[search] Stop query when a new one comes.

search/engine.cpp

@@ -19,8 +19,22 @@ void Engine::Search(string const & queryText,
                     m2::RectD const & rect,
                     function<void (Result const &)> const & f)
 {
+  {
+    threads::MutexGuard mutexGuard(m_mutex);
+    UNUSED_VALUE(mutexGuard);
+    if (m_pLastQuery)
+      m_pLastQuery->SetTerminateFlag();
+  }
+
   impl::Query * pQuery = new impl::Query(queryText, rect, m_pIndex);
   m_pRunner->Run(bind(&impl::Query::SearchAndDestroy, pQuery, f));
 }
 
+void Engine::OnQueryDelete()
+{
+  threads::MutexGuard mutexGuard(m_mutex);
+  UNUSED_VALUE(mutexGuard);
+  m_pLastQuery = NULL;
+}
+
 }  // namespace search

search/engine.hpp

@@ -2,6 +2,7 @@
 #include "../indexer/index.hpp"
 #include "../geometry/rect2d.hpp"
 #include "../base/base.hpp"
+#include "../base/mutex.hpp"
 #include "../base/runner.hpp"
 #include "../std/function.hpp"
 #include "../std/scoped_ptr.hpp"
@@ -13,6 +14,7 @@ class FeatureType;
 namespace search
 {
 
+namespace impl { class Query; }
 class Result;
 
 class Engine
@@ -26,9 +28,13 @@ public:
               m2::RectD const & rect,
               function<void (Result const &)> const & f);
 
+  void OnQueryDelete();
+
 private:
   IndexType const * m_pIndex;
   scoped_ptr<threads::IRunner> m_pRunner;
+  threads::Mutex m_mutex;
+  impl::Query * volatile m_pLastQuery;
 };
 
 }  // namespace search

search/query.cpp

@@ -120,6 +120,9 @@ void Query::Search(function<void (Result const &)> const & f)
     }
   }
 
+  if (m_bTerminate)
+    return;
+
   // Category matching.
   if (!m_prefix.empty())
   {
@@ -134,12 +137,21 @@ void Query::Search(function<void (Result const &)> const & f)
     }
   }
 
+  if (m_bTerminate)
+    return;
+
   // Feature matching.
   FeatureProcessor featureProcessor(*this);
   int const scale = scales::GetScaleLevel(m_viewport) + 1;
   if (scale > scales::GetUpperWorldScale())
+  {
     m_pIndex->ForEachInRect(featureProcessor, m_viewport, scales::GetUpperWorldScale());
+    if (m_bTerminate)
+      return;
+  }
   m_pIndex->ForEachInRect(featureProcessor, m_viewport, min(scales::GetUpperScale(), scale));
+  if (m_bTerminate)
+    return;
 
   vector<Result> results;
   results.reserve(m_results.size());