120 lines
3.1 KiB
PHP
120 lines
3.1 KiB
PHP
<?php
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namespace Amp\ByteStream;
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use Amp\Promise;
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/**
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* Allows compression of output streams using Zlib.
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*/
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final class ZlibOutputStream implements OutputStream
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{
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/** @var OutputStream|null */
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private $destination;
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/** @var int */
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private $encoding;
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/** @var array */
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private $options;
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/** @var resource|null */
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private $resource;
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/**
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* @param OutputStream $destination Output stream to write the compressed data to.
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* @param int $encoding Compression encoding to use, see `deflate_init()`.
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* @param array $options Compression options to use, see `deflate_init()`.
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*
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* @throws StreamException If an invalid encoding or invalid options have been passed.
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*
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* @see http://php.net/manual/en/function.deflate-init.php
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*/
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public function __construct(OutputStream $destination, int $encoding, array $options = [])
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{
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$this->destination = $destination;
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$this->encoding = $encoding;
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$this->options = $options;
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$this->resource = @\deflate_init($encoding, $options);
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if ($this->resource === false) {
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throw new StreamException("Failed initializing deflate context");
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}
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}
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/** @inheritdoc */
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public function write(string $data): Promise
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{
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if ($this->resource === null) {
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throw new ClosedException("The stream has already been closed");
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}
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\assert($this->destination !== null);
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$compressed = \deflate_add($this->resource, $data, \ZLIB_SYNC_FLUSH);
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if ($compressed === false) {
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throw new StreamException("Failed adding data to deflate context");
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}
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$promise = $this->destination->write($compressed);
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$promise->onResolve(function ($error) {
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if ($error) {
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$this->close();
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}
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});
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return $promise;
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}
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/** @inheritdoc */
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public function end(string $finalData = ""): Promise
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{
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if ($this->resource === null) {
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throw new ClosedException("The stream has already been closed");
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}
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\assert($this->destination !== null);
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$compressed = \deflate_add($this->resource, $finalData, \ZLIB_FINISH);
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if ($compressed === false) {
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throw new StreamException("Failed adding data to deflate context");
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}
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$promise = $this->destination->end($compressed);
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$promise->onResolve(function () {
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$this->close();
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});
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return $promise;
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}
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/**
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* @internal
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* @return void
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*/
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private function close()
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{
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$this->resource = null;
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$this->destination = null;
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}
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/**
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* Gets the used compression encoding.
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*
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* @return int Encoding specified on construction time.
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*/
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public function getEncoding(): int
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{
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return $this->encoding;
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}
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/**
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* Gets the used compression options.
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*
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* @return array Options array passed on construction time.
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*/
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public function getOptions(): array
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{
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return $this->options;
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}
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}
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