[android] Do not create Timers on Default main loops

Not supported, because we don't have control over the Looper
timeout like we do for Loopers we create. On the main thread,
Android takes care of making the application sleep and sets
an arbitrary timeout. This could be properly fixed by implementing
timers in Java, but we don't really have the use case of timers
in the main thread.

4 files changed, 12 insertions, 7 deletions

diff --git a/platform/android/src/run_loop.cpp b/platform/android/src/run_loop.cpp
index 6c6d3555e9..1656565e8e 100644
--- a/platform/android/src/run_loop.cpp
+++ b/platform/android/src/run_loop.cpp
@@ -80,6 +80,8 @@ RunLoop::Impl::Impl(RunLoop* runLoop_, RunLoop::Type type) : runLoop(runLoop_) {
     case Type::Default:
         ret = ALooper_addFd(loop, fds[PIPE_OUT], ALOOPER_POLL_CALLBACK,
             ALOOPER_EVENT_INPUT, looperCallbackDefault, this);
+        running = true;
+        isDefaultLoop = true;
         break;
     }
 
diff --git a/platform/android/src/run_loop_impl.hpp b/platform/android/src/run_loop_impl.hpp
index cb553d1f8a..9622efb368 100644
--- a/platform/android/src/run_loop_impl.hpp
+++ b/platform/android/src/run_loop_impl.hpp
@@ -41,6 +41,7 @@ public:
     ALooper* loop = nullptr;
     RunLoop* runLoop = nullptr;
     util::Atomic<bool> running;
+    bool isDefaultLoop = false;
 
 private:
     friend RunLoop;
diff --git a/platform/android/src/timer.cpp b/platform/android/src/timer.cpp
index 81cf0a68b0..6c0dc81eca 100644
--- a/platform/android/src/timer.cpp
+++ b/platform/android/src/timer.cpp
@@ -3,6 +3,7 @@
 #include <mbgl/util/run_loop.hpp>
 #include <mbgl/util/timer.hpp>
 
+#include <cassert>
 #include <functional>
 
 namespace mbgl {
@@ -11,6 +12,7 @@ namespace util {
 class Timer::Impl : public RunLoop::Impl::Runnable {
 public:
     Impl() {
+        assert(!loop->isDefaultLoop);
         loop->initRunnable(this);
     }
 
@@ -35,7 +37,7 @@ public:
     void reschedule() {
         if (repeat != Duration::zero()) {
             due = Clock::now() + repeat;
-            loop->addRunnable(this);
+            loop->wake();
         } else {
             stop();
         }
diff --git a/test/util/timer.cpp b/test/util/timer.cpp
index f6253ab6d3..c37440ed40 100644
--- a/test/util/timer.cpp
+++ b/test/util/timer.cpp
@@ -10,7 +10,7 @@
 using namespace mbgl::util;
 
 TEST(Timer, TEST_REQUIRES_ACCURATE_TIMING(Basic)) {
-    RunLoop loop;
+    RunLoop loop(RunLoop::Type::New);
 
     Timer timer;
 
@@ -34,7 +34,7 @@ TEST(Timer, TEST_REQUIRES_ACCURATE_TIMING(Basic)) {
 }
 
 TEST(Timer, TEST_REQUIRES_ACCURATE_TIMING(Repeat)) {
-    RunLoop loop;
+    RunLoop loop(RunLoop::Type::New);
 
     Timer timer;
 
@@ -60,7 +60,7 @@ TEST(Timer, TEST_REQUIRES_ACCURATE_TIMING(Repeat)) {
 }
 
 TEST(Timer, TEST_REQUIRES_ACCURATE_TIMING(Stop)) {
-    RunLoop loop;
+    RunLoop loop(RunLoop::Type::New);
 
     Timer timer1;
     Timer timer2;
@@ -96,7 +96,7 @@ TEST(Timer, TEST_REQUIRES_ACCURATE_TIMING(Stop)) {
 }
 
 TEST(Timer, TEST_REQUIRES_ACCURATE_TIMING(DestroyShouldStop)) {
-    RunLoop loop;
+    RunLoop loop(RunLoop::Type::New);
 
     auto timer1 = std::make_unique<Timer>();
     Timer timer2;
@@ -132,7 +132,7 @@ TEST(Timer, TEST_REQUIRES_ACCURATE_TIMING(DestroyShouldStop)) {
 }
 
 TEST(Timer, TEST_REQUIRES_ACCURATE_TIMING(StartOverrides)) {
-    RunLoop loop;
+    RunLoop loop(RunLoop::Type::New);
 
     Timer timer;
 
@@ -166,7 +166,7 @@ TEST(Timer, TEST_REQUIRES_ACCURATE_TIMING(StartOverrides)) {
 }
 
 TEST(Timer, TEST_REQUIRES_ACCURATE_TIMING(CanStopNonStartedTimer)) {
-    RunLoop loop;
+    RunLoop loop(RunLoop::Type::New);
 
     Timer timer;
     timer.stop();