334 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8//9// This file implements a family of utility functions which are useful for doing10// various things with files.11//12//===----------------------------------------------------------------------===//13 14#include "llvm/Support/FileUtilities.h"15#include "llvm/ADT/SmallString.h"16#include "llvm/ADT/StringExtras.h"17#include "llvm/Support/Error.h"18#include "llvm/Support/ErrorOr.h"19#include "llvm/Support/MemoryBuffer.h"20#include "llvm/Support/Process.h"21#include "llvm/Support/raw_ostream.h"22#include <cmath>23#include <cstdint>24#include <cstdlib>25#include <cstring>26#include <memory>27#include <system_error>28 29using namespace llvm;30 31static bool isSignedChar(char C) {32 return (C == '+' || C == '-');33}34 35static bool isExponentChar(char C) {36 switch (C) {37 case 'D': // Strange exponential notation.38 case 'd': // Strange exponential notation.39 case 'e':40 case 'E': return true;41 default: return false;42 }43}44 45static bool isNumberChar(char C) {46 switch (C) {47 case '0': case '1': case '2': case '3': case '4':48 case '5': case '6': case '7': case '8': case '9':49 case '.': return true;50 default: return isSignedChar(C) || isExponentChar(C);51 }52}53 54static const char *BackupNumber(const char *Pos, const char *FirstChar) {55 // If we didn't stop in the middle of a number, don't backup.56 if (!isNumberChar(*Pos)) return Pos;57 58 // Otherwise, return to the start of the number.59 bool HasPeriod = false;60 while (Pos > FirstChar && isNumberChar(Pos[-1])) {61 // Backup over at most one period.62 if (Pos[-1] == '.') {63 if (HasPeriod)64 break;65 HasPeriod = true;66 }67 68 --Pos;69 if (Pos > FirstChar && isSignedChar(Pos[0]) && !isExponentChar(Pos[-1]))70 break;71 }72 return Pos;73}74 75/// EndOfNumber - Return the first character that is not part of the specified76/// number. This assumes that the buffer is null terminated, so it won't fall77/// off the end.78static const char *EndOfNumber(const char *Pos) {79 while (isNumberChar(*Pos))80 ++Pos;81 return Pos;82}83 84/// CompareNumbers - compare two numbers, returning true if they are different.85static bool CompareNumbers(const char *&F1P, const char *&F2P,86 const char *F1End, const char *F2End,87 double AbsTolerance, double RelTolerance,88 std::string *ErrorMsg) {89 const char *F1NumEnd, *F2NumEnd;90 double V1 = 0.0, V2 = 0.0;91 92 // If one of the positions is at a space and the other isn't, chomp up 'til93 // the end of the space.94 while (isSpace(static_cast<unsigned char>(*F1P)) && F1P != F1End)95 ++F1P;96 while (isSpace(static_cast<unsigned char>(*F2P)) && F2P != F2End)97 ++F2P;98 99 // If we stop on numbers, compare their difference.100 if (!isNumberChar(*F1P) || !isNumberChar(*F2P)) {101 // The diff failed.102 F1NumEnd = F1P;103 F2NumEnd = F2P;104 } else {105 // Note that some ugliness is built into this to permit support for numbers106 // that use "D" or "d" as their exponential marker, e.g. "1.234D45". This107 // occurs in 200.sixtrack in spec2k.108 V1 = strtod(F1P, const_cast<char**>(&F1NumEnd));109 V2 = strtod(F2P, const_cast<char**>(&F2NumEnd));110 111 if (*F1NumEnd == 'D' || *F1NumEnd == 'd') {112 // Copy string into tmp buffer to replace the 'D' with an 'e'.113 SmallString<200> StrTmp(F1P, EndOfNumber(F1NumEnd)+1);114 // Strange exponential notation!115 StrTmp[static_cast<unsigned>(F1NumEnd-F1P)] = 'e';116 117 V1 = strtod(&StrTmp[0], const_cast<char**>(&F1NumEnd));118 F1NumEnd = F1P + (F1NumEnd-&StrTmp[0]);119 }120 121 if (*F2NumEnd == 'D' || *F2NumEnd == 'd') {122 // Copy string into tmp buffer to replace the 'D' with an 'e'.123 SmallString<200> StrTmp(F2P, EndOfNumber(F2NumEnd)+1);124 // Strange exponential notation!125 StrTmp[static_cast<unsigned>(F2NumEnd-F2P)] = 'e';126 127 V2 = strtod(&StrTmp[0], const_cast<char**>(&F2NumEnd));128 F2NumEnd = F2P + (F2NumEnd-&StrTmp[0]);129 }130 }131 132 if (F1NumEnd == F1P || F2NumEnd == F2P) {133 if (ErrorMsg) {134 *ErrorMsg = "FP Comparison failed, not a numeric difference between '";135 *ErrorMsg += F1P[0];136 *ErrorMsg += "' and '";137 *ErrorMsg += F2P[0];138 *ErrorMsg += "'";139 }140 return true;141 }142 143 // Check to see if these are inside the absolute tolerance144 if (AbsTolerance < std::abs(V1-V2)) {145 // Nope, check the relative tolerance...146 double Diff;147 if (V2)148 Diff = std::abs(V1/V2 - 1.0);149 else if (V1)150 Diff = std::abs(V2/V1 - 1.0);151 else152 Diff = 0; // Both zero.153 if (Diff > RelTolerance) {154 if (ErrorMsg) {155 raw_string_ostream(*ErrorMsg)156 << "Compared: " << V1 << " and " << V2 << '\n'157 << "abs. diff = " << std::abs(V1-V2) << " rel.diff = " << Diff << '\n'158 << "Out of tolerance: rel/abs: " << RelTolerance << '/'159 << AbsTolerance;160 }161 return true;162 }163 }164 165 // Otherwise, advance our read pointers to the end of the numbers.166 F1P = F1NumEnd; F2P = F2NumEnd;167 return false;168}169 170/// DiffFilesWithTolerance - Compare the two files specified, returning 0 if the171/// files match, 1 if they are different, and 2 if there is a file error. This172/// function differs from DiffFiles in that you can specify an absolute and173/// relative FP error that is allowed to exist. If you specify a string to fill174/// in for the error option, it will set the string to an error message if an175/// error occurs, allowing the caller to distinguish between a failed diff and a176/// file system error.177///178int llvm::DiffFilesWithTolerance(StringRef NameA,179 StringRef NameB,180 double AbsTol, double RelTol,181 std::string *Error) {182 // Now its safe to mmap the files into memory because both files183 // have a non-zero size.184 ErrorOr<std::unique_ptr<MemoryBuffer>> F1OrErr = MemoryBuffer::getFile(NameA);185 if (std::error_code EC = F1OrErr.getError()) {186 if (Error)187 *Error = EC.message();188 return 2;189 }190 MemoryBuffer &F1 = *F1OrErr.get();191 192 ErrorOr<std::unique_ptr<MemoryBuffer>> F2OrErr = MemoryBuffer::getFile(NameB);193 if (std::error_code EC = F2OrErr.getError()) {194 if (Error)195 *Error = EC.message();196 return 2;197 }198 MemoryBuffer &F2 = *F2OrErr.get();199 200 // Okay, now that we opened the files, scan them for the first difference.201 const char *File1Start = F1.getBufferStart();202 const char *File2Start = F2.getBufferStart();203 const char *File1End = F1.getBufferEnd();204 const char *File2End = F2.getBufferEnd();205 const char *F1P = File1Start;206 const char *F2P = File2Start;207 uint64_t A_size = F1.getBufferSize();208 uint64_t B_size = F2.getBufferSize();209 210 // Are the buffers identical? Common case: Handle this efficiently.211 if (A_size == B_size &&212 std::memcmp(File1Start, File2Start, A_size) == 0)213 return 0;214 215 // Otherwise, we are done a tolerances are set.216 if (AbsTol == 0 && RelTol == 0) {217 if (Error)218 *Error = "Files differ without tolerance allowance";219 return 1; // Files different!220 }221 222 bool CompareFailed = false;223 while (true) {224 // Scan for the end of file or next difference.225 while (F1P < File1End && F2P < File2End && *F1P == *F2P) {226 ++F1P;227 ++F2P;228 }229 230 if (F1P >= File1End || F2P >= File2End) break;231 232 // Okay, we must have found a difference. Backup to the start of the233 // current number each stream is at so that we can compare from the234 // beginning.235 F1P = BackupNumber(F1P, File1Start);236 F2P = BackupNumber(F2P, File2Start);237 238 // Now that we are at the start of the numbers, compare them, exiting if239 // they don't match.240 if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error)) {241 CompareFailed = true;242 break;243 }244 }245 246 // Okay, we reached the end of file. If both files are at the end, we247 // succeeded.248 bool F1AtEnd = F1P >= File1End;249 bool F2AtEnd = F2P >= File2End;250 if (!CompareFailed && (!F1AtEnd || !F2AtEnd)) {251 // Else, we might have run off the end due to a number: backup and retry.252 if (F1AtEnd && isNumberChar(F1P[-1])) --F1P;253 if (F2AtEnd && isNumberChar(F2P[-1])) --F2P;254 F1P = BackupNumber(F1P, File1Start);255 F2P = BackupNumber(F2P, File2Start);256 257 // Now that we are at the start of the numbers, compare them, exiting if258 // they don't match.259 if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error))260 CompareFailed = true;261 262 // If we found the end, we succeeded.263 if (F1P < File1End || F2P < File2End)264 CompareFailed = true;265 }266 267 return CompareFailed;268}269 270Expected<FilePermissionsApplier>271FilePermissionsApplier::create(StringRef InputFilename) {272 sys::fs::file_status Status;273 274 if (InputFilename != "-") {275 if (auto EC = sys::fs::status(InputFilename, Status))276 return createFileError(InputFilename, EC);277 } else {278 Status.permissions(static_cast<sys::fs::perms>(0777));279 }280 281 return FilePermissionsApplier(InputFilename, Status);282}283 284Error FilePermissionsApplier::apply(285 StringRef OutputFilename, bool CopyDates,286 std::optional<sys::fs::perms> OverwritePermissions) {287 sys::fs::file_status Status = InputStatus;288 289 if (OverwritePermissions)290 Status.permissions(*OverwritePermissions);291 292 int FD = 0;293 294 // Writing to stdout should not be treated as an error here, just295 // do not set access/modification times or permissions.296 if (OutputFilename == "-")297 return Error::success();298 299 if (std::error_code EC = sys::fs::openFileForWrite(OutputFilename, FD,300 sys::fs::CD_OpenExisting))301 return createFileError(OutputFilename, EC);302 303 if (CopyDates)304 if (std::error_code EC = sys::fs::setLastAccessAndModificationTime(305 FD, Status.getLastAccessedTime(), Status.getLastModificationTime()))306 return createFileError(OutputFilename, EC);307 308 sys::fs::file_status OStat;309 if (std::error_code EC = sys::fs::status(FD, OStat))310 return createFileError(OutputFilename, EC);311 if (OStat.type() == sys::fs::file_type::regular_file) {312#ifndef _WIN32313 // Keep ownership if llvm-objcopy is called under root.314 if (OutputFilename == InputFilename && OStat.getUser() == 0)315 sys::fs::changeFileOwnership(FD, Status.getUser(), Status.getGroup());316#endif317 318 sys::fs::perms Perm = Status.permissions();319 if (OutputFilename != InputFilename)320 Perm = static_cast<sys::fs::perms>(Perm & ~sys::fs::getUmask() & ~06000);321#ifdef _WIN32322 if (std::error_code EC = sys::fs::setPermissions(OutputFilename, Perm))323#else324 if (std::error_code EC = sys::fs::setPermissions(FD, Perm))325#endif326 return createFileError(OutputFilename, EC);327 }328 329 if (std::error_code EC = sys::Process::SafelyCloseFileDescriptor(FD))330 return createFileError(OutputFilename, EC);331 332 return Error::success();333}334