#
# Start of posixfile.py
#

#
# Extended file operations
#
# f = posixfile.open(filename, [mode, [bufsize]])
#       will create a new posixfile object
#
# f = posixfile.fileopen(fileobject)
#       will create a posixfile object from a builtin file object
#
# f.file()
#       will return the original builtin file object
#
# f.dup()
#       will return a new file object based on a new filedescriptor
#
# f.dup2(fd)
#       will return a new file object based on the given filedescriptor
#
# f.flags(mode)
#       will turn on the associated flag (merge)
#       mode can contain the following characters:
#
#   (character representing a flag)
#       a       append only flag
#       c       close on exec flag
#       n       no delay flag
#       s       synchronization flag
#   (modifiers)
#       !       turn flags 'off' instead of default 'on'
#       =       copy flags 'as is' instead of default 'merge'
#       ?       return a string in which the characters represent the flags
#               that are set
#
#       note: - the '!' and '=' modifiers are mutually exclusive.
#             - the '?' modifier will return the status of the flags after they
#               have been changed by other characters in the mode string
#
# f.lock(mode [, len [, start [, whence]]])
#       will (un)lock a region
#       mode can contain the following characters:
#
#   (character representing type of lock)
#       u       unlock
#       r       read lock
#       w       write lock
#   (modifiers)
#       |       wait until the lock can be granted
#       ?       return the first lock conflicting with the requested lock
#               or 'None' if there is no conflict. The lock returned is in the
#               format (mode, len, start, whence, pid) where mode is a
#               character representing the type of lock ('r' or 'w')
#
#       note: - the '?' modifier prevents a region from being locked; it is
#               query only
#

class _posixfile_:
	states = ['open', 'closed']
 
	#
	# Internal routines
	#
	def __repr__(self):
		file = self._file_
		return "<%s posixfile '%s', mode '%s' at %s>" % \
				(self.states[file.closed], file.name, file.mode, \
					hex(id(self))[2:])
 
	def __del__(self):
		self._file_.close()
 
	#
	# Initialization routines
	#
	def open(self, name, mode='r', bufsize=-1):
		import __builtin__
		return self.fileopen(__builtin__.open(name, mode, bufsize))
 
	def fileopen(self, file):
		if `type(file)` != "<type 'file'>":
			raise TypeError, 'posixfile.fileopen() arg must be file object'
		self._file_  = file
		# Copy basic file methods
		for method in file.__methods__:
			setattr(self, method, getattr(file, method))
		return self
 
	#
	# New methods
	#
	def file(self):
		return self._file_
 
	def dup(self):
		import posix
 
		try: ignore = posix.fdopen
		except: raise AttributeError, 'dup() method unavailable'
 
		return posix.fdopen(posix.dup(self._file_.fileno()), self._file_.mode)
 
	def dup2(self, fd):
		import posix
 
		try: ignore = posix.fdopen
		except: raise AttributeError, 'dup() method unavailable'
 
		posix.dup2(self._file_.fileno(), fd)
		return posix.fdopen(fd, self._file_.mode)
 
	def flags(self, *which):
		import fcntl, FCNTL
 
		if which:
			if len(which) > 1:
				raise TypeError, 'Too many arguments'
			which = which[0]
		else: which = '?'
 
		l_flags = 0
		if 'n' in which: l_flags = l_flags | FCNTL.O_NDELAY
		if 'a' in which: l_flags = l_flags | FCNTL.O_APPEND
		if 's' in which: l_flags = l_flags | FCNTL.O_SYNC
 
		file = self._file_
 
		if '=' not in which:
			cur_fl = fcntl.fcntl(file.fileno(), FCNTL.F_GETFL, 0)
			if '!' in which: l_flags = cur_fl & ~ l_flags
			else: l_flags = cur_fl | l_flags
 
		l_flags = fcntl.fcntl(file.fileno(), FCNTL.F_SETFL, l_flags)
 
		if 'c' in which:        
			arg = ('!' not in which)    # 0 is don't, 1 is do close on exec
			l_flags = fcntl.fcntl(file.fileno(), FCNTL.F_SETFD, arg)
 
		if '?' in which:
			which = ''                  # Return current flags
			l_flags = fcntl.fcntl(file.fileno(), FCNTL.F_GETFL, 0)
			if FCNTL.O_APPEND & l_flags: which = which + 'a'
			if fcntl.fcntl(file.fileno(), FCNTL.F_GETFD, 0) & 1:
				which = which + 'c'
			if FCNTL.O_NDELAY & l_flags: which = which + 'n'
			if FCNTL.O_SYNC & l_flags: which = which + 's'
			return which
 
	def lock(self, how, *args):
		import struct, fcntl, FCNTL
 
		if 'w' in how: l_type = FCNTL.F_WRLCK
		elif 'r' in how: l_type = FCNTL.F_RDLCK
		elif 'u' in how: l_type = FCNTL.F_UNLCK
		else: raise TypeError, 'no type of lock specified'
 
		if '|' in how: cmd = FCNTL.F_SETLKW
		elif '?' in how: cmd = FCNTL.F_GETLK
		else: cmd = FCNTL.F_SETLK
 
		l_whence = 0
		l_start = 0
		l_len = 0
 
		if len(args) == 1:
			l_len = args[0]
		elif len(args) == 2:
			l_len, l_start = args
		elif len(args) == 3:
			l_len, l_start, l_whence = args
		elif len(args) > 3:
			raise TypeError, 'too many arguments'
 
		# Hack by davem@magnet.com to get locking to go on freebsd;
		# additions for AIX by Vladimir.Marangozov@imag.fr
		import sys, os
		if sys.platform in ('netbsd1', 'freebsd2', 'freebsd3'):
			flock = struct.pack('lxxxxlxxxxlhh', \
					l_start, l_len, os.getpid(), l_type, l_whence) 
		elif sys.platform in ['aix3', 'aix4']:
			flock = struct.pack('hhlllii', \
					l_type, l_whence, l_start, l_len, 0, 0, 0)
		else:
			flock = struct.pack('hhllhh', \
					l_type, l_whence, l_start, l_len, 0, 0)
 
		flock = fcntl.fcntl(self._file_.fileno(), cmd, flock)
 
		if '?' in how:
			if sys.platform in ('netbsd1', 'freebsd2', 'freebsd3'):
				l_start, l_len, l_pid, l_type, l_whence = \
					struct.unpack('lxxxxlxxxxlhh', flock)
			elif sys.platform in ['aix3', 'aix4']:
				l_type, l_whence, l_start, l_len, l_sysid, l_pid, l_vfs = \
					struct.unpack('hhlllii', flock)
			elif sys.platform == "linux2":
				l_type, l_whence, l_start, l_len, l_pid, l_sysid = \
					struct.unpack('hhllhh', flock)
			else:
				l_type, l_whence, l_start, l_len, l_sysid, l_pid = \
					struct.unpack('hhllhh', flock)
 
			if l_type != FCNTL.F_UNLCK:
				if l_type == FCNTL.F_RDLCK:
					return 'r', l_len, l_start, l_whence, l_pid
				else:
					return 'w', l_len, l_start, l_whence, l_pid

#
# Public routine to obtain a posixfile object
#
def open(name, mode='r', bufsize=-1):
	return _posixfile_().open(name, mode, bufsize)

def fileopen(file):
	return _posixfile_().fileopen(file)

#
# Constants
#
SEEK_SET = 0
SEEK_CUR = 1
SEEK_END = 2

#
# End of posixfile.py
#
