Clear Context in EventLoop at construction time

We were exposing uninitialized memory and hoping our users wouldn't try
to access it.  This is an overly bold assumption.

Change-Id: I286fe5e932354581419059d128563c435b16071b
Signed-off-by: Austin Schuh <austin.schuh@bluerivertech.com>
diff --git a/aos/events/event_loop.cc b/aos/events/event_loop.cc
index df0390c..09a3834 100644
--- a/aos/events/event_loop.cc
+++ b/aos/events/event_loop.cc
@@ -89,6 +89,7 @@
   context_.realtime_event_time = realtime_clock::min_time;
   context_.realtime_remote_time = realtime_clock::min_time;
   context_.queue_index = 0xffffffff;
+  context_.remote_queue_index = 0xffffffffu;
   context_.size = 0;
   context_.data = nullptr;
   context_.buffer_index = -1;
@@ -600,6 +601,19 @@
   return result;
 }
 
+void EventLoop::ClearContext() {
+  context_.monotonic_event_time = monotonic_clock::min_time;
+  context_.monotonic_remote_time = monotonic_clock::min_time;
+  context_.realtime_event_time = realtime_clock::min_time;
+  context_.realtime_remote_time = realtime_clock::min_time;
+  context_.queue_index = 0xffffffffu;
+  context_.remote_queue_index = 0xffffffffu;
+  context_.size = 0u;
+  context_.data = nullptr;
+  context_.buffer_index = -1;
+  context_.source_boot_uuid = boot_uuid();
+}
+
 void EventLoop::SetTimerContext(
     monotonic_clock::time_point monotonic_event_time) {
   context_.monotonic_event_time = monotonic_event_time;
@@ -607,6 +621,7 @@
   context_.realtime_event_time = realtime_clock::min_time;
   context_.realtime_remote_time = realtime_clock::min_time;
   context_.queue_index = 0xffffffffu;
+  context_.remote_queue_index = 0xffffffffu;
   context_.size = 0u;
   context_.data = nullptr;
   context_.buffer_index = -1;
diff --git a/aos/events/event_loop.h b/aos/events/event_loop.h
index 27f0c76..ff1183f 100644
--- a/aos/events/event_loop.h
+++ b/aos/events/event_loop.h
@@ -856,6 +856,8 @@
   // Sets context_ for a timed event which is supposed to happen at the provided
   // time.
   void SetTimerContext(monotonic_clock::time_point monotonic_event_time);
+  // Clears context_ so it only has invalid times and elements in it.
+  void ClearContext();
 
  private:
   virtual pid_t GetTid() = 0;
diff --git a/aos/events/event_loop_param_test.cc b/aos/events/event_loop_param_test.cc
index 118b9ae..990cbe5 100644
--- a/aos/events/event_loop_param_test.cc
+++ b/aos/events/event_loop_param_test.cc
@@ -2562,6 +2562,17 @@
 TEST_P(AbstractEventLoopTest, SetContextOnRun) {
   auto loop = MakePrimary();
 
+  EXPECT_EQ(loop->context().monotonic_event_time, monotonic_clock::min_time);
+  EXPECT_EQ(loop->context().monotonic_remote_time, monotonic_clock::min_time);
+  EXPECT_EQ(loop->context().realtime_event_time, realtime_clock::min_time);
+  EXPECT_EQ(loop->context().realtime_remote_time, realtime_clock::min_time);
+  EXPECT_EQ(loop->context().source_boot_uuid, loop->boot_uuid());
+  EXPECT_EQ(loop->context().queue_index, 0xffffffffu);
+  EXPECT_EQ(loop->context().remote_queue_index, 0xffffffffu);
+  EXPECT_EQ(loop->context().size, 0u);
+  EXPECT_EQ(loop->context().data, nullptr);
+  EXPECT_EQ(loop->context().buffer_index, -1);
+
   // We want to check that monotonic event time is before monotonic now
   // called inside of callback, but after time point obtained callback.
   aos::monotonic_clock::time_point monotonic_event_time_on_run;
@@ -2574,6 +2585,7 @@
     EXPECT_EQ(loop->context().realtime_remote_time, realtime_clock::min_time);
     EXPECT_EQ(loop->context().source_boot_uuid, loop->boot_uuid());
     EXPECT_EQ(loop->context().queue_index, 0xffffffffu);
+    EXPECT_EQ(loop->context().remote_queue_index, 0xffffffffu);
     EXPECT_EQ(loop->context().size, 0u);
     EXPECT_EQ(loop->context().data, nullptr);
     EXPECT_EQ(loop->context().buffer_index, -1);
@@ -2585,6 +2597,17 @@
       loop->monotonic_now();
   Run();
   EXPECT_GE(monotonic_event_time_on_run, before_run_time);
+
+  EXPECT_EQ(loop->context().monotonic_event_time, monotonic_clock::min_time);
+  EXPECT_EQ(loop->context().monotonic_remote_time, monotonic_clock::min_time);
+  EXPECT_EQ(loop->context().realtime_event_time, realtime_clock::min_time);
+  EXPECT_EQ(loop->context().realtime_remote_time, realtime_clock::min_time);
+  EXPECT_EQ(loop->context().source_boot_uuid, loop->boot_uuid());
+  EXPECT_EQ(loop->context().queue_index, 0xffffffffu);
+  EXPECT_EQ(loop->context().remote_queue_index, 0xffffffffu);
+  EXPECT_EQ(loop->context().size, 0u);
+  EXPECT_EQ(loop->context().data, nullptr);
+  EXPECT_EQ(loop->context().buffer_index, -1);
 }
 
 // Tests that watchers fail when created on the wrong node.
diff --git a/aos/events/shm_event_loop.cc b/aos/events/shm_event_loop.cc
index 3c89a1c..b2502a7 100644
--- a/aos/events/shm_event_loop.cc
+++ b/aos/events/shm_event_loop.cc
@@ -227,6 +227,7 @@
       name_(FLAGS_application_name),
       node_(MaybeMyNode(configuration)) {
   CHECK(IsInitialized()) << ": Need to initialize AOS first.";
+  ClearContext();
   if (configuration->has_nodes()) {
     CHECK(node_ != nullptr) << ": Couldn't find node in config.";
   }
@@ -1185,6 +1186,7 @@
   // the event loop so the book keeping matches.  Do this in the thread that
   // created the timing reporter.
   timing_report_sender_.reset();
+  ClearContext();
 }
 
 void ShmEventLoop::Exit() { epoll_.Quit(); }
diff --git a/aos/events/simulated_event_loop.cc b/aos/events/simulated_event_loop.cc
index 83857b1..d2328fb 100644
--- a/aos/events/simulated_event_loop.cc
+++ b/aos/events/simulated_event_loop.cc
@@ -572,6 +572,7 @@
         tid_(tid),
         startup_tracker_(std::make_shared<StartupTracker>()),
         options_(options) {
+    ClearContext();
     startup_tracker_->loop = this;
     scheduler_->ScheduleOnStartup([startup_tracker = startup_tracker_]() {
       if (startup_tracker->loop) {
@@ -669,6 +670,7 @@
       ScopedMarkRealtimeRestorer rt(runtime_realtime_priority() > 0);
       SetTimerContext(monotonic_now());
       on_run();
+      ClearContext();
     });
   }
 
@@ -931,6 +933,7 @@
     ScopedMarkRealtimeRestorer rt(
         simulated_event_loop_->runtime_realtime_priority() > 0);
     DoCallCallback([monotonic_now]() { return monotonic_now; }, context);
+    simulated_event_loop_->ClearContext();
   }
 
   msgs_.pop_front();
@@ -1234,6 +1237,7 @@
     ScopedMarkRealtimeRestorer rt(
         simulated_event_loop_->runtime_realtime_priority() > 0);
     Call([monotonic_now]() { return monotonic_now; }, monotonic_now);
+    simulated_event_loop_->ClearContext();
   }
 }
 
@@ -1283,6 +1287,7 @@
          [this](monotonic_clock::time_point sleep_time) {
            Schedule(sleep_time);
          });
+    simulated_event_loop_->ClearContext();
   }
 }