RadonMetrics/CodeMetricsCalculator.py

# -*- coding: utf-8 -*-

# Copyright (c) 2015 Detlev Offenbach <detlev@die-offenbachs.de>
#

from __future__ import unicode_literals

try:
    str = unicode       # __IGNORE_EXCEPTION __IGNORE_WARNING__
except NameError:
    pass

import multiprocessing


def initService():
    """
    Initialize the service and return the entry point.
    
    @return the entry point for the background client (function)
    """
    return codeMetrics


def initBatchService():
    """
    Initialize the batch service and return the entry point.
    
    @return the entry point for the background client (function)
    """
    return batchCodeMetrics


def codeMetrics(file, text="", type_=""):
    """
    Private function to calculate selected code metrics of one file.
    
    @param file source filename
    @type str
    @param text source text
    @param str
    @return tuple containing the filename and the result list
    @rtype (str, list)
    """
    if type_ == "raw":
        return __rawCodeMetrics(file, text)
    elif type_ == "mi":
        return __maintainabilityIndex(file, text)
    
    res = {"error": "Unknown metrics '{0}'.".format(type_)}
    return (res, )


def batchCodeMetrics(argumentsList, send, fx, cancelled):
    """
    Module function to calculate selected code metrics for a batch of files.
    
    @param argumentsList list of arguments tuples as given for check
    @type list
    @param send reference to send function
    @type function
    @param fx registered service name
    @type str
    @param cancelled reference to function checking for a cancellation
    @type function
    """
    try:
        NumberOfProcesses = multiprocessing.cpu_count()
        if NumberOfProcesses >= 1:
            NumberOfProcesses -= 1
    except NotImplementedError:
        NumberOfProcesses = 1

    # Create queues
    taskQueue = multiprocessing.Queue()
    doneQueue = multiprocessing.Queue()

    # Submit tasks (initially two time number of processes
    initialTasks = 2 * NumberOfProcesses
    for task in argumentsList[:initialTasks]:
        taskQueue.put(task)

    # Start worker processes
    for i in range(NumberOfProcesses):
        multiprocessing.Process(target=worker, args=(taskQueue, doneQueue))\
            .start()

    # Get and send results
    endIndex = len(argumentsList) - initialTasks
    for i in range(len(argumentsList)):
        filename, result = doneQueue.get()
        send(fx, filename, result)
        if cancelled():
            # just exit the loop ignoring the results of queued tasks
            break
        if i < endIndex:
            taskQueue.put(argumentsList[i + initialTasks])

    # Tell child processes to stop
    for i in range(NumberOfProcesses):
        taskQueue.put('STOP')


def worker(input, output):
    """
    Module function acting as the parallel worker for the style check.
    
    @param input input queue
    @type multiprocessing.Queue
    @param output output queue
    @type multiprocessing.Queue
    """
    for filename, source, type_ in iter(input.get, 'STOP'):
        if type_ == "raw":
            result = __rawCodeMetrics(filename, source)
        elif type_ == "mi":
            result = __maintainabilityIndex(filename, source)
        else:
            result = {}
        output.put((filename, result))


def __rawCodeMetrics(file, text=""):
    """
    Private function to calculate the raw code metrics for one Python file.
    
    @param file source filename
    @type str
    @param text source text
    @type str
    @return tuple containing the result dictionary
    @rtype (tuple of dict)
    """
    from radon.raw import analyze
    try:
        res = __raw2Dict(analyze(text))
    except Exception as err:
        res = {"error": str(err)}
    return (res, )


def __raw2Dict(obj):
    """
    Private function to convert an object holding raw analysis results into a
    dictionary.
    
    @param obj object as returned from analyze()
    @type radon.raw.Module
    @return conversion result
    @rtype dict
    """
    result = {}
    for a in obj._fields:
        v = getattr(obj, a, None)
        if v is not None:
            result[a] = v
    return result


def __maintainabilityIndex(file, text=""):
    """
    Private function to calculate the maintainability index for one Python
    file.
    
    @param file source filename
    @type str
    @param text source text
    @type str
    @return tuple containing the result dictionary
    @rtype (tuple of dict)
    """
    from radon.metrics import mi_visit, mi_rank
    try:
        mi = mi_visit(text)
        rank = mi_rank(mi)
        res = {"mi": mi, "rank": rank}
    except Exception as err:
        res = {"error": str(err)}
    return (res, )