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##

""" Source code coverage report

    This module tracks source code coverage if requried modules are installed.
    Coverage tracking is disabled when the `coverage` library is missing.
"""

import contextlib

try:
    import coverage
    COVERAGE_ENABLED = True
except ImportError:
    COVERAGE_ENABLED = False


def cov_start():
    """ Start coverage tracking. """

    if not COVERAGE_ENABLED:
        return None

    cov = coverage.Coverage(auto_data=True)
    cov.load()
    cov.start()

    return cov

def cov_stop(cov):
    """ Stop coverage tracking. """

    if not cov:
        return

    cov.stop()
    cov.save()

def cov_html(directory):
    """ Produce HRML report from current coverage data. """

    if not COVERAGE_ENABLED:
        print("Coverage module not installed.")
        return

    cov = coverage.Coverage(auto_data=True)
    cov.load()
    cov.html_report(directory=directory,
                    include=[
                        '*/lldbmacros/*'
                    ],
                    omit=[
                        '*/lldbmacros/tests/*'
                    ])


class CoverageContext(contextlib.AbstractContextManager):
    """ Coverage tracking context manager. """

    def __init__(self):
        self._cov = None

    def __enter__(self):
        self._cov = cov_start()
        return super().__enter__()

    def __exit__(self, __exc_type, __exc_value, __traceback):
        cov_stop(self._cov)
        return super().__exit__(__exc_type, __exc_value, __traceback)