//===- llvm/Support/FileUtilities.h - File System Utilities -----*- C++ -*-===//
// 
//                     The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
// 
//===----------------------------------------------------------------------===//
//
// This file defines a family of utility functions which are useful for doing
// various things with files.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_SUPPORT_FILEUTILITIES_H
#define LLVM_SUPPORT_FILEUTILITIES_H

#include "llvm/System/Path.h"

namespace llvm {

/// DiffFiles - Compare the two files specified, returning true if they are
/// different or if there is a file error.  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.
///
bool DiffFiles(const std::string &FileA, const std::string &FileB,
               std::string *Error = 0);

/// 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 DiffFilesWithTolerance(const std::string &FileA, const std::string &FileB,
                           double AbsTol, double RelTol,
                           std::string *Error = 0);


/// MoveFileOverIfUpdated - If the file specified by New is different than Old,
/// or if Old does not exist, move the New file over the Old file.  Otherwise,
/// remove the New file.
///
void MoveFileOverIfUpdated(const std::string &New, const std::string &Old);
 
  /// FileRemover - This class is a simple object meant to be stack allocated.
  /// If an exception is thrown from a region, the object removes the filename
  /// specified (if deleteIt is true).
  ///
  class FileRemover {
    sys::Path Filename;
    bool DeleteIt;
  public:
    FileRemover(const sys::Path &filename, bool deleteIt = true)
      : Filename(filename), DeleteIt(deleteIt) {}
    
    ~FileRemover() {
      if (DeleteIt)
        try {
          Filename.destroyFile();
        } catch (...) {}             // Ignore problems deleting the file.
    }

    /// releaseFile - Take ownership of the file away from the FileRemover so it
    /// will not be removed when the object is destroyed.
    void releaseFile() { DeleteIt = false; }
  };
} // End llvm namespace

#endif