[general] moving ios and android project under ./platform folder

platform/android/src/thread.cpp

@@ -0,0 +1,64 @@
+#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";
+
+    if (prctl(PR_GET_NAME, name) == -1) {
+        Log::Warning(Event::General, "Couldn't get thread name");
+    }
+
+    return name;
+}
+
+void setCurrentThreadName(const std::string& name) {
+    if (prctl(PR_SET_NAME, name.c_str()) == -1) {
+        Log::Warning(Event::General, "Couldn't set thread name");
+    }
+}
+
+void makeThreadLowPriority() {
+    // ANDROID_PRIORITY_LOWEST = 19
+    //
+    // Supposedly would set the priority for the whole process, but
+    // on Linux/Android it only sets for the current thread.
+    setpriority(PRIO_PROCESS, 0, 19);
+}
+
+void setCurrentThreadPriority(double priority) {
+    if (priority < -20 || priority > 19) {
+        Log::Warning(Event::General, "Couldn't set thread priority");
+        return;
+    }
+    setpriority(PRIO_PROCESS, 0, int(priority));
+}
+
+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);
+}
+
+} // namespace platform
+} // namespace mbgl