llvm-6502/include/Support/FileUtilities.h

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//===- 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 SUPPORT_FILEUTILITIES_H
#define SUPPORT_FILEUTILITIES_H
#include <string>
namespace llvm {
/// CheckMagic - Returns true IFF the file named FN begins with Magic. FN must
/// name a readable file.
///
bool CheckMagic (const std::string &FN, const std::string &Magic);
/// IsArchive - Returns true IFF the file named FN appears to be a "ar" library
/// archive. The file named FN must exist.
///
bool IsArchive (const std::string &FN);
/// IsBytecode - Returns true IFF the file named FN appears to be an LLVM
/// bytecode file. The file named FN must exist.
///
bool IsBytecode (const std::string &FN);
/// IsSharedObject - Returns trus IFF the file named FN appears to be a shared
/// object with an ELF header. The file named FN must exist.
///
bool IsSharedObject(const std::string &FN);
/// FileOpenable - Returns true IFF Filename names an existing regular file
/// which we can successfully open.
///
bool FileOpenable (const std::string &Filename);
/// 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);
/// 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);
/// removeFile - Delete the specified file
///
void removeFile(const std::string &Filename);
/// getUniqueFilename - Return a filename with the specified prefix. If the
/// file does not exist yet, return it, otherwise add a suffix to make it
/// unique.
///
std::string getUniqueFilename(const std::string &FilenameBase);
/// MakeFileExecutable - This method turns on whatever access attributes are
/// needed to make the specified file executable. It returns true on success.
/// In case of failure, the file's access attributes are unspecified.
///
bool MakeFileExecutable(const std::string &Filename);
/// MakeFileReadable - This method turns on whatever access attributes are
/// needed to make the specified file readable. It returns true on success.
/// In case of failure, the file's access attributes are unspecified.
///
bool MakeFileReadable(const std::string &Filename);
/// getFileSize - Return the size of the specified file in bytes, or -1 if the
/// file cannot be read or does not exist.
long long getFileSize(const std::string &Filename);
/// getFileTimestamp - Get the last modified time for the specified file in an
/// unspecified format. This is useful to allow checking to see if a file was
/// updated since that last time the timestampt was aquired. If the file does
/// not exist or there is an error getting the time-stamp, zero is returned.
unsigned long long getFileTimestamp(const std::string &Filename);
/// FDHandle - Simple handle class to make sure a file descriptor gets closed
/// when the object is destroyed. This handle acts similarly to an
/// std::auto_ptr, in that the copy constructor and assignment operators
/// transfer ownership of the handle. This means that FDHandle's do not have
/// value semantics.
///
class FDHandle {
int FD;
public:
FDHandle() : FD(-1) {}
FDHandle(int fd) : FD(fd) {}
FDHandle(FDHandle &RHS) : FD(RHS.FD) {
RHS.FD = -1; // Transfer ownership
}
~FDHandle() throw();
/// get - Get the current file descriptor, without releasing ownership of it.
int get() const { return FD; }
operator int() const { return FD; }
FDHandle &operator=(int fd) throw();
FDHandle &operator=(FDHandle &RHS) {
int fd = RHS.FD;
RHS.FD = -1; // Transfer ownership
return operator=(fd);
}
/// release - Take ownership of the file descriptor away from the FDHandle
/// object, so that the file is not closed when the FDHandle is destroyed.
int release() {
int Ret = FD;
FD = -1;
return Ret;
}
};
/// 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 {
std::string Filename;
bool DeleteIt;
public:
FileRemover(const std::string &filename, bool deleteIt = true)
: Filename(filename), DeleteIt(deleteIt) {}
~FileRemover() {
if (DeleteIt) removeFile(Filename);
}
/// 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