compare-db.py

# Copyright (C) 2012 Red Hat, Inc.
# Authors: Jan Kaluza <jkaluza@redhat.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
# USA.

"""Compare contents of db with output from other version of file(1)."""

from __future__ import print_function

import sys
import mutex
from pyfile import *
from pyfile.threadpool import *


def compare_all_files(file_name='file', magdir='Magdir', exact=False):
    """
    Compares all saved file(1) output in db with that of other file(1) version.

    Creates a ThreadPool to do this in parallel. Uses a mutex lock to ensure
    that text output is not garbled.
    """
    n_threads = 4
    pool = ThreadPool(n_threads)
    print_lock = mutex.mutex()

    split_patterns(magdir, file_name)
    compile_patterns(file_name)
    compiled = is_compilation_supported(file_name)

    entries = get_stored_files("db")

    def store_mimedata(entry):
        """For a single db entry, calls file(1) and compares it to db data."""
        metadata = get_full_metadata(entry, file_name, compiled)
        stored_metadata = get_stored_metadata(entry)
        text = "PASS " + entry
        if is_regression(stored_metadata, metadata, exact):
            text = "FAIL " + entry + "\n" + \
                   get_diff(stored_metadata, metadata, exact)
        return text

    def data_print(data):
        """Print result for single entry and unlock print lock."""
        print(data)
        print_lock.unlock()

    def data_stored(data):
        """Call data_print as soon as print lock has been acquired."""
        print_lock.lock(data_print, data)

    for entry in entries:
        # Insert tasks into the queue and let them run
        pool.queueTask(store_mimedata, args=(entry, ),
                       callback=data_stored)

    # When all tasks are finished, allow the threads to terminate
    pool.joinAll()
    print('')


def main():
    """Parse arguments, call :py:func:`compare_all_files`."""
    file_name = 'file'
    magdir = "Magdir"
    exact = False

    if len(sys.argv) >= 3:
        file_name = sys.argv[1]
        magdir = sys.argv[2]
    elif (len(sys.argv) == 2 and sys.argv[1] == "-h") or len(sys.argv) == 1:
        print("Compares files in database with output of current file binary.")
        print(sys.argv[0] + " [path_to_magdir_directory] [file_name]")
        print("  Default path_to_magdir_directory='Magdir'")
        print("  Default file_name='file'")
        print("Examples:")
        print("  " + sys.argv[0] + " file-5.07;")
        print("  " + sys.argv[0] + " file-5.07 file-5.04/magic/Magdir;")
        sys.exit(0)

    if magdir == "exact":
        exact = True
        magdir = "Magdir"

    if len(sys.argv) == 4 and sys.argv[3] == "exact":
        exact = True

    file_name = sys.argv[1]
    compare_all_files(file_name, magdir, exact)


# run this only if started as script from command line
if __name__ == '__main__':
    main()