lib/Support/FileUtilities.cpp - llvm - Git at Google

 //===- Support/FileUtilities.cpp - File System Utilities ------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements a family of utility functions which are useful for doing
 // various things with files.
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/Support/FileUtilities.h"
 #include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cctype>
 #include <cmath>
 #include <cstdint>
 #include <cstdlib>
 #include <cstring>
 #include <memory>
 #include <system_error>

 using namespace llvm;

 static bool isSignedChar(char C) {
   return (C == '+' || C == '-');
 }

 static bool isExponentChar(char C) {
   switch (C) {
   case 'D':  // Strange exponential notation.
   case 'd':  // Strange exponential notation.
   case 'e':
   case 'E': return true;
   default: return false;
   }
 }

 static bool isNumberChar(char C) {
   switch (C) {
   case '0': case '1': case '2': case '3': case '4':
   case '5': case '6': case '7': case '8': case '9':
   case '.': return true;
   default: return isSignedChar(C) || isExponentChar(C);
   }
 }

 static const char *BackupNumber(const char *Pos, const char *FirstChar) {
   // If we didn't stop in the middle of a number, don't backup.
   if (!isNumberChar(*Pos)) return Pos;

   // Otherwise, return to the start of the number.
   bool HasPeriod = false;
   while (Pos > FirstChar && isNumberChar(Pos[-1])) {
     // Backup over at most one period.
     if (Pos[-1] == '.') {
       if (HasPeriod)
         break;
       HasPeriod = true;
     }

     --Pos;
     if (Pos > FirstChar && isSignedChar(Pos[0]) && !isExponentChar(Pos[-1]))
       break;
   }
   return Pos;
 }

 /// EndOfNumber - Return the first character that is not part of the specified
 /// number.  This assumes that the buffer is null terminated, so it won't fall
 /// off the end.
 static const char *EndOfNumber(const char *Pos) {
   while (isNumberChar(*Pos))
     ++Pos;
   return Pos;
 }

 /// CompareNumbers - compare two numbers, returning true if they are different.
 static bool CompareNumbers(const char *&F1P, const char *&F2P,
                            const char *F1End, const char *F2End,
                            double AbsTolerance, double RelTolerance,
                            std::string *ErrorMsg) {
   const char *F1NumEnd, *F2NumEnd;
   double V1 = 0.0, V2 = 0.0;

   // If one of the positions is at a space and the other isn't, chomp up 'til
   // the end of the space.
   while (isspace(static_cast<unsigned char>(*F1P)) && F1P != F1End)
     ++F1P;
   while (isspace(static_cast<unsigned char>(*F2P)) && F2P != F2End)
     ++F2P;

   // If we stop on numbers, compare their difference.
   if (!isNumberChar(*F1P) || !isNumberChar(*F2P)) {
     // The diff failed.
     F1NumEnd = F1P;
     F2NumEnd = F2P;
   } else {
     // Note that some ugliness is built into this to permit support for numbers
     // that use "D" or "d" as their exponential marker, e.g. "1.234D45".  This
     // occurs in 200.sixtrack in spec2k.
     V1 = strtod(F1P, const_cast<char**>(&F1NumEnd));
     V2 = strtod(F2P, const_cast<char**>(&F2NumEnd));

     if (*F1NumEnd == 'D' || *F1NumEnd == 'd') {
       // Copy string into tmp buffer to replace the 'D' with an 'e'.
       SmallString<200> StrTmp(F1P, EndOfNumber(F1NumEnd)+1);
       // Strange exponential notation!
       StrTmp[static_cast<unsigned>(F1NumEnd-F1P)] = 'e';

       V1 = strtod(&StrTmp[0], const_cast<char**>(&F1NumEnd));
       F1NumEnd = F1P + (F1NumEnd-&StrTmp[0]);
     }

     if (*F2NumEnd == 'D' || *F2NumEnd == 'd') {
       // Copy string into tmp buffer to replace the 'D' with an 'e'.
       SmallString<200> StrTmp(F2P, EndOfNumber(F2NumEnd)+1);
       // Strange exponential notation!
       StrTmp[static_cast<unsigned>(F2NumEnd-F2P)] = 'e';

       V2 = strtod(&StrTmp[0], const_cast<char**>(&F2NumEnd));
       F2NumEnd = F2P + (F2NumEnd-&StrTmp[0]);
     }
   }

   if (F1NumEnd == F1P || F2NumEnd == F2P) {
     if (ErrorMsg) {
       *ErrorMsg = "FP Comparison failed, not a numeric difference between '";
       *ErrorMsg += F1P[0];
       *ErrorMsg += "' and '";
       *ErrorMsg += F2P[0];
       *ErrorMsg += "'";
     }
     return true;
   }

   // Check to see if these are inside the absolute tolerance
   if (AbsTolerance < std::abs(V1-V2)) {
     // Nope, check the relative tolerance...
     double Diff;
     if (V2)
       Diff = std::abs(V1/V2 - 1.0);
     else if (V1)
       Diff = std::abs(V2/V1 - 1.0);
     else
       Diff = 0;  // Both zero.
     if (Diff > RelTolerance) {
       if (ErrorMsg) {
         raw_string_ostream(*ErrorMsg)
           << "Compared: " << V1 << " and " << V2 << '\n'
           << "abs. diff = " << std::abs(V1-V2) << " rel.diff = " << Diff << '\n'
           << "Out of tolerance: rel/abs: " << RelTolerance << '/'
           << AbsTolerance;
       }
       return true;
     }
   }

   // Otherwise, advance our read pointers to the end of the numbers.
   F1P = F1NumEnd;  F2P = F2NumEnd;
   return false;
 }

 /// DiffFilesWithTolerance - Compare the two files specified, returning 0 if the
 /// files match, 1 if they are different, and 2 if there is a file error.  This
 /// function differs from DiffFiles in that you can specify an absolete and
 /// relative FP error that is allowed to exist.  If you specify a string to fill
 /// in for the error option, it will set the string to an error message if an
 /// error occurs, allowing the caller to distinguish between a failed diff and a
 /// file system error.
 ///
 int llvm::DiffFilesWithTolerance(StringRef NameA,
                                  StringRef NameB,
                                  double AbsTol, double RelTol,
                                  std::string *Error) {
   // Now its safe to mmap the files into memory because both files
   // have a non-zero size.
   ErrorOr<std::unique_ptr<MemoryBuffer>> F1OrErr = MemoryBuffer::getFile(NameA);
   if (std::error_code EC = F1OrErr.getError()) {
     if (Error)
       *Error = EC.message();
     return 2;
   }
   MemoryBuffer &F1 = *F1OrErr.get();

   ErrorOr<std::unique_ptr<MemoryBuffer>> F2OrErr = MemoryBuffer::getFile(NameB);
   if (std::error_code EC = F2OrErr.getError()) {
     if (Error)
       *Error = EC.message();
     return 2;
   }
   MemoryBuffer &F2 = *F2OrErr.get();

   // Okay, now that we opened the files, scan them for the first difference.
   const char *File1Start = F1.getBufferStart();
   const char *File2Start = F2.getBufferStart();
   const char *File1End = F1.getBufferEnd();
   const char *File2End = F2.getBufferEnd();
   const char *F1P = File1Start;
   const char *F2P = File2Start;
   uint64_t A_size = F1.getBufferSize();
   uint64_t B_size = F2.getBufferSize();

   // Are the buffers identical?  Common case: Handle this efficiently.
   if (A_size == B_size &&
       std::memcmp(File1Start, File2Start, A_size) == 0)
     return 0;

   // Otherwise, we are done a tolerances are set.
   if (AbsTol == 0 && RelTol == 0) {
     if (Error)
       *Error = "Files differ without tolerance allowance";
     return 1;   // Files different!
   }

   bool CompareFailed = false;
   while (true) {
     // Scan for the end of file or next difference.
     while (F1P < File1End && F2P < File2End && *F1P == *F2P) {
       ++F1P;
       ++F2P;
     }

     if (F1P >= File1End || F2P >= File2End) break;

     // Okay, we must have found a difference.  Backup to the start of the
     // current number each stream is at so that we can compare from the
     // beginning.
     F1P = BackupNumber(F1P, File1Start);
     F2P = BackupNumber(F2P, File2Start);

     // Now that we are at the start of the numbers, compare them, exiting if
     // they don't match.
     if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error)) {
       CompareFailed = true;
       break;
     }
   }

   // Okay, we reached the end of file.  If both files are at the end, we
   // succeeded.
   bool F1AtEnd = F1P >= File1End;
   bool F2AtEnd = F2P >= File2End;
   if (!CompareFailed && (!F1AtEnd || !F2AtEnd)) {
     // Else, we might have run off the end due to a number: backup and retry.
     if (F1AtEnd && isNumberChar(F1P[-1])) --F1P;
     if (F2AtEnd && isNumberChar(F2P[-1])) --F2P;
     F1P = BackupNumber(F1P, File1Start);
     F2P = BackupNumber(F2P, File2Start);

     // Now that we are at the start of the numbers, compare them, exiting if
     // they don't match.
     if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error))
       CompareFailed = true;

     // If we found the end, we succeeded.
     if (F1P < File1End || F2P < File2End)
       CompareFailed = true;
   }

   return CompareFailed;
 }

 void llvm::AtomicFileWriteError::log(raw_ostream &OS) const {
   OS << "atomic_write_error: ";
   switch (Error) {
   case atomic_write_error::failed_to_create_uniq_file:
     OS << "failed_to_create_uniq_file";
     return;
   case atomic_write_error::output_stream_error:
     OS << "output_stream_error";
     return;
   case atomic_write_error::failed_to_rename_temp_file:
     OS << "failed_to_rename_temp_file";
     return;
   }
   llvm_unreachable("unknown atomic_write_error value in "
                    "failed_to_rename_temp_file::log()");
 }

 llvm::Error llvm::writeFileAtomically(StringRef TempPathModel,
                                       StringRef FinalPath, StringRef Buffer) {
   return writeFileAtomically(TempPathModel, FinalPath,
                              [&Buffer](llvm::raw_ostream &OS) {
                                OS.write(Buffer.data(), Buffer.size());
                                return llvm::Error::success();
                              });
 }

 llvm::Error llvm::writeFileAtomically(
     StringRef TempPathModel, StringRef FinalPath,
     std::function<llvm::Error(llvm::raw_ostream &)> Writer) {
   SmallString<128> GeneratedUniqPath;
   int TempFD;
   if (sys::fs::createUniqueFile(TempPathModel.str(), TempFD,
                                 GeneratedUniqPath)) {
     return llvm::make_error<AtomicFileWriteError>(
         atomic_write_error::failed_to_create_uniq_file);
   }
   llvm::FileRemover RemoveTmpFileOnFail(GeneratedUniqPath);

   raw_fd_ostream OS(TempFD, /*shouldClose=*/true);
   if (llvm::Error Err = Writer(OS)) {
     return Err;
   }

   OS.close();
   if (OS.has_error()) {
     OS.clear_error();
     return llvm::make_error<AtomicFileWriteError>(
         atomic_write_error::output_stream_error);
   }

   if (const std::error_code Error =
           sys::fs::rename(/*from=*/GeneratedUniqPath.c_str(),
                           /*to=*/FinalPath.str().c_str())) {
     return llvm::make_error<AtomicFileWriteError>(
         atomic_write_error::failed_to_rename_temp_file);
   }

   RemoveTmpFileOnFail.releaseFile();
   return Error::success();
 }

 char llvm::AtomicFileWriteError::ID;
	//===- Support/FileUtilities.cpp - File System Utilities ------------------===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//
	//
	// This file implements a family of utility functions which are useful for doing
	// various things with files.
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/Support/FileUtilities.h"
	#include "llvm/ADT/ScopeExit.h"
	#include "llvm/ADT/SmallString.h"
	#include "llvm/Support/Error.h"
	#include "llvm/Support/ErrorOr.h"
	#include "llvm/Support/MemoryBuffer.h"
	#include "llvm/Support/Path.h"
	#include "llvm/Support/raw_ostream.h"
	#include <cctype>
	#include <cmath>
	#include <cstdint>
	#include <cstdlib>
	#include <cstring>
	#include <memory>
	#include <system_error>

	using namespace llvm;

	static bool isSignedChar(char C) {
	return (C == '+' \|\| C == '-');
	}

	static bool isExponentChar(char C) {
	switch (C) {
	case 'D': // Strange exponential notation.
	case 'd': // Strange exponential notation.
	case 'e':
	case 'E': return true;
	default: return false;
	}
	}

	static bool isNumberChar(char C) {
	switch (C) {
	case '0': case '1': case '2': case '3': case '4':
	case '5': case '6': case '7': case '8': case '9':
	case '.': return true;
	default: return isSignedChar(C) \|\| isExponentChar(C);
	}
	}

	static const char BackupNumber(const char Pos, const char *FirstChar) {
	// If we didn't stop in the middle of a number, don't backup.
	if (!isNumberChar(*Pos)) return Pos;

	// Otherwise, return to the start of the number.
	bool HasPeriod = false;
	while (Pos > FirstChar && isNumberChar(Pos[-1])) {
	// Backup over at most one period.
	if (Pos[-1] == '.') {
	if (HasPeriod)
	break;
	HasPeriod = true;
	}

	--Pos;
	if (Pos > FirstChar && isSignedChar(Pos[0]) && !isExponentChar(Pos[-1]))
	break;
	}
	return Pos;
	}

	/// EndOfNumber - Return the first character that is not part of the specified
	/// number. This assumes that the buffer is null terminated, so it won't fall
	/// off the end.
	static const char EndOfNumber(const char Pos) {
	while (isNumberChar(*Pos))
	++Pos;
	return Pos;
	}

	/// CompareNumbers - compare two numbers, returning true if they are different.
	static bool CompareNumbers(const char &F1P, const char &F2P,
	const char F1End, const char F2End,
	double AbsTolerance, double RelTolerance,
	std::string *ErrorMsg) {
	const char F1NumEnd, F2NumEnd;
	double V1 = 0.0, V2 = 0.0;

	// If one of the positions is at a space and the other isn't, chomp up 'til
	// the end of the space.
	while (isspace(static_cast<unsigned char>(*F1P)) && F1P != F1End)
	++F1P;
	while (isspace(static_cast<unsigned char>(*F2P)) && F2P != F2End)
	++F2P;

	// If we stop on numbers, compare their difference.
	if (!isNumberChar(F1P) \|\| !isNumberChar(F2P)) {
	// The diff failed.
	F1NumEnd = F1P;
	F2NumEnd = F2P;
	} else {
	// Note that some ugliness is built into this to permit support for numbers
	// that use "D" or "d" as their exponential marker, e.g. "1.234D45". This
	// occurs in 200.sixtrack in spec2k.
	V1 = strtod(F1P, const_cast<char**>(&F1NumEnd));
	V2 = strtod(F2P, const_cast<char**>(&F2NumEnd));

	if (F1NumEnd == 'D' \|\| F1NumEnd == 'd') {
	// Copy string into tmp buffer to replace the 'D' with an 'e'.
	SmallString<200> StrTmp(F1P, EndOfNumber(F1NumEnd)+1);
	// Strange exponential notation!
	StrTmp[static_cast<unsigned>(F1NumEnd-F1P)] = 'e';

	V1 = strtod(&StrTmp[0], const_cast<char**>(&F1NumEnd));
	F1NumEnd = F1P + (F1NumEnd-&StrTmp[0]);
	}

	if (F2NumEnd == 'D' \|\| F2NumEnd == 'd') {
	// Copy string into tmp buffer to replace the 'D' with an 'e'.
	SmallString<200> StrTmp(F2P, EndOfNumber(F2NumEnd)+1);
	// Strange exponential notation!
	StrTmp[static_cast<unsigned>(F2NumEnd-F2P)] = 'e';

	V2 = strtod(&StrTmp[0], const_cast<char**>(&F2NumEnd));
	F2NumEnd = F2P + (F2NumEnd-&StrTmp[0]);
	}
	}

	if (F1NumEnd == F1P \|\| F2NumEnd == F2P) {
	if (ErrorMsg) {
	*ErrorMsg = "FP Comparison failed, not a numeric difference between '";
	*ErrorMsg += F1P[0];
	*ErrorMsg += "' and '";
	*ErrorMsg += F2P[0];
	*ErrorMsg += "'";
	}
	return true;
	}

	// Check to see if these are inside the absolute tolerance
	if (AbsTolerance < std::abs(V1-V2)) {
	// Nope, check the relative tolerance...
	double Diff;
	if (V2)
	Diff = std::abs(V1/V2 - 1.0);
	else if (V1)
	Diff = std::abs(V2/V1 - 1.0);
	else
	Diff = 0; // Both zero.
	if (Diff > RelTolerance) {
	if (ErrorMsg) {
	raw_string_ostream(*ErrorMsg)
	<< "Compared: " << V1 << " and " << V2 << '\n'
	<< "abs. diff = " << std::abs(V1-V2) << " rel.diff = " << Diff << '\n'
	<< "Out of tolerance: rel/abs: " << RelTolerance << '/'
	<< AbsTolerance;
	}
	return true;
	}
	}

	// Otherwise, advance our read pointers to the end of the numbers.
	F1P = F1NumEnd; F2P = F2NumEnd;
	return false;
	}

	/// DiffFilesWithTolerance - Compare the two files specified, returning 0 if the
	/// files match, 1 if they are different, and 2 if there is a file error. This
	/// function differs from DiffFiles in that you can specify an absolete and
	/// relative FP error that is allowed to exist. If you specify a string to fill
	/// in for the error option, it will set the string to an error message if an
	/// error occurs, allowing the caller to distinguish between a failed diff and a
	/// file system error.
	///
	int llvm::DiffFilesWithTolerance(StringRef NameA,
	StringRef NameB,
	double AbsTol, double RelTol,
	std::string *Error) {
	// Now its safe to mmap the files into memory because both files
	// have a non-zero size.
	ErrorOr<std::unique_ptr<MemoryBuffer>> F1OrErr = MemoryBuffer::getFile(NameA);
	if (std::error_code EC = F1OrErr.getError()) {
	if (Error)
	*Error = EC.message();
	return 2;
	}
	MemoryBuffer &F1 = *F1OrErr.get();

	ErrorOr<std::unique_ptr<MemoryBuffer>> F2OrErr = MemoryBuffer::getFile(NameB);
	if (std::error_code EC = F2OrErr.getError()) {
	if (Error)
	*Error = EC.message();
	return 2;
	}
	MemoryBuffer &F2 = *F2OrErr.get();

	// Okay, now that we opened the files, scan them for the first difference.
	const char *File1Start = F1.getBufferStart();
	const char *File2Start = F2.getBufferStart();
	const char *File1End = F1.getBufferEnd();
	const char *File2End = F2.getBufferEnd();
	const char *F1P = File1Start;
	const char *F2P = File2Start;
	uint64_t A_size = F1.getBufferSize();
	uint64_t B_size = F2.getBufferSize();

	// Are the buffers identical? Common case: Handle this efficiently.
	if (A_size == B_size &&
	std::memcmp(File1Start, File2Start, A_size) == 0)
	return 0;

	// Otherwise, we are done a tolerances are set.
	if (AbsTol == 0 && RelTol == 0) {
	if (Error)
	*Error = "Files differ without tolerance allowance";
	return 1; // Files different!
	}

	bool CompareFailed = false;
	while (true) {
	// Scan for the end of file or next difference.
	while (F1P < File1End && F2P < File2End && F1P == F2P) {
	++F1P;
	++F2P;
	}

	if (F1P >= File1End \|\| F2P >= File2End) break;

	// Okay, we must have found a difference. Backup to the start of the
	// current number each stream is at so that we can compare from the
	// beginning.
	F1P = BackupNumber(F1P, File1Start);
	F2P = BackupNumber(F2P, File2Start);

	// Now that we are at the start of the numbers, compare them, exiting if
	// they don't match.
	if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error)) {
	CompareFailed = true;
	break;
	}
	}

	// Okay, we reached the end of file. If both files are at the end, we
	// succeeded.
	bool F1AtEnd = F1P >= File1End;
	bool F2AtEnd = F2P >= File2End;
	if (!CompareFailed && (!F1AtEnd \|\| !F2AtEnd)) {
	// Else, we might have run off the end due to a number: backup and retry.
	if (F1AtEnd && isNumberChar(F1P[-1])) --F1P;
	if (F2AtEnd && isNumberChar(F2P[-1])) --F2P;
	F1P = BackupNumber(F1P, File1Start);
	F2P = BackupNumber(F2P, File2Start);

	// Now that we are at the start of the numbers, compare them, exiting if
	// they don't match.
	if (CompareNumbers(F1P, F2P, File1End, File2End, AbsTol, RelTol, Error))
	CompareFailed = true;

	// If we found the end, we succeeded.
	if (F1P < File1End \|\| F2P < File2End)
	CompareFailed = true;
	}

	return CompareFailed;
	}

	void llvm::AtomicFileWriteError::log(raw_ostream &OS) const {
	OS << "atomic_write_error: ";
	switch (Error) {
	case atomic_write_error::failed_to_create_uniq_file:
	OS << "failed_to_create_uniq_file";
	return;
	case atomic_write_error::output_stream_error:
	OS << "output_stream_error";
	return;
	case atomic_write_error::failed_to_rename_temp_file:
	OS << "failed_to_rename_temp_file";
	return;
	}
	llvm_unreachable("unknown atomic_write_error value in "
	"failed_to_rename_temp_file::log()");
	}

	llvm::Error llvm::writeFileAtomically(StringRef TempPathModel,
	StringRef FinalPath, StringRef Buffer) {
	return writeFileAtomically(TempPathModel, FinalPath,
	[&Buffer](llvm::raw_ostream &OS) {
	OS.write(Buffer.data(), Buffer.size());
	return llvm::Error::success();
	});
	}

	llvm::Error llvm::writeFileAtomically(
	StringRef TempPathModel, StringRef FinalPath,
	std::function<llvm::Error(llvm::raw_ostream &)> Writer) {
	SmallString<128> GeneratedUniqPath;
	int TempFD;
	if (sys::fs::createUniqueFile(TempPathModel.str(), TempFD,
	GeneratedUniqPath)) {
	return llvm::make_error<AtomicFileWriteError>(
	atomic_write_error::failed_to_create_uniq_file);
	}
	llvm::FileRemover RemoveTmpFileOnFail(GeneratedUniqPath);

	raw_fd_ostream OS(TempFD, /shouldClose=/true);
	if (llvm::Error Err = Writer(OS)) {
	return Err;
	}

	OS.close();
	if (OS.has_error()) {
	OS.clear_error();
	return llvm::make_error<AtomicFileWriteError>(
	atomic_write_error::output_stream_error);
	}

	if (const std::error_code Error =
	sys::fs::rename(/from=/GeneratedUniqPath.c_str(),
	/to=/FinalPath.str().c_str())) {
	return llvm::make_error<AtomicFileWriteError>(
	atomic_write_error::failed_to_rename_temp_file);
	}

	RemoveTmpFileOnFail.releaseFile();
	return Error::success();
	}

	char llvm::AtomicFileWriteError::ID;