Dynamic server commands

# =============================================================================
# >> IMPORTS
# =============================================================================
# Python
import collections
import os
import shlex
import sys

# binutils
import binutils

from binutils import Convention


# =============================================================================
# >> API
# =============================================================================
def register_command(name, callback):
    srv_cmds[name.lower()].add(callback)

def unregister_command(name, callback):
    srv_cmds[name.lower()].discard(callback)


# =============================================================================
# >> GLOBAL VARIABLES
# =============================================================================
# This dict holds all callbacks for a server command
srv_cmds = collections.defaultdict(set)

# Get the engine binary file
engine = binutils.find_binary('bin/engine')

if os.name == 'nt':
    IsCommand_ptr = engine.find_signature('\x55\x8B\xEC\x81\xEC\x08\x04\x2A\x2A\x8B\x45\x08')
else:
    IsCommand_ptr = engine['_ZN14CCvarUtilities9IsCommandERK8CCommand']

# CCvarUtilities::IsCommand(CCommand  const&)
IsCommand = IsCommand_ptr.make_function(Convention.THISCALL, 'pp)b')


# =============================================================================
# >> LOAD & UNLOAD
# =============================================================================
def load():
    IsCommand.add_pre_hook(is_command_hook)

def unload():
    IsCommand.remove_pre_hook(is_command_hook)


# =============================================================================
# >> CALLBACKS
# =============================================================================
def is_command_hook(args):
    arglist = shlex.split(args[1].get_string(8, False), ' ')
    name = arglist[0].lower()
    if name not in srv_cmds:
        # Continue as usual
        return

    for callback in srv_cmds[name]:
        try:
            callback(arglist[1:])
        except:
            sys.excepthook(*sys.exc_info())

    # Stop the message: "Unknown command: <cmd>"
    return True


# =============================================================================
# >> TESTS
# =============================================================================
def my_cmd_callback(args):
    print 'Args:', args

register_command('est_rocket', my_cmd_callback)