--- /dev/null
+<?php
+
+/**
+ * Reads lines of work from an input stream and farms them out to multiple
+ * child streams. Each child has exactly one piece of work in flight at a given
+ * moment. Writes the result of child's work to an output stream. If numProcs
+ * <= zero the work will be performed in process.
+ *
+ * This class amends ForkController with the requirement that the output is
+ * produced in the same exact order as input values were.
+ *
+ * Currently used by CirrusSearch extension to implement CLI search script.
+ *
+ * @ingroup Maintenance
+ * @since 1.30
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+class OrderedStreamingForkController extends ForkController {
+ /** @var callable */
+ protected $workCallback;
+ /** @var resource */
+ protected $input;
+ /** @var resource */
+ protected $output;
+ /** @var int */
+ protected $nextOutputId;
+ /** @var string[] Int key indicates order, value is data */
+ protected $delayedOutputData = [];
+
+ /**
+ * @param int $numProcs The number of worker processes to fork
+ * @param callable $workCallback A callback to call in the child process
+ * once for each line of work to process.
+ * @param resource $input A socket to read work lines from
+ * @param resource $output A socket to write the result of work to.
+ */
+ public function __construct( $numProcs, $workCallback, $input, $output ) {
+ parent::__construct( $numProcs );
+ $this->workCallback = $workCallback;
+ $this->input = $input;
+ $this->output = $output;
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ public function start() {
+ if ( $this->procsToStart > 0 ) {
+ $status = parent::start();
+ if ( $status === 'child' ) {
+ $this->consume();
+ }
+ } else {
+ $status = 'parent';
+ $this->consumeNoFork();
+ }
+ return $status;
+ }
+
+ /**
+ * @param int $numProcs
+ * @return string
+ */
+ protected function forkWorkers( $numProcs ) {
+ $this->prepareEnvironment();
+
+ $childSockets = [];
+ // Create the child processes
+ for ( $i = 0; $i < $numProcs; $i++ ) {
+ $sockets = stream_socket_pair( STREAM_PF_UNIX, STREAM_SOCK_STREAM, STREAM_IPPROTO_IP );
+ // Do the fork
+ $pid = pcntl_fork();
+ if ( $pid === -1 || $pid === false ) {
+ echo "Error creating child processes\n";
+ exit( 1 );
+ }
+
+ if ( !$pid ) {
+ $this->initChild();
+ $this->childNumber = $i;
+ $this->input = $sockets[0];
+ $this->output = $sockets[0];
+ fclose( $sockets[1] );
+ return 'child';
+ } else {
+ // This is the parent process
+ $this->children[$pid] = true;
+ fclose( $sockets[0] );
+ $childSockets[] = $sockets[1];
+ }
+ }
+ $this->feedChildren( $childSockets );
+ foreach ( $childSockets as $socket ) {
+ // if a child has already shutdown the sockets will be closed,
+ // closing a second time would raise a warning.
+ if ( is_resource( $socket ) ) {
+ fclose( $socket );
+ }
+ }
+ return 'parent';
+ }
+
+ /**
+ * Child worker process. Reads work from $this->input and writes the
+ * result of that work to $this->output when completed.
+ */
+ protected function consume() {
+ while ( !feof( $this->input ) ) {
+ $line = trim( fgets( $this->input ) );
+ if ( $line ) {
+ list( $id, $data ) = json_decode( $line );
+ $result = call_user_func( $this->workCallback, $data );
+ fwrite( $this->output, json_encode( [ $id, $result ] ) . "\n" );
+ }
+ }
+ }
+
+ /**
+ * Special cased version of self::consume() when no forking occurs
+ */
+ protected function consumeNoFork() {
+ while ( !feof( $this->input ) ) {
+ $line = trim( fgets( $this->input ) );
+ if ( $line ) {
+ $result = call_user_func( $this->workCallback, $line );
+ fwrite( $this->output, "$result\n" );
+ }
+ }
+ }
+
+ /**
+ * Reads lines of work from $this->input and farms them out to
+ * the provided socket.
+ *
+ * @param resource[] $sockets
+ */
+ protected function feedChildren( array $sockets ) {
+ $used = [];
+ $id = 0;
+ $this->nextOutputId = 0;
+
+ while ( !feof( $this->input ) ) {
+ $data = fgets( $this->input );
+ if ( $used ) {
+ do {
+ $this->updateAvailableSockets( $sockets, $used, $sockets ? 0 : 5 );
+ } while ( !$sockets );
+ }
+ $data = trim( $data );
+ if ( !$data ) {
+ continue;
+ }
+ $socket = array_pop( $sockets );
+ fwrite( $socket, json_encode( [ $id++, $data ] ) . "\n" );
+ $used[] = $socket;
+ }
+ while ( $used ) {
+ $this->updateAvailableSockets( $sockets, $used, 5 );
+ }
+ }
+
+ /**
+ * Moves sockets from $used to $sockets when they are available
+ * for more work
+ *
+ * @param resource[] &$sockets List of sockets that are waiting for work
+ * @param resource[] &$used List of sockets currently performing work
+ * @param int $timeout The number of seconds to block waiting. 0 for
+ * non-blocking operation.
+ */
+ protected function updateAvailableSockets( &$sockets, &$used, $timeout ) {
+ $read = $used;
+ $write = $except = [];
+ stream_select( $read, $write, $except, $timeout );
+ foreach ( $read as $socket ) {
+ $line = fgets( $socket );
+ list( $id, $data ) = json_decode( trim( $line ) );
+ $this->receive( (int)$id, $data );
+ $sockets[] = $socket;
+ $idx = array_search( $socket, $used );
+ unset( $used[$idx] );
+ }
+ }
+
+ /**
+ * @param int $id
+ * @param string $data
+ */
+ protected function receive( $id, $data ) {
+ if ( $id !== $this->nextOutputId ) {
+ $this->delayedOutputData[$id] = $data;
+ return;
+ }
+ fwrite( $this->output, $data . "\n" );
+ $this->nextOutputId = $id + 1;
+ while ( isset( $this->delayedOutputData[$this->nextOutputId] ) ) {
+ fwrite( $this->output, $this->delayedOutputData[$this->nextOutputId] . "\n" );
+ unset( $this->delayedOutputData[$this->nextOutputId] );
+ $this->nextOutputId++;
+ }
+ }
+}
dépôts / lhc / web / wiklou.git / commitdiff