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python3.2  3.2.2
Public Member Functions | Public Attributes | Private Member Functions | Private Attributes | Static Private Attributes
_pyio.BufferedWriter Class Reference
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List of all members.

Public Member Functions

def __init__
def write
def truncate
def flush
 Flush and close ###.
def tell
def seek
 Positioning ###.
def close
def detach
def seekable
 Inquiries ###.
def readable
def writable
def raw
def closed
def name
def mode
def __getstate__
def __repr__
def fileno
 Lower-level APIs ###.
def isatty
def read
def read1
def readinto
def __enter__
 Context manager ###.
def __exit__
def readline
 Readline[s] and writelines ###.
def __iter__
def __next__
def readlines
def writelines
def __new__
def register
def __instancecheck__
def __subclasscheck__

Public Attributes

 buffer_size

Private Member Functions

def _flush_unlocked

Private Attributes

 _write_buf
 _write_lock

Static Private Attributes

int _warning_stack_offset = 2

Detailed Description

A buffer for a writeable sequential RawIO object.

The constructor creates a BufferedWriter for the given writeable raw
stream. If the buffer_size is not given, it defaults to
DEFAULT_BUFFER_SIZE.

Definition at line 1048 of file _pyio.py.


Constructor & Destructor Documentation

def _pyio.BufferedWriter.__init__ (   self,
  raw,
  buffer_size = DEFAULT_BUFFER_SIZE,
  max_buffer_size = None 
)

Reimplemented in _pyio.BufferedRandom.

Definition at line 1060 of file _pyio.py.

01060 
01061                  buffer_size=DEFAULT_BUFFER_SIZE, max_buffer_size=None):
01062         if not raw.writable():
01063             raise IOError('"raw" argument must be writable.')
01064 
01065         _BufferedIOMixin.__init__(self, raw)
01066         if buffer_size <= 0:
01067             raise ValueError("invalid buffer size")
01068         if max_buffer_size is not None:
01069             warnings.warn("max_buffer_size is deprecated", DeprecationWarning,
01070                           self._warning_stack_offset)
01071         self.buffer_size = buffer_size
01072         self._write_buf = bytearray()
01073         self._write_lock = Lock()

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Member Function Documentation

def _pyio.IOBase.__enter__ (   self) [inherited]

Context manager ###.

Context management protocol.  Returns self (an instance of IOBase).

Definition at line 419 of file _pyio.py.

00419 
00420     def __enter__(self):  # That's a forward reference
00421         """Context management protocol.  Returns self (an instance of IOBase)."""
00422         self._checkClosed()
00423         return self

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def _pyio.IOBase.__exit__ (   self,
  args 
) [inherited]
Context management protocol.  Calls close()

Definition at line 424 of file _pyio.py.

00424 
00425     def __exit__(self, *args):
00426         """Context management protocol.  Calls close()"""
00427         self.close()

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def _pyio._BufferedIOMixin.__getstate__ (   self) [inherited]

Definition at line 761 of file _pyio.py.

00761 
00762     def __getstate__(self):
00763         raise TypeError("can not serialize a '{0}' object"
00764                         .format(self.__class__.__name__))

def abc.ABCMeta.__instancecheck__ (   cls,
  instance 
) [inherited]
Override for isinstance(instance, cls).

Definition at line 158 of file abc.py.

00158 
00159     def __instancecheck__(cls, instance):
00160         """Override for isinstance(instance, cls)."""
00161         # Inline the cache checking
00162         subclass = instance.__class__
00163         if subclass in cls._abc_cache:
00164             return True
00165         subtype = type(instance)
00166         if subtype is subclass:
00167             if (cls._abc_negative_cache_version ==
00168                 ABCMeta._abc_invalidation_counter and
00169                 subclass in cls._abc_negative_cache):
00170                 return False
00171             # Fall back to the subclass check.
00172             return cls.__subclasscheck__(subclass)
00173         return any(cls.__subclasscheck__(c) for c in {subclass, subtype})

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def _pyio.IOBase.__iter__ (   self) [inherited]

Definition at line 486 of file _pyio.py.

00486 
00487     def __iter__(self):
00488         self._checkClosed()
00489         return self

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def abc.ABCMeta.__new__ (   mcls,
  name,
  bases,
  namespace 
) [inherited]

Definition at line 116 of file abc.py.

00116 
00117     def __new__(mcls, name, bases, namespace):
00118         cls = super().__new__(mcls, name, bases, namespace)
00119         # Compute set of abstract method names
00120         abstracts = {name
00121                      for name, value in namespace.items()
00122                      if getattr(value, "__isabstractmethod__", False)}
00123         for base in bases:
00124             for name in getattr(base, "__abstractmethods__", set()):
00125                 value = getattr(cls, name, None)
00126                 if getattr(value, "__isabstractmethod__", False):
00127                     abstracts.add(name)
00128         cls.__abstractmethods__ = frozenset(abstracts)
00129         # Set up inheritance registry
00130         cls._abc_registry = WeakSet()
00131         cls._abc_cache = WeakSet()
00132         cls._abc_negative_cache = WeakSet()
00133         cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
00134         return cls

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def _pyio.IOBase.__next__ (   self) [inherited]

Reimplemented in _pyio.TextIOWrapper.

Definition at line 490 of file _pyio.py.

00490 
00491     def __next__(self):
00492         line = self.readline()
00493         if not line:
00494             raise StopIteration
00495         return line

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def _pyio._BufferedIOMixin.__repr__ (   self) [inherited]

Definition at line 765 of file _pyio.py.

00765 
00766     def __repr__(self):
00767         clsname = self.__class__.__name__
00768         try:
00769             name = self.name
00770         except AttributeError:
00771             return "<_pyio.{0}>".format(clsname)
00772         else:
00773             return "<_pyio.{0} name={1!r}>".format(clsname, name)

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def abc.ABCMeta.__subclasscheck__ (   cls,
  subclass 
) [inherited]
Override for issubclass(subclass, cls).

Definition at line 174 of file abc.py.

00174 
00175     def __subclasscheck__(cls, subclass):
00176         """Override for issubclass(subclass, cls)."""
00177         # Check cache
00178         if subclass in cls._abc_cache:
00179             return True
00180         # Check negative cache; may have to invalidate
00181         if cls._abc_negative_cache_version < ABCMeta._abc_invalidation_counter:
00182             # Invalidate the negative cache
00183             cls._abc_negative_cache = WeakSet()
00184             cls._abc_negative_cache_version = ABCMeta._abc_invalidation_counter
00185         elif subclass in cls._abc_negative_cache:
00186             return False
00187         # Check the subclass hook
00188         ok = cls.__subclasshook__(subclass)
00189         if ok is not NotImplemented:
00190             assert isinstance(ok, bool)
00191             if ok:
00192                 cls._abc_cache.add(subclass)
00193             else:
00194                 cls._abc_negative_cache.add(subclass)
00195             return ok
00196         # Check if it's a direct subclass
00197         if cls in getattr(subclass, '__mro__', ()):
00198             cls._abc_cache.add(subclass)
00199             return True
00200         # Check if it's a subclass of a registered class (recursive)
00201         for rcls in cls._abc_registry:
00202             if issubclass(subclass, rcls):
00203                 cls._abc_cache.add(subclass)
00204                 return True
00205         # Check if it's a subclass of a subclass (recursive)
00206         for scls in cls.__subclasses__():
00207             if issubclass(subclass, scls):
00208                 cls._abc_cache.add(subclass)
00209                 return True
00210         # No dice; update negative cache
00211         cls._abc_negative_cache.add(subclass)
00212         return False

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def _pyio.BufferedWriter._flush_unlocked (   self) [private]

Definition at line 1117 of file _pyio.py.

01117 
01118     def _flush_unlocked(self):
01119         if self.closed:
01120             raise ValueError("flush of closed file")
01121         written = 0
01122         try:
01123             while self._write_buf:
01124                 try:
01125                     n = self.raw.write(self._write_buf)
01126                 except IOError as e:
01127                     if e.errno != EINTR:
01128                         raise
01129                     continue
01130                 if n > len(self._write_buf) or n < 0:
01131                     raise IOError("write() returned incorrect number of bytes")
01132                 del self._write_buf[:n]
01133                 written += n
01134         except BlockingIOError as e:
01135             n = e.characters_written
01136             del self._write_buf[:n]
01137             written += n
01138             raise BlockingIOError(e.errno, e.strerror, written)

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def _pyio._BufferedIOMixin.close (   self) [inherited]
Flush and close the IO object.

This method has no effect if the file is already closed.

Reimplemented from _pyio.IOBase.

Definition at line 721 of file _pyio.py.

00721 
00722     def close(self):
00723         if self.raw is not None and not self.closed:
00724             self.flush()
00725             self.raw.close()

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def _pyio._BufferedIOMixin.closed (   self) [inherited]
closed: bool.  True iff the file has been closed.

For backwards compatibility, this is a property, not a predicate.

Reimplemented from _pyio.IOBase.

Definition at line 750 of file _pyio.py.

00750 
00751     def closed(self):
00752         return self.raw.closed

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def _pyio._BufferedIOMixin.detach (   self) [inherited]
Separate the underlying raw stream from the buffer and return it.

After the raw stream has been detached, the buffer is in an unusable
state.

Reimplemented from _pyio.BufferedIOBase.

Definition at line 726 of file _pyio.py.

00726 
00727     def detach(self):
00728         if self.raw is None:
00729             raise ValueError("raw stream already detached")
00730         self.flush()
00731         raw = self._raw
00732         self._raw = None
00733         return raw

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def _pyio._BufferedIOMixin.fileno (   self) [inherited]

Lower-level APIs ###.

Reimplemented from _pyio.IOBase.

Definition at line 776 of file _pyio.py.

00776 
00777     def fileno(self):
00778         return self.raw.fileno()

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Flush and close ###.

Reimplemented from _pyio._BufferedIOMixin.

Definition at line 1113 of file _pyio.py.

01113 
01114     def flush(self):
01115         with self._write_lock:
01116             self._flush_unlocked()

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def _pyio._BufferedIOMixin.isatty (   self) [inherited]
Return a bool indicating whether this is an 'interactive' stream.

Return False if it can't be determined.

Reimplemented from _pyio.IOBase.

Definition at line 779 of file _pyio.py.

00779 
00780     def isatty(self):
00781         return self.raw.isatty()
00782 

def _pyio._BufferedIOMixin.mode (   self) [inherited]

Definition at line 758 of file _pyio.py.

00758 
00759     def mode(self):
00760         return self.raw.mode

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def _pyio._BufferedIOMixin.name (   self) [inherited]

Definition at line 754 of file _pyio.py.

00754 
00755     def name(self):
00756         return self.raw.name

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def _pyio._BufferedIOMixin.raw (   self) [inherited]

Definition at line 746 of file _pyio.py.

00746 
00747     def raw(self):
00748         return self._raw

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def _pyio.BufferedIOBase.read (   self,
  n = None 
) [inherited]
Read and return up to n bytes, where n is an int.

If the argument is omitted, None, or negative, reads and
returns all data until EOF.

If the argument is positive, and the underlying raw stream is
not 'interactive', multiple raw reads may be issued to satisfy
the byte count (unless EOF is reached first).  But for
interactive raw streams (XXX and for pipes?), at most one raw
read will be issued, and a short result does not imply that
EOF is imminent.

Returns an empty bytes array on EOF.

Raises BlockingIOError if the underlying raw stream has no
data at the moment.

Reimplemented in _pyio.BufferedRandom, _pyio.BufferedRWPair, _pyio.BufferedReader, and _pyio.BytesIO.

Definition at line 604 of file _pyio.py.

00604 
00605     def read(self, n=None):
00606         """Read and return up to n bytes, where n is an int.
00607 
00608         If the argument is omitted, None, or negative, reads and
00609         returns all data until EOF.
00610 
00611         If the argument is positive, and the underlying raw stream is
00612         not 'interactive', multiple raw reads may be issued to satisfy
00613         the byte count (unless EOF is reached first).  But for
00614         interactive raw streams (XXX and for pipes?), at most one raw
00615         read will be issued, and a short result does not imply that
00616         EOF is imminent.
00617 
00618         Returns an empty bytes array on EOF.
00619 
00620         Raises BlockingIOError if the underlying raw stream has no
00621         data at the moment.
00622         """
00623         self._unsupported("read")

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def _pyio.BufferedIOBase.read1 (   self,
  n = None 
) [inherited]
Read up to n bytes with at most one read() system call,
where n is an int.

Reimplemented in _pyio.BufferedRandom, _pyio.BufferedRWPair, _pyio.BufferedReader, and _pyio.BytesIO.

Definition at line 624 of file _pyio.py.

00624 
00625     def read1(self, n=None):
00626         """Read up to n bytes with at most one read() system call,
00627         where n is an int.
00628         """
00629         self._unsupported("read1")

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def _pyio._BufferedIOMixin.readable (   self) [inherited]
Return a bool indicating whether object was opened for reading.

If False, read() will raise UnsupportedOperation.

Reimplemented from _pyio.IOBase.

Definition at line 739 of file _pyio.py.

00739 
00740     def readable(self):
00741         return self.raw.readable()

def _pyio.BufferedIOBase.readinto (   self,
  b 
) [inherited]
Read up to len(b) bytes into bytearray b.

Like read(), this may issue multiple reads to the underlying raw
stream, unless the latter is 'interactive'.

Returns an int representing the number of bytes read (0 for EOF).

Raises BlockingIOError if the underlying raw stream has no
data at the moment.

Reimplemented in _pyio.BufferedRandom, and _pyio.BufferedRWPair.

Definition at line 630 of file _pyio.py.

00630 
00631     def readinto(self, b):
00632         """Read up to len(b) bytes into bytearray b.
00633 
00634         Like read(), this may issue multiple reads to the underlying raw
00635         stream, unless the latter is 'interactive'.
00636 
00637         Returns an int representing the number of bytes read (0 for EOF).
00638 
00639         Raises BlockingIOError if the underlying raw stream has no
00640         data at the moment.
00641         """
00642         # XXX This ought to work with anything that supports the buffer API
00643         data = self.read(len(b))
00644         n = len(data)
00645         try:
00646             b[:n] = data
00647         except TypeError as err:
00648             import array
00649             if not isinstance(b, array.array):
00650                 raise err
00651             b[:n] = array.array('b', data)
00652         return n

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def _pyio.IOBase.readline (   self,
  limit = -1 
) [inherited]

Readline[s] and writelines ###.

Reimplemented in _pyio.TextIOWrapper.

Definition at line 449 of file _pyio.py.

00449 
00450     def readline(self, limit=-1):
00451         r"""Read and return a line of bytes from the stream.
00452 
00453         If limit is specified, at most limit bytes will be read.
00454         Limit should be an int.
00455 
00456         The line terminator is always b'\n' for binary files; for text
00457         files, the newlines argument to open can be used to select the line
00458         terminator(s) recognized.
00459         """
00460         # For backwards compatibility, a (slowish) readline().
00461         if hasattr(self, "peek"):
00462             def nreadahead():
00463                 readahead = self.peek(1)
00464                 if not readahead:
00465                     return 1
00466                 n = (readahead.find(b"\n") + 1) or len(readahead)
00467                 if limit >= 0:
00468                     n = min(n, limit)
00469                 return n
00470         else:
00471             def nreadahead():
00472                 return 1
00473         if limit is None:
00474             limit = -1
00475         elif not isinstance(limit, int):
00476             raise TypeError("limit must be an integer")
00477         res = bytearray()
00478         while limit < 0 or len(res) < limit:
00479             b = self.read(nreadahead())
00480             if not b:
00481                 break
00482             res += b
00483             if res.endswith(b"\n"):
00484                 break
00485         return bytes(res)

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def _pyio.IOBase.readlines (   self,
  hint = None 
) [inherited]
Return a list of lines from the stream.

hint can be specified to control the number of lines read: no more
lines will be read if the total size (in bytes/characters) of all
lines so far exceeds hint.

Definition at line 496 of file _pyio.py.

00496 
00497     def readlines(self, hint=None):
00498         """Return a list of lines from the stream.
00499 
00500         hint can be specified to control the number of lines read: no more
00501         lines will be read if the total size (in bytes/characters) of all
00502         lines so far exceeds hint.
00503         """
00504         if hint is None or hint <= 0:
00505             return list(self)
00506         n = 0
00507         lines = []
00508         for line in self:
00509             lines.append(line)
00510             n += len(line)
00511             if n >= hint:
00512                 break
00513         return lines

def abc.ABCMeta.register (   cls,
  subclass 
) [inherited]
Register a virtual subclass of an ABC.

Definition at line 135 of file abc.py.

00135 
00136     def register(cls, subclass):
00137         """Register a virtual subclass of an ABC."""
00138         if not isinstance(subclass, type):
00139             raise TypeError("Can only register classes")
00140         if issubclass(subclass, cls):
00141             return  # Already a subclass
00142         # Subtle: test for cycles *after* testing for "already a subclass";
00143         # this means we allow X.register(X) and interpret it as a no-op.
00144         if issubclass(cls, subclass):
00145             # This would create a cycle, which is bad for the algorithm below
00146             raise RuntimeError("Refusing to create an inheritance cycle")
00147         cls._abc_registry.add(subclass)
00148         ABCMeta._abc_invalidation_counter += 1  # Invalidate negative cache

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def _pyio.BufferedWriter.seek (   self,
  pos,
  whence = 0 
)

Positioning ###.

Reimplemented from _pyio._BufferedIOMixin.

Reimplemented in _pyio.BufferedRandom.

Definition at line 1142 of file _pyio.py.

01142 
01143     def seek(self, pos, whence=0):
01144         if not (0 <= whence <= 2):
01145             raise ValueError("invalid whence")
01146         with self._write_lock:
01147             self._flush_unlocked()
01148             return _BufferedIOMixin.seek(self, pos, whence)
01149 

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def _pyio._BufferedIOMixin.seekable (   self) [inherited]

Inquiries ###.

Reimplemented from _pyio.IOBase.

Definition at line 736 of file _pyio.py.

00736 
00737     def seekable(self):
00738         return self.raw.seekable()

def _pyio.BufferedWriter.tell (   self)
Return an int indicating the current stream position.

Reimplemented from _pyio._BufferedIOMixin.

Reimplemented in _pyio.BufferedRandom.

Definition at line 1139 of file _pyio.py.

01139 
01140     def tell(self):
01141         return _BufferedIOMixin.tell(self) + len(self._write_buf)

def _pyio.BufferedWriter.truncate (   self,
  pos = None 
)
Truncate file to size bytes.

Size defaults to the current IO position as reported by tell().  Return
the new size.

Reimplemented from _pyio._BufferedIOMixin.

Reimplemented in _pyio.BufferedRandom.

Definition at line 1106 of file _pyio.py.

01106 
01107     def truncate(self, pos=None):
01108         with self._write_lock:
01109             self._flush_unlocked()
01110             if pos is None:
01111                 pos = self.raw.tell()
01112             return self.raw.truncate(pos)

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def _pyio._BufferedIOMixin.writable (   self) [inherited]
Return a bool indicating whether object was opened for writing.

If False, write() and truncate() will raise UnsupportedOperation.

Reimplemented from _pyio.IOBase.

Definition at line 742 of file _pyio.py.

00742 
00743     def writable(self):
00744         return self.raw.writable()

def _pyio.BufferedWriter.write (   self,
  b 
)
Write the given bytes buffer to the IO stream.

Return the number of bytes written, which is never less than
len(b).

Raises BlockingIOError if the buffer is full and the
underlying raw stream cannot accept more data at the moment.

Reimplemented from _pyio.BufferedIOBase.

Reimplemented in _pyio.BufferedRandom.

Definition at line 1074 of file _pyio.py.

01074 
01075     def write(self, b):
01076         if self.closed:
01077             raise ValueError("write to closed file")
01078         if isinstance(b, str):
01079             raise TypeError("can't write str to binary stream")
01080         with self._write_lock:
01081             # XXX we can implement some more tricks to try and avoid
01082             # partial writes
01083             if len(self._write_buf) > self.buffer_size:
01084                 # We're full, so let's pre-flush the buffer
01085                 try:
01086                     self._flush_unlocked()
01087                 except BlockingIOError as e:
01088                     # We can't accept anything else.
01089                     # XXX Why not just let the exception pass through?
01090                     raise BlockingIOError(e.errno, e.strerror, 0)
01091             before = len(self._write_buf)
01092             self._write_buf.extend(b)
01093             written = len(self._write_buf) - before
01094             if len(self._write_buf) > self.buffer_size:
01095                 try:
01096                     self._flush_unlocked()
01097                 except BlockingIOError as e:
01098                     if len(self._write_buf) > self.buffer_size:
01099                         # We've hit the buffer_size. We have to accept a partial
01100                         # write and cut back our buffer.
01101                         overage = len(self._write_buf) - self.buffer_size
01102                         written -= overage
01103                         self._write_buf = self._write_buf[:self.buffer_size]
01104                         raise BlockingIOError(e.errno, e.strerror, written)
01105             return written

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def _pyio.IOBase.writelines (   self,
  lines 
) [inherited]

Definition at line 514 of file _pyio.py.

00514 
00515     def writelines(self, lines):
00516         self._checkClosed()
00517         for line in lines:
00518             self.write(line)
00519 
00520 io.IOBase.register(IOBase)
00521 


Member Data Documentation

Reimplemented in _pyio.BufferedRandom.

Definition at line 1057 of file _pyio.py.

Definition at line 1071 of file _pyio.py.

Definition at line 1072 of file _pyio.py.

Definition at line 1070 of file _pyio.py.


The documentation for this class was generated from the following file: