add stream wrapper to calculate hash on write

src/HashWrapper.php

@@ -23,15 +23,8 @@
 
 namespace Icewind\Streams;
 
-/**
- * Wrapper that calculates the hash on the stream on read
- *
- * The stream and hash should be passed in when wrapping the stream.
- * On close the callback will be called with the calculated checksum.
- *
- * For supported hashes see: http://php.net/manual/en/function.hash-algos.php
- */
-class HashWrapper extends Wrapper {
+
+abstract class HashWrapper extends Wrapper {
 
 	/**
 	 * @var callable
@@ -49,15 +42,15 @@ class HashWrapper extends Wrapper {
 	 * @param resource $source
 	 * @param string $hash
 	 * @param callable $callback
-	 * @return resource
+	 * @return resource|bool
 	 *
 	 * @throws \BadMethodCallException
 	 */
 	public static function wrap($source, $hash, $callback) {
-		$context = array(
+		$context = [
 			'hash' => $hash,
 			'callback' => $callback,
-		);
+		];
 		return self::wrapSource($source, $context);
 	}
 
@@ -72,12 +65,8 @@ class HashWrapper extends Wrapper {
 		return true;
 	}
 
-	public function stream_read($count) {
-		$data = parent::stream_read($count);
-		if ($this->hashContext !== false) {
-			hash_update($this->hashContext, $data);
-		}
-		return $data;
+	protected function updateHash($data) {
+		hash_update($this->hashContext, $data);
 	}
 
 	public function stream_close() {
@@ -87,4 +76,5 @@ class HashWrapper extends Wrapper {
 		}
 		return parent::stream_close();
 	}
-}
+
+}

src/ReadHashWrapper.php

@@ -0,0 +1,40 @@
+<?php
+/**
+ * @copyright Copyright (c) 2019, Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * @author Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Icewind\Streams;
+
+/**
+ * Wrapper that calculates the hash on the stream on read
+ *
+ * The stream and hash should be passed in when wrapping the stream.
+ * On close the callback will be called with the calculated checksum.
+ *
+ * For supported hashes see: http://php.net/manual/en/function.hash-algos.php
+ */
+class ReadHashWrapper extends HashWrapper {
+	public function stream_read($count) {
+		$data = parent::stream_read($count);
+		$this->updateHash($data);
+		return $data;
+	}
+}

src/WriteHashWrapper.php

@@ -0,0 +1,37 @@
+<?php
+/**
+ * @copyright Copyright (c) 2019 Robin Appelman <robin@icewind.nl>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Icewind\Streams;
+
+/**
+ * Wrapper that calculates the hash on the stream on write
+ *
+ * The stream and hash should be passed in when wrapping the stream.
+ * On close the callback will be called with the calculated checksum.
+ *
+ * For supported hashes see: http://php.net/manual/en/function.hash-algos.php
+ */
+class WriteHashWrapper extends HashWrapper {
+	public function stream_write($data) {
+		$this->updateHash($data);
+		return parent::stream_write($data);
+	}
+}