From 230224bf82ad8f65051476f7331f181f85f8f1c2 Mon Sep 17 00:00:00 2001
From: Constantin Shalnev <c.shalnev@corp.mail.ru>
Date: Wed, 5 Aug 2015 14:30:30 +0300
Subject: [PATCH] Implemented SimpleThread which is the same as std::thread but
 executes callable object in a JVM environment

---
 base/base_tests/threads_test.cpp | 57 ++++++++++++++++++++++++++++++++
 base/thread.cpp                  | 19 +++++++++++
 base/thread.hpp                  | 41 +++++++++++++++++++++++
 3 files changed, 117 insertions(+)

diff --git a/base/base_tests/threads_test.cpp b/base/base_tests/threads_test.cpp
index a72d42f9ff..6a70938b63 100644
--- a/base/base_tests/threads_test.cpp
+++ b/base/base_tests/threads_test.cpp
@@ -58,3 +58,60 @@ UNIT_TEST(Simple_Threads)
   TEST_EQUAL(vec.size(), MAX_COUNT, ("vector size"));
   TEST_EQUAL(summ, checkSumm, ("check summ"));
 }
+
+class SomeClass
+{
+public:
+  void Increment(int * a, int b)
+  {
+    *a = *a + b;
+  }
+};
+
+static void Increment(int * a, int b)
+{
+  *a = *a + b;
+}
+
+UNIT_TEST(SimpleThreadTest1)
+{
+  int a = 0;
+
+  auto fn = [&a](){ a = 1; };
+
+  threads::SimpleThread t(fn);
+  t.join();
+
+  TEST_EQUAL(a, 1, ("test a"));
+}
+
+UNIT_TEST(SimpleThreadTest2)
+{
+  int a = 0;
+
+  threads::SimpleThread t([&a](){ a = 1; });
+  t.join();
+
+  TEST_EQUAL(a, 1, ("test a"));
+}
+
+UNIT_TEST(SimpleThreadTest3)
+{
+  int a = 0;
+
+  SomeClass instance;
+  threads::SimpleThread t(&SomeClass::Increment, &instance, &a, 1);
+  t.join();
+
+  TEST_EQUAL(a, 1, ("test a"));
+}
+
+UNIT_TEST(SimpleThreadTest4)
+{
+  int a = 0;
+
+  threads::SimpleThread t(&Increment, &a, 1);
+  t.join();
+
+  TEST_EQUAL(a, 1, ("test a"));
+}
diff --git a/base/thread.cpp b/base/thread.cpp
index 16880cdb1a..7ca97a895f 100644
--- a/base/thread.cpp
+++ b/base/thread.cpp
@@ -79,6 +79,9 @@ void Thread::Join()
 
 IRoutine * Thread::GetRoutine() { return m_routine.get(); }
 
+/////////////////////////////////////////////////////////////////////
+// SimpleThreadPool implementation
+
 SimpleThreadPool::SimpleThreadPool(size_t reserve) { m_pool.reserve(reserve); }
 
 void SimpleThreadPool::Add(unique_ptr<IRoutine> && routine)
@@ -98,4 +101,20 @@ IRoutine * SimpleThreadPool::GetRoutine(size_t i) const { return m_pool[i]->GetR
 void Sleep(size_t ms) { this_thread::sleep_for(milliseconds(ms)); }
 
 ThreadID GetCurrentThreadID() { return this_thread::get_id(); }
+
+/////////////////////////////////////////////////////////////////////
+// SimpleThread implementation
+
+void SimpleThread::ThreadFunc(function<void()> fn)
+{
+#if defined(OMIM_OS_ANDROID)
+  AndroidThreadAttachToJVM();
+#endif  // defined(OMIM_OS_ANDROID)
+
+  fn();
+
+#if defined(OMIM_OS_ANDROID)
+  AndroidThreadDetachFromJVM();
+#endif  // defined(OMIM_OS_ANDROID)
+}
 }
diff --git a/base/thread.hpp b/base/thread.hpp
index 654dea5d81..2ec7b8b835 100644
--- a/base/thread.hpp
+++ b/base/thread.hpp
@@ -4,7 +4,9 @@
 #include "base/cancellable.hpp"
 #include "base/macros.hpp"
 
+#include "std/bind.hpp"
 #include "std/cstdint.hpp"
+#include "std/function.hpp"
 #include "std/noncopyable.hpp"
 #include "std/shared_ptr.hpp"
 #include "std/target_os.hpp"
@@ -94,4 +96,43 @@ typedef thread::id ThreadID;
 
 ThreadID GetCurrentThreadID();
 
+/// A wrapper around a std thread which executes callable object in android envorinment
+/// Class has the same interface as std::thread
+class SimpleThread
+{
+public:
+  using id = thread::id;
+  using native_handle_type = thread::native_handle_type;
+
+  SimpleThread() noexcept {}
+  SimpleThread(SimpleThread && x) noexcept
+    : m_thread(move(x.m_thread))
+  {}
+
+  template <class Fn, class... Args>
+  explicit SimpleThread(Fn && fn, Args &&... args)
+    : m_thread(&SimpleThread::ThreadFunc, bind(forward<Fn>(fn), forward<Args>(args)...))
+  {}
+
+  SimpleThread & operator= (SimpleThread && x) noexcept
+  {
+    m_thread = move(x.m_thread);
+    return *this;
+  }
+
+  SimpleThread(const SimpleThread &) = delete;
+  SimpleThread & operator= (const SimpleThread &) = delete;
+
+  void detach() { m_thread.detach(); }
+  id get_id() const noexcept { return m_thread.get_id(); }
+  void join() { m_thread.join(); }
+  bool joinable() const noexcept { return m_thread.joinable(); }
+  native_handle_type native_handle() { return m_thread.native_handle(); }
+  void swap(SimpleThread & x) noexcept { m_thread.swap(x.m_thread); }
+
+private:
+  static void ThreadFunc(function<void()> fn);
+
+  thread m_thread;
+};
 }  // namespace threads