::fs::mapped_file_region; 21adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 22adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledziknamespace llvm { 236bc86018d189e9ab62d30ef8190bac961dd22248Michael J. SpencerFileOutputBuffer::FileOutputBuffer(mapped_file_region * R, 246bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer StringRef Path, StringRef TmpPath) 256bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer : Region(R) 266bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer , FinalPath(Path) 276bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer , TempPath(TmpPath) { 28adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik} 29adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 30adfe2637b839efe041165f27c9ad57e3befb2be0Nick KledzikFileOutputBuffer::~FileOutputBuffer() { 3136b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines sys::fs::remove(Twine(TempPath)); 32adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik} 33adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 34cd81d94322a39503e4a3e87b6ee03d4fcb3465fbStephen Hinesstd::error_code 35cd81d94322a39503e4a3e87b6ee03d4fcb3465fbStephen HinesFileOutputBuffer::create(StringRef FilePath, size_t Size, 36cd81d94322a39503e4a3e87b6ee03d4fcb3465fbStephen Hines std::unique_ptr<FileOutputBuffer> &Result, 37cd81d94322a39503e4a3e87b6ee03d4fcb3465fbStephen Hines unsigned Flags) { 38adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // If file already exists, it must be a regular file (to be mappable). 39adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik sys::fs::file_status Stat; 40cd81d94322a39503e4a3e87b6ee03d4fcb3465fbStephen Hines std::error_code EC = sys::fs::status(FilePath, Stat); 41adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik switch (Stat.type()) { 42adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik case sys::fs::file_type::file_not_found: 43adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // If file does not exist, we'll create one. 44adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik break; 45adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik case sys::fs::file_type::regular_file: { 46adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // If file is not currently writable, error out. 47adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // FIXME: There is no sys::fs:: api for checking this. 48adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // FIXME: In posix, you use the access() call to check this. 49adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik } 50adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik break; 51adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik default: 52adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik if (EC) 53adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik return EC; 54adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik else 55adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik return make_error_code(errc::operation_not_permitted); 56adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik } 57adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 58adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // Delete target file. 5936b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines EC = sys::fs::remove(FilePath); 60adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik if (EC) 61adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik return EC; 626bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer 6373e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola unsigned Mode = sys::fs::all_read | sys::fs::all_write; 6473e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola // If requested, make the output file executable. 6573e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola if (Flags & F_executable) 6673e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola Mode |= sys::fs::all_exe; 6773e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola 68adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // Create new file in same directory but with random name. 69adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik SmallString<128> TempFilePath; 70adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik int FD; 7173e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola EC = sys::fs::createUniqueFile(Twine(FilePath) + ".tmp%%%%%%%", FD, 7273e97d0f48cf9ed3093019064f6340617ac8de9eRafael Espindola TempFilePath, Mode); 73adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik if (EC) 74adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik return EC; 756bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer 7636b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines std::unique_ptr<mapped_file_region> MappedFile(new mapped_file_region( 77cc3a595ab938352f3acf8652c5858ddf879524a5Michael J. Spencer FD, true, mapped_file_region::readwrite, Size, 0, EC)); 78adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik if (EC) 79adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik return EC; 806bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer 816bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer Result.reset(new FileOutputBuffer(MappedFile.get(), FilePath, TempFilePath)); 826bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer if (Result) 8336b56886974eae4f9c5ebc96befd3e7bfe5de338Stephen Hines MappedFile.release(); 84adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 85cd81d94322a39503e4a3e87b6ee03d4fcb3465fbStephen Hines return std::error_code(); 866bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer} 87adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik 88cd81d94322a39503e4a3e87b6ee03d4fcb3465fbStephen Hinesstd::error_code FileOutputBuffer::commit(int64_t NewSmallerSize) { 89adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // Unmap buffer, letting OS flush dirty pages to file on disk. 90dce4a407a24b04eebc6a376f8e62b41aaa7b071fStephen Hines Region.reset(nullptr); 916bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer 92adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // If requested, resize file as part of commit. 93adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik if ( NewSmallerSize != -1 ) { 94cd81d94322a39503e4a3e87b6ee03d4fcb3465fbStephen Hines std::error_code EC = sys::fs::resize_file(Twine(TempPath), NewSmallerSize); 95adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik if (EC) 96adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik return EC; 97adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik } 986bc86018d189e9ab62d30ef8190bac961dd22248Michael J. Spencer 99adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik // Rename file to final name. 100adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik return sys::fs::rename(Twine(TempPath), Twine(FinalPath)); 101adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik} 102adfe2637b839efe041165f27c9ad57e3befb2be0Nick Kledzik} // namespace 103