# Copyright 2009 Jason Stitt
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

import ctypes
import sys
import threading

try:
    from cStringIO import StringIO
except ImportError:
    from StringIO import StringIO 

__all__ = ['Sink', 'create_sink', 'destroy_sink']

#----------------------------------------------------------------------------#
# Globals

sinks = {} # of int: Sink
last_sink_id = 0
sink_id_lock = threading.Lock()

#----------------------------------------------------------------------------#
# ctypes type definitions

PutByteType = ctypes.CFUNCTYPE(None, ctypes.c_int, ctypes.c_char)

class TidyOutputSink(ctypes.Structure):
    """ Mirrors the _TidyOutputSink structure in tidy.h """
    _fields_ = [
        ('sinkData', ctypes.c_int),
        ('putByte', PutByteType)
        ]
        
#----------------------------------------------------------------------------#
# Python interface
    
class Sink(object):
    """ Represent a buffer to which Tidy writes errors with a callback function """
    def __init__(self, sink_id):
        self.data = StringIO()
        self.sink_id = sink_id
        self.struct = TidyOutputSink()
        self.struct.sinkData = sink_id
        write_func = self.data.write # Avoid 2 attr accesses per byte
        def put_byte(sink_id, byte):
            # We don't need sink_id because we have a separate put_byte
            # function for each sink
            write_func(byte)
        self.struct.putByte = PutByteType(put_byte)
        self._as_parameter_ = ctypes.byref(self.struct)
    
    def __str__(self):
        return self.data.getvalue()
        
def create_sink():
    """ Return a new Sink with a numeric ID incremented in a threadsafe way """
    global last_sink_id, sink_id_lock, sinks
    sink_id_lock.acquire()
    try:
        this_sink_id = last_sink_id
        last_sink_id = (last_sink_id + 1) % sys.maxint
        # If you have more than maxint sinks open at a time, you're screwed
    finally:
        sink_id_lock.release()
    sink = Sink(this_sink_id)
    sinks[this_sink_id] = sink
    return sink
    
def destroy_sink(sink):
    """ Free a Sink object by eliminating the reference from the global map """
    global sinks
    del sinks[sink.sink_id]
    del sink

#----------------------------------------------------------------------------#

