better InflatingExpressionTransform

dbms/src/Processors/ISimpleTransform.cpp

@@ -100,7 +100,7 @@ void ISimpleTransform::work()
         return;
     }
 
-    has_input = false;
+    has_input = !needInputData();
 
     if (!skip_empty_chunks || current_data.chunk)
         transformed = true;

dbms/src/Processors/ISimpleTransform.h

@@ -27,6 +27,7 @@ protected:
     bool set_input_not_needed_after_read = false;
 
     virtual void transform(Chunk & chunk) = 0;
+    virtual bool needInputData() const { return true; }
     void stopReading() { no_more_data_needed = true; }
 
 public:

dbms/src/Processors/Transforms/InflatingExpressionTransform.cpp

@@ -18,35 +18,6 @@ InflatingExpressionTransform::InflatingExpressionTransform(Block input_header, E
     , default_totals(default_totals_)
 {}
 
-void InflatingExpressionTransform::work()
-{
-    if (current_data.exception)
-        return;
-
-    try
-    {
-        transform(current_data.chunk);
-    }
-    catch (DB::Exception &)
-    {
-        current_data.exception = std::current_exception();
-        current_data.chunk.clear();
-        transformed = true;
-        has_input = false;
-        return;
-    }
-
-    if (!not_processed)
-        has_input = false;
-
-    if (!skip_empty_chunks || current_data.chunk)
-        transformed = true;
-
-    if (transformed && !current_data.chunk)
-        /// Support invariant that chunks must have the same number of columns as header.
-        current_data.chunk = Chunk(getOutputPort().getHeader().cloneEmpty().getColumns(), 0);
-}
-
 void InflatingExpressionTransform::transform(Chunk & chunk)
 {
     if (!initialized)

dbms/src/Processors/Transforms/InflatingExpressionTransform.h

@@ -15,10 +15,10 @@ public:
                                  bool on_totals_ = false, bool default_totals_ = false);
 
     String getName() const override { return "InflatingExpressionTransform"; }
-    void work() override;
 
 protected:
     void transform(Chunk & chunk) override;
+    bool needInputData() const override { return !not_processed; }
 
 private:
     ExpressionActionsPtr expression;