diff options
Diffstat (limited to 'Lib/_pyio.py')
| -rw-r--r-- | Lib/_pyio.py | 201 |
1 files changed, 120 insertions, 81 deletions
diff --git a/Lib/_pyio.py b/Lib/_pyio.py index dc2b433..aab60db 100644 --- a/Lib/_pyio.py +++ b/Lib/_pyio.py @@ -5,7 +5,6 @@ Python implementation of the io module. import os import abc import codecs -import warnings import errno # Import _thread instead of threading to reduce startup cost try: @@ -15,7 +14,11 @@ except ImportError: import io from io import (__all__, SEEK_SET, SEEK_CUR, SEEK_END) -from errno import EINTR + +valid_seek_flags = {0, 1, 2} # Hardwired values +if hasattr(os, 'SEEK_HOLE') : + valid_seek_flags.add(os.SEEK_HOLE) + valid_seek_flags.add(os.SEEK_DATA) # open() uses st_blksize whenever we can DEFAULT_BUFFER_SIZE = 8 * 1024 # bytes @@ -24,20 +27,12 @@ DEFAULT_BUFFER_SIZE = 8 * 1024 # bytes # defined in io.py. We don't use real inheritance though, because we don't # want to inherit the C implementations. - -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): - super().__init__(errno, strerror) - if not isinstance(characters_written, int): - raise TypeError("characters_written must be a integer") - self.characters_written = characters_written +# Rebind for compatibility +BlockingIOError = BlockingIOError def open(file, mode="r", buffering=-1, encoding=None, errors=None, - newline=None, closefd=True): + newline=None, closefd=True, opener=None): r"""Open file and return a stream. Raise IOError upon failure. @@ -47,21 +42,22 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None, 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: + 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), 'x' for exclusive creation of a new file, 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 + 'x' create a new file and open it for writing 'a' open for writing, appending to the end of the file if it exists 'b' binary mode 't' text mode (default) @@ -72,7 +68,8 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None, 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. + 'r+b' opens the file without truncation. The 'x' mode implies 'w' and + raises an `FileExistsError` if the file already exists. Python distinguishes between files opened in binary and text modes, even when the underlying operating system doesn't. Files opened in @@ -132,6 +129,12 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None, 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. + A custom opener can be used by passing a callable as *opener*. The + underlying file descriptor for the file object is then obtained by calling + *opener* with (*file*, *flags*). *opener* must return an open file + descriptor (passing os.open as *opener* results in functionality similar to + passing None). + 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', @@ -157,8 +160,9 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None, if errors is not None and not isinstance(errors, str): raise TypeError("invalid errors: %r" % errors) modes = set(mode) - if modes - set("arwb+tU") or len(mode) > len(modes): + if modes - set("axrwb+tU") or len(mode) > len(modes): raise ValueError("invalid mode: %r" % mode) + creating = "x" in modes reading = "r" in modes writing = "w" in modes appending = "a" in modes @@ -166,14 +170,14 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None, text = "t" in modes binary = "b" in modes if "U" in modes: - if writing or appending: + if creating or 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: + if creating + reading + writing + appending > 1: raise ValueError("can't have read/write/append mode at once") - if not (reading or writing or appending): + if not (creating or 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") @@ -182,11 +186,12 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None, if binary and newline is not None: raise ValueError("binary mode doesn't take a newline argument") raw = FileIO(file, + (creating and "x" or "") + (reading and "r" or "") + (writing and "w" or "") + (appending and "a" or "") + (updating and "+" or ""), - closefd) + closefd, opener=opener) line_buffering = False if buffering == 1 or buffering < 0 and raw.isatty(): buffering = -1 @@ -208,7 +213,7 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None, raise ValueError("can't have unbuffered text I/O") if updating: buffer = BufferedRandom(raw, buffering) - elif writing or appending: + elif creating or writing or appending: buffer = BufferedWriter(raw, buffering) elif reading: buffer = BufferedReader(raw, buffering) @@ -305,6 +310,7 @@ class IOBase(metaclass=abc.ABCMeta): * 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 + Some operating systems / file systems could provide additional values. Return an int indicating the new absolute position. """ @@ -340,8 +346,10 @@ class IOBase(metaclass=abc.ABCMeta): This method has no effect if the file is already closed. """ if not self.__closed: - self.flush() - self.__closed = True + try: + self.flush() + finally: + self.__closed = True def __del__(self): """Destructor. Calls close().""" @@ -865,7 +873,7 @@ class BytesIO(BufferedIOBase): elif whence == 2: self._pos = max(0, len(self._buffer) + pos) else: - raise ValueError("invalid whence value") + raise ValueError("unsupported whence value") return self._pos def tell(self): @@ -954,15 +962,19 @@ class BufferedReader(_BufferedIOMixin): # Special case for when the number of bytes to read is unspecified. if n is None or n == -1: self._reset_read_buf() + if hasattr(self.raw, 'readall'): + chunk = self.raw.readall() + if chunk is None: + return buf[pos:] or None + else: + return buf[pos:] + chunk chunks = [buf[pos:]] # Strip the consumed bytes. current_size = 0 while True: # Read until EOF or until read() would block. try: chunk = self.raw.read() - except IOError as e: - if e.errno != EINTR: - raise + except InterruptedError: continue if chunk in empty_values: nodata_val = chunk @@ -984,9 +996,7 @@ class BufferedReader(_BufferedIOMixin): while avail < n: try: chunk = self.raw.read(wanted) - except IOError as e: - if e.errno != EINTR: - raise + except InterruptedError: continue if chunk in empty_values: nodata_val = chunk @@ -1019,9 +1029,7 @@ class BufferedReader(_BufferedIOMixin): while True: try: current = self.raw.read(to_read) - except IOError as e: - if e.errno != EINTR: - raise + except InterruptedError: continue break if current: @@ -1046,7 +1054,7 @@ class BufferedReader(_BufferedIOMixin): return _BufferedIOMixin.tell(self) - len(self._read_buf) + self._read_pos def seek(self, pos, whence=0): - if not (0 <= whence <= 2): + if whence not in valid_seek_flags: raise ValueError("invalid whence value") with self._read_lock: if whence == 1: @@ -1064,19 +1072,13 @@ class BufferedWriter(_BufferedIOMixin): DEFAULT_BUFFER_SIZE. """ - _warning_stack_offset = 2 - - def __init__(self, raw, - buffer_size=DEFAULT_BUFFER_SIZE, max_buffer_size=None): + def __init__(self, raw, buffer_size=DEFAULT_BUFFER_SIZE): if not raw.writable(): raise IOError('"raw" argument must be writable.') _BufferedIOMixin.__init__(self, raw) if buffer_size <= 0: raise ValueError("invalid buffer size") - if max_buffer_size is not None: - warnings.warn("max_buffer_size is deprecated", DeprecationWarning, - self._warning_stack_offset) self.buffer_size = buffer_size self._write_buf = bytearray() self._write_lock = Lock() @@ -1126,13 +1128,11 @@ class BufferedWriter(_BufferedIOMixin): while self._write_buf: try: n = self.raw.write(self._write_buf) + except InterruptedError: + continue except BlockingIOError: raise RuntimeError("self.raw should implement RawIOBase: it " "should not raise BlockingIOError") - except IOError as e: - if e.errno != EINTR: - raise - continue if n is None: raise BlockingIOError( errno.EAGAIN, @@ -1145,8 +1145,8 @@ class BufferedWriter(_BufferedIOMixin): return _BufferedIOMixin.tell(self) + len(self._write_buf) def seek(self, pos, whence=0): - if not (0 <= whence <= 2): - raise ValueError("invalid whence") + if whence not in valid_seek_flags: + raise ValueError("invalid whence value") with self._write_lock: self._flush_unlocked() return _BufferedIOMixin.seek(self, pos, whence) @@ -1168,15 +1168,11 @@ class BufferedRWPair(BufferedIOBase): # 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): + def __init__(self, reader, writer, buffer_size=DEFAULT_BUFFER_SIZE): """Constructor. The arguments are two RawIO instances. """ - if max_buffer_size is not None: - warnings.warn("max_buffer_size is deprecated", DeprecationWarning, 2) - if not reader.readable(): raise IOError('"reader" argument must be readable.') @@ -1233,17 +1229,14 @@ class BufferedRandom(BufferedWriter, BufferedReader): defaults to DEFAULT_BUFFER_SIZE. """ - _warning_stack_offset = 3 - - def __init__(self, raw, - buffer_size=DEFAULT_BUFFER_SIZE, max_buffer_size=None): + def __init__(self, raw, buffer_size=DEFAULT_BUFFER_SIZE): raw._checkSeekable() BufferedReader.__init__(self, raw, buffer_size) - BufferedWriter.__init__(self, raw, buffer_size, max_buffer_size) + BufferedWriter.__init__(self, raw, buffer_size) def seek(self, pos, whence=0): - if not (0 <= whence <= 2): - raise ValueError("invalid whence") + if whence not in valid_seek_flags: + raise ValueError("invalid whence value") self.flush() if self._read_buf: # Undo read ahead. @@ -1455,7 +1448,7 @@ 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. + decoded or encoded with. It defaults to locale.getpreferredencoding(False). errors determines the strictness of encoding and decoding (see the codecs.register) and defaults to "strict". @@ -1476,6 +1469,9 @@ class TextIOWrapper(TextIOBase): _CHUNK_SIZE = 2048 + # The write_through argument has no effect here since this + # implementation always writes through. The argument is present only + # so that the signature can match the signature of the C version. def __init__(self, buffer, encoding=None, errors=None, newline=None, line_buffering=False, write_through=False): if newline is not None and not isinstance(newline, str): @@ -1494,7 +1490,7 @@ class TextIOWrapper(TextIOBase): # Importing locale may fail if Python is being built encoding = "ascii" else: - encoding = locale.getpreferredencoding() + encoding = locale.getpreferredencoding(False) if not isinstance(encoding, str): raise ValueError("invalid encoding: %r" % encoding) @@ -1521,6 +1517,7 @@ class TextIOWrapper(TextIOBase): self._snapshot = None # info for reconstructing decoder state self._seekable = self._telling = self.buffer.seekable() self._has_read1 = hasattr(self.buffer, 'read1') + self._b2cratio = 0.0 if self._seekable and self.writable(): position = self.buffer.tell() @@ -1589,8 +1586,10 @@ class TextIOWrapper(TextIOBase): def close(self): if self.buffer is not None and not self.closed: - self.flush() - self.buffer.close() + try: + self.flush() + finally: + self.buffer.close() @property def closed(self): @@ -1693,7 +1692,12 @@ class TextIOWrapper(TextIOBase): else: input_chunk = self.buffer.read(self._CHUNK_SIZE) eof = not input_chunk - self._set_decoded_chars(self._decoder.decode(input_chunk, eof)) + decoded_chars = self._decoder.decode(input_chunk, eof) + self._set_decoded_chars(decoded_chars) + if decoded_chars: + self._b2cratio = len(input_chunk) / len(self._decoded_chars) + else: + self._b2cratio = 0.0 if self._telling: # At the snapshot point, len(dec_buffer) bytes before the read, @@ -1747,20 +1751,56 @@ class TextIOWrapper(TextIOBase): # forward until it gives us enough decoded characters. saved_state = decoder.getstate() try: + # Fast search for an acceptable start point, close to our + # current pos. + # Rationale: calling decoder.decode() has a large overhead + # regardless of chunk size; we want the number of such calls to + # be O(1) in most situations (common decoders, non-crazy input). + # Actually, it will be exactly 1 for fixed-size codecs (all + # 8-bit codecs, also UTF-16 and UTF-32). + skip_bytes = int(self._b2cratio * chars_to_skip) + skip_back = 1 + assert skip_bytes <= len(next_input) + while skip_bytes > 0: + decoder.setstate((b'', dec_flags)) + # Decode up to temptative start point + n = len(decoder.decode(next_input[:skip_bytes])) + if n <= chars_to_skip: + b, d = decoder.getstate() + if not b: + # Before pos and no bytes buffered in decoder => OK + dec_flags = d + chars_to_skip -= n + break + # Skip back by buffered amount and reset heuristic + skip_bytes -= len(b) + skip_back = 1 + else: + # We're too far ahead, skip back a bit + skip_bytes -= skip_back + skip_back = skip_back * 2 + else: + skip_bytes = 0 + decoder.setstate((b'', dec_flags)) + # 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 + start_pos = position + skip_bytes + start_flags = dec_flags + if chars_to_skip == 0: + # We haven't moved from the start point. + return self._pack_cookie(start_pos, start_flags) # 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). - next_byte = bytearray(1) - for next_byte[0] in next_input: + bytes_fed = 0 + need_eof = 0 + # Chars decoded since `start_pos` + chars_decoded = 0 + for i in range(skip_bytes, len(next_input)): bytes_fed += 1 - chars_decoded += len(decoder.decode(next_byte)) + chars_decoded += len(decoder.decode(next_input[i:i+1])) 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. @@ -1819,8 +1859,7 @@ class TextIOWrapper(TextIOBase): self._decoder.reset() return position if whence != 0: - raise ValueError("invalid whence (%r, should be 0, 1 or 2)" % - (whence,)) + raise ValueError("unsupported whence (%r)" % (whence,)) if cookie < 0: raise ValueError("negative seek position %r" % (cookie,)) self.flush() |