[android] Implement watch handler in RunLoop

2 files changed, 36 insertions, 4 deletions

diff --git a/platform/android/src/run_loop.cpp b/platform/android/src/run_loop.cpp
index d62816d8cd..c344353fc9 100644
--- a/platform/android/src/run_loop.cpp
+++ b/platform/android/src/run_loop.cpp
@@ -55,6 +55,17 @@ int looperCallbackDefault(int fd, int, void* data) {
     return 1;
 }
 
+int looperCallbackReadEvent(int fd, int, void* data) {
+    auto runLoopImpl = reinterpret_cast<RunLoop::Impl*>(data);
+
+    auto it = runLoopImpl->readPoll.find(fd);
+    if (it != runLoopImpl->readPoll.end()) {
+        assert(it->second);
+        it->second(fd, RunLoop::Event::Read);
+    }
+    return 1;
+}
+
 } // namespace
 
 namespace mbgl {
@@ -243,12 +254,28 @@ void RunLoop::stop() {
     });
 }
 
-void RunLoop::addWatch(int, Event, std::function<void(int, Event)>&&) {
-    throw std::runtime_error("Not implemented.");
+void RunLoop::addWatch(int fd, Event event, std::function<void(int, Event)>&& cb) {
+    MBGL_VERIFY_THREAD(tid);
+
+    if (event == Event::Read) {
+        impl->readPoll[fd] = std::move(cb);
+
+        ALooper* looper = ALooper_forThread();
+        ALooper_addFd(
+            looper, fd, ALOOPER_POLL_CALLBACK, ALOOPER_EVENT_INPUT, looperCallbackReadEvent, this->impl.get());
+    }
 }
 
-void RunLoop::removeWatch(int) {
-    throw std::runtime_error("Not implemented.");
+void RunLoop::removeWatch(int fd) {
+    MBGL_VERIFY_THREAD(tid);
+
+    auto it = impl->readPoll.find(fd);
+    if (it != impl->readPoll.end()) {
+        impl->readPoll.erase(it);
+
+        ALooper* looper = ALooper_forThread();
+        ALooper_removeFd(looper, fd);
+    }
 }
 
 } // namespace util
diff --git a/platform/android/src/run_loop_impl.hpp b/platform/android/src/run_loop_impl.hpp
index c6a1b23a7b..8f0a07f8ba 100644
--- a/platform/android/src/run_loop_impl.hpp
+++ b/platform/android/src/run_loop_impl.hpp
@@ -9,12 +9,15 @@
 #include <list>
 #include <memory>
 #include <mutex>
+#include <unordered_map>
 
 struct ALooper;
 
 namespace mbgl {
 namespace util {
 
+using WatchCallback = std::function<void(int, RunLoop::Event)>;
+
 template <typename T> class Thread;
 class Alarm;
 
@@ -43,6 +46,8 @@ public:
     std::atomic<bool> running;
     std::atomic_flag coalesce = ATOMIC_FLAG_INIT;
 
+    std::unordered_map<int, WatchCallback> readPoll;
+
 private:
     friend RunLoop;