gecko-dev/dom/base/usecounters.py

# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

import buildconfig
import collections
import re
from six import StringIO
import sys

def read_conf(conf_filename):
    # Can't read/write from a single StringIO, so make a new one for reading.
    stream = open(conf_filename, 'rU')

    def parse_counters(stream):
        for line_num, line in enumerate(stream):
            line = line.rstrip('\n')
            if not line or line.startswith('//'):
                # empty line or comment
                continue
            m = re.match(r'method ([A-Za-z0-9]+)\.([A-Za-z0-9]+)$', line)
            if m:
                interface_name, method_name = m.groups()
                yield { 'type': 'method',
                        'interface_name': interface_name,
                        'method_name': method_name }
                continue
            m = re.match(r'attribute ([A-Za-z0-9]+)\.([A-Za-z0-9]+)$', line)
            if m:
                interface_name, attribute_name = m.groups()
                yield { 'type': 'attribute',
                        'interface_name': interface_name,
                        'attribute_name': attribute_name }
                continue
            m = re.match(r'custom ([A-Za-z0-9_]+) (.*)$', line)
            if m:
                name, desc = m.groups()
                yield { 'type': 'custom',
                        'name': name,
                        'desc': desc }
                continue
            raise ValueError('error parsing %s at line %d' % (conf_filename, line_num))

    return parse_counters(stream)

def generate_histograms(filename, is_for_worker=False):
    # The mapping for use counters to telemetry histograms depends on the
    # ordering of items in the dictionary.

    # The ordering of the ending for workers depends on the WorkerType defined
    # in WorkerPrivate.h.
    endings = ["DEDICATED_WORKER", "SHARED_WORKER", "SERVICE_WORKER"] if is_for_worker else ["DOCUMENT", "PAGE"]

    items = collections.OrderedDict()
    for counter in read_conf(filename):
        def append_counter(name, desc):
            items[name] = { 'expires_in_version': 'never',
                            'kind' : 'boolean',
                            'description': desc }

        def append_counters(name, desc):
            for ending in endings:
                append_counter('USE_COUNTER2_%s_%s' % (name, ending),
                               'Whether a %s %s' % (ending.replace('_', ' ').lower(), desc))

        if counter['type'] == 'method':
            method = '%s.%s' % (counter['interface_name'], counter['method_name'])
            append_counters(method.replace('.', '_').upper(), 'called %s' % method)
        elif counter['type'] == 'attribute':
            attr = '%s.%s' % (counter['interface_name'], counter['attribute_name'])
            counter_name = attr.replace('.', '_').upper()
            append_counters('%s_getter' % counter_name, 'got %s' % attr)
            append_counters('%s_setter' % counter_name, 'set %s' % attr)
        elif counter['type'] == 'custom':
            append_counters(counter['name'].upper(), counter['desc'])

    return items