[Jython-checkins] jython: Pulled CPython io.py from CPython 2.6 and added a bunch of _. This should all
frank.wierzbicki
jython-checkins at python.org
Thu Mar 15 21:39:34 CET 2012
http://hg.python.org/jython/rev/415132e13a2b
changeset: 6393:415132e13a2b
user: Frank Wierzbicki <fwierzbicki at gmail.com>
date: Thu Mar 15 13:39:25 2012 -0700
summary:
Pulled CPython io.py from CPython 2.6 and added a bunch of _. This should all
get reimplented in Java at some point.
files:
Lib/_io.py | 1908 ++++++++++++++++++++++++++++++++++++++++
1 files changed, 1908 insertions(+), 0 deletions(-)
diff --git a/Lib/_io.py b/Lib/_io.py
new file mode 100644
--- /dev/null
+++ b/Lib/_io.py
@@ -0,0 +1,1908 @@
+"""
+XXX: This is actually io.py pulled from CPython 2.6 with the addition of some _
+onto the names of types. Eventually we should implement this stuff in Java.
+
+The _io module provides the Python interfaces to stream handling. The
+builtin open function is defined in this module.
+
+At the top of the I/O hierarchy is the abstract base class _IOBase. It
+defines the basic interface to a stream. Note, however, that there is no
+separation between reading and writing to streams; implementations are
+allowed to throw an IOError if they do not support a given operation.
+
+Extending _IOBase is _RawIOBase which deals simply with the reading and
+writing of raw bytes to a stream. FileIO subclasses _RawIOBase to provide
+an interface to OS files.
+
+_BufferedIOBase deals with buffering on a raw byte stream (_RawIOBase). Its
+subclasses, BufferedWriter, BufferedReader, and BufferedRWPair buffer
+streams that are readable, writable, and both respectively.
+BufferedRandom provides a buffered interface to random access
+streams. BytesIO is a simple stream of in-memory bytes.
+
+Another _IOBase subclass, _TextIOBase, deals with the encoding and decoding
+of streams into text. TextIOWrapper, which extends it, is a buffered text
+interface to a buffered raw stream (`_BufferedIOBase`). Finally, StringIO
+is a in-memory stream for text.
+
+Argument names are not part of the specification, and only the arguments
+of open() are intended to be used as keyword arguments.
+
+data:
+
+DEFAULT_BUFFER_SIZE
+
+ An int containing the default buffer size used by the module's buffered
+ I/O classes. open() uses the file's blksize (as obtained by os.stat) if
+ possible.
+"""
+# New I/O library conforming to PEP 3116.
+
+# This is a prototype; hopefully eventually some of this will be
+# reimplemented in C.
+
+# XXX edge cases when switching between reading/writing
+# XXX need to support 1 meaning line-buffered
+# XXX whenever an argument is None, use the default value
+# XXX read/write ops should check readable/writable
+# XXX buffered readinto should work with arbitrary buffer objects
+# XXX use incremental encoder for text output, at least for UTF-16 and UTF-8-SIG
+# XXX check writable, readable and seekable in appropriate places
+from __future__ import print_function
+from __future__ import unicode_literals
+
+__author__ = ("Guido van Rossum <guido at python.org>, "
+ "Mike Verdone <mike.verdone at gmail.com>, "
+ "Mark Russell <mark.russell at zen.co.uk>")
+
+__all__ = ["BlockingIOError", "open", "_IOBase", "_RawIOBase", "FileIO",
+ "BytesIO", "StringIO", "_BufferedIOBase",
+ "BufferedReader", "BufferedWriter", "BufferedRWPair",
+ "BufferedRandom", "_TextIOBase", "TextIOWrapper"]
+
+import os
+import abc
+import codecs
+import _fileio
+import threading
+
+# open() uses st_blksize whenever we can
+DEFAULT_BUFFER_SIZE = 8 * 1024 # bytes
+
+# py3k has only new style classes
+__metaclass__ = type
+
+class BlockingIOError(IOError):
+
+ """Exception raised when I/O would block on a non-blocking I/O stream."""
+
+ def __init__(self, errno, strerror, characters_written=0):
+ IOError.__init__(self, errno, strerror)
+ self.characters_written = characters_written
+
+
+def open(file, mode="r", buffering=None, encoding=None, errors=None,
+ newline=None, closefd=True):
+ r"""Open file and return a stream. If the file cannot be opened, an IOError is
+ raised.
+
+ file is either a string giving the name (and the path if the file
+ isn't in the current working directory) of the file to be opened or an
+ integer file descriptor of the file to be wrapped. (If a file
+ descriptor is given, it is closed when the returned I/O object is
+ closed, unless closefd is set to False.)
+
+ mode is an optional string that specifies the mode in which the file
+ is opened. It defaults to 'r' which means open for reading in text
+ mode. Other common values are 'w' for writing (truncating the file if
+ it already exists), and 'a' for appending (which on some Unix systems,
+ means that all writes append to the end of the file regardless of the
+ current seek position). In text mode, if encoding is not specified the
+ encoding used is platform dependent. (For reading and writing raw
+ bytes use binary mode and leave encoding unspecified.) The available
+ modes are:
+
+ ========= ===============================================================
+ Character Meaning
+ --------- ---------------------------------------------------------------
+ 'r' open for reading (default)
+ 'w' open for writing, truncating the file first
+ 'a' open for writing, appending to the end of the file if it exists
+ 'b' binary mode
+ 't' text mode (default)
+ '+' open a disk file for updating (reading and writing)
+ 'U' universal newline mode (for backwards compatibility; unneeded
+ for new code)
+ ========= ===============================================================
+
+ The default mode is 'rt' (open for reading text). For binary random
+ access, the mode 'w+b' opens and truncates the file to 0 bytes, while
+ 'r+b' opens the file without truncation.
+
+ Python distinguishes between files opened in binary and text modes,
+ even when the underlying operating system doesn't. Files opened in
+ binary mode (appending 'b' to the mode argument) return contents as
+ bytes objects without any decoding. In text mode (the default, or when
+ 't' is appended to the mode argument), the contents of the file are
+ returned as strings, the bytes having been first decoded using a
+ platform-dependent encoding or using the specified encoding if given.
+
+ buffering is an optional integer used to set the buffering policy.
+ Pass 0 to switch buffering off (only allowed in binary mode), 1 to select
+ line buffering (only usable in text mode), and an integer > 1 to indicate
+ the size of a fixed-size chunk buffer. When no buffering argument is
+ given, the default buffering policy works as follows:
+
+ * Binary files are buffered in fixed-size chunks; the size of the buffer
+ is chosen using a heuristic trying to determine the underlying device's
+ "block size" and falling back on `_io.DEFAULT_BUFFER_SIZE`.
+ On many systems, the buffer will typically be 4096 or 8192 bytes long.
+
+ * "Interactive" text files (files for which isatty() returns True)
+ use line buffering. Other text files use the policy described above
+ for binary files.
+
+ encoding is the name of the encoding used to decode or encode the
+ file. This should only be used in text mode. The default encoding is
+ platform dependent, but any encoding supported by Python can be
+ passed. See the codecs module for the list of supported encodings.
+
+ errors is an optional string that specifies how encoding errors are to
+ be handled---this argument should not be used in binary mode. Pass
+ 'strict' to raise a ValueError exception if there is an encoding error
+ (the default of None has the same effect), or pass 'ignore' to ignore
+ errors. (Note that ignoring encoding errors can lead to data loss.)
+ See the documentation for codecs.register for a list of the permitted
+ encoding error strings.
+
+ newline controls how universal newlines works (it only applies to text
+ mode). It can be None, '', '\n', '\r', and '\r\n'. It works as
+ follows:
+
+ * On input, if newline is None, universal newlines mode is
+ enabled. Lines in the input can end in '\n', '\r', or '\r\n', and
+ these are translated into '\n' before being returned to the
+ caller. If it is '', universal newline mode is enabled, but line
+ endings are returned to the caller untranslated. If it has any of
+ the other legal values, input lines are only terminated by the given
+ string, and the line ending is returned to the caller untranslated.
+
+ * On output, if newline is None, any '\n' characters written are
+ translated to the system default line separator, os.linesep. If
+ newline is '', no translation takes place. If newline is any of the
+ other legal values, any '\n' characters written are translated to
+ the given string.
+
+ If closefd is False, the underlying file descriptor will be kept open
+ when the file is closed. This does not work when a file name is given
+ and must be True in that case.
+
+ open() returns a file object whose type depends on the mode, and
+ through which the standard file operations such as reading and writing
+ are performed. When open() is used to open a file in a text mode ('w',
+ 'r', 'wt', 'rt', etc.), it returns a TextIOWrapper. When used to open
+ a file in a binary mode, the returned class varies: in read binary
+ mode, it returns a BufferedReader; in write binary and append binary
+ modes, it returns a BufferedWriter, and in read/write mode, it returns
+ a BufferedRandom.
+
+ It is also possible to use a string or bytearray as a file for both
+ reading and writing. For strings StringIO can be used like a file
+ opened in a text mode, and for bytes a BytesIO can be used like a file
+ opened in a binary mode.
+ """
+ if not isinstance(file, (basestring, int)):
+ raise TypeError("invalid file: %r" % file)
+ if not isinstance(mode, basestring):
+ raise TypeError("invalid mode: %r" % mode)
+ if buffering is not None and not isinstance(buffering, int):
+ raise TypeError("invalid buffering: %r" % buffering)
+ if encoding is not None and not isinstance(encoding, basestring):
+ raise TypeError("invalid encoding: %r" % encoding)
+ if errors is not None and not isinstance(errors, basestring):
+ raise TypeError("invalid errors: %r" % errors)
+ modes = set(mode)
+ if modes - set("arwb+tU") or len(mode) > len(modes):
+ raise ValueError("invalid mode: %r" % mode)
+ reading = "r" in modes
+ writing = "w" in modes
+ appending = "a" in modes
+ updating = "+" in modes
+ text = "t" in modes
+ binary = "b" in modes
+ if "U" in modes:
+ if writing or appending:
+ raise ValueError("can't use U and writing mode at once")
+ reading = True
+ if text and binary:
+ raise ValueError("can't have text and binary mode at once")
+ if reading + writing + appending > 1:
+ raise ValueError("can't have read/write/append mode at once")
+ if not (reading or writing or appending):
+ raise ValueError("must have exactly one of read/write/append mode")
+ if binary and encoding is not None:
+ raise ValueError("binary mode doesn't take an encoding argument")
+ if binary and errors is not None:
+ raise ValueError("binary mode doesn't take an errors argument")
+ if binary and newline is not None:
+ raise ValueError("binary mode doesn't take a newline argument")
+ raw = FileIO(file,
+ (reading and "r" or "") +
+ (writing and "w" or "") +
+ (appending and "a" or "") +
+ (updating and "+" or ""),
+ closefd)
+ if buffering is None:
+ buffering = -1
+ line_buffering = False
+ if buffering == 1 or buffering < 0 and raw.isatty():
+ buffering = -1
+ line_buffering = True
+ if buffering < 0:
+ buffering = DEFAULT_BUFFER_SIZE
+ try:
+ bs = os.fstat(raw.fileno()).st_blksize
+ except (os.error, AttributeError):
+ pass
+ else:
+ if bs > 1:
+ buffering = bs
+ if buffering < 0:
+ raise ValueError("invalid buffering size")
+ if buffering == 0:
+ if binary:
+ return raw
+ raise ValueError("can't have unbuffered text I/O")
+ if updating:
+ buffer = BufferedRandom(raw, buffering)
+ elif writing or appending:
+ buffer = BufferedWriter(raw, buffering)
+ elif reading:
+ buffer = BufferedReader(raw, buffering)
+ else:
+ raise ValueError("unknown mode: %r" % mode)
+ if binary:
+ return buffer
+ text = TextIOWrapper(buffer, encoding, errors, newline, line_buffering)
+ text.mode = mode
+ return text
+
+class _DocDescriptor:
+ """Helper for builtins.open.__doc__
+ """
+ def __get__(self, obj, typ):
+ return (
+ "open(file, mode='r', buffering=None, encoding=None, "
+ "errors=None, newline=None, closefd=True)\n\n" +
+ open.__doc__)
+
+class OpenWrapper:
+ """Wrapper for builtins.open
+
+ Trick so that open won't become a bound method when stored
+ as a class variable (as dumbdbm does).
+
+ See initstdio() in Python/pythonrun.c.
+ """
+ __doc__ = _DocDescriptor()
+
+ def __new__(cls, *args, **kwargs):
+ return open(*args, **kwargs)
+
+
+class UnsupportedOperation(ValueError, IOError):
+ pass
+
+
+class _IOBase(object):
+
+ """The abstract base class for all I/O classes, acting on streams of
+ bytes. There is no public constructor.
+
+ This class provides dummy implementations for many methods that
+ derived classes can override selectively; the default implementations
+ represent a file that cannot be read, written or seeked.
+
+ Even though _IOBase does not declare read, readinto, or write because
+ their signatures will vary, implementations and clients should
+ consider those methods part of the interface. Also, implementations
+ may raise a IOError when operations they do not support are called.
+
+ The basic type used for binary data read from or written to a file is
+ bytes. bytearrays are accepted too, and in some cases (such as
+ readinto) needed. Text I/O classes work with str data.
+
+ Note that calling any method (even inquiries) on a closed stream is
+ undefined. Implementations may raise IOError in this case.
+
+ _IOBase (and its subclasses) support the iterator protocol, meaning
+ that an _IOBase object can be iterated over yielding the lines in a
+ stream.
+
+ _IOBase also supports the :keyword:`with` statement. In this example,
+ fp is closed after the suite of the with statment is complete:
+
+ with open('spam.txt', 'r') as fp:
+ fp.write('Spam and eggs!')
+ """
+
+ __metaclass__ = abc.ABCMeta
+
+ ### Internal ###
+
+ def _unsupported(self, name):
+ """Internal: raise an exception for unsupported operations."""
+ raise UnsupportedOperation("%s.%s() not supported" %
+ (self.__class__.__name__, name))
+
+ ### Positioning ###
+
+ def seek(self, pos, whence = 0):
+ """Change stream position.
+
+ Change the stream position to byte offset offset. offset is
+ interpreted relative to the position indicated by whence. Values
+ for whence are:
+
+ * 0 -- start of stream (the default); offset should be zero or positive
+ * 1 -- current stream position; offset may be negative
+ * 2 -- end of stream; offset is usually negative
+
+ Return the new absolute position.
+ """
+ self._unsupported("seek")
+
+ def tell(self):
+ """Return current stream position."""
+ return self.seek(0, 1)
+
+ def truncate(self, pos = None):
+ """Truncate file to size bytes.
+
+ Size defaults to the current IO position as reported by tell(). Return
+ the new size.
+ """
+ self._unsupported("truncate")
+
+ ### Flush and close ###
+
+ def flush(self):
+ """Flush write buffers, if applicable.
+
+ This is not implemented for read-only and non-blocking streams.
+ """
+ if self.__closed:
+ raise ValueError("flush of closed file")
+ #self._checkClosed()
+ # XXX Should this return the number of bytes written???
+
+ __closed = False
+
+ def close(self):
+ """Flush and close the IO object.
+
+ This method has no effect if the file is already closed.
+ """
+ if not self.__closed:
+ self.flush()
+ self.__closed = True
+
+ def __del__(self):
+ """Destructor. Calls close()."""
+ # The try/except block is in case this is called at program
+ # exit time, when it's possible that globals have already been
+ # deleted, and then the close() call might fail. Since
+ # there's nothing we can do about such failures and they annoy
+ # the end users, we suppress the traceback.
+ try:
+ self.close()
+ except:
+ pass
+
+ ### Inquiries ###
+
+ def seekable(self):
+ """Return whether object supports random access.
+
+ If False, seek(), tell() and truncate() will raise IOError.
+ This method may need to do a test seek().
+ """
+ return False
+
+ def _checkSeekable(self, msg=None):
+ """Internal: raise an IOError if file is not seekable
+ """
+ if not self.seekable():
+ raise IOError("File or stream is not seekable."
+ if msg is None else msg)
+
+
+ def readable(self):
+ """Return whether object was opened for reading.
+
+ If False, read() will raise IOError.
+ """
+ return False
+
+ def _checkReadable(self, msg=None):
+ """Internal: raise an IOError if file is not readable
+ """
+ if not self.readable():
+ raise IOError("File or stream is not readable."
+ if msg is None else msg)
+
+ def writable(self):
+ """Return whether object was opened for writing.
+
+ If False, write() and truncate() will raise IOError.
+ """
+ return False
+
+ def _checkWritable(self, msg=None):
+ """Internal: raise an IOError if file is not writable
+ """
+ if not self.writable():
+ raise IOError("File or stream is not writable."
+ if msg is None else msg)
+
+ @property
+ def closed(self):
+ """closed: bool. True iff the file has been closed.
+
+ For backwards compatibility, this is a property, not a predicate.
+ """
+ return self.__closed
+
+ def _checkClosed(self, msg=None):
+ """Internal: raise an ValueError if file is closed
+ """
+ if self.closed:
+ raise ValueError("I/O operation on closed file."
+ if msg is None else msg)
+
+ ### Context manager ###
+
+ def __enter__(self):
+ """Context management protocol. Returns self."""
+ self._checkClosed()
+ return self
+
+ def __exit__(self, *args):
+ """Context management protocol. Calls close()"""
+ self.close()
+
+ ### Lower-level APIs ###
+
+ # XXX Should these be present even if unimplemented?
+
+ def fileno(self):
+ """Returns underlying file descriptor if one exists.
+
+ An IOError is raised if the IO object does not use a file descriptor.
+ """
+ self._unsupported("fileno")
+
+ def isatty(self):
+ """Return whether this is an 'interactive' stream.
+
+ Return False if it can't be determined.
+ """
+ self._checkClosed()
+ return False
+
+ ### Readline[s] and writelines ###
+
+ def readline(self, limit = -1):
+ r"""Read and return a line from the stream.
+
+ If limit is specified, at most limit bytes will be read.
+
+ The line terminator is always b'\n' for binary files; for text
+ files, the newlines argument to open can be used to select the line
+ terminator(s) recognized.
+ """
+ self._checkClosed()
+ if hasattr(self, "peek"):
+ def nreadahead():
+ readahead = self.peek(1)
+ if not readahead:
+ return 1
+ n = (readahead.find(b"\n") + 1) or len(readahead)
+ if limit >= 0:
+ n = min(n, limit)
+ return n
+ else:
+ def nreadahead():
+ return 1
+ if limit is None:
+ limit = -1
+ if not isinstance(limit, (int, long)):
+ raise TypeError("limit must be an integer")
+ res = bytearray()
+ while limit < 0 or len(res) < limit:
+ b = self.read(nreadahead())
+ if not b:
+ break
+ res += b
+ if res.endswith(b"\n"):
+ break
+ return bytes(res)
+
+ def __iter__(self):
+ self._checkClosed()
+ return self
+
+ def next(self):
+ line = self.readline()
+ if not line:
+ raise StopIteration
+ return line
+
+ def readlines(self, hint=None):
+ """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.
+ """
+ if hint is None:
+ hint = -1
+ if not isinstance(hint, (int, long)):
+ raise TypeError("hint must be an integer")
+ if hint <= 0:
+ return list(self)
+ n = 0
+ lines = []
+ for line in self:
+ lines.append(line)
+ n += len(line)
+ if n >= hint:
+ break
+ return lines
+
+ def writelines(self, lines):
+ self._checkClosed()
+ for line in lines:
+ self.write(line)
+
+
+class _RawIOBase(_IOBase):
+
+ """Base class for raw binary I/O."""
+
+ # The read() method is implemented by calling readinto(); derived
+ # classes that want to support read() only need to implement
+ # readinto() as a primitive operation. In general, readinto() can be
+ # more efficient than read().
+
+ # (It would be tempting to also provide an implementation of
+ # readinto() in terms of read(), in case the latter is a more suitable
+ # primitive operation, but that would lead to nasty recursion in case
+ # a subclass doesn't implement either.)
+
+ def read(self, n = -1):
+ """Read and return up to n bytes.
+
+ Returns an empty bytes array on EOF, or None if the object is
+ set not to block and has no data to read.
+ """
+ if n is None:
+ n = -1
+ if n < 0:
+ return self.readall()
+ b = bytearray(n.__index__())
+ n = self.readinto(b)
+ del b[n:]
+ return bytes(b)
+
+ def readall(self):
+ """Read until EOF, using multiple read() call."""
+ res = bytearray()
+ while True:
+ data = self.read(DEFAULT_BUFFER_SIZE)
+ if not data:
+ break
+ res += data
+ return bytes(res)
+
+ def readinto(self, b):
+ """Read up to len(b) bytes into b.
+
+ Returns number of bytes read (0 for EOF), or None if the object
+ is set not to block as has no data to read.
+ """
+ self._unsupported("readinto")
+
+ def write(self, b):
+ """Write the given buffer to the IO stream.
+
+ Returns the number of bytes written, which may be less than len(b).
+ """
+ self._unsupported("write")
+
+
+class FileIO(_fileio._FileIO, _RawIOBase):
+
+ """Raw I/O implementation for OS files."""
+
+ # This multiply inherits from _FileIO and _RawIOBase to make
+ # isinstance(_io.FileIO(), _io._RawIOBase) return True without requiring
+ # that _fileio._FileIO inherits from _io._RawIOBase (which would be hard
+ # to do since _fileio.c is written in C).
+
+ def __init__(self, name, mode="r", closefd=True):
+ _fileio._FileIO.__init__(self, name, mode, closefd)
+ self._name = name
+
+ def close(self):
+ _fileio._FileIO.close(self)
+ _RawIOBase.close(self)
+
+ @property
+ def name(self):
+ return self._name
+
+
+class _BufferedIOBase(_IOBase):
+
+ """Base class for buffered IO objects.
+
+ The main difference with _RawIOBase is that the read() method
+ supports omitting the size argument, and does not have a default
+ implementation that defers to readinto().
+
+ In addition, read(), readinto() and write() may raise
+ BlockingIOError if the underlying raw stream is in non-blocking
+ mode and not ready; unlike their raw counterparts, they will never
+ return None.
+
+ A typical implementation should not inherit from a _RawIOBase
+ implementation, but wrap one.
+ """
+
+ def read(self, n = None):
+ """Read and return up to n bytes.
+
+ 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.
+ """
+ self._unsupported("read")
+
+ def readinto(self, b):
+ """Read up to len(b) bytes into b.
+
+ Like read(), this may issue multiple reads to the underlying raw
+ stream, unless the latter is 'interactive'.
+
+ Returns the number of bytes read (0 for EOF).
+
+ Raises BlockingIOError if the underlying raw stream has no
+ data at the moment.
+ """
+ # XXX This ought to work with anything that supports the buffer API
+ data = self.read(len(b))
+ n = len(data)
+ try:
+ b[:n] = data
+ except TypeError as err:
+ import array
+ if not isinstance(b, array.array):
+ raise err
+ b[:n] = array.array(b'b', data)
+ return n
+
+ def write(self, b):
+ """Write the given 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.
+ """
+ self._unsupported("write")
+
+
+class _BufferedIOMixin(_BufferedIOBase):
+
+ """A mixin implementation of _BufferedIOBase with an underlying raw stream.
+
+ This passes most requests on to the underlying raw stream. It
+ does *not* provide implementations of read(), readinto() or
+ write().
+ """
+
+ def __init__(self, raw):
+ self.raw = raw
+
+ ### Positioning ###
+
+ def seek(self, pos, whence=0):
+ return self.raw.seek(pos, whence)
+
+ def tell(self):
+ return self.raw.tell()
+
+ def truncate(self, pos=None):
+ # Flush the stream. We're mixing buffered I/O with lower-level I/O,
+ # and a flush may be necessary to synch both views of the current
+ # file state.
+ self.flush()
+
+ if pos is None:
+ pos = self.tell()
+ # XXX: Should seek() be used, instead of passing the position
+ # XXX directly to truncate?
+ return self.raw.truncate(pos)
+
+ ### Flush and close ###
+
+ def flush(self):
+ self.raw.flush()
+
+ def close(self):
+ if not self.closed:
+ self.flush()
+ self.raw.close()
+
+ ### Inquiries ###
+
+ def seekable(self):
+ return self.raw.seekable()
+
+ def readable(self):
+ return self.raw.readable()
+
+ def writable(self):
+ return self.raw.writable()
+
+ @property
+ def closed(self):
+ return self.raw.closed
+
+ @property
+ def name(self):
+ return self.raw.name
+
+ @property
+ def mode(self):
+ return self.raw.mode
+
+ ### Lower-level APIs ###
+
+ def fileno(self):
+ return self.raw.fileno()
+
+ def isatty(self):
+ return self.raw.isatty()
+
+
+class _BytesIO(_BufferedIOBase):
+
+ """Buffered I/O implementation using an in-memory bytes buffer."""
+
+ # XXX More docs
+
+ def __init__(self, initial_bytes=None):
+ buf = bytearray()
+ if initial_bytes is not None:
+ buf += bytearray(initial_bytes)
+ self._buffer = buf
+ self._pos = 0
+
+ def getvalue(self):
+ """Return the bytes value (contents) of the buffer
+ """
+ if self.closed:
+ raise ValueError("getvalue on closed file")
+ return bytes(self._buffer)
+
+ def read(self, n=None):
+ if self.closed:
+ raise ValueError("read from closed file")
+ if n is None:
+ n = -1
+ if not isinstance(n, (int, long)):
+ raise TypeError("argument must be an integer")
+ if n < 0:
+ n = len(self._buffer)
+ if len(self._buffer) <= self._pos:
+ return b""
+ newpos = min(len(self._buffer), self._pos + n)
+ b = self._buffer[self._pos : newpos]
+ self._pos = newpos
+ return bytes(b)
+
+ def read1(self, n):
+ """this is the same as read.
+ """
+ return self.read(n)
+
+ def write(self, b):
+ if self.closed:
+ raise ValueError("write to closed file")
+ if isinstance(b, unicode):
+ raise TypeError("can't write unicode to binary stream")
+ n = len(b)
+ if n == 0:
+ return 0
+ pos = self._pos
+ if pos > len(self._buffer):
+ # Inserts null bytes between the current end of the file
+ # and the new write position.
+ padding = b'\x00' * (pos - len(self._buffer))
+ self._buffer += padding
+ self._buffer[pos:pos + n] = b
+ self._pos += n
+ return n
+
+ def seek(self, pos, whence=0):
+ if self.closed:
+ raise ValueError("seek on closed file")
+ try:
+ pos.__index__
+ except AttributeError:
+ raise TypeError("an integer is required") # from err
+ if whence == 0:
+ if pos < 0:
+ raise ValueError("negative seek position %r" % (pos,))
+ self._pos = pos
+ elif whence == 1:
+ self._pos = max(0, self._pos + pos)
+ elif whence == 2:
+ self._pos = max(0, len(self._buffer) + pos)
+ else:
+ raise ValueError("invalid whence value")
+ return self._pos
+
+ def tell(self):
+ if self.closed:
+ raise ValueError("tell on closed file")
+ return self._pos
+
+ def truncate(self, pos=None):
+ if self.closed:
+ raise ValueError("truncate on closed file")
+ if pos is None:
+ pos = self._pos
+ else:
+ try:
+ pos.__index__
+ except AttributeError:
+ raise TypeError("an integer is required")
+ if pos < 0:
+ raise ValueError("negative truncate position %r" % (pos,))
+ del self._buffer[pos:]
+ return pos
+
+ def readable(self):
+ return True
+
+ def writable(self):
+ return True
+
+ def seekable(self):
+ return True
+
+# Use the faster implementation of BytesIO if available
+try:
+ import _bytesio
+
+ class BytesIO(_bytesio._BytesIO, _BufferedIOBase):
+ __doc__ = _bytesio._BytesIO.__doc__
+
+except ImportError:
+ BytesIO = _BytesIO
+
+
+class BufferedReader(_BufferedIOMixin):
+
+ """BufferedReader(raw[, buffer_size])
+
+ A buffer for a readable, sequential BaseRawIO object.
+
+ The constructor creates a BufferedReader for the given readable raw
+ stream and buffer_size. If buffer_size is omitted, DEFAULT_BUFFER_SIZE
+ is used.
+ """
+
+ def __init__(self, raw, buffer_size=DEFAULT_BUFFER_SIZE):
+ """Create a new buffered reader using the given readable raw IO object.
+ """
+ raw._checkReadable()
+ _BufferedIOMixin.__init__(self, raw)
+ self.buffer_size = buffer_size
+ self._reset_read_buf()
+ self._read_lock = threading.Lock()
+
+ def _reset_read_buf(self):
+ self._read_buf = b""
+ self._read_pos = 0
+
+ def read(self, n=None):
+ """Read n bytes.
+
+ Returns exactly n bytes of data unless the underlying raw IO
+ stream reaches EOF or if the call would block in non-blocking
+ mode. If n is negative, read until EOF or until read() would
+ block.
+ """
+ with self._read_lock:
+ return self._read_unlocked(n)
+
+ def _read_unlocked(self, n=None):
+ nodata_val = b""
+ empty_values = (b"", None)
+ buf = self._read_buf
+ pos = self._read_pos
+
+ # Special case for when the number of bytes to read is unspecified.
+ if n is None or n == -1:
+ self._reset_read_buf()
+ chunks = [buf[pos:]] # Strip the consumed bytes.
+ current_size = 0
+ while True:
+ # Read until EOF or until read() would block.
+ chunk = self.raw.read()
+ if chunk in empty_values:
+ nodata_val = chunk
+ break
+ current_size += len(chunk)
+ chunks.append(chunk)
+ return b"".join(chunks) or nodata_val
+
+ # The number of bytes to read is specified, return at most n bytes.
+ avail = len(buf) - pos # Length of the available buffered data.
+ if n <= avail:
+ # Fast path: the data to read is fully buffered.
+ self._read_pos += n
+ return buf[pos:pos+n]
+ # Slow path: read from the stream until enough bytes are read,
+ # or until an EOF occurs or until read() would block.
+ chunks = [buf[pos:]]
+ wanted = max(self.buffer_size, n)
+ while avail < n:
+ chunk = self.raw.read(wanted)
+ if chunk in empty_values:
+ nodata_val = chunk
+ break
+ avail += len(chunk)
+ chunks.append(chunk)
+ # n is more then avail only when an EOF occurred or when
+ # read() would have blocked.
+ n = min(n, avail)
+ out = b"".join(chunks)
+ self._read_buf = out[n:] # Save the extra data in the buffer.
+ self._read_pos = 0
+ return out[:n] if out else nodata_val
+
+ def peek(self, n=0):
+ """Returns buffered bytes without advancing the position.
+
+ The argument indicates a desired minimal number of bytes; we
+ do at most one raw read to satisfy it. We never return more
+ than self.buffer_size.
+ """
+ with self._read_lock:
+ return self._peek_unlocked(n)
+
+ def _peek_unlocked(self, n=0):
+ want = min(n, self.buffer_size)
+ have = len(self._read_buf) - self._read_pos
+ if have < want:
+ to_read = self.buffer_size - have
+ current = self.raw.read(to_read)
+ if current:
+ self._read_buf = self._read_buf[self._read_pos:] + current
+ self._read_pos = 0
+ return self._read_buf[self._read_pos:]
+
+ def read1(self, n):
+ """Reads up to n bytes, with at most one read() system call."""
+ # Returns up to n bytes. If at least one byte is buffered, we
+ # only return buffered bytes. Otherwise, we do one raw read.
+ if n <= 0:
+ return b""
+ with self._read_lock:
+ self._peek_unlocked(1)
+ return self._read_unlocked(
+ min(n, len(self._read_buf) - self._read_pos))
+
+ def tell(self):
+ return self.raw.tell() - len(self._read_buf) + self._read_pos
+
+ def seek(self, pos, whence=0):
+ with self._read_lock:
+ if whence == 1:
+ pos -= len(self._read_buf) - self._read_pos
+ pos = self.raw.seek(pos, whence)
+ self._reset_read_buf()
+ return pos
+
+
+class BufferedWriter(_BufferedIOMixin):
+
+ """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
+ DEAFULT_BUFFER_SIZE. If max_buffer_size is omitted, it defaults to
+ twice the buffer size.
+ """
+
+ def __init__(self, raw,
+ buffer_size=DEFAULT_BUFFER_SIZE, max_buffer_size=None):
+ raw._checkWritable()
+ _BufferedIOMixin.__init__(self, raw)
+ self.buffer_size = buffer_size
+ self.max_buffer_size = (2*buffer_size
+ if max_buffer_size is None
+ else max_buffer_size)
+ self._write_buf = bytearray()
+ self._write_lock = threading.Lock()
+
+ def write(self, b):
+ if self.closed:
+ raise ValueError("write to closed file")
+ if isinstance(b, unicode):
+ raise TypeError("can't write unicode to binary stream")
+ with self._write_lock:
+ # XXX we can implement some more tricks to try and avoid
+ # partial writes
+ if len(self._write_buf) > self.buffer_size:
+ # We're full, so let's pre-flush the buffer
+ try:
+ self._flush_unlocked()
+ except BlockingIOError as e:
+ # We can't accept anything else.
+ # XXX Why not just let the exception pass through?
+ raise BlockingIOError(e.errno, e.strerror, 0)
+ before = len(self._write_buf)
+ self._write_buf.extend(b)
+ written = len(self._write_buf) - before
+ if len(self._write_buf) > self.buffer_size:
+ try:
+ self._flush_unlocked()
+ except BlockingIOError as e:
+ if len(self._write_buf) > self.max_buffer_size:
+ # We've hit max_buffer_size. We have to accept a
+ # partial write and cut back our buffer.
+ overage = len(self._write_buf) - self.max_buffer_size
+ self._write_buf = self._write_buf[:self.max_buffer_size]
+ raise BlockingIOError(e.errno, e.strerror, overage)
+ return written
+
+ def truncate(self, pos=None):
+ with self._write_lock:
+ self._flush_unlocked()
+ if pos is None:
+ pos = self.raw.tell()
+ return self.raw.truncate(pos)
+
+ def flush(self):
+ if self.closed:
+ raise ValueError("flush of closed file")
+ with self._write_lock:
+ self._flush_unlocked()
+
+ def _flush_unlocked(self):
+ if self.closed:
+ raise ValueError("flush of closed file")
+ written = 0
+ try:
+ while self._write_buf:
+ n = self.raw.write(self._write_buf)
+ del self._write_buf[:n]
+ written += n
+ except BlockingIOError as e:
+ n = e.characters_written
+ del self._write_buf[:n]
+ written += n
+ raise BlockingIOError(e.errno, e.strerror, written)
+
+ def tell(self):
+ return self.raw.tell() + len(self._write_buf)
+
+ def seek(self, pos, whence=0):
+ with self._write_lock:
+ self._flush_unlocked()
+ return self.raw.seek(pos, whence)
+
+
+class BufferedRWPair(_BufferedIOBase):
+
+ """A buffered reader and writer object together.
+
+ A buffered reader object and buffered writer object put together to
+ form a sequential IO object that can read and write. This is typically
+ used with a socket or two-way pipe.
+
+ reader and writer are _RawIOBase objects that are readable and
+ writeable respectively. If the buffer_size is omitted it defaults to
+ DEFAULT_BUFFER_SIZE. The max_buffer_size (for the buffered writer)
+ defaults to twice the buffer size.
+ """
+
+ # XXX The usefulness of this (compared to having two separate IO
+ # objects) is questionable.
+
+ def __init__(self, reader, writer,
+ buffer_size=DEFAULT_BUFFER_SIZE, max_buffer_size=None):
+ """Constructor.
+
+ The arguments are two RawIO instances.
+ """
+ reader._checkReadable()
+ writer._checkWritable()
+ self.reader = BufferedReader(reader, buffer_size)
+ self.writer = BufferedWriter(writer, buffer_size, max_buffer_size)
+
+ def read(self, n=None):
+ if n is None:
+ n = -1
+ return self.reader.read(n)
+
+ def readinto(self, b):
+ return self.reader.readinto(b)
+
+ def write(self, b):
+ return self.writer.write(b)
+
+ def peek(self, n=0):
+ return self.reader.peek(n)
+
+ def read1(self, n):
+ return self.reader.read1(n)
+
+ def readable(self):
+ return self.reader.readable()
+
+ def writable(self):
+ return self.writer.writable()
+
+ def flush(self):
+ return self.writer.flush()
+
+ def close(self):
+ self.writer.close()
+ self.reader.close()
+
+ def isatty(self):
+ return self.reader.isatty() or self.writer.isatty()
+
+ @property
+ def closed(self):
+ return self.writer.closed
+
+
+class BufferedRandom(BufferedWriter, BufferedReader):
+
+ """A buffered interface to random access streams.
+
+ The constructor creates a reader and writer for a seekable stream,
+ raw, given in the first argument. If the buffer_size is omitted it
+ defaults to DEFAULT_BUFFER_SIZE. The max_buffer_size (for the buffered
+ writer) defaults to twice the buffer size.
+ """
+
+ def __init__(self, raw,
+ buffer_size=DEFAULT_BUFFER_SIZE, max_buffer_size=None):
+ raw._checkSeekable()
+ BufferedReader.__init__(self, raw, buffer_size)
+ BufferedWriter.__init__(self, raw, buffer_size, max_buffer_size)
+
+ def seek(self, pos, whence=0):
+ self.flush()
+ # First do the raw seek, then empty the read buffer, so that
+ # if the raw seek fails, we don't lose buffered data forever.
+ if self._read_buf and whence == 1:
+ # Undo read ahead.
+ with self._read_lock:
+ self.raw.seek(self._read_pos - len(self._read_buf), 1)
+ pos = self.raw.seek(pos, whence)
+ with self._read_lock:
+ self._reset_read_buf()
+ return pos
+
+ def tell(self):
+ if self._write_buf:
+ return self.raw.tell() + len(self._write_buf)
+ else:
+ return BufferedReader.tell(self)
+
+ def truncate(self, pos=None):
+ if pos is None:
+ pos = self.tell()
+ # Use seek to flush the read buffer.
+ return BufferedWriter.truncate(self, pos)
+
+ def read(self, n=None):
+ if n is None:
+ n = -1
+ self.flush()
+ return BufferedReader.read(self, n)
+
+ def readinto(self, b):
+ self.flush()
+ return BufferedReader.readinto(self, b)
+
+ def peek(self, n=0):
+ self.flush()
+ return BufferedReader.peek(self, n)
+
+ def read1(self, n):
+ self.flush()
+ return BufferedReader.read1(self, n)
+
+ def write(self, b):
+ if self._read_buf:
+ # Undo readahead
+ with self._read_lock:
+ self.raw.seek(self._read_pos - len(self._read_buf), 1)
+ self._reset_read_buf()
+ return BufferedWriter.write(self, b)
+
+
+class _TextIOBase(_IOBase):
+
+ """Base class for text I/O.
+
+ This class provides a character and line based interface to stream
+ I/O. There is no readinto method because Python's character strings
+ are immutable. There is no public constructor.
+ """
+
+ def read(self, n = -1):
+ """Read at most n characters from stream.
+
+ Read from underlying buffer until we have n characters or we hit EOF.
+ If n is negative or omitted, read until EOF.
+ """
+ self._unsupported("read")
+
+ def write(self, s):
+ """Write string s to stream."""
+ self._unsupported("write")
+
+ def truncate(self, pos = None):
+ """Truncate size to pos."""
+ self._unsupported("truncate")
+
+ def readline(self):
+ """Read until newline or EOF.
+
+ Returns an empty string if EOF is hit immediately.
+ """
+ self._unsupported("readline")
+
+ @property
+ def encoding(self):
+ """Subclasses should override."""
+ return None
+
+ @property
+ def newlines(self):
+ """Line endings translated so far.
+
+ Only line endings translated during reading are considered.
+
+ Subclasses should override.
+ """
+ return None
+
+
+class IncrementalNewlineDecoder(codecs.IncrementalDecoder):
+ """Codec used when reading a file in universal newlines mode.
+ It wraps another incremental decoder, translating \\r\\n and \\r into \\n.
+ It also records the types of newlines encountered.
+ When used with translate=False, it ensures that the newline sequence is
+ returned in one piece.
+ """
+ def __init__(self, decoder, translate, errors='strict'):
+ codecs.IncrementalDecoder.__init__(self, errors=errors)
+ self.translate = translate
+ self.decoder = decoder
+ self.seennl = 0
+ self.pendingcr = False
+
+ def decode(self, input, final=False):
+ # decode input (with the eventual \r from a previous pass)
+ output = self.decoder.decode(input, final=final)
+ if self.pendingcr and (output or final):
+ output = "\r" + output
+ self.pendingcr = False
+
+ # retain last \r even when not translating data:
+ # then readline() is sure to get \r\n in one pass
+ if output.endswith("\r") and not final:
+ output = output[:-1]
+ self.pendingcr = True
+
+ # Record which newlines are read
+ crlf = output.count('\r\n')
+ cr = output.count('\r') - crlf
+ lf = output.count('\n') - crlf
+ self.seennl |= (lf and self._LF) | (cr and self._CR) \
+ | (crlf and self._CRLF)
+
+ if self.translate:
+ if crlf:
+ output = output.replace("\r\n", "\n")
+ if cr:
+ output = output.replace("\r", "\n")
+
+ return output
+
+ def getstate(self):
+ buf, flag = self.decoder.getstate()
+ flag <<= 1
+ if self.pendingcr:
+ flag |= 1
+ return buf, flag
+
+ def setstate(self, state):
+ buf, flag = state
+ self.pendingcr = bool(flag & 1)
+ self.decoder.setstate((buf, flag >> 1))
+
+ def reset(self):
+ self.seennl = 0
+ self.pendingcr = False
+ self.decoder.reset()
+
+ _LF = 1
+ _CR = 2
+ _CRLF = 4
+
+ @property
+ def newlines(self):
+ return (None,
+ "\n",
+ "\r",
+ ("\r", "\n"),
+ "\r\n",
+ ("\n", "\r\n"),
+ ("\r", "\r\n"),
+ ("\r", "\n", "\r\n")
+ )[self.seennl]
+
+
+class TextIOWrapper(_TextIOBase):
+
+ r"""Character and line based layer over a _BufferedIOBase object, buffer.
+
+ encoding gives the name of the encoding that the stream will be
+ decoded or encoded with. It defaults to locale.getpreferredencoding.
+
+ errors determines the strictness of encoding and decoding (see the
+ codecs.register) and defaults to "strict".
+
+ newline can be None, '', '\n', '\r', or '\r\n'. It controls the
+ handling of line endings. If it is None, universal newlines is
+ enabled. With this enabled, on input, the lines endings '\n', '\r',
+ or '\r\n' are translated to '\n' before being returned to the
+ caller. Conversely, on output, '\n' is translated to the system
+ default line separator, os.linesep. If newline is any other of its
+ legal values, that newline becomes the newline when the file is read
+ and it is returned untranslated. On output, '\n' is converted to the
+ newline.
+
+ If line_buffering is True, a call to flush is implied when a call to
+ write contains a newline character.
+ """
+
+ _CHUNK_SIZE = 128
+
+ def __init__(self, buffer, encoding=None, errors=None, newline=None,
+ line_buffering=False):
+ if newline not in (None, "", "\n", "\r", "\r\n"):
+ raise ValueError("illegal newline value: %r" % (newline,))
+ if encoding is None:
+ try:
+ encoding = os.device_encoding(buffer.fileno())
+ except (AttributeError, UnsupportedOperation):
+ pass
+ if encoding is None:
+ try:
+ import locale
+ except ImportError:
+ # Importing locale may fail if Python is being built
+ encoding = "ascii"
+ else:
+ encoding = locale.getpreferredencoding()
+
+ if not isinstance(encoding, basestring):
+ raise ValueError("invalid encoding: %r" % encoding)
+
+ if errors is None:
+ errors = "strict"
+ else:
+ if not isinstance(errors, basestring):
+ raise ValueError("invalid errors: %r" % errors)
+
+ self.buffer = buffer
+ self._line_buffering = line_buffering
+ self._encoding = encoding
+ self._errors = errors
+ self._readuniversal = not newline
+ self._readtranslate = newline is None
+ self._readnl = newline
+ self._writetranslate = newline != ''
+ self._writenl = newline or os.linesep
+ self._encoder = None
+ self._decoder = None
+ self._decoded_chars = '' # buffer for text returned from decoder
+ self._decoded_chars_used = 0 # offset into _decoded_chars for read()
+ self._snapshot = None # info for reconstructing decoder state
+ self._seekable = self._telling = self.buffer.seekable()
+
+ if self._seekable and self.writable():
+ position = self.buffer.tell()
+ if position != 0:
+ try:
+ self._get_encoder().setstate(0)
+ except LookupError:
+ # Sometimes the encoder doesn't exist
+ pass
+
+ # self._snapshot is either None, or a tuple (dec_flags, next_input)
+ # where dec_flags is the second (integer) item of the decoder state
+ # and next_input is the chunk of input bytes that comes next after the
+ # snapshot point. We use this to reconstruct decoder states in tell().
+
+ # Naming convention:
+ # - "bytes_..." for integer variables that count input bytes
+ # - "chars_..." for integer variables that count decoded characters
+
+ @property
+ def encoding(self):
+ return self._encoding
+
+ @property
+ def errors(self):
+ return self._errors
+
+ @property
+ def line_buffering(self):
+ return self._line_buffering
+
+ def seekable(self):
+ return self._seekable
+
+ def readable(self):
+ return self.buffer.readable()
+
+ def writable(self):
+ return self.buffer.writable()
+
+ def flush(self):
+ self.buffer.flush()
+ self._telling = self._seekable
+
+ def close(self):
+ if not self.closed:
+ self.flush()
+ self.buffer.close()
+
+ @property
+ def closed(self):
+ return self.buffer.closed
+
+ @property
+ def name(self):
+ return self.buffer.name
+
+ def fileno(self):
+ return self.buffer.fileno()
+
+ def isatty(self):
+ return self.buffer.isatty()
+
+ def write(self, s):
+ if self.closed:
+ raise ValueError("write to closed file")
+ if not isinstance(s, unicode):
+ raise TypeError("can't write %s to text stream" %
+ s.__class__.__name__)
+ length = len(s)
+ haslf = (self._writetranslate or self._line_buffering) and "\n" in s
+ if haslf and self._writetranslate and self._writenl != "\n":
+ s = s.replace("\n", self._writenl)
+ encoder = self._encoder or self._get_encoder()
+ # XXX What if we were just reading?
+ b = encoder.encode(s)
+ self.buffer.write(b)
+ if self._line_buffering and (haslf or "\r" in s):
+ self.flush()
+ self._snapshot = None
+ if self._decoder:
+ self._decoder.reset()
+ return length
+
+ def _get_encoder(self):
+ make_encoder = codecs.getincrementalencoder(self._encoding)
+ self._encoder = make_encoder(self._errors)
+ return self._encoder
+
+ def _get_decoder(self):
+ make_decoder = codecs.getincrementaldecoder(self._encoding)
+ decoder = make_decoder(self._errors)
+ if self._readuniversal:
+ decoder = IncrementalNewlineDecoder(decoder, self._readtranslate)
+ self._decoder = decoder
+ return decoder
+
+ # The following three methods implement an ADT for _decoded_chars.
+ # Text returned from the decoder is buffered here until the client
+ # requests it by calling our read() or readline() method.
+ def _set_decoded_chars(self, chars):
+ """Set the _decoded_chars buffer."""
+ self._decoded_chars = chars
+ self._decoded_chars_used = 0
+
+ def _get_decoded_chars(self, n=None):
+ """Advance into the _decoded_chars buffer."""
+ offset = self._decoded_chars_used
+ if n is None:
+ chars = self._decoded_chars[offset:]
+ else:
+ chars = self._decoded_chars[offset:offset + n]
+ self._decoded_chars_used += len(chars)
+ return chars
+
+ def _rewind_decoded_chars(self, n):
+ """Rewind the _decoded_chars buffer."""
+ if self._decoded_chars_used < n:
+ raise AssertionError("rewind decoded_chars out of bounds")
+ self._decoded_chars_used -= n
+
+ def _read_chunk(self):
+ """
+ Read and decode the next chunk of data from the BufferedReader.
+
+ The return value is True unless EOF was reached. The decoded string
+ is placed in self._decoded_chars (replacing its previous value).
+ The entire input chunk is sent to the decoder, though some of it
+ may remain buffered in the decoder, yet to be converted.
+ """
+
+ if self._decoder is None:
+ raise ValueError("no decoder")
+
+ if self._telling:
+ # To prepare for tell(), we need to snapshot a point in the
+ # file where the decoder's input buffer is empty.
+
+ dec_buffer, dec_flags = self._decoder.getstate()
+ # Given this, we know there was a valid snapshot point
+ # len(dec_buffer) bytes ago with decoder state (b'', dec_flags).
+
+ # Read a chunk, decode it, and put the result in self._decoded_chars.
+ input_chunk = self.buffer.read1(self._CHUNK_SIZE)
+ eof = not input_chunk
+ self._set_decoded_chars(self._decoder.decode(input_chunk, eof))
+
+ if self._telling:
+ # At the snapshot point, len(dec_buffer) bytes before the read,
+ # the next input to be decoded is dec_buffer + input_chunk.
+ self._snapshot = (dec_flags, dec_buffer + input_chunk)
+
+ return not eof
+
+ def _pack_cookie(self, position, dec_flags=0,
+ bytes_to_feed=0, need_eof=0, chars_to_skip=0):
+ # The meaning of a tell() cookie is: seek to position, set the
+ # decoder flags to dec_flags, read bytes_to_feed bytes, feed them
+ # into the decoder with need_eof as the EOF flag, then skip
+ # chars_to_skip characters of the decoded result. For most simple
+ # decoders, tell() will often just give a byte offset in the file.
+ return (position | (dec_flags<<64) | (bytes_to_feed<<128) |
+ (chars_to_skip<<192) | bool(need_eof)<<256)
+
+ def _unpack_cookie(self, bigint):
+ rest, position = divmod(bigint, 1<<64)
+ rest, dec_flags = divmod(rest, 1<<64)
+ rest, bytes_to_feed = divmod(rest, 1<<64)
+ need_eof, chars_to_skip = divmod(rest, 1<<64)
+ return position, dec_flags, bytes_to_feed, need_eof, chars_to_skip
+
+ def tell(self):
+ if not self._seekable:
+ raise IOError("underlying stream is not seekable")
+ if not self._telling:
+ raise IOError("telling position disabled by next() call")
+ self.flush()
+ position = self.buffer.tell()
+ decoder = self._decoder
+ if decoder is None or self._snapshot is None:
+ if self._decoded_chars:
+ # This should never happen.
+ raise AssertionError("pending decoded text")
+ return position
+
+ # Skip backward to the snapshot point (see _read_chunk).
+ dec_flags, next_input = self._snapshot
+ position -= len(next_input)
+
+ # How many decoded characters have been used up since the snapshot?
+ chars_to_skip = self._decoded_chars_used
+ if chars_to_skip == 0:
+ # We haven't moved from the snapshot point.
+ return self._pack_cookie(position, dec_flags)
+
+ # Starting from the snapshot position, we will walk the decoder
+ # forward until it gives us enough decoded characters.
+ saved_state = decoder.getstate()
+ try:
+ # Note our initial start point.
+ decoder.setstate((b'', dec_flags))
+ start_pos = position
+ start_flags, bytes_fed, chars_decoded = dec_flags, 0, 0
+ need_eof = 0
+
+ # Feed the decoder one byte at a time. As we go, note the
+ # nearest "safe start point" before the current location
+ # (a point where the decoder has nothing buffered, so seek()
+ # can safely start from there and advance to this location).
+ for next_byte in next_input:
+ bytes_fed += 1
+ chars_decoded += len(decoder.decode(next_byte))
+ dec_buffer, dec_flags = decoder.getstate()
+ if not dec_buffer and chars_decoded <= chars_to_skip:
+ # Decoder buffer is empty, so this is a safe start point.
+ start_pos += bytes_fed
+ chars_to_skip -= chars_decoded
+ start_flags, bytes_fed, chars_decoded = dec_flags, 0, 0
+ if chars_decoded >= chars_to_skip:
+ break
+ else:
+ # We didn't get enough decoded data; signal EOF to get more.
+ chars_decoded += len(decoder.decode(b'', final=True))
+ need_eof = 1
+ if chars_decoded < chars_to_skip:
+ raise IOError("can't reconstruct logical file position")
+
+ # The returned cookie corresponds to the last safe start point.
+ return self._pack_cookie(
+ start_pos, start_flags, bytes_fed, need_eof, chars_to_skip)
+ finally:
+ decoder.setstate(saved_state)
+
+ def truncate(self, pos=None):
+ self.flush()
+ if pos is None:
+ pos = self.tell()
+ return self.buffer.truncate(pos)
+
+ def seek(self, cookie, whence=0):
+ if self.closed:
+ raise ValueError("tell on closed file")
+ if not self._seekable:
+ raise IOError("underlying stream is not seekable")
+ if whence == 1: # seek relative to current position
+ if cookie != 0:
+ raise IOError("can't do nonzero cur-relative seeks")
+ # Seeking to the current position should attempt to
+ # sync the underlying buffer with the current position.
+ whence = 0
+ cookie = self.tell()
+ if whence == 2: # seek relative to end of file
+ if cookie != 0:
+ raise IOError("can't do nonzero end-relative seeks")
+ self.flush()
+ position = self.buffer.seek(0, 2)
+ self._set_decoded_chars('')
+ self._snapshot = None
+ if self._decoder:
+ self._decoder.reset()
+ return position
+ if whence != 0:
+ raise ValueError("invalid whence (%r, should be 0, 1 or 2)" %
+ (whence,))
+ if cookie < 0:
+ raise ValueError("negative seek position %r" % (cookie,))
+ self.flush()
+
+ # The strategy of seek() is to go back to the safe start point
+ # and replay the effect of read(chars_to_skip) from there.
+ start_pos, dec_flags, bytes_to_feed, need_eof, chars_to_skip = \
+ self._unpack_cookie(cookie)
+
+ # Seek back to the safe start point.
+ self.buffer.seek(start_pos)
+ self._set_decoded_chars('')
+ self._snapshot = None
+
+ # Restore the decoder to its state from the safe start point.
+ if self._decoder or dec_flags or chars_to_skip:
+ self._decoder = self._decoder or self._get_decoder()
+ self._decoder.setstate((b'', dec_flags))
+ self._snapshot = (dec_flags, b'')
+
+ if chars_to_skip:
+ # Just like _read_chunk, feed the decoder and save a snapshot.
+ input_chunk = self.buffer.read(bytes_to_feed)
+ self._set_decoded_chars(
+ self._decoder.decode(input_chunk, need_eof))
+ self._snapshot = (dec_flags, input_chunk)
+
+ # Skip chars_to_skip of the decoded characters.
+ if len(self._decoded_chars) < chars_to_skip:
+ raise IOError("can't restore logical file position")
+ self._decoded_chars_used = chars_to_skip
+
+ # Finally, reset the encoder (merely useful for proper BOM handling)
+ try:
+ encoder = self._encoder or self._get_encoder()
+ except LookupError:
+ # Sometimes the encoder doesn't exist
+ pass
+ else:
+ if cookie != 0:
+ encoder.setstate(0)
+ else:
+ encoder.reset()
+ return cookie
+
+ def read(self, n=None):
+ if n is None:
+ n = -1
+ decoder = self._decoder or self._get_decoder()
+ try:
+ n.__index__
+ except AttributeError:
+ raise TypeError("an integer is required")
+ if n < 0:
+ # Read everything.
+ result = (self._get_decoded_chars() +
+ decoder.decode(self.buffer.read(), final=True))
+ self._set_decoded_chars('')
+ self._snapshot = None
+ return result
+ else:
+ # Keep reading chunks until we have n characters to return.
+ eof = False
+ result = self._get_decoded_chars(n)
+ while len(result) < n and not eof:
+ eof = not self._read_chunk()
+ result += self._get_decoded_chars(n - len(result))
+ return result
+
+ def next(self):
+ self._telling = False
+ line = self.readline()
+ if not line:
+ self._snapshot = None
+ self._telling = self._seekable
+ raise StopIteration
+ return line
+
+ def readline(self, limit=None):
+ if self.closed:
+ raise ValueError("read from closed file")
+ if limit is None:
+ limit = -1
+ if not isinstance(limit, (int, long)):
+ raise TypeError("limit must be an integer")
+
+ # Grab all the decoded text (we will rewind any extra bits later).
+ line = self._get_decoded_chars()
+
+ start = 0
+ decoder = self._decoder or self._get_decoder()
+
+ pos = endpos = None
+ while True:
+ if self._readtranslate:
+ # Newlines are already translated, only search for \n
+ pos = line.find('\n', start)
+ if pos >= 0:
+ endpos = pos + 1
+ break
+ else:
+ start = len(line)
+
+ elif self._readuniversal:
+ # Universal newline search. Find any of \r, \r\n, \n
+ # The decoder ensures that \r\n are not split in two pieces
+
+ # In C we'd look for these in parallel of course.
+ nlpos = line.find("\n", start)
+ crpos = line.find("\r", start)
+ if crpos == -1:
+ if nlpos == -1:
+ # Nothing found
+ start = len(line)
+ else:
+ # Found \n
+ endpos = nlpos + 1
+ break
+ elif nlpos == -1:
+ # Found lone \r
+ endpos = crpos + 1
+ break
+ elif nlpos < crpos:
+ # Found \n
+ endpos = nlpos + 1
+ break
+ elif nlpos == crpos + 1:
+ # Found \r\n
+ endpos = crpos + 2
+ break
+ else:
+ # Found \r
+ endpos = crpos + 1
+ break
+ else:
+ # non-universal
+ pos = line.find(self._readnl)
+ if pos >= 0:
+ endpos = pos + len(self._readnl)
+ break
+
+ if limit >= 0 and len(line) >= limit:
+ endpos = limit # reached length limit
+ break
+
+ # No line ending seen yet - get more data
+ more_line = ''
+ while self._read_chunk():
+ if self._decoded_chars:
+ break
+ if self._decoded_chars:
+ line += self._get_decoded_chars()
+ else:
+ # end of file
+ self._set_decoded_chars('')
+ self._snapshot = None
+ return line
+
+ if limit >= 0 and endpos > limit:
+ endpos = limit # don't exceed limit
+
+ # Rewind _decoded_chars to just after the line ending we found.
+ self._rewind_decoded_chars(len(line) - endpos)
+ return line[:endpos]
+
+ @property
+ def newlines(self):
+ return self._decoder.newlines if self._decoder else None
+
+class StringIO(TextIOWrapper):
+
+ """An in-memory stream for text. The initial_value argument sets the
+ value of object. The other arguments are like those of TextIOWrapper's
+ constructor.
+ """
+
+ def __init__(self, initial_value="", encoding="utf-8",
+ errors="strict", newline="\n"):
+ super(StringIO, self).__init__(BytesIO(),
+ encoding=encoding,
+ errors=errors,
+ newline=newline)
+ # Issue #5645: make universal newlines semantics the same as in the
+ # C version, even under Windows.
+ if newline is None:
+ self._writetranslate = False
+ if initial_value:
+ if not isinstance(initial_value, unicode):
+ initial_value = unicode(initial_value)
+ self.write(initial_value)
+ self.seek(0)
+
+ def getvalue(self):
+ self.flush()
+ return self.buffer.getvalue().decode(self._encoding, self._errors)
--
Repository URL: http://hg.python.org/jython
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