include/llvm/Support/FileUtilities.h

   1 //===- llvm/Support/FileUtilities.h - File System Utilities -----*- C++ -*-===//
   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 defines a family of utility functions which are useful for doing
  10 // various things with files.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_SUPPORT_FILEUTILITIES_H
  15 #define LLVM_SUPPORT_FILEUTILITIES_H
  16
  17 #include "llvm/ADT/StringRef.h"
  18 #include "llvm/Support/Errc.h"
  19 #include "llvm/Support/ErrorHandling.h"
  20 #include "llvm/Support/FileSystem.h"
  21 #include "llvm/Support/Path.h"
  22
  23 namespace llvm {
  24
  25   /// DiffFilesWithTolerance - Compare the two files specified, returning 0 if
  26   /// the files match, 1 if they are different, and 2 if there is a file error.
  27   /// This function allows you to specify an absolute and relative FP error that
  28   /// is allowed to exist.  If you specify a string to fill in for the error
  29   /// option, it will set the string to an error message if an error occurs, or
  30   /// if the files are different.
  31   ///
  32   int DiffFilesWithTolerance(StringRef FileA,
  33                              StringRef FileB,
  34                              double AbsTol, double RelTol,
  35                              std::string *Error = nullptr);
  36
  37
  38   /// FileRemover - This class is a simple object meant to be stack allocated.
  39   /// If an exception is thrown from a region, the object removes the filename
  40   /// specified (if deleteIt is true).
  41   ///
  42   class FileRemover {
  43     SmallString<128> Filename;
  44     bool DeleteIt;
  45   public:
  46     FileRemover() : DeleteIt(false) {}
  47
  48     explicit FileRemover(const Twine& filename, bool deleteIt = true)
  49       : DeleteIt(deleteIt) {
  50       filename.toVector(Filename);
  51     }
  52
  53     ~FileRemover() {
  54       if (DeleteIt) {
  55         // Ignore problems deleting the file.
  56         sys::fs::remove(Filename);
  57       }
  58     }
  59
  60     /// setFile - Give ownership of the file to the FileRemover so it will
  61     /// be removed when the object is destroyed.  If the FileRemover already
  62     /// had ownership of a file, remove it first.
  63     void setFile(const Twine& filename, bool deleteIt = true) {
  64       if (DeleteIt) {
  65         // Ignore problems deleting the file.
  66         sys::fs::remove(Filename);
  67       }
  68
  69       Filename.clear();
  70       filename.toVector(Filename);
  71       DeleteIt = deleteIt;
  72     }
  73
  74     /// releaseFile - Take ownership of the file away from the FileRemover so it
  75     /// will not be removed when the object is destroyed.
  76     void releaseFile() { DeleteIt = false; }
  77   };
  78
  79   enum class atomic_write_error {
  80     failed_to_create_uniq_file = 0,
  81     output_stream_error,
  82     failed_to_rename_temp_file
  83   };
  84
  85   class AtomicFileWriteError : public llvm::ErrorInfo<AtomicFileWriteError> {
  86   public:
  87     AtomicFileWriteError(atomic_write_error Error) : Error(Error) {}
  88
  89     void log(raw_ostream &OS) const override;
  90
  91     const atomic_write_error Error;
  92     static char ID;
  93
  94   private:
  95     // Users are not expected to use error_code.
  96     std::error_code convertToErrorCode() const override {
  97       return llvm::inconvertibleErrorCode();
  98     }
  99   };
 100
 101   // atomic_write_error + whatever the Writer can return
 102
 103   /// Creates a unique file with name according to the given \p TempPathModel,
 104   /// writes content of \p Buffer to the file and renames it to \p FinalPath.
 105   ///
 106   /// \returns \c AtomicFileWriteError in case of error.
 107   llvm::Error writeFileAtomically(StringRef TempPathModel, StringRef FinalPath,
 108                                   StringRef Buffer);
 109
 110   llvm::Error
 111   writeFileAtomically(StringRef TempPathModel, StringRef FinalPath,
 112                       std::function<llvm::Error(llvm::raw_ostream &)> Writer);
 113 } // End llvm namespace
 114
 115 #endif