[android] attach/detach core thread pool's threads to JVMupstream/lp-thread-detaching-14048

3 files changed, 23 insertions, 7 deletions

diff --git a/platform/android/src/run_loop.cpp b/platform/android/src/run_loop.cpp
index fc45539e5e..d8c9ade3e8 100644
--- a/platform/android/src/run_loop.cpp
+++ b/platform/android/src/run_loop.cpp
@@ -1,6 +1,7 @@
 #include "run_loop_impl.hpp"
 
 #include <mbgl/util/platform.hpp>
+#include <mbgl/platform/thread.hpp>
 #include <mbgl/util/thread_local.hpp>
 #include <mbgl/util/thread.hpp>
 #include <mbgl/util/timer.hpp>
@@ -81,8 +82,7 @@ private:
 };
 
 RunLoop::Impl::Impl(RunLoop* runLoop_, RunLoop::Type type) : runLoop(runLoop_) {
-    using namespace mbgl::android;
-    detach = attach_jni_thread(theJVM, &env, platform::getCurrentThreadName());
+    platform::attachThread();
 
     loop = ALooper_prepare(0);
     assert(loop);
@@ -130,8 +130,7 @@ RunLoop::Impl::~Impl() {
 
     ALooper_release(loop);
 
-    using namespace mbgl::android;
-    detach_jni_thread(theJVM, &env, detach);
+    platform::detachThread();
 }
 
 void RunLoop::Impl::wake() {
diff --git a/platform/android/src/run_loop_impl.hpp b/platform/android/src/run_loop_impl.hpp
index 0a9ea156fd..a76d636188 100644
--- a/platform/android/src/run_loop_impl.hpp
+++ b/platform/android/src/run_loop_impl.hpp
@@ -47,9 +47,6 @@ private:
 
     int fds[2];
 
-    JNIEnv *env = nullptr;
-    bool detach = false;
-
     std::unique_ptr<Thread<Alarm>> alarm;
 
     std::mutex mutex;
diff --git a/platform/android/src/thread.cpp b/platform/android/src/thread.cpp
index c708dfdceb..f0a346ec5a 100644
--- a/platform/android/src/thread.cpp
+++ b/platform/android/src/thread.cpp
@@ -1,14 +1,21 @@
 #include <mbgl/util/logging.hpp>
 #include <mbgl/util/platform.hpp>
+#include <mbgl/platform/thread.hpp>
 
 #include <sys/prctl.h>
 #include <sys/resource.h>
 
+#include <cassert>
+#include "jni.hpp"
+
 // Implementation based on Chromium's platform_thread_android.cc.
 
 namespace mbgl {
 namespace platform {
 
+thread_local static JNIEnv* env;
+thread_local static bool detach;
+
 std::string getCurrentThreadName() {
     char name[32] = "unknown";
 
@@ -33,5 +40,18 @@ void makeThreadLowPriority() {
     setpriority(PRIO_PROCESS, 0, 19);
 }
 
+void attachThread() {
+    using namespace android;
+    assert(env == nullptr);
+    detach = attach_jni_thread(theJVM, &env, platform::getCurrentThreadName());
+}
+
+void detachThread() {
+    using namespace android;
+    assert(env);
+    detach_jni_thread(theJVM, &env, detach);
+    detach = false;
+}
+
 } // namespace platform
 } // namespace mbgl