import sys, py, os

def wrapper(func_to_run):
    def f(frame, event, arg):
        func_to_run()
        return f
    return f

def run_with_tracing(f, func_to_run, args=()):
    sys.settrace(wrapper(func_to_run))
    f(*args)
    sys.settrace(None)

def trace_in_another_process(filename, source_code, func_name, measure_func,
                             executable, args=()):
    source = py.code.Source(source_code, """
    import sys
    sys.path.insert(0, '%s')
    from tracer import run_with_tracing

    def write():
        sys.stdout.write('c')
        sys.stdout.flush()
        sys.stdin.read(1)

    if __name__ == '__main__':
        run_with_tracing(%s, write, %s)
        sys.stdout.write('F')
        sys.stdout.flush()
    """ % (py.magic.autopath().dirpath(), func_name, args))

    f = py.path.local(filename)
    f.write(source)
    cmd = "%s -u %s" % (executable, f)
    stdout, stdin = os.popen2(cmd)
    while 1:
        ch = stdin.read(1)
        if ch == 'F':
            break
        assert ch == 'c'
        stdout.write('c')
        stdout.flush()
        measure_func()