Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 1 | """Stream-related things.""" |
| 2 | |
| 3 | __all__ = ['StreamReader', 'StreamReaderProtocol', 'open_connection'] |
| 4 | |
| 5 | import collections |
| 6 | |
| 7 | from . import events |
| 8 | from . import futures |
| 9 | from . import protocols |
| 10 | from . import tasks |
| 11 | |
| 12 | |
| 13 | _DEFAULT_LIMIT = 2**16 |
| 14 | |
| 15 | |
| 16 | @tasks.coroutine |
| 17 | def open_connection(host=None, port=None, *, |
| 18 | loop=None, limit=_DEFAULT_LIMIT, **kwds): |
| 19 | """A wrapper for create_connection() returning a (reader, writer) pair. |
| 20 | |
| 21 | The reader returned is a StreamReader instance; the writer is a |
| 22 | Transport. |
| 23 | |
| 24 | The arguments are all the usual arguments to create_connection() |
| 25 | except protocol_factory; most common are positional host and port, |
| 26 | with various optional keyword arguments following. |
| 27 | |
| 28 | Additional optional keyword arguments are loop (to set the event loop |
| 29 | instance to use) and limit (to set the buffer limit passed to the |
| 30 | StreamReader). |
| 31 | |
| 32 | (If you want to customize the StreamReader and/or |
| 33 | StreamReaderProtocol classes, just copy the code -- there's |
| 34 | really nothing special here except some convenience.) |
| 35 | """ |
| 36 | if loop is None: |
| 37 | loop = events.get_event_loop() |
| 38 | reader = StreamReader(limit=limit, loop=loop) |
| 39 | protocol = StreamReaderProtocol(reader) |
| 40 | transport, _ = yield from loop.create_connection( |
| 41 | lambda: protocol, host, port, **kwds) |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 42 | writer = StreamWriter(transport, protocol, reader, loop) |
| 43 | return reader, writer |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 44 | |
| 45 | |
| 46 | class StreamReaderProtocol(protocols.Protocol): |
| 47 | """Trivial helper class to adapt between Protocol and StreamReader. |
| 48 | |
| 49 | (This is a helper class instead of making StreamReader itself a |
| 50 | Protocol subclass, because the StreamReader has other potential |
| 51 | uses, and to prevent the user of the StreamReader to accidentally |
| 52 | call inappropriate methods of the protocol.) |
| 53 | """ |
| 54 | |
| 55 | def __init__(self, stream_reader): |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 56 | self._stream_reader = stream_reader |
| 57 | self._drain_waiter = None |
| 58 | self._paused = False |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 59 | |
| 60 | def connection_made(self, transport): |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 61 | self._stream_reader.set_transport(transport) |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 62 | |
| 63 | def connection_lost(self, exc): |
| 64 | if exc is None: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 65 | self._stream_reader.feed_eof() |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 66 | else: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 67 | self._stream_reader.set_exception(exc) |
| 68 | # Also wake up the writing side. |
| 69 | if self._paused: |
| 70 | waiter = self._drain_waiter |
| 71 | if waiter is not None: |
| 72 | self._drain_waiter = None |
| 73 | if not waiter.done(): |
| 74 | if exc is None: |
| 75 | waiter.set_result(None) |
| 76 | else: |
| 77 | waiter.set_exception(exc) |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 78 | |
| 79 | def data_received(self, data): |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 80 | self._stream_reader.feed_data(data) |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 81 | |
| 82 | def eof_received(self): |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 83 | self._stream_reader.feed_eof() |
| 84 | |
| 85 | def pause_writing(self): |
| 86 | assert not self._paused |
| 87 | self._paused = True |
| 88 | |
| 89 | def resume_writing(self): |
| 90 | assert self._paused |
| 91 | self._paused = False |
| 92 | waiter = self._drain_waiter |
| 93 | if waiter is not None: |
| 94 | self._drain_waiter = None |
| 95 | if not waiter.done(): |
| 96 | waiter.set_result(None) |
| 97 | |
| 98 | |
| 99 | class StreamWriter: |
| 100 | """Wraps a Transport. |
| 101 | |
| 102 | This exposes write(), writelines(), [can_]write_eof(), |
| 103 | get_extra_info() and close(). It adds drain() which returns an |
| 104 | optional Future on which you can wait for flow control. It also |
| 105 | adds a transport attribute which references the Transport |
| 106 | directly. |
| 107 | """ |
| 108 | |
| 109 | def __init__(self, transport, protocol, reader, loop): |
| 110 | self._transport = transport |
| 111 | self._protocol = protocol |
| 112 | self._reader = reader |
| 113 | self._loop = loop |
| 114 | |
| 115 | @property |
| 116 | def transport(self): |
| 117 | return self._transport |
| 118 | |
| 119 | def write(self, data): |
| 120 | self._transport.write(data) |
| 121 | |
| 122 | def writelines(self, data): |
| 123 | self._transport.writelines(data) |
| 124 | |
| 125 | def write_eof(self): |
| 126 | return self._transport.write_eof() |
| 127 | |
| 128 | def can_write_eof(self): |
| 129 | return self._transport.can_write_eof() |
| 130 | |
| 131 | def close(self): |
| 132 | return self._transport.close() |
| 133 | |
| 134 | def get_extra_info(self, name, default=None): |
| 135 | return self._transport.get_extra_info(name, default) |
| 136 | |
| 137 | def drain(self): |
| 138 | """This method has an unusual return value. |
| 139 | |
| 140 | The intended use is to write |
| 141 | |
| 142 | w.write(data) |
| 143 | yield from w.drain() |
| 144 | |
| 145 | When there's nothing to wait for, drain() returns (), and the |
| 146 | yield-from continues immediately. When the transport buffer |
| 147 | is full (the protocol is paused), drain() creates and returns |
| 148 | a Future and the yield-from will block until that Future is |
| 149 | completed, which will happen when the buffer is (partially) |
| 150 | drained and the protocol is resumed. |
| 151 | """ |
| 152 | if self._reader._exception is not None: |
| 153 | raise self._writer._exception |
| 154 | if self._transport._conn_lost: # Uses private variable. |
| 155 | raise ConnectionResetError('Connection lost') |
| 156 | if not self._protocol._paused: |
| 157 | return () |
| 158 | waiter = self._protocol._drain_waiter |
| 159 | assert waiter is None or waiter.cancelled() |
| 160 | waiter = futures.Future(loop=self._loop) |
| 161 | self._protocol._drain_waiter = waiter |
| 162 | return waiter |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 163 | |
| 164 | |
| 165 | class StreamReader: |
| 166 | |
| 167 | def __init__(self, limit=_DEFAULT_LIMIT, loop=None): |
| 168 | # The line length limit is a security feature; |
| 169 | # it also doubles as half the buffer limit. |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 170 | self._limit = limit |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 171 | if loop is None: |
| 172 | loop = events.get_event_loop() |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 173 | self._loop = loop |
| 174 | self._buffer = collections.deque() # Deque of bytes objects. |
| 175 | self._byte_count = 0 # Bytes in buffer. |
| 176 | self._eof = False # Whether we're done. |
| 177 | self._waiter = None # A future. |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 178 | self._exception = None |
| 179 | self._transport = None |
| 180 | self._paused = False |
| 181 | |
| 182 | def exception(self): |
| 183 | return self._exception |
| 184 | |
| 185 | def set_exception(self, exc): |
| 186 | self._exception = exc |
| 187 | |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 188 | waiter = self._waiter |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 189 | if waiter is not None: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 190 | self._waiter = None |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 191 | if not waiter.cancelled(): |
| 192 | waiter.set_exception(exc) |
| 193 | |
| 194 | def set_transport(self, transport): |
| 195 | assert self._transport is None, 'Transport already set' |
| 196 | self._transport = transport |
| 197 | |
| 198 | def _maybe_resume_transport(self): |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 199 | if self._paused and self._byte_count <= self._limit: |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 200 | self._paused = False |
Guido van Rossum | 57497ad | 2013-10-18 07:58:20 -0700 | [diff] [blame] | 201 | self._transport.resume_reading() |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 202 | |
| 203 | def feed_eof(self): |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 204 | self._eof = True |
| 205 | waiter = self._waiter |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 206 | if waiter is not None: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 207 | self._waiter = None |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 208 | if not waiter.cancelled(): |
| 209 | waiter.set_result(True) |
| 210 | |
| 211 | def feed_data(self, data): |
| 212 | if not data: |
| 213 | return |
| 214 | |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 215 | self._buffer.append(data) |
| 216 | self._byte_count += len(data) |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 217 | |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 218 | waiter = self._waiter |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 219 | if waiter is not None: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 220 | self._waiter = None |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 221 | if not waiter.cancelled(): |
| 222 | waiter.set_result(False) |
| 223 | |
| 224 | if (self._transport is not None and |
| 225 | not self._paused and |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 226 | self._byte_count > 2*self._limit): |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 227 | try: |
Guido van Rossum | 57497ad | 2013-10-18 07:58:20 -0700 | [diff] [blame] | 228 | self._transport.pause_reading() |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 229 | except NotImplementedError: |
| 230 | # The transport can't be paused. |
| 231 | # We'll just have to buffer all data. |
| 232 | # Forget the transport so we don't keep trying. |
| 233 | self._transport = None |
| 234 | else: |
| 235 | self._paused = True |
| 236 | |
| 237 | @tasks.coroutine |
| 238 | def readline(self): |
| 239 | if self._exception is not None: |
| 240 | raise self._exception |
| 241 | |
| 242 | parts = [] |
| 243 | parts_size = 0 |
| 244 | not_enough = True |
| 245 | |
| 246 | while not_enough: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 247 | while self._buffer and not_enough: |
| 248 | data = self._buffer.popleft() |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 249 | ichar = data.find(b'\n') |
| 250 | if ichar < 0: |
| 251 | parts.append(data) |
| 252 | parts_size += len(data) |
| 253 | else: |
| 254 | ichar += 1 |
| 255 | head, tail = data[:ichar], data[ichar:] |
| 256 | if tail: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 257 | self._buffer.appendleft(tail) |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 258 | not_enough = False |
| 259 | parts.append(head) |
| 260 | parts_size += len(head) |
| 261 | |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 262 | if parts_size > self._limit: |
| 263 | self._byte_count -= parts_size |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 264 | self._maybe_resume_transport() |
| 265 | raise ValueError('Line is too long') |
| 266 | |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 267 | if self._eof: |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 268 | break |
| 269 | |
| 270 | if not_enough: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 271 | assert self._waiter is None |
| 272 | self._waiter = futures.Future(loop=self._loop) |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 273 | try: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 274 | yield from self._waiter |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 275 | finally: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 276 | self._waiter = None |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 277 | |
| 278 | line = b''.join(parts) |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 279 | self._byte_count -= parts_size |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 280 | self._maybe_resume_transport() |
| 281 | |
| 282 | return line |
| 283 | |
| 284 | @tasks.coroutine |
| 285 | def read(self, n=-1): |
| 286 | if self._exception is not None: |
| 287 | raise self._exception |
| 288 | |
| 289 | if not n: |
| 290 | return b'' |
| 291 | |
| 292 | if n < 0: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 293 | while not self._eof: |
| 294 | assert not self._waiter |
| 295 | self._waiter = futures.Future(loop=self._loop) |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 296 | try: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 297 | yield from self._waiter |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 298 | finally: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 299 | self._waiter = None |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 300 | else: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 301 | if not self._byte_count and not self._eof: |
| 302 | assert not self._waiter |
| 303 | self._waiter = futures.Future(loop=self._loop) |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 304 | try: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 305 | yield from self._waiter |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 306 | finally: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 307 | self._waiter = None |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 308 | |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 309 | if n < 0 or self._byte_count <= n: |
| 310 | data = b''.join(self._buffer) |
| 311 | self._buffer.clear() |
| 312 | self._byte_count = 0 |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 313 | self._maybe_resume_transport() |
| 314 | return data |
| 315 | |
| 316 | parts = [] |
| 317 | parts_bytes = 0 |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 318 | while self._buffer and parts_bytes < n: |
| 319 | data = self._buffer.popleft() |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 320 | data_bytes = len(data) |
| 321 | if n < parts_bytes + data_bytes: |
| 322 | data_bytes = n - parts_bytes |
| 323 | data, rest = data[:data_bytes], data[data_bytes:] |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 324 | self._buffer.appendleft(rest) |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 325 | |
| 326 | parts.append(data) |
| 327 | parts_bytes += data_bytes |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 328 | self._byte_count -= data_bytes |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 329 | self._maybe_resume_transport() |
| 330 | |
| 331 | return b''.join(parts) |
| 332 | |
| 333 | @tasks.coroutine |
| 334 | def readexactly(self, n): |
| 335 | if self._exception is not None: |
| 336 | raise self._exception |
| 337 | |
| 338 | if n <= 0: |
| 339 | return b'' |
| 340 | |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 341 | while self._byte_count < n and not self._eof: |
| 342 | assert not self._waiter |
| 343 | self._waiter = futures.Future(loop=self._loop) |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 344 | try: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 345 | yield from self._waiter |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 346 | finally: |
Guido van Rossum | 355491d | 2013-10-18 15:17:11 -0700 | [diff] [blame^] | 347 | self._waiter = None |
Guido van Rossum | 27b7c7e | 2013-10-17 13:40:50 -0700 | [diff] [blame] | 348 | |
| 349 | return (yield from self.read(n)) |