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|
<?php
namespace React\Promise\Stream;
use Evenement\EventEmitter;
use InvalidArgumentException;
use React\Promise\CancellablePromiseInterface;
use React\Promise\PromiseInterface;
use React\Stream\WritableStreamInterface;
/**
* @internal
* @see unwrapWritable() instead
*/
class UnwrapWritableStream extends EventEmitter implements WritableStreamInterface
{
private $promise;
private $stream;
private $buffer = array();
private $closed = false;
private $ending = false;
/**
* Instantiate new unwrapped writable stream for given `Promise` which resolves with a `WritableStreamInterface`.
*
* @param PromiseInterface $promise Promise<WritableStreamInterface, Exception>
*/
public function __construct(PromiseInterface $promise)
{
$out = $this;
$store =& $this->stream;
$buffer =& $this->buffer;
$ending =& $this->ending;
$closed =& $this->closed;
$this->promise = $promise->then(
function ($stream) {
if (!$stream instanceof WritableStreamInterface) {
throw new InvalidArgumentException('Not a writable stream');
}
return $stream;
}
)->then(
function (WritableStreamInterface $stream) use ($out, &$store, &$buffer, &$ending, &$closed) {
// stream is already closed, make sure to close output stream
if (!$stream->isWritable()) {
$out->close();
return $stream;
}
// resolves but output is already closed, make sure to close stream silently
if ($closed) {
$stream->close();
return $stream;
}
// forward drain events for back pressure
$stream->on('drain', function () use ($out) {
$out->emit('drain', array($out));
});
// error events cancel output stream
$stream->on('error', function ($error) use ($out) {
$out->emit('error', array($error, $out));
$out->close();
});
// close both streams once either side closes
$stream->on('close', array($out, 'close'));
$out->on('close', array($stream, 'close'));
if ($buffer) {
// flush buffer to stream and check if its buffer is not exceeded
$drained = true;
foreach ($buffer as $chunk) {
if (!$stream->write($chunk)) {
$drained = false;
}
}
$buffer = array();
if ($drained) {
// signal drain event, because the output stream previous signalled a full buffer
$out->emit('drain', array($out));
}
}
if ($ending) {
$stream->end();
} else {
$store = $stream;
}
return $stream;
},
function ($e) use ($out, &$closed) {
if (!$closed) {
$out->emit('error', array($e, $out));
$out->close();
}
}
);
}
public function write($data)
{
if ($this->ending) {
return false;
}
// forward to inner stream if possible
if ($this->stream !== null) {
return $this->stream->write($data);
}
// append to buffer and signal the buffer is full
$this->buffer[] = $data;
return false;
}
public function end($data = null)
{
if ($this->ending) {
return;
}
$this->ending = true;
// forward to inner stream if possible
if ($this->stream !== null) {
return $this->stream->end($data);
}
// append to buffer
if ($data !== null) {
$this->buffer[] = $data;
}
}
public function isWritable()
{
return !$this->ending;
}
public function close()
{
if ($this->closed) {
return;
}
$this->buffer = array();
$this->ending = true;
$this->closed = true;
// try to cancel promise once the stream closes
if ($this->promise instanceof CancellablePromiseInterface) {
$this->promise->cancel();
}
$this->promise = $this->stream = null;
$this->emit('close');
$this->removeAllListeners();
}
}
|
