mirror of
https://github.com/janeczku/calibre-web
synced 2024-11-17 15:24:53 +00:00
347 lines
10 KiB
Python
347 lines
10 KiB
Python
# -*- coding: utf-8 -*-
|
|
r"""
|
|
werkzeug.contrib.iterio
|
|
~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
This module implements a :class:`IterIO` that converts an iterator into
|
|
a stream object and the other way round. Converting streams into
|
|
iterators requires the `greenlet`_ module.
|
|
|
|
To convert an iterator into a stream all you have to do is to pass it
|
|
directly to the :class:`IterIO` constructor. In this example we pass it
|
|
a newly created generator::
|
|
|
|
def foo():
|
|
yield "something\n"
|
|
yield "otherthings"
|
|
stream = IterIO(foo())
|
|
print stream.read() # read the whole iterator
|
|
|
|
The other way round works a bit different because we have to ensure that
|
|
the code execution doesn't take place yet. An :class:`IterIO` call with a
|
|
callable as first argument does two things. The function itself is passed
|
|
an :class:`IterIO` stream it can feed. The object returned by the
|
|
:class:`IterIO` constructor on the other hand is not an stream object but
|
|
an iterator::
|
|
|
|
def foo(stream):
|
|
stream.write("some")
|
|
stream.write("thing")
|
|
stream.flush()
|
|
stream.write("otherthing")
|
|
iterator = IterIO(foo)
|
|
print iterator.next() # prints something
|
|
print iterator.next() # prints otherthing
|
|
iterator.next() # raises StopIteration
|
|
|
|
.. _greenlet: http://codespeak.net/py/dist/greenlet.html
|
|
|
|
:copyright: (c) 2013 by the Werkzeug Team, see AUTHORS for more details.
|
|
:license: BSD, see LICENSE for more details.
|
|
"""
|
|
try:
|
|
import greenlet
|
|
except ImportError:
|
|
greenlet = None
|
|
|
|
from werkzeug._compat import implements_iterator
|
|
|
|
|
|
def _mixed_join(iterable, sentinel):
|
|
"""concatenate any string type in an intelligent way."""
|
|
iterator = iter(iterable)
|
|
first_item = next(iterator, sentinel)
|
|
if isinstance(first_item, bytes):
|
|
return first_item + b''.join(iterator)
|
|
return first_item + u''.join(iterator)
|
|
|
|
|
|
def _newline(reference_string):
|
|
if isinstance(reference_string, bytes):
|
|
return b'\n'
|
|
return u'\n'
|
|
|
|
|
|
@implements_iterator
|
|
class IterIO(object):
|
|
"""Instances of this object implement an interface compatible with the
|
|
standard Python :class:`file` object. Streams are either read-only or
|
|
write-only depending on how the object is created.
|
|
|
|
If the first argument is an iterable a file like object is returned that
|
|
returns the contents of the iterable. In case the iterable is empty
|
|
read operations will return the sentinel value.
|
|
|
|
If the first argument is a callable then the stream object will be
|
|
created and passed to that function. The caller itself however will
|
|
not receive a stream but an iterable. The function will be be executed
|
|
step by step as something iterates over the returned iterable. Each
|
|
call to :meth:`flush` will create an item for the iterable. If
|
|
:meth:`flush` is called without any writes in-between the sentinel
|
|
value will be yielded.
|
|
|
|
Note for Python 3: due to the incompatible interface of bytes and
|
|
streams you should set the sentinel value explicitly to an empty
|
|
bytestring (``b''``) if you are expecting to deal with bytes as
|
|
otherwise the end of the stream is marked with the wrong sentinel
|
|
value.
|
|
|
|
.. versionadded:: 0.9
|
|
`sentinel` parameter was added.
|
|
"""
|
|
|
|
def __new__(cls, obj, sentinel=''):
|
|
try:
|
|
iterator = iter(obj)
|
|
except TypeError:
|
|
return IterI(obj, sentinel)
|
|
return IterO(iterator, sentinel)
|
|
|
|
def __iter__(self):
|
|
return self
|
|
|
|
def tell(self):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
return self.pos
|
|
|
|
def isatty(self):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
return False
|
|
|
|
def seek(self, pos, mode=0):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
raise IOError(9, 'Bad file descriptor')
|
|
|
|
def truncate(self, size=None):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
raise IOError(9, 'Bad file descriptor')
|
|
|
|
def write(self, s):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
raise IOError(9, 'Bad file descriptor')
|
|
|
|
def writelines(self, list):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
raise IOError(9, 'Bad file descriptor')
|
|
|
|
def read(self, n=-1):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
raise IOError(9, 'Bad file descriptor')
|
|
|
|
def readlines(self, sizehint=0):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
raise IOError(9, 'Bad file descriptor')
|
|
|
|
def readline(self, length=None):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
raise IOError(9, 'Bad file descriptor')
|
|
|
|
def flush(self):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
raise IOError(9, 'Bad file descriptor')
|
|
|
|
def __next__(self):
|
|
if self.closed:
|
|
raise StopIteration()
|
|
line = self.readline()
|
|
if not line:
|
|
raise StopIteration()
|
|
return line
|
|
|
|
|
|
class IterI(IterIO):
|
|
"""Convert an stream into an iterator."""
|
|
|
|
def __new__(cls, func, sentinel=''):
|
|
if greenlet is None:
|
|
raise RuntimeError('IterI requires greenlet support')
|
|
stream = object.__new__(cls)
|
|
stream._parent = greenlet.getcurrent()
|
|
stream._buffer = []
|
|
stream.closed = False
|
|
stream.sentinel = sentinel
|
|
stream.pos = 0
|
|
|
|
def run():
|
|
func(stream)
|
|
stream.close()
|
|
|
|
g = greenlet.greenlet(run, stream._parent)
|
|
while 1:
|
|
rv = g.switch()
|
|
if not rv:
|
|
return
|
|
yield rv[0]
|
|
|
|
def close(self):
|
|
if not self.closed:
|
|
self.closed = True
|
|
self._flush_impl()
|
|
|
|
def write(self, s):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
if s:
|
|
self.pos += len(s)
|
|
self._buffer.append(s)
|
|
|
|
def writelines(self, list):
|
|
for item in list:
|
|
self.write(item)
|
|
|
|
def flush(self):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
self._flush_impl()
|
|
|
|
def _flush_impl(self):
|
|
data = _mixed_join(self._buffer, self.sentinel)
|
|
self._buffer = []
|
|
if not data and self.closed:
|
|
self._parent.switch()
|
|
else:
|
|
self._parent.switch((data,))
|
|
|
|
|
|
class IterO(IterIO):
|
|
"""Iter output. Wrap an iterator and give it a stream like interface."""
|
|
|
|
def __new__(cls, gen, sentinel=''):
|
|
self = object.__new__(cls)
|
|
self._gen = gen
|
|
self._buf = None
|
|
self.sentinel = sentinel
|
|
self.closed = False
|
|
self.pos = 0
|
|
return self
|
|
|
|
def __iter__(self):
|
|
return self
|
|
|
|
def _buf_append(self, string):
|
|
'''Replace string directly without appending to an empty string,
|
|
avoiding type issues.'''
|
|
if not self._buf:
|
|
self._buf = string
|
|
else:
|
|
self._buf += string
|
|
|
|
def close(self):
|
|
if not self.closed:
|
|
self.closed = True
|
|
if hasattr(self._gen, 'close'):
|
|
self._gen.close()
|
|
|
|
def seek(self, pos, mode=0):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
if mode == 1:
|
|
pos += self.pos
|
|
elif mode == 2:
|
|
self.read()
|
|
self.pos = min(self.pos, self.pos + pos)
|
|
return
|
|
elif mode != 0:
|
|
raise IOError('Invalid argument')
|
|
buf = []
|
|
try:
|
|
tmp_end_pos = len(self._buf)
|
|
while pos > tmp_end_pos:
|
|
item = self._gen.next()
|
|
tmp_end_pos += len(item)
|
|
buf.append(item)
|
|
except StopIteration:
|
|
pass
|
|
if buf:
|
|
self._buf_append(_mixed_join(buf, self.sentinel))
|
|
self.pos = max(0, pos)
|
|
|
|
def read(self, n=-1):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
if n < 0:
|
|
self._buf_append(_mixed_join(self._gen, self.sentinel))
|
|
result = self._buf[self.pos:]
|
|
self.pos += len(result)
|
|
return result
|
|
new_pos = self.pos + n
|
|
buf = []
|
|
try:
|
|
tmp_end_pos = 0 if self._buf is None else len(self._buf)
|
|
while new_pos > tmp_end_pos or (self._buf is None and not buf):
|
|
item = next(self._gen)
|
|
tmp_end_pos += len(item)
|
|
buf.append(item)
|
|
except StopIteration:
|
|
pass
|
|
if buf:
|
|
self._buf_append(_mixed_join(buf, self.sentinel))
|
|
|
|
if self._buf is None:
|
|
return self.sentinel
|
|
|
|
new_pos = max(0, new_pos)
|
|
try:
|
|
return self._buf[self.pos:new_pos]
|
|
finally:
|
|
self.pos = min(new_pos, len(self._buf))
|
|
|
|
def readline(self, length=None):
|
|
if self.closed:
|
|
raise ValueError('I/O operation on closed file')
|
|
|
|
nl_pos = -1
|
|
if self._buf:
|
|
nl_pos = self._buf.find(_newline(self._buf), self.pos)
|
|
buf = []
|
|
try:
|
|
pos = self.pos
|
|
while nl_pos < 0:
|
|
item = next(self._gen)
|
|
local_pos = item.find(_newline(item))
|
|
buf.append(item)
|
|
if local_pos >= 0:
|
|
nl_pos = pos + local_pos
|
|
break
|
|
pos += len(item)
|
|
except StopIteration:
|
|
pass
|
|
if buf:
|
|
self._buf_append(_mixed_join(buf, self.sentinel))
|
|
|
|
if self._buf is None:
|
|
return self.sentinel
|
|
|
|
if nl_pos < 0:
|
|
new_pos = len(self._buf)
|
|
else:
|
|
new_pos = nl_pos + 1
|
|
if length is not None and self.pos + length < new_pos:
|
|
new_pos = self.pos + length
|
|
try:
|
|
return self._buf[self.pos:new_pos]
|
|
finally:
|
|
self.pos = min(new_pos, len(self._buf))
|
|
|
|
def readlines(self, sizehint=0):
|
|
total = 0
|
|
lines = []
|
|
line = self.readline()
|
|
while line:
|
|
lines.append(line)
|
|
total += len(line)
|
|
if 0 < sizehint <= total:
|
|
break
|
|
line = self.readline()
|
|
return lines
|