From 731f917dc31edcffec2c6a777f3698c33bea8f01 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Florian=20Wolfsj=C3=A4ger?= <florian@wolfsjaeger.at>
Date: Thu, 28 Oct 2021 10:31:13 +0200
Subject: [PATCH] [Filesystem] Add third argument `$lockFile` to
 `Filesystem::appendToFile()`

---
 CHANGELOG.md   | 1 +
 Filesystem.php | 7 +++++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 41e6405ee..fcb7170ca 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@ CHANGELOG
 ---
 
  * Add `Path` class
+ * Add `$lock` argument to `Filesystem::appendToFile()`
 
 5.0.0
 -----
diff --git a/Filesystem.php b/Filesystem.php
index 4ec9cb24c..524d17c2b 100644
--- a/Filesystem.php
+++ b/Filesystem.php
@@ -692,10 +692,11 @@ public function dumpFile(string $filename, $content)
      * Appends content to an existing file.
      *
      * @param string|resource $content The content to append
+     * @param bool            $lock    Whether the file should be locked when writing to it
      *
      * @throws IOException If the file is not writable
      */
-    public function appendToFile(string $filename, $content)
+    public function appendToFile(string $filename, $content/*, bool $lock = false*/)
     {
         if (\is_array($content)) {
             throw new \TypeError(sprintf('Argument 2 passed to "%s()" must be string or resource, array given.', __METHOD__));
@@ -707,7 +708,9 @@ public function appendToFile(string $filename, $content)
             $this->mkdir($dir);
         }
 
-        if (false === self::box('file_put_contents', $filename, $content, \FILE_APPEND)) {
+        $lock = \func_num_args() > 2 && func_get_arg(2);
+
+        if (false === self::box('file_put_contents', $filename, $content, \FILE_APPEND | ($lock ? \LOCK_EX : 0))) {
             throw new IOException(sprintf('Failed to write file "%s": ', $filename).self::$lastError, 0, null, $filename);
         }
     }