Make the dependency on stdbuf optional for everything but notify

src/Exception/DependencyException.php

@@ -0,0 +1,11 @@
+<?php
+/**
+ * Copyright (c) 2016 Robin Appelman <icewind@owncloud.com>
+ * This file is licensed under the Licensed under the MIT license:
+ * http://opensource.org/licenses/MIT
+ */
+
+namespace Icewind\SMB\Exception;
+
+class DependencyException extends Exception {
+}

src/Share.php

@@ -8,6 +8,7 @@
 namespace Icewind\SMB;
 
 use Icewind\SMB\Exception\ConnectionException;
+use Icewind\SMB\Exception\DependencyException;
 use Icewind\SMB\Exception\FileInUseException;
 use Icewind\SMB\Exception\InvalidTypeException;
 use Icewind\SMB\Exception\NotFoundException;
@@ -53,7 +54,8 @@ class Share extends AbstractShare {
 
 	protected function getConnection() {
 		$workgroupArgument = ($this->server->getWorkgroup()) ? ' -W ' . escapeshellarg($this->server->getWorkgroup()) : '';
-		$command = sprintf('stdbuf -o0 %s %s --authentication-file=%s %s',
+		$command = sprintf('%s%s %s --authentication-file=%s %s',
+			$this->system->hasStdBuf() ? 'stdbuf -o0 ' : '',
 			$this->system->getSmbclientPath(),
 			$workgroupArgument,
 			System::getFD(3),
@@ -353,8 +355,13 @@ class Share extends AbstractShare {
 	 * @param string $path
 	 * @param callable $callback callable which will be called for each received change
 	 * @return mixed
+	 * @throws ConnectionException
+	 * @throws DependencyException
 	 */
 	public function notify($path, callable $callback) {
+		if (!$this->system->hasStdBuf()) { //stdbuf is required to disable smbclient's output buffering
+			throw new DependencyException('stdbuf is required for usage of the notify command');
+		}
 		$connection = $this->getConnection(); // use a fresh connection since the notify command blocks the process
 		$command = 'notify ' . $this->escapePath($path);
 		$connection->write($command . PHP_EOL);

src/System.php

@@ -14,6 +14,8 @@ class System {
 
 	private $net;
 
+	private $stdbuf;
+
 	public static function getFD($num) {
 		$folders = array(
 			'/proc/self/fd',
@@ -40,4 +42,14 @@ class System {
 		}
 		return $this->net;
 	}
+
+	public function hasStdBuf() {
+		if (!$this->stdbuf) {
+			$result = null;
+			$output = array();
+			exec('which stdbuf 2>&1', $output, $result);
+			$this->stdbuf = $result === 0;
+		}
+		return $this->stdbuf;
+	}
 }