From 1d68837456b9ee7a95fb97d985774c76cf4a5822 Mon Sep 17 00:00:00 2001
From: Brian Gianforcaro <b.gianfo@gmail.com>
Date: Sun, 26 Apr 2020 02:23:37 -0700
Subject: [PATCH] Kernel: Refactor TimeQueue::add_timer to use timeval

The current API of add_timer makes it hard to use as
you are forced to do a bunch of time arithmetic at the
caller. Ideally we would have overloads for common time
types like timespec or timeval to keep the API as straight
forward as possible. This change moves us in that direction.

While I'm here, we should really also use the machines actual
ticks per second, instead of the OPTIMAL_TICKS_PER_SECOND_RATE.
---
 Kernel/TimerQueue.cpp | 12 +++++++++---
 Kernel/TimerQueue.h   | 14 +++++++-------
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/Kernel/TimerQueue.cpp b/Kernel/TimerQueue.cpp
index 0e2add6a3f..4222102b42 100644
--- a/Kernel/TimerQueue.cpp
+++ b/Kernel/TimerQueue.cpp
@@ -28,6 +28,7 @@
 #include <AK/NonnullOwnPtr.h>
 #include <AK/OwnPtr.h>
 #include <Kernel/Scheduler.h>
+#include <Kernel/Time/TimeManagement.h>
 #include <Kernel/TimerQueue.h>
 
 namespace Kernel {
@@ -41,9 +42,14 @@ TimerQueue& TimerQueue::the()
     return *s_the;
 }
 
+TimerQueue::TimerQueue()
+{
+    m_ticks_per_second = TimeManagement::the().ticks_per_second();
+}
+
 u64 TimerQueue::add_timer(NonnullOwnPtr<Timer>&& timer)
 {
-    ASSERT(timer->expires > g_uptime);
+    ASSERT(timer->expires >= g_uptime);
 
     timer->id = ++m_timer_id_count;
 
@@ -58,10 +64,10 @@ u64 TimerQueue::add_timer(NonnullOwnPtr<Timer>&& timer)
     return m_timer_id_count;
 }
 
-u64 TimerQueue::add_timer(u64 duration, TimeUnit unit, Function<void()>&& callback)
+u64 TimerQueue::add_timer(timeval& deadline, Function<void()>&& callback)
 {
     NonnullOwnPtr timer = make<Timer>();
-    timer->expires = g_uptime + duration * unit;
+    timer->expires = g_uptime + seconds_to_ticks(deadline.tv_sec) + microseconds_to_ticks(deadline.tv_usec);
     timer->callback = move(callback);
     return add_timer(move(timer));
 }
diff --git a/Kernel/TimerQueue.h b/Kernel/TimerQueue.h
index 4398a71448..d0fd9d0381 100644
--- a/Kernel/TimerQueue.h
+++ b/Kernel/TimerQueue.h
@@ -52,26 +52,26 @@ struct Timer {
     }
 };
 
-enum TimeUnit {
-    MS = OPTIMAL_TICKS_PER_SECOND_RATE / 1000,
-    S = OPTIMAL_TICKS_PER_SECOND_RATE,
-    M = OPTIMAL_TICKS_PER_SECOND_RATE * 60
-};
-
 class TimerQueue {
 public:
     static TimerQueue& the();
 
     u64 add_timer(NonnullOwnPtr<Timer>&&);
-    u64 add_timer(u64 duration, TimeUnit, Function<void()>&& callback);
+    u64 add_timer(timeval& timeout, Function<void()>&& callback);
     bool cancel_timer(u64 id);
     void fire();
 
 private:
+    TimerQueue();
+
     void update_next_timer_due();
 
+    u64 microseconds_to_ticks(u64 micro_seconds) { return micro_seconds * (m_ticks_per_second / 1'000'000); }
+    u64 seconds_to_ticks(u64 seconds) { return seconds * m_ticks_per_second; }
+
     u64 m_next_timer_due { 0 };
     u64 m_timer_id_count { 0 };
+    u64 m_ticks_per_second { 0 };
     SinglyLinkedList<NonnullOwnPtr<Timer>> m_timer_queue;
 };