# FILE:     autoload/conque_term/conque_sole_shared_memory.py {{{
# AUTHOR:   Nico Raffo <nicoraffo@gmail.com>
# WEBSITE:  http://conque.googlecode.com
# MODIFIED: 2010-11-15
# VERSION:  2.0, for Vim 7.0
# LICENSE:
# Conque - Vim terminal/console emulator
# Copyright (C) 2009-2010 Nico Raffo
#
# MIT License
#
# 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. }}}

"""Wrapper class for shared memory between Windows python processes"""

import mmap
import sys

if sys.version_info[0] == 2:
    CONQUE_PYTHON_VERSION = 2
else:
    CONQUE_PYTHON_VERSION = 3

if CONQUE_PYTHON_VERSION == 2:
    import cPickle as pickle
else:
    import pickle


class ConqueSoleSharedMemory():

    # ****************************************************************************
    # class properties

    # {{{

    # is the data being stored not fixed length
    fixed_length = False

    # fill memory with this character when clearing and fixed_length is true
    fill_char = ' '

    # serialize and unserialize data automatically
    serialize = False

    # size of shared memory, in bytes / chars
    mem_size = None

    # size of shared memory, in bytes / chars
    mem_type = None

    # unique key, so multiple console instances are possible
    mem_key = None

    # mmap instance
    shm = None

    # character encoding, dammit
    encoding = 'ascii'

    # pickle terminator
    TERMINATOR = None

    # }}}

    # ****************************************************************************
    # constructor I guess

    def __init__(self, mem_size, mem_type, mem_key, fixed_length=False, fill_char=' ', serialize=False, encoding='ascii'): # {{{

        self.mem_size = mem_size
        self.mem_type = mem_type
        self.mem_key = mem_key
        self.fixed_length = fixed_length
        self.fill_char = fill_char
        self.serialize = serialize
        self.encoding = encoding
        self.TERMINATOR = str(chr(0)).encode(self.encoding)

    # }}}

    # ****************************************************************************
    # create memory block

    def create(self, access='write'): # {{{

        if access == 'write':
            mmap_access = mmap.ACCESS_WRITE
        else:
            mmap_access = mmap.ACCESS_READ

        name = "conque_%s_%s" % (self.mem_type, self.mem_key)

        self.shm = mmap.mmap(0, self.mem_size, name, mmap_access)

        if not self.shm:
            return False
        else:
            return True

        # }}}

    # ****************************************************************************
    # read data

    def read(self, chars=1, start=0): # {{{

        # invalid reads
        if self.fixed_length and (chars == 0 or start + chars > self.mem_size):
            return ''

        # go to start position
        self.shm.seek(start)

        if not self.fixed_length:
            chars = self.shm.find(self.TERMINATOR)

        if chars == 0:
            return ''

        shm_str = self.shm.read(chars)

        # return unpickled byte object
        if self.serialize:
            return pickle.loads(shm_str)

        # decode byes in python 3
        if CONQUE_PYTHON_VERSION == 3:
            return str(shm_str, self.encoding)

        # encoding
        if self.encoding != 'ascii':
            shm_str = unicode(shm_str, self.encoding)

        return shm_str

        # }}}

    # ****************************************************************************
    # write data

    def write(self, text, start=0): # {{{

        # simple scenario, let pickle create bytes
        if self.serialize:
            if CONQUE_PYTHON_VERSION == 3:
                tb = pickle.dumps(text, 0)
            else:
                tb = pickle.dumps(text, 0).encode(self.encoding)

        else:
            tb = text.encode(self.encoding, 'replace')

        self.shm.seek(start)

        # write to memory
        if self.fixed_length:
            self.shm.write(tb)
        else:
            self.shm.write(tb + self.TERMINATOR)

        # }}}

    # ****************************************************************************
    # clear

    def clear(self, start=0): # {{{

        self.shm.seek(start)

        if self.fixed_length:
            self.shm.write(str(self.fill_char * self.mem_size).encode(self.encoding))
        else:
            self.shm.write(self.TERMINATOR)

        # }}}

    # ****************************************************************************
    # close

    def close(self):

        self.shm.close()


# vim:foldmethod=marker