From fc56154edb0d375d4549737a3f34f212c3a0325f Mon Sep 17 00:00:00 2001
From: Simon Vieille <simon@deblan.fr>
Date: Wed, 13 Apr 2022 15:54:45 +0200
Subject: [PATCH] add lock mechanism

---
 server/src/Server.php          | 22 ++++++++++++++++++++++
 server/src/resource/server.php | 12 +++++-------
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/server/src/Server.php b/server/src/Server.php
index d486655..f785e86 100644
--- a/server/src/Server.php
+++ b/server/src/Server.php
@@ -25,6 +25,11 @@ class Server implements MessageComponentInterface
      */
     protected $output;
 
+    /**
+     * @var array
+     */
+    protected $locks = [];
+
     /**
      * Constructor.
      */
@@ -109,4 +114,21 @@ class Server implements MessageComponentInterface
     {
         $conn->close();
     }
+
+    public function addLock($key)
+    {
+        $this->locks[$key] = true;
+    }
+
+    public function hasLock($key)
+    {
+        return isset($this->locks[$key]);
+    }
+
+    public function removeLock($key)
+    {
+        if ($this->hasLock($key)) {
+            unset($this->locks[$key]);
+        }
+    }
 }
diff --git a/server/src/resource/server.php b/server/src/resource/server.php
index 4eb5f53..d5e67ae 100644
--- a/server/src/resource/server.php
+++ b/server/src/resource/server.php
@@ -167,16 +167,14 @@ $server->addMessageHandler('text', function (ConnectionInterface $from, array $d
     }
 });
 
-$server->addMessageHandler('screenshot', function (ConnectionInterface $from, array $data) use ($shell, $messageOutput) {
-    $tmpFilename = sprintf('%s/remote_i3wm_ws_screenshot.lock', sys_get_temp_dir());
-    $qualities = ['hq' => 95, 'lq' => 5];
-
-    if (file_exists($tmpFilename) && time() - filemtime($tmpFilename) < 10) {
+$server->addMessageHandler('screenshot', function (ConnectionInterface $from, array $data) use ($shell, $messageOutput, $server) {
+    if ($server->hasLock('screenshot')) {
         return;
     }
 
-    touch($tmpFilename);
+    $server->addLock('screenshot');
 
+    $qualities = ['hq' => 95, 'lq' => 5];
     $content = $shell->exec(sprintf('import -window root -quality %d -display :0 jpeg:-', $qualities[$data['quality'] ?? 'hq']));
 
     if (!empty($content)) {
@@ -188,7 +186,7 @@ $server->addMessageHandler('screenshot', function (ConnectionInterface $from, ar
         ]));
     }
 
-    unlink($tmpFilename);
+    $server->removeLock('screenshot');
 });
 
 $server->addMessageHandler('messages', function (ConnectionInterface $from, array $data) use ($server, $serverOutput) {