os: implement waitable management.

This implements waitable management for Events (and
implements Events). It also refactors PM to use new
Event/Waitable semantics, and also adds STS_ASSERT
as a macro for asserting a boolean expression. The
rest of stratosphere has been refactored to use
STS_ASSERT whenever possible.

stratosphere/libstratosphere/source/os/os_event.cpp

@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2018-2019 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stratosphere.hpp>
+#include "impl/os_waitable_object_list.hpp"
+
+namespace sts::os {
+
+    Event::Event(bool a, bool s) : auto_clear(a), signaled(s) {
+        new (GetPointer(this->waitable_object_list_storage)) impl::WaitableObjectList();
+    }
+
+    Event::~Event() {
+        GetReference(this->waitable_object_list_storage).~WaitableObjectList();
+    }
+
+    void Event::Signal() {
+        std::scoped_lock lk(this->lock);
+
+        /* If we're already signaled, nothing more to do. */
+        if (this->signaled) {
+            return;
+        }
+
+        this->signaled = true;
+
+        /* Signal! */
+        if (this->auto_clear) {
+            /* If we're auto clear, signal one thread, which will clear. */
+            this->cv.Signal();
+        } else {
+            /* If we're manual clear, increment counter and wake all. */
+            this->counter++;
+            this->cv.Broadcast();
+        }
+
+        /* Wake up whatever manager, if any. */
+        GetReference(this->waitable_object_list_storage).SignalAllThreads();
+    }
+
+    void Event::Reset() {
+        std::scoped_lock lk(this->lock);
+        this->signaled = false;
+    }
+
+    void Event::Wait() {
+        std::scoped_lock lk(this->lock);
+
+        u64 cur_counter = this->counter;
+        while (!this->signaled) {
+            if (this->counter != cur_counter) {
+                break;
+            }
+            this->cv.Wait(&this->lock);
+        }
+
+        if (this->auto_clear) {
+            this->signaled = false;
+        }
+    }
+
+    bool Event::TryWait() {
+        std::scoped_lock lk(this->lock);
+
+        const bool success = this->signaled;
+        if (this->auto_clear) {
+            this->signaled = false;
+        }
+
+        return success;
+    }
+
+    bool Event::TimedWait(u64 ns) {
+        TimeoutHelper timeout_helper(ns);
+        std::scoped_lock lk(this->lock);
+
+        u64 cur_counter = this->counter;
+        while (!this->signaled) {
+            if (this->counter != cur_counter) {
+                break;
+            }
+            if (R_FAILED(this->cv.TimedWait(&this->lock, timeout_helper.NsUntilTimeout()))) {
+                return false;
+            }
+        }
+
+        if (this->auto_clear) {
+            this->signaled = false;
+        }
+
+        return true;
+    }
+
+}