"""
Linked layer structure.
"""
from __future__ import absolute_import, unicode_literals
import attr
import io
import logging
from psd_tools.constants import LinkedLayerType
from psd_tools.psd.base import BaseElement, ListElement
from psd_tools.psd.descriptor import DescriptorBlock
from psd_tools.validators import in_, range_
from psd_tools.utils import (
read_fmt, write_fmt, read_length_block, write_length_block, is_readable,
write_bytes, read_unicode_string, write_unicode_string, read_pascal_string,
write_pascal_string, write_padding
)
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, lambda f: item.write(f), 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