1 //===- Support/FileUtilities.cpp - File System Utilities ------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements a family of utility functions which are useful for doing 10 // various things with files. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Support/FileUtilities.h" 15 #include "llvm/ADT/ScopeExit.h" 16 #include "llvm/ADT/SmallString.h" 17 #include "llvm/ADT/StringExtras.h" 18 #include "llvm/Support/Error.h" 19 #include "llvm/Support/ErrorOr.h" 20 #include "llvm/Support/MemoryBuffer.h" 21 #include "llvm/Support/Path.h" 22 #include "llvm/Support/raw_ostream.h" 23 #include <cctype> 24 #include <cmath> 25 #include <cstdint> 26 #include <cstdlib> 27 #include <cstring> 28 #include <memory> 29 #include <system_error> 30 31 using namespace llvm; 32 33 static bool isSignedChar(char C) { 34 return (C == '+' || C == '-'); 35 } 36 37 static bool isExponentChar(char C) { 38 switch (C) { 39 case 'D': // Strange exponential notation. 40 case 'd': // Strange exponential notation. 41 case 'e': 42 case 'E': return true; 43 default: return false; 44 } 45 } 46 47 static bool isNumberChar(char C) { 48 switch (C) { 49 case '0': case '1': case '2': case '3': case '4': 50 case '5': case '6': case '7': case '8': case '9': 51 case '.': return true; 52 default: return isSignedChar(C) || isExponentChar(C); 53 } 54 } 55 56 static const char *BackupNumber(const char *Pos, const char *FirstChar) { 57 // If we didn't stop in the middle of a number, don't backup. 58 if (!isNumberChar(*Pos)) return Pos; 59 60 // Otherwise, return to the start of the number. 61 bool HasPeriod = false; 62 while (Pos > FirstChar && isNumberChar(Pos[-1])) { 63 // Backup over at most one period. 64 if (Pos[-1] == '.') { 65 if (HasPeriod) 66 break; 67 HasPeriod = true; 68 } 69 70 --Pos; 71 if (Pos > FirstChar && isSignedChar(Pos[0]) && !isExponentChar(Pos[-1])) 72 break; 73 } 74 return Pos; 75 } 76 77 /// EndOfNumber - Return the first character that is not part of the specified 78 /// number. This assumes that the buffer is null terminated, so it won't fall 79 /// off the end. 80 static const char *EndOfNumber(const char *Pos) { 81 while (isNumberChar(*Pos)) 82 ++Pos; 83 return Pos; 84 } 85 86 /// CompareNumbers - compare two numbers, returning true if they are different. 87 static bool CompareNumbers(const char *&F1P, const char *&F2P, 88 const char *F1End, const char *F2End, 89 double AbsTolerance, double RelTolerance, 90 std::string *ErrorMsg) { 91 const char *F1NumEnd, *F2NumEnd; 92 double V1 = 0.0, V2 = 0.0; 93 94 // If one of the positions is at a space and the other isn't, chomp up 'til 95 // the end of the space. 96 while (isSpace(static_cast<unsigned char>(*F1P)) && F1P != F1End) 97 ++F1P; 98 while (isSpace(static_cast<unsigned char>(*F2P)) && F2P != F2End) 99 ++F2P; 100 101 // If we stop on numbers, compare their difference. 102 if (!isNumberChar(*F1P) || !isNumberChar(*F2P)) { 103 // The diff failed. 104 F1NumEnd = F1P; 105 F2NumEnd = F2P; 106 } else { 107 // Note that some ugliness is built into this to permit support for numbers 108 // that use "D" or "d" as their exponential marker, e.g. "1.234D45". This 109 // occurs in 200.sixtrack in spec2k. 110 V1 = strtod(F1P, const_cast<char**>(&F1NumEnd)); 111 V2 = strtod(F2P, const_cast<char**>(&F2NumEnd)); 112 113 if (*F1NumEnd == 'D' || *F1NumEnd == 'd') { 114 // Copy string into tmp buffer to replace the 'D' with an 'e'. 115 SmallString<200> StrTmp(F1P, EndOfNumber(F1NumEnd)+1); 116 // Strange exponential notation! 117 StrTmp[static_cast<unsigned>(F1NumEnd-F1P)] = 'e'; 118 119 V1 = strtod(&StrTmp[0], const_cast<char**>(&F1NumEnd)); 120 F1NumEnd = F1P + (F1NumEnd-&StrTmp[0]); 121 } 122 123 if (*F2NumEnd == 'D' || *F2NumEnd == 'd') { 124 // Copy string into tmp buffer to replace the 'D' with an 'e'. 125 SmallString<200> StrTmp(F2P, EndOfNumber(F2NumEnd)+1); 126 // Strange exponential notation! 127 StrTmp[static_cast<unsigned>(F2NumEnd-F2P)] = 'e'; 128 129 V2 = strtod(&StrTmp[0], const_cast<char**>(&F2NumEnd)); 130 F2NumEnd = F2P + (F2NumEnd-&StrTmp[0]); 131 } 132 } 133 134 if (F1NumEnd == F1P || F2NumEnd == F2P) { 135 if (ErrorMsg) { 136 *ErrorMsg = "FP Comparison failed, not a numeric difference between '"; 137 *ErrorMsg += F1P[0]; 138 *ErrorMsg += "' and '"; 139 *ErrorMsg += F2P[0]; 140 *ErrorMsg += "'"; 141 } 142 return true; 143 } 144 145 // Check to see if these are inside the absolute tolerance 146 if (AbsTolerance < std::abs(V1-V2)) { 147 // Nope, check the relative tolerance... 148 double Diff; 149 if (V2) 150 Diff = std::abs(V1/V2 - 1.0); 151 else if (V1) 152 Diff = std::abs(V2/V1 - 1.0); 153 else 154 Diff = 0; // Both zero. 155 if (Diff > RelTolerance) { 156 if (ErrorMsg) { 157 raw_string_ostream(*ErrorMsg) 158 << "Compared: " << V1 << " and " << V2 << '\n' 159 << "abs. diff = " << std::abs(V1-V2) << " rel.diff = " << Diff << '\n' 160 << "Out of tolerance: rel/abs: " << RelTolerance << '/' 161 << AbsTolerance; 162 } 163 return true; 164 } 165 } 166 167 // Otherwise, advance our read pointers to the end of the numbers. 168 F1P = F1NumEnd; F2P = F2NumEnd; 169 return false; 170 } 171 172 /// DiffFilesWithTolerance - Compare the two files specified, returning 0 if the 173 /// files match, 1 if they are different, and 2 if there is a file error. This 174 /// function differs from DiffFiles in that you can specify an absolete and 175 /// relative FP error that is allowed to exist. If you specify a string to fill 176 /// in for the error option, it will set the string to an error message if an 177 /// error occurs, allowing the caller to distinguish between a failed diff and a 178 /// file system error. 179 /// 180 int llvm::DiffFilesWithTolerance(StringRef NameA, 181 StringRef NameB, 182 double AbsTol, double RelTol, 183 std::string *Error) { 184 // Now its safe to mmap the files into memory because both files 185 // have a non-zero size. 186 ErrorOr<std::unique_ptr<MemoryBuffer>> F1OrErr = MemoryBuffer::getFile(NameA); 187 if (std::error_code EC = F1OrErr.getError()) { 188 if (Error) 189 *Error = EC.message(); 190 return 2; 191 } 192 MemoryBuffer &F1 = *F1OrErr.get(); 193 194 ErrorOr<std::unique_ptr<MemoryBuffer>> F2OrErr = MemoryBuffer::getFile(NameB); 195 if (std::error_code EC = F2OrErr.getError()) { 196 if (Error) 197 *Error = EC.message(); 198 return 2; 199 } 200 MemoryBuffer &F2 = *F2OrErr.get(); 201 202 // Okay, now that we opened the files, scan them for the first difference. 203 const char *File1Start = F1.getBufferStart(); 204 const char *File2Start = F2.getBufferStart(); 205 const char *File1End = F1.getBufferEnd(); 206 const char *File2End = F2.getBufferEnd(); 207 const char *F1P = File1Start; 208 const char *F2P = File2Start; 209 uint64_t A_size = F1.getBufferSize(); 210 uint64_t B_size = F2.getBufferSize(); 211 212 // Are the buffers identical? Common case: Handle this efficiently. 213 if (A_size == B_size && 214 std::memcmp(File1Start, File2Start, A_size) == 0) 215 return 0; 216 217 // Otherwise, we are done a tolerances are set. 218 if (AbsTol == 0 && RelTol == 0) { 219 if (Error) 220 *Error = "Files differ without tolerance allowance"; 221 return 1; // Files different! 222 } 223 224 bool CompareFailed = false; 225 while (true) { 226 // Scan for the end of file or next difference. 227 while (F1P < File1End && F2P < File2End && *F1P == *F2P) { 228 ++F1P; 229 ++F2P; 230 } 231 232 if (F1P >= File1End || F2P >= File2End) break; 233 234 // Okay, we must have found a difference. Backup to the start of the 235 // current number each stream is at so that we can compare from the 236 // beginning. 237 F1P = BackupNumber(F1P, File1Start); 238 F2P = BackupNumber(F2P, File2Start); 239 240 // Now that we are at the start of the numbers, compare them, exiting if 241 // they don't match. 242 if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error)) { 243 CompareFailed = true; 244 break; 245 } 246 } 247 248 // Okay, we reached the end of file. If both files are at the end, we 249 // succeeded. 250 bool F1AtEnd = F1P >= File1End; 251 bool F2AtEnd = F2P >= File2End; 252 if (!CompareFailed && (!F1AtEnd || !F2AtEnd)) { 253 // Else, we might have run off the end due to a number: backup and retry. 254 if (F1AtEnd && isNumberChar(F1P[-1])) --F1P; 255 if (F2AtEnd && isNumberChar(F2P[-1])) --F2P; 256 F1P = BackupNumber(F1P, File1Start); 257 F2P = BackupNumber(F2P, File2Start); 258 259 // Now that we are at the start of the numbers, compare them, exiting if 260 // they don't match. 261 if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error)) 262 CompareFailed = true; 263 264 // If we found the end, we succeeded. 265 if (F1P < File1End || F2P < File2End) 266 CompareFailed = true; 267 } 268 269 return CompareFailed; 270 } 271 272 void llvm::AtomicFileWriteError::log(raw_ostream &OS) const { 273 OS << "atomic_write_error: "; 274 switch (Error) { 275 case atomic_write_error::failed_to_create_uniq_file: 276 OS << "failed_to_create_uniq_file"; 277 return; 278 case atomic_write_error::output_stream_error: 279 OS << "output_stream_error"; 280 return; 281 case atomic_write_error::failed_to_rename_temp_file: 282 OS << "failed_to_rename_temp_file"; 283 return; 284 } 285 llvm_unreachable("unknown atomic_write_error value in " 286 "failed_to_rename_temp_file::log()"); 287 } 288 289 llvm::Error llvm::writeFileAtomically(StringRef TempPathModel, 290 StringRef FinalPath, StringRef Buffer) { 291 return writeFileAtomically(TempPathModel, FinalPath, 292 [&Buffer](llvm::raw_ostream &OS) { 293 OS.write(Buffer.data(), Buffer.size()); 294 return llvm::Error::success(); 295 }); 296 } 297 298 llvm::Error llvm::writeFileAtomically( 299 StringRef TempPathModel, StringRef FinalPath, 300 std::function<llvm::Error(llvm::raw_ostream &)> Writer) { 301 SmallString<128> GeneratedUniqPath; 302 int TempFD; 303 if (sys::fs::createUniqueFile(TempPathModel.str(), TempFD, 304 GeneratedUniqPath)) { 305 return llvm::make_error<AtomicFileWriteError>( 306 atomic_write_error::failed_to_create_uniq_file); 307 } 308 llvm::FileRemover RemoveTmpFileOnFail(GeneratedUniqPath); 309 310 raw_fd_ostream OS(TempFD, /*shouldClose=*/true); 311 if (llvm::Error Err = Writer(OS)) { 312 return Err; 313 } 314 315 OS.close(); 316 if (OS.has_error()) { 317 OS.clear_error(); 318 return llvm::make_error<AtomicFileWriteError>( 319 atomic_write_error::output_stream_error); 320 } 321 322 if (sys::fs::rename(/*from=*/GeneratedUniqPath.c_str(), 323 /*to=*/FinalPath.str().c_str())) { 324 return llvm::make_error<AtomicFileWriteError>( 325 atomic_write_error::failed_to_rename_temp_file); 326 } 327 328 RemoveTmpFileOnFail.releaseFile(); 329 return Error::success(); 330 } 331 332 char llvm::AtomicFileWriteError::ID; 333