Mike Verdone's checkpoint, cleaned up.
Also implemented Neal's suggestion (add fileno() to SocketIO)
and some unrelated changes, e.g. remove Google copyright
and make BytesIO a subclass of BufferedIOBase.
diff --git a/Lib/io.py b/Lib/io.py
index d2945ca..3ad9e90 100644
--- a/Lib/io.py
+++ b/Lib/io.py
@@ -1,6 +1,3 @@
-# Copyright 2006 Google, Inc. All Rights Reserved.
-# Licensed to PSF under a Contributor Agreement.
-
"""New I/O library.
This is an early prototype; eventually some of this will be
@@ -9,12 +6,17 @@
See PEP XXX; for now: http://docs.google.com/Doc?id=dfksfvqd_1cn5g5m
"""
-__author__ = "Guido van Rossum <guido@python.org>"
+__author__ = ("Guido van Rossum <guido@python.org>, "
+ "Mike Verdone <mike.verdone@gmail.com>")
-__all__ = ["open", "RawIOBase", "FileIO", "SocketIO", "BytesIO"]
+__all__ = ["open", "RawIOBase", "FileIO", "SocketIO", "BytesIO",
+ "BufferedReader", "BufferedWriter", "BufferedRWPair", "EOF"]
import os
+DEFAULT_BUFFER_SIZE = 8 * 1024 # bytes
+EOF = b""
+
def open(filename, mode="r", buffering=None, *, encoding=None):
"""Replacement for the built-in open function.
@@ -71,8 +73,8 @@
(appending and "a" or "") +
(updating and "+" or ""))
if buffering is None:
- buffering = 8*1024 # International standard buffer size
- # Should default to line buffering if os.isatty(raw.fileno())
+ buffering = DEFAULT_BUFFER_SIZE
+ # XXX Should default to line buffering if os.isatty(raw.fileno())
try:
bs = os.fstat(raw.fileno()).st_blksize
except (os.error, AttributeError):
@@ -219,7 +221,7 @@
def fileno(self):
return self._fd
-
+
class SocketIO(RawIOBase):
"""Raw I/O implementation for stream sockets."""
@@ -249,12 +251,18 @@
def writable(self):
return "w" in self._mode
- # XXX(nnorwitz)??? def fileno(self): return self._sock.fileno()
+ def fileno(self):
+ return self._sock.fileno()
-class BytesIO(RawIOBase):
+class BufferedIOBase(RawIOBase):
- """Raw I/O implementation for bytes, like StringIO."""
+ """XXX Docstring."""
+
+
+class BytesIO(BufferedIOBase):
+
+ """Buffered I/O implementation using a bytes buffer, like StringIO."""
# XXX More docs
@@ -267,7 +275,9 @@
def getvalue(self):
return self._buffer
- def read(self, n):
+ def read(self, n=None):
+ if n is None:
+ n = len(self._buffer)
assert n >= 0
newpos = min(len(self._buffer), self._pos + n)
b = self._buffer[self._pos : newpos]
@@ -312,3 +322,113 @@
def seekable(self):
return True
+
+
+class BufferedReader(BufferedIOBase):
+
+ """Buffered reader.
+
+ Buffer for a readable sequential RawIO object. Does not allow
+ random access (seek, tell).
+ """
+
+ def __init__(self, raw):
+ """
+ Create a new buffered reader using the given readable raw IO object.
+ """
+ assert raw.readable()
+ self.raw = raw
+ self._read_buf = b''
+ if hasattr(raw, 'fileno'):
+ self.fileno = raw.fileno
+
+ def read(self, n=None):
+ """
+ Read n bytes. Returns exactly n bytes of data unless the underlying
+ raw IO stream reaches EOF of if the call would block in non-blocking
+ mode. If n is None, read until EOF or until read() would block.
+ """
+ nodata_val = EOF
+ while (len(self._read_buf) < n) if (n is not None) else True:
+ current = self.raw.read(n)
+ if current in (EOF, None):
+ nodata_val = current
+ break
+ self._read_buf += current # XXX using += is bad
+ read = self._read_buf[:n]
+ if (not self._read_buf):
+ return nodata_val
+ self._read_buf = self._read_buf[n if n else 0:]
+ return read
+
+ def write(self, b):
+ raise IOError(".write() unsupported")
+
+ def readable(self):
+ return True
+
+ def flush(self):
+ # Flush is a no-op
+ pass
+
+
+class BufferedWriter(BufferedIOBase):
+
+ """Buffered writer.
+
+ XXX More docs.
+ """
+
+ def __init__(self, raw, buffer_size=DEFAULT_BUFFER_SIZE):
+ assert raw.writeable()
+ self.raw = raw
+ self.buffer_size = buffer_size
+ self._write_buf_stack = []
+ self._write_buf_size = 0
+ if hasattr(raw, 'fileno'):
+ self.fileno = raw.fileno
+
+ def read(self, n=None):
+ raise IOError(".read() not supported")
+
+ def write(self, b):
+ assert issubclass(type(b), bytes)
+ self._write_buf_stack.append(b)
+ self._write_buf_size += len(b)
+ if (self._write_buf_size > self.buffer_size):
+ self.flush()
+
+ def writeable(self):
+ return True
+
+ def flush(self):
+ buf = b''.join(self._write_buf_stack)
+ while len(buf):
+ buf = buf[self.raw.write(buf):]
+ self._write_buf_stack = []
+ self._write_buf_size = 0
+
+ # XXX support flushing buffer on close, del
+
+
+class BufferedRWPair(BufferedReader, BufferedWriter):
+
+ """Buffered Read/Write Pair.
+
+ A buffered reader object and buffered writer object put together to
+ form a sequential IO object that can read and write.
+ """
+
+ def __init__(self, bufferedReader, bufferedWriter):
+ assert bufferedReader.readable()
+ assert bufferedWriter.writeable()
+ self.bufferedReader = bufferedReader
+ self.bufferedWriter = bufferedWriter
+ self.read = bufferedReader.read
+ self.write = bufferedWriter.write
+ self.flush = bufferedWriter.flush
+ self.readable = bufferedReader.readable
+ self.writeable = bufferedWriter.writeable
+
+ def seekable(self):
+ return False