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Diffstat (limited to 'vendor/react/stream/src/WritableStreamInterface.php')
| -rw-r--r-- | vendor/react/stream/src/WritableStreamInterface.php | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/vendor/react/stream/src/WritableStreamInterface.php b/vendor/react/stream/src/WritableStreamInterface.php new file mode 100644 index 0000000..9b54680 --- /dev/null +++ b/vendor/react/stream/src/WritableStreamInterface.php @@ -0,0 +1,347 @@ +<?php + +namespace React\Stream; + +use Evenement\EventEmitterInterface; + +/** + * The `WritableStreamInterface` is responsible for providing an interface for + * write-only streams and the writable side of duplex streams. + * + * Besides defining a few methods, this interface also implements the + * `EventEmitterInterface` which allows you to react to certain events: + * + * drain event: + * The `drain` event will be emitted whenever the write buffer became full + * previously and is now ready to accept more data. + * + * ```php + * $stream->on('drain', function () use ($stream) { + * echo 'Stream is now ready to accept more data'; + * }); + * ``` + * + * This event SHOULD be emitted once every time the buffer became full + * previously and is now ready to accept more data. + * In other words, this event MAY be emitted any number of times, which may + * be zero times if the buffer never became full in the first place. + * This event SHOULD NOT be emitted if the buffer has not become full + * previously. + * + * This event is mostly used internally, see also `write()` for more details. + * + * pipe event: + * The `pipe` event will be emitted whenever a readable stream is `pipe()`d + * into this stream. + * The event receives a single `ReadableStreamInterface` argument for the + * source stream. + * + * ```php + * $stream->on('pipe', function (ReadableStreamInterface $source) use ($stream) { + * echo 'Now receiving piped data'; + * + * // explicitly close target if source emits an error + * $source->on('error', function () use ($stream) { + * $stream->close(); + * }); + * }); + * + * $source->pipe($stream); + * ``` + * + * This event MUST be emitted once for each readable stream that is + * successfully piped into this destination stream. + * In other words, this event MAY be emitted any number of times, which may + * be zero times if no stream is ever piped into this stream. + * This event MUST NOT be emitted if either the source is not readable + * (closed already) or this destination is not writable (closed already). + * + * This event is mostly used internally, see also `pipe()` for more details. + * + * error event: + * The `error` event will be emitted once a fatal error occurs, usually while + * trying to write to this stream. + * The event receives a single `Exception` argument for the error instance. + * + * ```php + * $stream->on('error', function (Exception $e) { + * echo 'Error: ' . $e->getMessage() . PHP_EOL; + * }); + * ``` + * + * This event SHOULD be emitted once the stream detects a fatal error, such + * as a fatal transmission error. + * It SHOULD NOT be emitted after a previous `error` or `close` event. + * It MUST NOT be emitted if this is not a fatal error condition, such as + * a temporary network issue that did not cause any data to be lost. + * + * After the stream errors, it MUST close the stream and SHOULD thus be + * followed by a `close` event and then switch to non-writable mode, see + * also `close()` and `isWritable()`. + * + * Many common streams (such as a TCP/IP connection or a file-based stream) + * only deal with data transmission and may choose + * to only emit this for a fatal transmission error once and will then + * close (terminate) the stream in response. + * + * If this stream is a `DuplexStreamInterface`, you should also notice + * how the readable side of the stream also implements an `error` event. + * In other words, an error may occur while either reading or writing the + * stream which should result in the same error processing. + * + * close event: + * The `close` event will be emitted once the stream closes (terminates). + * + * ```php + * $stream->on('close', function () { + * echo 'CLOSED'; + * }); + * ``` + * + * This event SHOULD be emitted once or never at all, depending on whether + * the stream ever terminates. + * It SHOULD NOT be emitted after a previous `close` event. + * + * After the stream is closed, it MUST switch to non-writable mode, + * see also `isWritable()`. + * + * This event SHOULD be emitted whenever the stream closes, irrespective of + * whether this happens implicitly due to an unrecoverable error or + * explicitly when either side closes the stream. + * + * Many common streams (such as a TCP/IP connection or a file-based stream) + * will likely choose to emit this event after flushing the buffer from + * the `end()` method, after receiving a *successful* `end` event or after + * a fatal transmission `error` event. + * + * If this stream is a `DuplexStreamInterface`, you should also notice + * how the readable side of the stream also implements a `close` event. + * In other words, after receiving this event, the stream MUST switch into + * non-writable AND non-readable mode, see also `isReadable()`. + * Note that this event should not be confused with the `end` event. + * + * The event callback functions MUST be a valid `callable` that obeys strict + * parameter definitions and MUST accept event parameters exactly as documented. + * The event callback functions MUST NOT throw an `Exception`. + * The return value of the event callback functions will be ignored and has no + * effect, so for performance reasons you're recommended to not return any + * excessive data structures. + * + * Every implementation of this interface MUST follow these event semantics in + * order to be considered a well-behaving stream. + * + * > Note that higher-level implementations of this interface may choose to + * define additional events with dedicated semantics not defined as part of + * this low-level stream specification. Conformance with these event semantics + * is out of scope for this interface, so you may also have to refer to the + * documentation of such a higher-level implementation. + * + * @see EventEmitterInterface + * @see DuplexStreamInterface + */ +interface WritableStreamInterface extends EventEmitterInterface +{ + /** + * Checks whether this stream is in a writable state (not closed already). + * + * This method can be used to check if the stream still accepts writing + * any data or if it is ended or closed already. + * Writing any data to a non-writable stream is a NO-OP: + * + * ```php + * assert($stream->isWritable() === false); + * + * $stream->write('end'); // NO-OP + * $stream->end('end'); // NO-OP + * ``` + * + * A successfully opened stream always MUST start in writable mode. + * + * Once the stream ends or closes, it MUST switch to non-writable mode. + * This can happen any time, explicitly through `end()` or `close()` or + * implicitly due to a remote close or an unrecoverable transmission error. + * Once a stream has switched to non-writable mode, it MUST NOT transition + * back to writable mode. + * + * If this stream is a `DuplexStreamInterface`, you should also notice + * how the readable side of the stream also implements an `isReadable()` + * method. Unless this is a half-open duplex stream, they SHOULD usually + * have the same return value. + * + * @return bool + */ + public function isWritable(); + + /** + * Write some data into the stream. + * + * A successful write MUST be confirmed with a boolean `true`, which means + * that either the data was written (flushed) immediately or is buffered and + * scheduled for a future write. Note that this interface gives you no + * control over explicitly flushing the buffered data, as finding the + * appropriate time for this is beyond the scope of this interface and left + * up to the implementation of this interface. + * + * Many common streams (such as a TCP/IP connection or file-based stream) + * may choose to buffer all given data and schedule a future flush by using + * an underlying EventLoop to check when the resource is actually writable. + * + * If a stream cannot handle writing (or flushing) the data, it SHOULD emit + * an `error` event and MAY `close()` the stream if it can not recover from + * this error. + * + * If the internal buffer is full after adding `$data`, then `write()` + * SHOULD return `false`, indicating that the caller should stop sending + * data until the buffer drains. + * The stream SHOULD send a `drain` event once the buffer is ready to accept + * more data. + * + * Similarly, if the the stream is not writable (already in a closed state) + * it MUST NOT process the given `$data` and SHOULD return `false`, + * indicating that the caller should stop sending data. + * + * The given `$data` argument MAY be of mixed type, but it's usually + * recommended it SHOULD be a `string` value or MAY use a type that allows + * representation as a `string` for maximum compatibility. + * + * Many common streams (such as a TCP/IP connection or a file-based stream) + * will only accept the raw (binary) payload data that is transferred over + * the wire as chunks of `string` values. + * + * Due to the stream-based nature of this, the sender may send any number + * of chunks with varying sizes. There are no guarantees that these chunks + * will be received with the exact same framing the sender intended to send. + * In other words, many lower-level protocols (such as TCP/IP) transfer the + * data in chunks that may be anywhere between single-byte values to several + * dozens of kilobytes. You may want to apply a higher-level protocol to + * these low-level data chunks in order to achieve proper message framing. + * + * @param mixed|string $data + * @return bool + */ + public function write($data); + + /** + * Successfully ends the stream (after optionally sending some final data). + * + * This method can be used to successfully end the stream, i.e. close + * the stream after sending out all data that is currently buffered. + * + * ```php + * $stream->write('hello'); + * $stream->write('world'); + * $stream->end(); + * ``` + * + * If there's no data currently buffered and nothing to be flushed, then + * this method MAY `close()` the stream immediately. + * + * If there's still data in the buffer that needs to be flushed first, then + * this method SHOULD try to write out this data and only then `close()` + * the stream. + * Once the stream is closed, it SHOULD emit a `close` event. + * + * Note that this interface gives you no control over explicitly flushing + * the buffered data, as finding the appropriate time for this is beyond the + * scope of this interface and left up to the implementation of this + * interface. + * + * Many common streams (such as a TCP/IP connection or file-based stream) + * may choose to buffer all given data and schedule a future flush by using + * an underlying EventLoop to check when the resource is actually writable. + * + * You can optionally pass some final data that is written to the stream + * before ending the stream. If a non-`null` value is given as `$data`, then + * this method will behave just like calling `write($data)` before ending + * with no data. + * + * ```php + * // shorter version + * $stream->end('bye'); + * + * // same as longer version + * $stream->write('bye'); + * $stream->end(); + * ``` + * + * After calling this method, the stream MUST switch into a non-writable + * mode, see also `isWritable()`. + * This means that no further writes are possible, so any additional + * `write()` or `end()` calls have no effect. + * + * ```php + * $stream->end(); + * assert($stream->isWritable() === false); + * + * $stream->write('nope'); // NO-OP + * $stream->end(); // NO-OP + * ``` + * + * If this stream is a `DuplexStreamInterface`, calling this method SHOULD + * also end its readable side, unless the stream supports half-open mode. + * In other words, after calling this method, these streams SHOULD switch + * into non-writable AND non-readable mode, see also `isReadable()`. + * This implies that in this case, the stream SHOULD NOT emit any `data` + * or `end` events anymore. + * Streams MAY choose to use the `pause()` method logic for this, but + * special care may have to be taken to ensure a following call to the + * `resume()` method SHOULD NOT continue emitting readable events. + * + * Note that this method should not be confused with the `close()` method. + * + * @param mixed|string|null $data + * @return void + */ + public function end($data = null); + + /** + * Closes the stream (forcefully). + * + * This method can be used to forcefully close the stream, i.e. close + * the stream without waiting for any buffered data to be flushed. + * If there's still data in the buffer, this data SHOULD be discarded. + * + * ```php + * $stream->close(); + * ``` + * + * Once the stream is closed, it SHOULD emit a `close` event. + * Note that this event SHOULD NOT be emitted more than once, in particular + * if this method is called multiple times. + * + * After calling this method, the stream MUST switch into a non-writable + * mode, see also `isWritable()`. + * This means that no further writes are possible, so any additional + * `write()` or `end()` calls have no effect. + * + * ```php + * $stream->close(); + * assert($stream->isWritable() === false); + * + * $stream->write('nope'); // NO-OP + * $stream->end(); // NO-OP + * ``` + * + * Note that this method should not be confused with the `end()` method. + * Unlike the `end()` method, this method does not take care of any existing + * buffers and simply discards any buffer contents. + * Likewise, this method may also be called after calling `end()` on a + * stream in order to stop waiting for the stream to flush its final data. + * + * ```php + * $stream->end(); + * Loop::addTimer(1.0, function () use ($stream) { + * $stream->close(); + * }); + * ``` + * + * If this stream is a `DuplexStreamInterface`, you should also notice + * how the readable side of the stream also implements a `close()` method. + * In other words, after calling this method, the stream MUST switch into + * non-writable AND non-readable mode, see also `isReadable()`. + * + * @return void + * @see ReadableStreamInterface::close() + */ + public function close(); +} |