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Path.inc

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00001 //===- llvm/System/Unix/Path.cpp - Unix Path Implementation -----*- C++ -*-===//
00002 // 
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by Reid Spencer and is distributed under the 
00006 // University of Illinois Open Source License. See LICENSE.TXT for details.
00007 // 
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This file implements the Unix specific portion of the Path class.
00011 //
00012 //===----------------------------------------------------------------------===//
00013 
00014 //===----------------------------------------------------------------------===//
00015 //=== WARNING: Implementation here must contain only generic UNIX code that
00016 //===          is guaranteed to work on *all* UNIX variants.
00017 //===----------------------------------------------------------------------===//
00018 
00019 #include "llvm/Config/alloca.h"
00020 #include "Unix.h"
00021 #if HAVE_SYS_STAT_H
00022 #include <sys/stat.h>
00023 #endif
00024 #if HAVE_FCNTL_H
00025 #include <fcntl.h>
00026 #endif
00027 #if HAVE_UTIME_H
00028 #include <utime.h>
00029 #endif
00030 #if HAVE_TIME_H
00031 #include <time.h>
00032 #endif
00033 #if HAVE_DIRENT_H
00034 # include <dirent.h>
00035 # define NAMLEN(dirent) strlen((dirent)->d_name)
00036 #else
00037 # define dirent direct
00038 # define NAMLEN(dirent) (dirent)->d_namlen
00039 # if HAVE_SYS_NDIR_H
00040 #  include <sys/ndir.h>
00041 # endif
00042 # if HAVE_SYS_DIR_H
00043 #  include <sys/dir.h>
00044 # endif
00045 # if HAVE_NDIR_H
00046 #  include <ndir.h>
00047 # endif
00048 #endif
00049 
00050 // Put in a hack for Cygwin which falsely reports that the mkdtemp function
00051 // is available when it is not.
00052 #ifdef __CYGWIN__
00053 # undef HAVE_MKDTEMP
00054 #endif
00055 
00056 namespace {
00057 inline bool lastIsSlash(const std::string& path) {
00058   return !path.empty() && path[path.length() - 1] == '/';
00059 }
00060 
00061 }
00062 
00063 namespace llvm {
00064 using namespace sys;
00065 
00066 Path::Path(const std::string& unverified_path) : path(unverified_path) {
00067   if (unverified_path.empty())
00068     return;
00069   if (this->isValid()) 
00070     return;
00071   // oops, not valid.
00072   path.clear();
00073   ThrowErrno(unverified_path + ": path is not valid");
00074 }
00075 
00076 bool 
00077 Path::isValid() const {
00078   // Check some obvious things
00079   if (path.empty()) 
00080     return false;
00081   else if (path.length() >= MAXPATHLEN)
00082     return false;
00083 
00084   // Check that the characters are ascii chars
00085   size_t len = path.length();
00086   unsigned i = 0;
00087   while (i < len && isascii(path[i])) 
00088     ++i;
00089   return i >= len; 
00090 }
00091 
00092 Path
00093 Path::GetRootDirectory() {
00094   Path result;
00095   result.set("/");
00096   return result;
00097 }
00098 
00099 Path
00100 Path::GetTemporaryDirectory() {
00101 #if defined(HAVE_MKDTEMP)
00102   // The best way is with mkdtemp but that's not available on many systems, 
00103   // Linux and FreeBSD have it. Others probably won't.
00104   char pathname[MAXPATHLEN];
00105   strcpy(pathname,"/tmp/llvm_XXXXXX");
00106   if (0 == mkdtemp(pathname))
00107     ThrowErrno(std::string(pathname) + ": can't create temporary directory");
00108   Path result;
00109   result.set(pathname);
00110   assert(result.isValid() && "mkdtemp didn't create a valid pathname!");
00111   return result;
00112 #elif defined(HAVE_MKSTEMP)
00113   // If no mkdtemp is available, mkstemp can be used to create a temporary file
00114   // which is then removed and created as a directory. We prefer this over
00115   // mktemp because of mktemp's inherent security and threading risks. We still
00116   // have a slight race condition from the time the temporary file is created to
00117   // the time it is re-created as a directoy. 
00118   char pathname[MAXPATHLEN];
00119   strcpy(pathname, "/tmp/llvm_XXXXXX");
00120   int fd = 0;
00121   if (-1 == (fd = mkstemp(pathname)))
00122     ThrowErrno(std::string(pathname) + ": can't create temporary directory");
00123   ::close(fd);
00124   ::unlink(pathname); // start race condition, ignore errors
00125   if (-1 == ::mkdir(pathname, S_IRWXU)) // end race condition
00126     ThrowErrno(std::string(pathname) + ": can't create temporary directory");
00127   Path result;
00128   result.set(pathname);
00129   assert(result.isValid() && "mkstemp didn't create a valid pathname!");
00130   return result;
00131 #elif defined(HAVE_MKTEMP)
00132   // If a system doesn't have mkdtemp(3) or mkstemp(3) but it does have
00133   // mktemp(3) then we'll assume that system (e.g. AIX) has a reasonable
00134   // implementation of mktemp(3) and doesn't follow BSD 4.3's lead of replacing
00135   // the XXXXXX with the pid of the process and a letter. That leads to only
00136   // twenty six temporary files that can be generated.
00137   char pathname[MAXPATHLEN];
00138   strcpy(pathname, "/tmp/llvm_XXXXXX");
00139   char *TmpName = ::mktemp(pathname);
00140   if (TmpName == 0)
00141     ThrowErrno(std::string(TmpName) + ": can't create unique directory name");
00142   if (-1 == ::mkdir(TmpName, S_IRWXU))
00143     ThrowErrno(std::string(TmpName) + ": can't create temporary directory");
00144   Path result;
00145   result.set(TmpName);
00146   assert(result.isValid() && "mktemp didn't create a valid pathname!");
00147   return result;
00148 #else
00149   // This is the worst case implementation. tempnam(3) leaks memory unless its
00150   // on an SVID2 (or later) system. On BSD 4.3 it leaks. tmpnam(3) has thread
00151   // issues. The mktemp(3) function doesn't have enough variability in the
00152   // temporary name generated. So, we provide our own implementation that 
00153   // increments an integer from a random number seeded by the current time. This
00154   // should be sufficiently unique that we don't have many collisions between
00155   // processes. Generally LLVM processes don't run very long and don't use very
00156   // many temporary files so this shouldn't be a big issue for LLVM.
00157   static time_t num = ::time(0);
00158   char pathname[MAXPATHLEN];
00159   do {
00160     num++;
00161     sprintf(pathname, "/tmp/llvm_%010u", unsigned(num));
00162   } while ( 0 == access(pathname, F_OK ) );
00163   if (-1 == ::mkdir(pathname, S_IRWXU))
00164     ThrowErrno(std::string(pathname) + ": can't create temporary directory");
00165   Path result;
00166   result.set(pathname);
00167   assert(result.isValid() && "mkstemp didn't create a valid pathname!");
00168   return result;
00169 #endif
00170 }
00171 
00172 static void getPathList(const char*path, std::vector<sys::Path>& Paths) {
00173   const char* at = path;
00174   const char* delim = strchr(at, ':');
00175   Path tmpPath;
00176   while( delim != 0 ) {
00177     std::string tmp(at, size_t(delim-at));
00178     if (tmpPath.set(tmp))
00179       if (tmpPath.canRead())
00180         Paths.push_back(tmpPath);
00181     at = delim + 1;
00182     delim = strchr(at, ':');
00183   }
00184   if (*at != 0)
00185     if (tmpPath.set(std::string(at)))
00186       if (tmpPath.canRead())
00187         Paths.push_back(tmpPath);
00188 
00189 }
00190 
00191 void 
00192 Path::GetSystemLibraryPaths(std::vector<sys::Path>& Paths) {
00193 #ifdef LTDL_SHLIBPATH_VAR
00194   char* env_var = getenv(LTDL_SHLIBPATH_VAR);
00195   if (env_var != 0) {
00196     getPathList(env_var,Paths);
00197   }
00198 #endif
00199   // FIXME: Should this look at LD_LIBRARY_PATH too?
00200   Paths.push_back(sys::Path("/usr/local/lib/"));
00201   Paths.push_back(sys::Path("/usr/X11R6/lib/"));
00202   Paths.push_back(sys::Path("/usr/lib/"));
00203   Paths.push_back(sys::Path("/lib/"));
00204 }
00205 
00206 void
00207 Path::GetBytecodeLibraryPaths(std::vector<sys::Path>& Paths) {
00208   char * env_var = getenv("LLVM_LIB_SEARCH_PATH");
00209   if (env_var != 0) {
00210     getPathList(env_var,Paths);
00211   }
00212 #ifdef LLVM_LIBDIR
00213   {
00214     Path tmpPath;
00215     if (tmpPath.set(LLVM_LIBDIR))
00216       if (tmpPath.canRead())
00217         Paths.push_back(tmpPath);
00218   }
00219 #endif
00220   GetSystemLibraryPaths(Paths);
00221 }
00222 
00223 Path 
00224 Path::GetLLVMDefaultConfigDir() {
00225   return Path("/etc/llvm/");
00226 }
00227 
00228 Path
00229 Path::GetUserHomeDirectory() {
00230   const char* home = getenv("HOME");
00231   if (home) {
00232     Path result;
00233     if (result.set(home))
00234       return result;
00235   }
00236   return GetRootDirectory();
00237 }
00238 
00239 bool
00240 Path::isFile() const {
00241   if (!exists())
00242     return false;
00243   struct stat buf;
00244   if (0 != stat(path.c_str(), &buf)) {
00245     ThrowErrno(path + ": can't determine type of path object: ");
00246   }
00247   return S_ISREG(buf.st_mode);
00248 }
00249 
00250 bool
00251 Path::isDirectory() const {
00252   if (!exists())
00253     return false;
00254   struct stat buf;
00255   if (0 != stat(path.c_str(), &buf)) {
00256     ThrowErrno(path + ": can't determine type of path object: ");
00257   }
00258   return S_ISDIR(buf.st_mode);
00259 }
00260 
00261 bool
00262 Path::isHidden() const {
00263   if (!exists())
00264     return false;
00265   size_t slash = path.rfind('/');
00266   return (slash != std::string::npos && 
00267           slash < path.length()-1 && 
00268           path[slash+1] == '.') || 
00269          (!path.empty() && slash == std::string::npos && path[0] == '.');
00270 }
00271 
00272 std::string
00273 Path::getBasename() const {
00274   // Find the last slash
00275   size_t slash = path.rfind('/');
00276   if (slash == std::string::npos)
00277     slash = 0;
00278   else
00279     slash++;
00280 
00281   size_t dot = path.rfind('.');
00282   if (dot == std::string::npos || dot < slash)
00283     return path.substr(slash);
00284   else
00285     return path.substr(slash, dot - slash);
00286 }
00287 
00288 bool Path::hasMagicNumber(const std::string &Magic) const {
00289   if (!isFile())
00290     return false;
00291   size_t len = Magic.size();
00292   assert(len < 1024 && "Request for magic string too long");
00293   char* buf = (char*) alloca(1 + len);
00294   int fd = ::open(path.c_str(),O_RDONLY);
00295   if (fd < 0)
00296     return false;
00297   size_t read_len = ::read(fd, buf, len);
00298   close(fd);
00299   if (len != read_len)
00300     return false;
00301   buf[len] = '\0';
00302   return Magic == buf;
00303 }
00304 
00305 bool Path::getMagicNumber(std::string& Magic, unsigned len) const {
00306   if (!isFile())
00307     return false;
00308   assert(len < 1024 && "Request for magic string too long");
00309   char* buf = (char*) alloca(1 + len);
00310   int fd = ::open(path.c_str(),O_RDONLY);
00311   if (fd < 0)
00312     return false;
00313   ssize_t bytes_read = ::read(fd, buf, len);
00314   ::close(fd);
00315   if (ssize_t(len) != bytes_read) {
00316     Magic.clear();
00317     return false;
00318   }
00319   Magic.assign(buf,len);
00320   return true;
00321 }
00322 
00323 bool 
00324 Path::isBytecodeFile() const {
00325   if (!isFile())
00326     return false;
00327   char buffer[ 4];
00328   buffer[0] = 0;
00329   int fd = ::open(path.c_str(),O_RDONLY);
00330   if (fd < 0)
00331     return false;
00332   ssize_t bytes_read = ::read(fd, buffer, 4);
00333   ::close(fd);
00334   if (4 != bytes_read) 
00335     return false;
00336 
00337   return (buffer[0] == 'l' && buffer[1] == 'l' && buffer[2] == 'v' &&
00338       (buffer[3] == 'c' || buffer[3] == 'm'));
00339 }
00340 
00341 bool
00342 Path::exists() const {
00343   return 0 == access(path.c_str(), F_OK );
00344 }
00345 
00346 bool
00347 Path::canRead() const {
00348   return 0 == access(path.c_str(), F_OK | R_OK );
00349 }
00350 
00351 bool
00352 Path::canWrite() const {
00353   return 0 == access(path.c_str(), F_OK | W_OK );
00354 }
00355 
00356 bool
00357 Path::canExecute() const {
00358   if (0 != access(path.c_str(), R_OK | X_OK ))
00359     return false;
00360   struct stat st;
00361   int r = stat(path.c_str(), &st);
00362   if (r != 0 || !S_ISREG(st.st_mode))
00363     return false;
00364   return true;
00365 }
00366 
00367 std::string 
00368 Path::getLast() const {
00369   // Find the last slash
00370   size_t pos = path.rfind('/');
00371 
00372   // Handle the corner cases
00373   if (pos == std::string::npos)
00374     return path;
00375 
00376   // If the last character is a slash
00377   if (pos == path.length()-1) {
00378     // Find the second to last slash
00379     size_t pos2 = path.rfind('/', pos-1);
00380     if (pos2 == std::string::npos)
00381       return path.substr(0,pos);
00382     else
00383       return path.substr(pos2+1,pos-pos2-1);
00384   }
00385   // Return everything after the last slash
00386   return path.substr(pos+1);
00387 }
00388 
00389 void
00390 Path::getStatusInfo(StatusInfo& info) const {
00391   struct stat buf;
00392   if (0 != stat(path.c_str(), &buf)) {
00393     ThrowErrno(path + ": can't determine type of path object: ");
00394   }
00395   info.fileSize = buf.st_size;
00396   info.modTime.fromEpochTime(buf.st_mtime);
00397   info.mode = buf.st_mode;
00398   info.user = buf.st_uid;
00399   info.group = buf.st_gid;
00400   info.isDir = S_ISDIR(buf.st_mode);
00401 }
00402 
00403 static bool AddPermissionBits(const std::string& Filename, int bits) {
00404   // Get the umask value from the operating system.  We want to use it
00405   // when changing the file's permissions. Since calling umask() sets
00406   // the umask and returns its old value, we must call it a second
00407   // time to reset it to the user's preference.
00408   int mask = umask(0777); // The arg. to umask is arbitrary.
00409   umask(mask);            // Restore the umask.
00410 
00411   // Get the file's current mode.
00412   struct stat st;
00413   if ((stat(Filename.c_str(), &st)) == -1)
00414     return false;
00415 
00416   // Change the file to have whichever permissions bits from 'bits'
00417   // that the umask would not disable.
00418   if ((chmod(Filename.c_str(), (st.st_mode | (bits & ~mask)))) == -1)
00419     return false;
00420 
00421   return true;
00422 }
00423 
00424 void Path::makeReadableOnDisk() {
00425   if (!AddPermissionBits(path,0444))
00426     ThrowErrno(path + ": can't make file readable");
00427 }
00428 
00429 void Path::makeWriteableOnDisk() {
00430   if (!AddPermissionBits(path,0222))
00431     ThrowErrno(path + ": can't make file writable");
00432 }
00433 
00434 void Path::makeExecutableOnDisk() {
00435   if (!AddPermissionBits(path,0111))
00436     ThrowErrno(path + ": can't make file executable");
00437 }
00438 
00439 bool
00440 Path::getDirectoryContents(std::set<Path>& result) const {
00441   if (!isDirectory())
00442     return false;
00443   DIR* direntries = ::opendir(path.c_str());
00444   if (direntries == 0)
00445     ThrowErrno(path + ": can't open directory");
00446 
00447   std::string dirPath = path;
00448   if (!lastIsSlash(dirPath))
00449     dirPath += '/';
00450 
00451   result.clear();
00452   struct dirent* de = ::readdir(direntries);
00453   for ( ; de != 0; de = ::readdir(direntries)) {
00454     if (de->d_name[0] != '.') {
00455       Path aPath(dirPath + (const char*)de->d_name);
00456       struct stat buf;
00457       if (0 != stat(aPath.path.c_str(), &buf)) {
00458         int stat_errno = errno;
00459         struct stat st;
00460         if (0 == lstat(aPath.path.c_str(), &st) && S_ISLNK(st.st_mode))
00461           continue; // dangling symlink -- ignore
00462         ThrowErrno(aPath.path + 
00463           ": can't determine file object type", stat_errno);
00464       }
00465       result.insert(aPath);
00466     }
00467   }
00468   
00469   closedir(direntries);
00470   return true;
00471 }
00472 
00473 bool
00474 Path::set(const std::string& a_path) {
00475   if (a_path.empty())
00476     return false;
00477   std::string save(path);
00478   path = a_path;
00479   if (!isValid()) {
00480     path = save;
00481     return false;
00482   }
00483   return true;
00484 }
00485 
00486 bool
00487 Path::appendComponent(const std::string& name) {
00488   if (name.empty())
00489     return false;
00490   std::string save(path);
00491   if (!lastIsSlash(path))
00492     path += '/';
00493   path += name;
00494   if (!isValid()) {
00495     path = save;
00496     return false;
00497   }
00498   return true;
00499 }
00500 
00501 bool
00502 Path::eraseComponent() {
00503   size_t slashpos = path.rfind('/',path.size());
00504   if (slashpos == 0 || slashpos == std::string::npos) {
00505     path.erase();
00506     return true;
00507   }
00508   if (slashpos == path.size() - 1)
00509     slashpos = path.rfind('/',slashpos-1);
00510   if (slashpos == std::string::npos) {
00511     path.erase();
00512     return true;
00513   }
00514   path.erase(slashpos);
00515   return true;
00516 }
00517 
00518 bool
00519 Path::appendSuffix(const std::string& suffix) {
00520   std::string save(path);
00521   path.append(".");
00522   path.append(suffix);
00523   if (!isValid()) {
00524     path = save;
00525     return false;
00526   }
00527   return true;
00528 }
00529 
00530 bool
00531 Path::eraseSuffix() {
00532   std::string save = path;
00533   size_t dotpos = path.rfind('.',path.size());
00534   size_t slashpos = path.rfind('/',path.size());
00535   if (dotpos != std::string::npos) {
00536     if (slashpos == std::string::npos || dotpos > slashpos+1) {
00537       path.erase(dotpos, path.size()-dotpos);
00538       return true;
00539     }
00540   }
00541   if (!isValid())
00542     path = save;
00543   return false;
00544 }
00545 
00546 bool
00547 Path::createDirectoryOnDisk( bool create_parents) {
00548   // Get a writeable copy of the path name
00549   char pathname[MAXPATHLEN];
00550   path.copy(pathname,MAXPATHLEN);
00551 
00552   // Null-terminate the last component
00553   int lastchar = path.length() - 1 ; 
00554   if (pathname[lastchar] == '/') 
00555     pathname[lastchar] = 0;
00556   else 
00557     pathname[lastchar+1] = 0;
00558 
00559   // If we're supposed to create intermediate directories
00560   if ( create_parents ) {
00561     // Find the end of the initial name component
00562     char * next = strchr(pathname,'/');
00563     if ( pathname[0] == '/') 
00564       next = strchr(&pathname[1],'/');
00565 
00566     // Loop through the directory components until we're done 
00567     while ( next != 0 ) {
00568       *next = 0;
00569       if (0 != access(pathname, F_OK | R_OK | W_OK))
00570         if (0 != mkdir(pathname, S_IRWXU | S_IRWXG))
00571           ThrowErrno(std::string(pathname) + ": can't create directory");
00572       char* save = next;
00573       next = strchr(next+1,'/');
00574       *save = '/';
00575     }
00576   } 
00577 
00578   if (0 != access(pathname, F_OK | R_OK))
00579     if (0 != mkdir(pathname, S_IRWXU | S_IRWXG))
00580       ThrowErrno(std::string(pathname) + ": can't create directory");
00581   return true;
00582 }
00583 
00584 bool
00585 Path::createFileOnDisk() {
00586   // Create the file
00587   int fd = ::creat(path.c_str(), S_IRUSR | S_IWUSR);
00588   if (fd < 0)
00589     ThrowErrno(path + ": can't create file");
00590   ::close(fd);
00591 
00592   return true;
00593 }
00594 
00595 bool
00596 Path::createTemporaryFileOnDisk(bool reuse_current) {
00597   // Make this into a unique file name
00598   makeUnique( reuse_current );
00599 
00600   // create the file
00601   int outFile = ::open(path.c_str(), O_WRONLY|O_CREAT|O_TRUNC, 0666);
00602   if (outFile != -1) {
00603     ::close(outFile);
00604     return true;
00605   }
00606   return false;
00607 }
00608 
00609 bool
00610 Path::eraseFromDisk(bool remove_contents) const {
00611   // Make sure we're dealing with a directory
00612   if (isFile()) {
00613     if (0 != unlink(path.c_str()))
00614       ThrowErrno(path + ": can't destroy file");
00615   } else if (isDirectory()) {
00616     if (remove_contents) {
00617       // Recursively descend the directory to remove its content
00618       std::string cmd("/bin/rm -rf ");
00619       cmd += path;
00620       system(cmd.c_str());
00621     } else {
00622       // Otherwise, try to just remove the one directory
00623       char pathname[MAXPATHLEN];
00624       path.copy(pathname,MAXPATHLEN);
00625       int lastchar = path.length() - 1 ; 
00626       if (pathname[lastchar] == '/') 
00627         pathname[lastchar] = 0;
00628       else
00629         pathname[lastchar+1] = 0;
00630       if ( 0 != rmdir(pathname))
00631         ThrowErrno(std::string(pathname) + ": can't destroy directory");
00632     }
00633   }
00634   else
00635     return false;
00636   return true;
00637 }
00638 
00639 bool
00640 Path::renamePathOnDisk(const Path& newName) {
00641   if (0 != ::rename(path.c_str(), newName.c_str()))
00642     ThrowErrno(std::string("can't rename '") + path + "' as '" + 
00643                newName.toString() + "' ");
00644   return true;
00645 }
00646 
00647 bool
00648 Path::setStatusInfoOnDisk(const StatusInfo& si) const {
00649   struct utimbuf utb;
00650   utb.actime = si.modTime.toPosixTime();
00651   utb.modtime = utb.actime;
00652   if (0 != ::utime(path.c_str(),&utb))
00653     ThrowErrno(path + ": can't set file modification time");
00654   if (0 != ::chmod(path.c_str(),si.mode))
00655     ThrowErrno(path + ": can't set mode");
00656   return true;
00657 }
00658 
00659 void 
00660 sys::CopyFile(const sys::Path &Dest, const sys::Path &Src) {
00661   int inFile = -1;
00662   int outFile = -1;
00663   try {
00664     inFile = ::open(Src.c_str(), O_RDONLY);
00665     if (inFile == -1)
00666       ThrowErrno(Src.toString() + ": can't open source file to copy: ");
00667 
00668     outFile = ::open(Dest.c_str(), O_WRONLY|O_CREAT, 0666);
00669     if (outFile == -1)
00670       ThrowErrno(Dest.toString() +": can't create destination file for copy: ");
00671 
00672     char Buffer[16*1024];
00673     while (ssize_t Amt = ::read(inFile, Buffer, 16*1024)) {
00674       if (Amt == -1) {
00675         if (errno != EINTR && errno != EAGAIN) 
00676           ThrowErrno(Src.toString()+": can't read source file: ");
00677       } else {
00678         char *BufPtr = Buffer;
00679         while (Amt) {
00680           ssize_t AmtWritten = ::write(outFile, BufPtr, Amt);
00681           if (AmtWritten == -1) {
00682             if (errno != EINTR && errno != EAGAIN) 
00683               ThrowErrno(Dest.toString() + ": can't write destination file: ");
00684           } else {
00685             Amt -= AmtWritten;
00686             BufPtr += AmtWritten;
00687           }
00688         }
00689       }
00690     }
00691     ::close(inFile);
00692     ::close(outFile);
00693   } catch (...) {
00694     if (inFile != -1)
00695       ::close(inFile);
00696     if (outFile != -1)
00697       ::close(outFile);
00698     throw;
00699   }
00700 }
00701 
00702 void 
00703 Path::makeUnique(bool reuse_current) {
00704   if (reuse_current && !exists())
00705     return; // File doesn't exist already, just use it!
00706 
00707   // Append an XXXXXX pattern to the end of the file for use with mkstemp, 
00708   // mktemp or our own implementation.
00709   char *FNBuffer = (char*) alloca(path.size()+8);
00710   path.copy(FNBuffer,path.size());
00711   strcpy(FNBuffer+path.size(), "-XXXXXX");
00712 
00713 #if defined(HAVE_MKSTEMP)
00714   int TempFD;
00715   if ((TempFD = mkstemp(FNBuffer)) == -1) {
00716     ThrowErrno(path + ": can't make unique filename");
00717   }
00718 
00719   // We don't need to hold the temp file descriptor... we will trust that no one
00720   // will overwrite/delete the file before we can open it again.
00721   close(TempFD);
00722 
00723   // Save the name
00724   path = FNBuffer;
00725 #elif defined(HAVE_MKTEMP)
00726   // If we don't have mkstemp, use the old and obsolete mktemp function.
00727   if (mktemp(FNBuffer) == 0) {
00728     ThrowErrno(path + ": can't make unique filename");
00729   }
00730 
00731   // Save the name
00732   path = FNBuffer;
00733 #else
00734   // Okay, looks like we have to do it all by our lonesome.
00735   static unsigned FCounter = 0;
00736   unsigned offset = path.size() + 1;
00737   while ( FCounter < 999999 && exists()) {
00738     sprintf(FNBuffer+offset,"%06u",++FCounter);
00739     path = FNBuffer;
00740   }
00741   if (FCounter > 999999)
00742     throw std::string(path + ": can't make unique filename: too many files");
00743 #endif
00744 
00745 }
00746 }
00747