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//===- Support/FileUtilities.cpp - File System Utilities ------------------===//
//
// 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 implements a family of utility functions which are useful for doing
// various things with files.
//
//===----------------------------------------------------------------------===//
#include "Support/FileUtilities.h"
#include "Config/unistd.h"
#include "Config/sys/stat.h"
#include "Config/sys/types.h"
#include <fstream>
#include <iostream>
#include <cstdio>
/// 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) {
char buf[1 + Magic.size ()];
std::ifstream f (FN.c_str ());
f.read (buf, Magic.size ());
buf[Magic.size ()] = '\0';
return Magic == buf;
}
/// 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) {
// Inspect the beginning of the file to see if it contains the "ar"
// library archive format magic string.
return CheckMagic (FN, "!<arch>\012");
}
/// 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) {
// Inspect the beginning of the file to see if it contains the LLVM
// bytecode format magic string.
return CheckMagic (FN, "llvm");
}
/// FileOpenable - Returns true IFF Filename names an existing regular
/// file which we can successfully open.
///
bool FileOpenable (const std::string &Filename) {
struct stat s;
if (stat (Filename.c_str (), &s) == -1)
return false; // Cannot stat file
if (!S_ISREG (s.st_mode))
return false; // File is not a regular file
std::ifstream FileStream (Filename.c_str ());
if (!FileStream)
return false; // File is not openable
return true;
}
/// 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) {
std::ifstream FileAStream(FileA.c_str());
if (!FileAStream) {
if (Error) *Error = "Couldn't open file '" + FileA + "'";
return true;
}
std::ifstream FileBStream(FileB.c_str());
if (!FileBStream) {
if (Error) *Error = "Couldn't open file '" + FileB + "'";
return true;
}
// Compare the two files...
int C1, C2;
do {
C1 = FileAStream.get();
C2 = FileBStream.get();
if (C1 != C2) return true;
} while (C1 != EOF);
return false;
}
/// 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) {
if (DiffFiles(New, Old)) {
if (std::rename(New.c_str(), Old.c_str()))
std::cerr << "Error renaming '" << New << "' to '" << Old << "'!\n";
} else {
std::remove(New.c_str());
}
}
/// removeFile - Delete the specified file
///
void removeFile(const std::string &Filename) {
std::remove(Filename.c_str());
}
/// 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) {
if (!std::ifstream(FilenameBase.c_str()))
return FilenameBase; // Couldn't open the file? Use it!
// Create a pattern for mkstemp...
char *FNBuffer = new char[FilenameBase.size()+8];
strcpy(FNBuffer, FilenameBase.c_str());
strcpy(FNBuffer+FilenameBase.size(), "-XXXXXX");
// Agree on a temporary file name to use....
int TempFD;
if ((TempFD = mkstemp(FNBuffer)) == -1) {
std::cerr << "bugpoint: ERROR: Cannot create temporary file in the current "
<< " directory!\n";
exit(1);
}
// We don't need to hold the temp file descriptor... we will trust that no one
// will overwrite/delete the file while we are working on it...
close(TempFD);
std::string Result(FNBuffer);
delete[] FNBuffer;
return Result;
}
static bool AddPermissionsBits (const std::string &Filename, mode_t bits) {
// Get the umask value from the operating system. We want to use it
// when changing the file's permissions. Since calling umask() sets
// the umask and returns its old value, we must call it a second
// time to reset it to the user's preference.
mode_t mask = umask (0777); // The arg. to umask is arbitrary...
umask (mask);
// Get the file's current mode.
struct stat st;
if ((stat (Filename.c_str(), &st)) == -1)
return false;
// Change the file to have whichever permissions bits from 'bits'
// that the umask would not disable.
if ((chmod(Filename.c_str(), (st.st_mode | (bits & ~mask)))) == -1)
return false;
return true;
}
/// MakeFileExecutable - Make the file named Filename executable by
/// setting whichever execute permissions bits the process's current
/// umask would allow. Filename must name an existing file or
/// directory. Returns true on success, false on error.
///
bool MakeFileExecutable (const std::string &Filename) {
return AddPermissionsBits (Filename, 0111);
}
/// MakeFileReadable - Make the file named Filename readable by
/// setting whichever read permissions bits the process's current
/// umask would allow. Filename must name an existing file or
/// directory. Returns true on success, false on error.
///
bool MakeFileReadable (const std::string &Filename) {
return AddPermissionsBits (Filename, 0444);
}
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