Source code for psd_tools.psd.linked_layer

"""
Linked layer structure.
"""

from __future__ import absolute_import, unicode_literals

import io
import logging

import attr

from psd_tools.constants import LinkedLayerType
from psd_tools.psd.base import BaseElement, ListElement
from psd_tools.psd.descriptor import DescriptorBlock
from psd_tools.utils import (
    is_readable,
    read_fmt,
    read_length_block,
    read_pascal_string,
    read_unicode_string,
    write_bytes,
    write_fmt,
    write_length_block,
    write_padding,
    write_pascal_string,
    write_unicode_string,
)
from psd_tools.validators import in_, range_

logger = logging.getLogger(__name__)


[docs] class LinkedLayers(ListElement): """ List of LinkedLayer structure. See :py:class:`.LinkedLayer`. """ @classmethod def read(cls, fp, **kwargs): items = [] while is_readable(fp, 8): data = read_length_block(fp, fmt="Q", padding=4) with io.BytesIO(data) as f: items.append(LinkedLayer.read(f)) return cls(items) def write(self, fp, **kwargs): written = 0 for item in self: written += write_length_block(fp, item.write, fmt="Q", padding=4) return written
[docs] @attr.s(repr=False, slots=True) class LinkedLayer(BaseElement): """ LinkedLayer structure. .. py:attribute:: kind .. py:attribute:: version .. py:attribute:: uuid .. py:attribute:: filename .. py:attribute:: filetype .. py:attribute:: creator .. py:attribute:: filesize .. py:attribute:: open_file .. py:attribute:: linked_file .. py:attribute:: timestamp .. py:attribute:: data .. py:attribute:: child_id .. py:attribute:: mod_time .. py:attribute:: lock_state """ kind = attr.ib(default=LinkedLayerType.ALIAS, validator=in_(LinkedLayerType)) version = attr.ib(default=1, validator=range_(1, 7)) uuid = attr.ib(default="", type=str) filename = attr.ib(default="", type=str) filetype = attr.ib(default=b"\x00\x00\x00\x00", type=bytes) creator = attr.ib(default=b"\x00\x00\x00\x00", type=bytes) filesize = attr.ib(default=None) open_file = attr.ib(default=None) linked_file = attr.ib(default=None) timestamp = attr.ib(default=None) data = attr.ib(default=None) child_id = attr.ib(default=None) mod_time = attr.ib(default=None) lock_state = attr.ib(default=None) @classmethod def read(cls, fp, **kwargs): kind = LinkedLayerType(read_fmt("4s", fp)[0]) version = read_fmt("I", fp)[0] assert 1 <= version and version <= 7, "Invalid version %d" % (version) uuid = read_pascal_string(fp, "macroman", padding=1) filename = read_unicode_string(fp) filetype, creator, datasize, open_file = read_fmt("4s4sQB", fp) if open_file: open_file = DescriptorBlock.read(fp, padding=1) else: open_file = None linked_file = None timestamp = None data = None filesize = None child_id = None mod_time = None lock_state = None if kind == LinkedLayerType.EXTERNAL: linked_file = DescriptorBlock.read(fp, padding=1) if version > 3: timestamp = read_fmt("I4Bd", fp) filesize = read_fmt("Q", fp)[0] # External file size. if version > 2: data = fp.read(datasize) elif kind == LinkedLayerType.ALIAS: read_fmt("8x", fp) if kind == LinkedLayerType.DATA: data = fp.read(datasize) assert len(data) == datasize, "(%d vs %d)" % (len(data), datasize) # The followings are not well documented... if version >= 5: child_id = read_unicode_string(fp) if version >= 6: mod_time = read_fmt("d", fp)[0] if version >= 7: lock_state = read_fmt("B", fp)[0] if kind == LinkedLayerType.EXTERNAL and version == 2: data = fp.read(datasize) return cls( kind, version, uuid, filename, filetype, creator, filesize, open_file, linked_file, timestamp, data, child_id, mod_time, lock_state, ) def write(self, fp, padding=1, **kwargs): written = write_fmt(fp, "4sI", self.kind.value, self.version) written += write_pascal_string(fp, self.uuid, "macroman", padding=1) written += write_unicode_string(fp, self.filename) written += write_fmt( fp, "4s4sQB", self.filetype, self.creator, len(self.data) if self.data is not None else 0, self.open_file is not None, ) if self.open_file is not None: written += self.open_file.write(fp, padding=1) if self.kind == LinkedLayerType.EXTERNAL: written += self.linked_file.write(fp, padding=1) if self.version > 3: written += write_fmt(fp, "I4Bd", *self.timestamp) written += write_fmt(fp, "Q", self.filesize) if self.version > 2: written += write_bytes(fp, self.data) elif self.kind == LinkedLayerType.ALIAS: written += write_fmt(fp, "8x") if self.kind == LinkedLayerType.DATA: written += write_bytes(fp, self.data) if self.child_id is not None: written += write_unicode_string(fp, self.child_id) if self.mod_time is not None: written += write_fmt(fp, "d", self.mod_time) if self.lock_state is not None: written += write_fmt(fp, "B", self.lock_state) if self.kind == LinkedLayerType.EXTERNAL and self.version == 2: written += write_bytes(fp, self.data) written += write_padding(fp, written, padding) return written