1 """The io module provides the Python interfaces to stream handling. The 2 builtin open function is defined in this module. 3 4 At the top of the I/O hierarchy is the abstract base class IOBase. It 5 defines the basic interface to a stream. Note, however, that there is no 6 separation between reading and writing to streams; implementations are 7 allowed to throw an IOError if they do not support a given operation. 8 9 Extending IOBase is RawIOBase which deals simply with the reading and 10 writing of raw bytes to a stream. FileIO subclasses RawIOBase to provide 11 an interface to OS files. 12 13 BufferedIOBase deals with buffering on a raw byte stream (RawIOBase). Its 14 subclasses, BufferedWriter, BufferedReader, and BufferedRWPair buffer 15 streams that are readable, writable, and both respectively. 16 BufferedRandom provides a buffered interface to random access 17 streams. BytesIO is a simple stream of in-memory bytes. 18 19 Another IOBase subclass, TextIOBase, deals with the encoding and decoding 20 of streams into text. TextIOWrapper, which extends it, is a buffered text 21 interface to a buffered raw stream (`BufferedIOBase`). Finally, StringIO 22 is a in-memory stream for text. 23 24 Argument names are not part of the specification, and only the arguments 25 of open() are intended to be used as keyword arguments. 26 27 data: 28 29 DEFAULT_BUFFER_SIZE 30 31 An int containing the default buffer size used by the module's buffered 32 I/O classes. open() uses the file's blksize (as obtained by os.stat) if 33 possible. 34 """ 35 # New I/O library conforming to PEP 3116. 36 37 # XXX edge cases when switching between reading/writing 38 # XXX need to support 1 meaning line-buffered 39 # XXX whenever an argument is None, use the default value 40 # XXX read/write ops should check readable/writable 41 # XXX buffered readinto should work with arbitrary buffer objects 42 # XXX use incremental encoder for text output, at least for UTF-16 and UTF-8-SIG 43 # XXX check writable, readable and seekable in appropriate places 44 45 46 __author__ = ("Guido van Rossum <guido (at] python.org>, " 47 "Mike Verdone <mike.verdone (at] gmail.com>, " 48 "Mark Russell <mark.russell (at] zen.co.uk>, " 49 "Antoine Pitrou <solipsis (at] pitrou.net>, " 50 "Amaury Forgeot d'Arc <amauryfa (at] gmail.com>, " 51 "Benjamin Peterson <benjamin (at] python.org>") 52 53 __all__ = ["BlockingIOError", "open", "IOBase", "RawIOBase", "FileIO", 54 "BytesIO", "StringIO", "BufferedIOBase", 55 "BufferedReader", "BufferedWriter", "BufferedRWPair", 56 "BufferedRandom", "TextIOBase", "TextIOWrapper", 57 "UnsupportedOperation", "SEEK_SET", "SEEK_CUR", "SEEK_END"] 58 59 60 import _io 61 import abc 62 63 from _io import (DEFAULT_BUFFER_SIZE, BlockingIOError, UnsupportedOperation, 64 open, FileIO, BytesIO, StringIO, BufferedReader, 65 BufferedWriter, BufferedRWPair, BufferedRandom, 66 IncrementalNewlineDecoder, TextIOWrapper) 67 68 OpenWrapper = _io.open # for compatibility with _pyio 69 70 # for seek() 71 SEEK_SET = 0 72 SEEK_CUR = 1 73 SEEK_END = 2 74 75 # Declaring ABCs in C is tricky so we do it here. 76 # Method descriptions and default implementations are inherited from the C 77 # version however. 78 class IOBase(_io._IOBase): 79 __metaclass__ = abc.ABCMeta 80 81 class RawIOBase(_io._RawIOBase, IOBase): 82 pass 83 84 class BufferedIOBase(_io._BufferedIOBase, IOBase): 85 pass 86 87 class TextIOBase(_io._TextIOBase, IOBase): 88 pass 89 90 RawIOBase.register(FileIO) 91 92 for klass in (BytesIO, BufferedReader, BufferedWriter, BufferedRandom, 93 BufferedRWPair): 94 BufferedIOBase.register(klass) 95 96 for klass in (StringIO, TextIOWrapper): 97 TextIOBase.register(klass) 98 del klass 99
