--- /dev/null
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Process;
+
+use Symfony\Component\Process\Exception\RuntimeException;
+
+/**
+ * Provides a way to continuously write to the input of a Process until the InputStream is closed.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+class InputStream implements \IteratorAggregate
+{
+ private $onEmpty = null;
+ private $input = array();
+ private $open = true;
+
+ /**
+ * Sets a callback that is called when the write buffer becomes empty.
+ */
+ public function onEmpty(callable $onEmpty = null)
+ {
+ $this->onEmpty = $onEmpty;
+ }
+
+ /**
+ * Appends an input to the write buffer.
+ *
+ * @param resource|scalar|\Traversable|null The input to append as stream resource, scalar or \Traversable
+ */
+ public function write($input)
+ {
+ if (null === $input) {
+ return;
+ }
+ if ($this->isClosed()) {
+ throw new RuntimeException(sprintf('%s is closed', static::class));
+ }
+ $this->input[] = ProcessUtils::validateInput(__METHOD__, $input);
+ }
+
+ /**
+ * Closes the write buffer.
+ */
+ public function close()
+ {
+ $this->open = false;
+ }
+
+ /**
+ * Tells whether the write buffer is closed or not.
+ */
+ public function isClosed()
+ {
+ return !$this->open;
+ }
+
+ public function getIterator()
+ {
+ $this->open = true;
+
+ while ($this->open || $this->input) {
+ if (!$this->input) {
+ yield '';
+ continue;
+ }
+ $current = array_shift($this->input);
+
+ if ($current instanceof \Iterator) {
+ foreach ($current as $cur) {
+ yield $cur;
+ }
+ } else {
+ yield $current;
+ }
+ if (!$this->input && $this->open && null !== $onEmpty = $this->onEmpty) {
+ $this->write($onEmpty($this));
+ }
+ }
+ }
+}