From 0963b80234b3be7f4c7256d7ab4d126625dd7a17 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Wed, 8 Jul 2020 11:17:12 -0400
Subject: [PATCH] jtk.timer: make thread safe

---
 src/jtk/init.d  |  4 ++++
 src/jtk/timer.d | 31 +++++++++++++++++++++++++++----
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/src/jtk/init.d b/src/jtk/init.d
index aca3ea5..d6de12c 100644
--- a/src/jtk/init.d
+++ b/src/jtk/init.d
@@ -1,5 +1,7 @@
 module jtk.init;
 
+static import jtk.timer;
+
 private extern(C) bool jtk_init();
 
 bool init()
@@ -9,5 +11,7 @@ bool init()
         return false;
     }
 
+    jtk.timer.Timer.timer_init();
+
     return true;
 }
diff --git a/src/jtk/timer.d b/src/jtk/timer.d
index df053dc..1ce0ac0 100644
--- a/src/jtk/timer.d
+++ b/src/jtk/timer.d
@@ -2,10 +2,14 @@ module jtk.timer;
 
 import jtk.time;
 import std.algorithm;
+import core.sync.mutex;
+
+private extern(C) void jtk_wake();
 
 class Timer
 {
-    private static Timer[Timer] timers;
+    private static __gshared Timer[Timer] timers;
+    private static __gshared Mutex timers_mutex;
 
     private ulong next;
 
@@ -19,12 +23,19 @@ class Timer
         this.next = current_time + (delay * 1000u);
         this.interval = interval * 1000u;
         this.user = user;
+        timers_mutex.lock_nothrow();
         timers[this] = this;
+        timers_mutex.unlock_nothrow();
+        /* Wake the wait loop in case this timer will expire before the
+         * previously calculated timeout. */
+        jtk_wake();
     }
 
     void remove()
     {
+        timers_mutex.lock_nothrow();
         timers.remove(this);
+        timers_mutex.unlock_nothrow();
     }
 
     package void service()
@@ -42,28 +53,40 @@ class Timer
     package static Timer get_expired_timer()
     {
         ulong current_time = us_time();
+        Timer expired_timer = null;
+        timers_mutex.lock_nothrow();
         foreach (Timer timer; timers)
         {
             if (timer.next <= current_time)
             {
-                return timer;
+                expired_timer = timer;
+                break;
             }
         }
-        return null;
+        timers_mutex.unlock_nothrow();
+        return expired_timer;
     }
 
     package static ulong time_to_next_timer_expiration()
     {
         ulong rv = cast(ulong)-1;
         ulong current_time = us_time();
+        timers_mutex.lock_nothrow();
         foreach (Timer timer; timers)
         {
             if (timer.next <= current_time)
             {
-                return 0u;
+                rv = 0u;
+                break;
             }
             rv = min(rv, timer.next - current_time);
         }
+        timers_mutex.unlock_nothrow();
         return rv;
     }
+
+    package static void timer_init()
+    {
+        timers_mutex = new Mutex;
+    }
 }