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eyeD3 / src / eyed3 / core.py

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# -*- coding: utf-8 -*-
################################################################################
#  Copyright (C) 2012  Travis Shirk <travis@pobox.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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
################################################################################
'''Basic core types and utilities.'''
import os
import time
from . import Exception, LOCAL_FS_ENCODING
from .utils import guessMimetype

import logging
log = logging.getLogger(__name__)

AUDIO_NONE = 0
'''Audio type selecter for no audio.'''
AUDIO_MP3  = 1
'''Audio type selecter for mpeg (mp3) audio.'''

AUDIO_TYPES = (AUDIO_NONE, AUDIO_MP3)


def load(path, tag_version=None):
    '''Loads the file identified by ``path`` and returns a concrete type of
    :class:`eyed3.core.AudioFile`. If ``path`` is not a file an ``IOError`` is
    raised. ``None`` is returned when the file type (i.e. mime-type) is not
    recognized.
    The following AudioFile types are supported:

      * :class:`eyed3.mp3.Mp3AudioFile` - For mp3 audio files.
      * :class:`eyed3.id3.TagFile` - For raw ID3 data files.

    If ``tag_version`` is not None (the default) only a specific version of
    metadata is loaded. This value must be a version constant specific to the
    eventual format of the metadata.
    '''
    from . import mp3, id3
    log.info("Loading file: %s" % path)

    if os.path.exists(path):
        if not os.path.isfile(path):
            raise IOError("not a file: %s" % path)
    else:
        raise IOError("file not found: %s" % path)

    mtype = guessMimetype(path)
    if mtype in mp3.MIME_TYPES:
        return mp3.Mp3AudioFile(path, tag_version)
    elif mtype == "application/x-id3":
        return id3.TagFile(path, tag_version)
    else:
        return None


class AudioInfo(object):
    '''A base container for common audio details.'''
    time_secs  = 0
    '''The number of seconds of audio data (i.e., the playtime)'''
    size_bytes = 0
    '''The number of bytes of audio data.'''


class Tag(object):
    '''An abstract interface for audio tag (meta) data (e.g. artist, title,
    etc.)'''

    def _setArtist(self, val):
        raise NotImplementedError
    def _getArtist(self):
        raise NotImplementedError

    def _setAlbum(self, val):
        raise NotImplementedError
    def _getAlbum(self):
        raise NotImplementedError

    def _setTitle(self, val):
        raise NotImplementedError
    def _getTitle(self):
        raise NotImplementedError

    def _setTrackNum(self, val):
        raise NotImplementedError
    def _getTrackNum(self):
        raise NotImplementedError

    @property
    def artist(self):
        return self._getArtist()
    @artist.setter
    def artist(self, v):
        self._setArtist(v)

    @property
    def album(self):
        return self._getAlbum()
    @album.setter
    def album(self, v):
        self._setAlbum(v)

    @property
    def title(self):
        return self._getTitle()
    @title.setter
    def title(self, v):
        self._setTitle(v)

    @property
    def track_num(self):
        '''Track number property.
        Must return a 2-tuple of (track-number, total-number-of-tracks).
        Either tuple value may be ``None``.
        '''
        return self._getTrackNum()
    @track_num.setter
    def track_num(self, v):
        self._setTrackNum(v)


class AudioFile(object):
    '''Abstract base class for audio file types (AudioInfo + Tag)'''

    def _read(self):
        '''Subclasses MUST override this method and set ``self._info``,
        ``self._tag`` and ``self.type``.
        '''
        raise NotImplementedError()

    def rename(self, name, fsencoding=LOCAL_FS_ENCODING):
        '''Rename the file to ``name``.
        The encoding used for the file name is :attr:`eyed3.LOCAL_FS_ENCODING`
        unless overridden by ``fsencoding``. Note, if the target file already
        exists, or the full path contains non-existent directories the
        operation will fail with :class:`eyed3.Exception`.'''
        base = os.path.basename(self.path)
        base_ext = os.path.splitext(base)[1]
        dir = os.path.dirname(self.path)
        if not dir:
            dir = u'.'

        new_name = u"%s%s" % (os.path.join(dir, name), base_ext)
        if os.path.exists(new_name):
            raise IOError("File '%s' exists, will not overwrite" % new_name)
        elif not os.path.exists(os.path.dirname(new_name)):
            raise IOError("Target directory '%s' does not exists, will not "
                          "create" % os.path.dirname(new_name))

        os.rename(self.path, new_name)
        self.path = new_name

    @property
    def path(self):
        '''The absolute path of this file.'''
        return self._path
    @path.setter
    def path(self, t):
        '''Set the path'''
        from os.path import abspath, realpath, normpath
        self._path = normpath(realpath(abspath(t)))
    @property
    def info(self):
        '''Returns a concrete implemenation of :class:`eyed3.core.AudioInfo`'''
        return self._info
    @property
    def tag(self):
        '''Returns a concrete implemenation of :class:`eyed3.core.Tag`'''
        return self._tag
    @tag.setter
    def tag(self, t):
        self._tag = t

    def __init__(self, path):
        '''Construct with a path and invoke ``_read``.
        All other members are set to None.'''
        self.path = path

        self.type = None
        self._info = None
        self._tag = None
        self._read()


class Date(object):
    '''
    A class for representing a date and time (optional). This class differs
    from ``datetime.datetime`` in that the default values for month, day,
    hour, minute, and second is ``None`` and not 'January 1, 00:00:00'.
    This allows for an object that is simply 1987, and not January 1 12AM,
    for example.
    '''

    TIME_STAMP_FORMATS = ["%Y",
                          "%Y-%m",
                          "%Y-%m-%d",
                          "%Y-%m-%dT%H",
                          "%Y-%m-%dT%H:%M",
                          "%Y-%m-%dT%H:%M:%S",
                          # The following end with 'Z' signally time is UTC
                          "%Y-%m-%dT%HZ",
                          "%Y-%m-%dT%H:%MZ",
                          "%Y-%m-%dT%H:%M:%SZ",
                          # The following are wrong per the specs, but ...
                          "%Y-%m-%d %H:%M:%S",
                          "%Y-00-00",
                         ]
    '''Valid time stamp formats per ISO 8601 and used by \c strptime.'''

    def __init__(self, year, month=None, day=None,
                 hour=None, minute=None, second=None):
        # Validate with datetime
        from datetime import datetime
        _ = datetime(year, month if month is not None else 1,
                     day if day is not None else 1,
                     hour if hour is not None else 0,
                     minute if minute is not None else 0,
                     second if second is not None else 0)

        self._year = year
        self._month = month
        self._day = day
        self._hour = hour
        self._minute = minute
        self._second = second

        # Python's date classes do a lot more date validation than does not
        # need to be duplicated here.  Validate it
        _ = Date._validateFormat(str(self))

    @property
    def year(self):
        return self._year
    @property
    def month(self):
        return self._month
    @property
    def day(self):
        return self._day
    @property
    def hour(self):
        return self._hour
    @property
    def minute(self):
        return self._minute
    @property
    def second(self):
        return self._second

    def __eq__(self, rhs):
        return (self.year == rhs.year and
                self.month == rhs.month and
                self.day == rhs.day and
                self.hour == rhs.hour and
                self.minute == rhs.minute and
                self.second == rhs.second)

    @staticmethod
    def _validateFormat(s):
        pdate = None
        for fmt in Date.TIME_STAMP_FORMATS:
            try:
                pdate = time.strptime(s, fmt)
                break
            except ValueError:
                # date string did not match format.
                continue

        if pdate is None:
            raise ValueError("Invalid date string: %s" % s)

        assert(pdate)
        return pdate, fmt

    @staticmethod
    def parse(s):
        s = s.strip('\x00')

        pdate, fmt = Date._validateFormat(s)

        # Here is the difference with Python date/datetime objects, some
        # of the members can be None
        kwargs = {}
        if "%m" in fmt:
            kwargs["month"] = pdate.tm_mon
        if "%d" in fmt:
            kwargs["day"] = pdate.tm_mday
        if "%H" in fmt:
            kwargs["hour"] = pdate.tm_hour
        if "%M" in fmt:
            kwargs["minute"] = pdate.tm_min
        if "%S" in fmt:
            kwargs["second"] = pdate.tm_sec

        return Date(pdate.tm_year, **kwargs)

    def __str__(self):
        s = "%d" % self.year
        if self.month:
            s += "-%s" % str(self.month).rjust(2, '0')
            if self.day:
                s += "-%s" % str(self.day).rjust(2, '0')
                if self.hour is not None:
                    s += "T%s" % str(self.hour).rjust(2, '0')
                    if self.minute is not None:
                        s += ":%s" % str(self.minute).rjust(2, '0')
                        if self.second is not None:
                            s += ":%s" % str(self.second).rjust(2, '0')
        return s

    def __unicode__(self):
        return unicode(str(self), "latin1")


def parseError(ex):
    log.warning(ex)