TFuture add IsReady method

IsReady returns true if exception or value was set.
allows to check readiness without locking cheсker-thread
NOTE: returns true even if value was extracted from promise
good replace for HasValue() || HasException()
b2d64093e25cef5a350dfebe784c449203a5b383

library/cpp/threading/future/core/future-inl.h

@@ -116,6 +116,9 @@ namespace NThreading {
             bool HasException() const {
                 return AtomicGet(State) == ExceptionSet;
             }
+            bool IsReady() const {
+                return AtomicGet(State) != NotReady;
+            }
 
             const T& GetValue(TDuration timeout = TDuration::Zero()) const {
                 AccessValue(timeout, ValueRead);
@@ -297,6 +300,9 @@ namespace NThreading {
             bool HasException() const {
                 return AtomicGet(State) == ExceptionSet;
             }
+            bool IsReady() const {
+                return AtomicGet(State) != NotReady;
+            }
 
             void GetValue(TDuration timeout = TDuration::Zero()) const {
                 TAtomicBase state = AtomicGet(State);
@@ -583,6 +589,10 @@ namespace NThreading {
     inline bool TFuture<T>::HasException() const {
         return State && State->HasException();
     }
+    template <typename T>
+    inline bool TFuture<T>::IsReady() const {
+        return State && State->IsReady();
+    }
 
     template <typename T>
     inline void TFuture<T>::Wait() const {
@@ -688,6 +698,9 @@ namespace NThreading {
     inline bool TFuture<void>::HasException() const {
         return State && State->HasException();
     }
+    inline bool TFuture<void>::IsReady() const {
+        return State && State->IsReady();
+    }
 
     inline void TFuture<void>::Wait() const {
         EnsureInitialized();
@@ -823,6 +836,11 @@ namespace NThreading {
         return State && State->HasException();
     }
 
+    template <typename T>
+    inline bool TPromise<T>::IsReady() const {
+        return State && State->IsReady();
+    }
+
     template <typename T>
     inline void TPromise<T>::SetException(const TString& e) {
         EnsureInitialized();
@@ -904,6 +922,10 @@ namespace NThreading {
         return State && State->HasException();
     }
 
+    inline bool TPromise<void>::IsReady() const {
+        return State && State->IsReady();
+    }
+
     inline void TPromise<void>::SetException(const TString& e) {
         EnsureInitialized();
         State->SetException(std::make_exception_ptr(yexception() << e));

library/cpp/threading/future/core/future.h

@@ -98,6 +98,12 @@ namespace NThreading {
         void TryRethrow() const;
         bool HasException() const;
 
+        // returns true if exception or value was set.
+        //   allows to check readiness without locking cheker-thread
+        //   NOTE: returns true even if value was extracted from promise
+        //   good replace for HasValue() || HasException()
+        bool IsReady() const;
+
         void Wait() const;
         bool Wait(TDuration timeout) const;
         bool Wait(TInstant deadline) const;
@@ -153,6 +159,11 @@ namespace NThreading {
         void TryRethrow() const;
         bool HasException() const;
 
+        // returns true if exception or value was set.
+        //   allows to check readiness without locking cheker-thread
+        //   good replace for HasValue() || HasException()
+        bool IsReady() const;
+
         void Wait() const;
         bool Wait(TDuration timeout) const;
         bool Wait(TInstant deadline) const;
@@ -216,6 +227,12 @@ namespace NThreading {
 
         void TryRethrow() const;
         bool HasException() const;
+
+        // returns true if exception or value was set.
+        //   allows to check readiness without locking cheker-thread
+        //   NOTE: returns true even if value was extracted from promise
+        //   good replace for HasValue() || HasException()
+        bool IsReady() const;
         void SetException(const TString& e);
         void SetException(std::exception_ptr e);
         bool TrySetException(std::exception_ptr e);
@@ -256,6 +273,11 @@ namespace NThreading {
 
         void TryRethrow() const;
         bool HasException() const;
+
+        // returns true if exception or value was set.
+        //   allows to check readiness without locking cheker-thread
+        //   good replace for HasValue() || HasException()
+        bool IsReady() const;
         void SetException(const TString& e);
         void SetException(std::exception_ptr e);
         bool TrySetException(std::exception_ptr e);

library/cpp/threading/future/future_ut.cpp

@@ -105,6 +105,7 @@ namespace {
 
             future = MakeFuture(345);
             UNIT_ASSERT(future.HasValue());
+            UNIT_ASSERT(future.IsReady());
             UNIT_ASSERT_EQUAL(future.GetValue(), 345);
         }
 
@@ -115,6 +116,7 @@ namespace {
 
             TFuture<void> future = promise.GetFuture();
             UNIT_ASSERT(future.HasValue());
+            UNIT_ASSERT(future.IsReady());
 
             future = MakeFuture();
             UNIT_ASSERT(future.HasValue());
@@ -523,6 +525,7 @@ namespace {
         {
             auto future1 = MakeErrorFuture<void>(std::make_exception_ptr(TFutureException()));
             UNIT_ASSERT(future1.HasException());
+            UNIT_ASSERT(future1.IsReady());
             UNIT_CHECK_GENERATED_EXCEPTION(future1.GetValue(), TFutureException);
 
             auto future2 = MakeErrorFuture<int>(std::make_exception_ptr(TFutureException()));
@@ -563,6 +566,7 @@ namespace {
             promise2.SetException("foo-exception");
             wait.Wait();
             UNIT_ASSERT(future2.HasException());
+            UNIT_ASSERT(!future1.IsReady());
             UNIT_ASSERT(!future1.HasValue() && !future1.HasException());
         }