python-ecasound 2.9.1-7build1 / usr / share / pyshared / ecacontrol.py

"""Native python ECI (ecasound control interface) implementation

   Can be used to replace the C implementation 'pyecasound.so'.
"""

authors="""Kai Vehmanen, Eric S. Tiedemann and Janne Halttunen."""

import sys
if sys.hexversion < 0x02040000:
    print >>sys.stderr, "ERROR: Python 2.4 or newer is required by ecacontrol.py"
    sys.exit(-1)

import re
import subprocess
from select import select
import os
import signal
import string
import time

_ecasound=[]

type_override={}
eci_str_sync_lost= 'Connection to the processing engine was lost.\n'

class ECA_CONTROL_INTERFACE:
    
    def __init__(I, verbose=1):
        """Instantiate new ECI session
        
        verbose: set this false to get rid of startup-messages
        """

        I.verbose=verbose
        I._cmd=''
        I._type=''
        I._timeout=5 # in seconds
        I._resp={}
        I.initialize()
        
    def __call__(I, cmd, f=None):
        if f != None:
            val=I.command_float_arg(cmd, f)
        else:
            cmds=string.split(cmd, '\n')
            if len(cmds) > 1:
                v=[]
                for c in cmds:
                    c=string.strip(c)
                    if c:
                        v.append(I.command(c))
                    
                        if I.error():
                            raise Exception(v[-1])
                    
                val=string.join(map(str, v), '\n')
            else:
                val=I.command(cmd)
                    
        if I.error():
            raise Exception(val)
        
        return val            

    def _readline(I):
        return string.strip(I.eca.stdout.readline())
        
    def _read_eca(I):
        buffer=''
        while select([I.eca.stdout.fileno()],[],[I.eca.stdout.fileno()],0.01)[0]:
           buffer=buffer+I.eca.stdout.read(1)
        return buffer
    
    def _parse_response(I):
        tm=''; r=(); failcount=0
        if I.verbose > 2:
            print 'c=' + I._cmd
        while 1:
            
            s=I._read_eca()
            #print 'read s=' + s
            if s:
                if I.verbose > 3:
                    print 's=<', s, '>'
            else:
                failcount = failcount + 1
                if failcount < I._timeout * 10:
                #if failcount < 0:
                    time.sleep(0.01)
                    continue
                else:
                    print 'timeout: s=<' + s, '>, cmd=' + I._cmd + '.'
                    r=('e', eci_str_sync_lost)
                    break
            tm=tm+s
            m=expand_eiam_response(tm)
            r=parse_eiam_response(tm, m)
            if r:
                if I.verbose > 2:
                    print 'r=', r
                break

        if not r:
            I._resp['e']='-'            
            I._type='e'
            r=None
        else:
            I._type=r[0]
            
            if I._cmd in type_override.keys():
                I._type=type_override[I._cmd]
            
            if I._type == 'S':
                    I._resp[I._type]=string.split(r[1], ',')            
            elif I._type == 'Sn':
                    I._resp[I._type]=string.split(r[1], '\n')
            elif I._type == 'f':
                    I._resp[I._type]=float(r[1])
            elif I._type == 'i':
                    I._resp[I._type]=int(r[1])
            elif I._type == 'li':
                    I._resp[I._type]=long(r[1])
            else:
                    I._resp[I._type]=r[1]

        return I._resp[I._type]

    
    def initialize(I):
        """Reserve resources"""
                
##        if _ecasound is not None:
##            I.cleanup()             # exit previous ecasound session cleanly
           
        global _ecasound

        try:
            ecasound_binary = os.environ['ECASOUND']
        except KeyError:
            ecasound_binary = ''

        if ecasound_binary == '':
            ecasound_binary = 'ecasound'

        p = subprocess.Popen(ecasound_binary + ' -c -d:256 2>/dev/null',
                             shell=True, bufsize=0, stdin=subprocess.PIPE, stdout=subprocess.PIPE, close_fds=True)
        _ecasound.append(p)
        
        I.eca=_ecasound[-1]
        
        lines=''
        
        lines=lines+I._readline()+'\n'

        version=I._readline()
            
        s=string.find(version, 'ecasound v')
        if float(version[s+10:s+13])>=2.2:
            lines=lines+version+'\n'
        else:
            raise RuntimeError('ecasound version 2.2 required!')
        
        lines=lines+I._readline()+'\n'
        
        if I.verbose:
            print lines
            print __doc__
            print 'by', authors
            print '\n(to get rid of this message, pass zero to instance init)'
            
        I.command('int-output-mode-wellformed')
        #I._read_eca()
        #I.command('debug 256')
        
    def cleanup(I):
        """Free all reserved resources"""
        
        I.eca.stdin.write('quit\n')

        os.kill(I.eca.pid, signal.SIGTERM)
                
        signal.signal(signal.SIGALRM, handler)
        signal.alarm(2)
        
        try:
            return I.eca.wait()
        except:
            pass
        
        signal.alarm(0)
        os.kill(I.eca.pid, signal.SIGKILL)
        
        
    def command(I,cmd):
        """Issue an EIAM command"""
        
        cmd=string.strip(cmd)
        if cmd:
            I._cmd=cmd
            I.eca.stdin.write(cmd+'\n')
            return I._parse_response()
        
    def command_float_arg(I,cmd,f=None):
        """Issue an EIAM command
        
        This function can be used instead of command(string), 
        if the command in question requires exactly one numerical parameter."""
        
        cmd=string.strip(cmd)
        if cmd:
            I._cmd=cmd
            if f:
                    I.eca.stdin.write('%s %f\n' % (cmd,f))
            else:
                    I.eca.stdin.write(cmd+'\n')
            return I._parse_response()
            
    def error(I):
        """Return true if error has occured during the execution of last EIAM command"""
        
        if I._type=='e': return 1
        
    def last_error(I):
        """Return a string describing the last error"""
        
        if I.error():
            return I._resp.get('e')
        else: 
            return ''
        
    def last_float(I):
        """Return the last floating-point return value"""
        return I._resp.get('f')
    
    def last_integer(I):
        """Return the last integer return value
        
        This function is also used to return boolean values."""
        return I._resp.get('i')
    
    def last_long_integer(I):
        """Return the last long integer return value
        
        Long integers are used to pass values like 'length_in_samples' 
        and 'length_in_bytes'.  It's implementation specific whether there's 
        any real difference between integers and long integers."""
        return I._resp.get('li')
    
    def last_string(I):
        """Return the last string return value"""
        return I._resp.get('s')
    
    def last_string_list(I):
        """Return the last collection of strings (one or more strings)"""
        return I._resp.get('S')
    
    def last_type(I):
        return I._type
    
    def current_event(I):
        """** not implemented **"""
        pass
    def events_available(I): 
        """** not implemented **"""
        pass
    def next_event(I): 
        """** not implemented **"""
        pass


def handler(*args):
    print 'AARGH!'
    raise Exception, 'killing me not so softly'

expand=re.compile('256 ([0-9]{1,5}) (.+)\r\n(.*)\r\n\r\n.*', re.MULTILINE | re.S)

def expand_eiam_response(st):
    """Checks wheter 'str' is a valid EIAM response.

    @return Regex match object.
    """

    m = expand.search(st)
    return m

parse=re.compile('256 ([0-9]{1,5}) (.+)\r\n(.*)', re.MULTILINE | re.S)

def parse_eiam_response(st, m=None):
    """Parses a valid EIAM response.

    @param m Valid regex match object.
    @param str The whole EIAM response.

    @return tuple of return value type and value
    """

    if not m:
        m = parse.search(st)
        if not m:
            return ()

    if m and len(m.groups()) == 0:
        #print "(pyeca) Matching groups failed: %s" % str(m.groups())
        return ('e','Matching groups failed')

    if m and len(m.groups()) == 3:
        #print 'received=', len(m.group(3)), ', expected=', m.group(1)
        if int(m.group(1)) != len(m.group(3)):
            print '(pyeca) Response length error. Received ', len(m.group(3)), ', expected for ', m.group(1), '.'
            #print 'g=', m.group(3)
            return ('e', 'Response length error.')

    if m:
        return (m.group(2), m.group(3))

    return ('e','')


class base:
    def __init__(I, eci, cmd):
        I.eci=eci
        I.cmd=string.replace(cmd, '_', '-')

    def __call__(I):
        return I.eci(I.cmd)

class string_argument(base):
    def __call__(I, s):
        return I.eci('%s %s' % (I.cmd,s))

class EIAM:
    def __init__(I, verbose=0):
        I._eci=ECA_CONTROL_INTERFACE(verbose)
        I._cmds=I._eci('int-cmd-list')

        for c in I._cmds:
            c=string.replace(c, '-', '_')
            if string.count(c, 'add') \
            or string.count(c, 'select'):
                I.__dict__[c]=string_argument(I._eci,c)
            else:
                I.__dict__[c]=base(I._eci,c)

def main():
    e=ECA_CONTROL_INTERFACE()
    print e.command('c-add huppaa')
    print e.command('c-list')

    print e("""

    c-list
    c-status
    """)

    print e.cleanup()

if __name__ == '__main__':
    main()