Changes to io.py and socket.py by Christian Heimes.
- Replace all asserts by ValuleErrors or TypeErrors as appropriate.
- Add _checkReadable, _checkWritable methods; these check self.closed too.
- Add a test that everything exported by io.py exists, and is either
an exception or an IOBase instance (except for the open function).
- Default buffering to 1 if isatty() (I had to tweak this to enforce
the *default* bit -- GvR).
diff --git a/Lib/io.py b/Lib/io.py
index 40c2186..3ebf5ae 100644
--- a/Lib/io.py
+++ b/Lib/io.py
@@ -12,13 +12,12 @@
variable are part of the specification.
XXX edge cases when switching between reading/writing
-XXX need to default buffer size to 1 if isatty()
XXX need to support 1 meaning line-buffered
-XXX don't use assert to validate input requirements
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
"""
__author__ = ("Guido van Rossum <guido@python.org>, "
@@ -26,7 +25,7 @@
"Mark Russell <mark.russell@zen.co.uk>")
__all__ = ["BlockingIOError", "open", "IOBase", "RawIOBase", "FileIO",
- "SocketIO", "BytesIO", "StringIO", "BufferedIOBase",
+ "BytesIO", "StringIO", "BufferedIOBase",
"BufferedReader", "BufferedWriter", "BufferedRWPair",
"BufferedRandom", "TextIOBase", "TextIOWrapper"]
@@ -38,7 +37,7 @@
import io
import warnings
-# XXX Shouldn't we use st_blksize whenever we can?
+# open() uses st_blksize whenever we can
DEFAULT_BUFFER_SIZE = 8 * 1024 # bytes
@@ -105,11 +104,14 @@
binary stream, a buffered binary stream, or a buffered text
stream, open for reading and/or writing.
"""
- # XXX Don't use asserts for these checks; raise TypeError or ValueError
- assert isinstance(file, (basestring, int)), repr(file)
- assert isinstance(mode, basestring), repr(mode)
- assert buffering is None or isinstance(buffering, int), repr(buffering)
- assert encoding is None or isinstance(encoding, basestring), repr(encoding)
+ 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)
modes = set(mode)
if modes - set("arwb+tU") or len(mode) > len(modes):
raise ValueError("invalid mode: %r" % mode)
@@ -140,9 +142,10 @@
(updating and "+" or ""))
if buffering is None:
buffering = -1
+ if buffering < 0 and raw.isatty():
+ buffering = 1
if buffering < 0:
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):
@@ -162,9 +165,10 @@
buffer = BufferedRandom(raw, buffering)
elif writing or appending:
buffer = BufferedWriter(raw, buffering)
- else:
- assert reading
+ elif reading:
buffer = BufferedReader(raw, buffering)
+ else:
+ raise ValueError("unknown mode: %r" % mode)
if binary:
buffer.name = file
buffer.mode = mode
@@ -273,6 +277,14 @@
"""
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) -> bool:
"""readable() -> bool. Return whether object was opened for reading.
@@ -280,6 +292,13 @@
"""
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) -> bool:
"""writable() -> bool. Return whether object was opened for writing.
@@ -287,6 +306,13 @@
"""
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.
@@ -295,6 +321,13 @@
"""
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) -> "IOBase": # That's a forward reference
@@ -321,8 +354,7 @@
Returns False if we don't know.
"""
- if self.closed:
- raise ValueError("isatty() on closed file")
+ self._checkClosed()
return False
### Readline[s] and writelines ###
@@ -354,8 +386,7 @@
return res
def __iter__(self):
- if self.closed:
- raise ValueError("__iter__ on closed file")
+ self._checkClosed()
return self
def __next__(self):
@@ -377,8 +408,7 @@
return lines
def writelines(self, lines):
- if self.closed:
- raise ValueError("write to closed file")
+ self._checkClosed()
for line in lines:
self.write(line)
@@ -677,7 +707,7 @@
def __init__(self, raw, buffer_size=DEFAULT_BUFFER_SIZE):
"""Create a new buffered reader using the given readable raw IO object.
"""
- assert raw.readable()
+ raw._checkReadable()
_BufferedIOMixin.__init__(self, raw)
self._read_buf = b""
self.buffer_size = buffer_size
@@ -760,7 +790,7 @@
def __init__(self, raw,
buffer_size=DEFAULT_BUFFER_SIZE, max_buffer_size=None):
- assert raw.writable()
+ raw._checkWritable()
_BufferedIOMixin.__init__(self, raw)
self.buffer_size = buffer_size
self.max_buffer_size = (2*buffer_size
@@ -842,8 +872,8 @@
The arguments are two RawIO instances.
"""
- assert reader.readable()
- assert writer.writable()
+ reader._checkReadable()
+ writer._checkWritable()
self.reader = BufferedReader(reader, buffer_size)
self.writer = BufferedWriter(writer, buffer_size, max_buffer_size)
@@ -891,7 +921,7 @@
def __init__(self, raw,
buffer_size=DEFAULT_BUFFER_SIZE, max_buffer_size=None):
- assert raw.seekable()
+ raw._checkSeekable()
BufferedReader.__init__(self, raw, buffer_size)
BufferedWriter.__init__(self, raw, buffer_size, max_buffer_size)
@@ -1086,7 +1116,8 @@
return decoder
def _read_chunk(self):
- assert self._decoder is not None
+ if self._decoder is None:
+ raise ValueError("no decoder")
if not self._telling:
readahead = self.buffer.read1(self._CHUNK_SIZE)
pending = self._decoder.decode(readahead, not readahead)
@@ -1122,7 +1153,8 @@
position = self.buffer.tell()
decoder = self._decoder
if decoder is None or self._snapshot is None:
- assert self._pending == ""
+ if self._pending:
+ raise ValueError("pending data")
return position
decoder_state, readahead, pending = self._snapshot
position -= len(readahead)