Split client_context::after_command() into two stages, before

sending result to client and after the result was sent. Added
s_result state to client_context states.

include/trrep/client_context.hpp

@@ -120,6 +120,10 @@ namespace trrep
              * system.
              */
             s_exec,
+            /*!
+             * Client handler is sending result to client.
+             */
+            s_result,
             /*!
              * The client session is terminating.
              */
@@ -136,32 +140,40 @@ namespace trrep
         }
 
         /*!
-         * Virtual method which should be called before the client
+         * Method which should be called before the client
          * starts processing the command received from the application.
          * This method will wait until the possible synchronous
          * rollback for associated transaction has finished.
          * The method has a side effect of changing the client
          * context state to executing.
          *
-         * If overridden, the implementation should call base
-         * class method before any implementation specific operations.
-         *
          * \return Zero in case of success, non-zero in case of the
          *         associated transaction was BF aborted.
          */
-        virtual int before_command();
+        int before_command();
 
         /*!
-         * Virtual method which should be called before returning
+         * Method which should be called before returning
          * the control back to application which uses the DBMS system.
          * This method will check if the transaction associated to
-         * the connection has been aborted. This method has a side effect
-         * of changing the client state to idle.
-         *
-         * If overridden, the implementation should call base
-         * class metods after any implementation specifict operations.
+         * the connection has been aborted. Rollback is performed
+         * if needed.
          */
-        virtual void after_command();
+        void after_command_before_result();
+
+        /*!
+         * Method which should be called after returning the
+         * control back to application which uses the DBMS system.
+         * The method will do the check if the transaction associated
+         * to the connection has been aborted. If so, rollback is
+         * performed and the transaction is left to aborted state
+         * so that the client will get appropriate error on next
+         * command.
+         *
+         * This method has a side effect of changing state to
+         * idle.
+         */
+        void after_command_after_result();
 
         /*!
          * Before statement execution operations.
@@ -176,7 +188,7 @@ namespace trrep
          *         is not allowed to be executed due to read or write
          *         isolation requirements.
          */
-        virtual int before_statement();
+        int before_statement();
 
         /*!
          * After statement execution operations.
@@ -187,7 +199,7 @@ namespace trrep
          * If overridden by the implementation, base class method
          * should be called after any implementation specific operations.
          */
-        virtual void after_statement();
+        void after_statement();
 
         int start_transaction()
         {

src/client_context.cpp

@@ -40,9 +40,10 @@ int trrep::client_context::before_command()
     return 0;
 }
 
-void trrep::client_context::after_command()
+void trrep::client_context::after_command_before_result()
 {
     trrep::unique_lock<trrep::mutex> lock(mutex_);
+    assert(state() == s_exec);
     if (transaction_.active() &&
         transaction_.state() == trrep::transaction_context::s_must_abort)
     {
@@ -54,6 +55,26 @@ void trrep::client_context::after_command()
         assert(transaction_.state() == trrep::transaction_context::s_aborted);
         assert(current_error() != trrep::e_success);
     }
+    state(lock, s_result);
+}
+
+void trrep::client_context::after_command_after_result()
+{
+    trrep::unique_lock<trrep::mutex> lock(mutex_);
+    assert(state() == s_result);
+    if (transaction_.active() &&
+        transaction_.state() == trrep::transaction_context::s_must_abort)
+    {
+        // Note: Error is not overridden here as the result has already
+        // been sent to client. The error should be set in before_command()
+        // when the client issues next command.
+        lock.unlock();
+        rollback();
+        transaction_.after_statement();
+        lock.lock();
+        assert(transaction_.state() == trrep::transaction_context::s_aborted);
+        assert(current_error() != trrep::e_success);
+    }
     state(lock, s_idle);
 }
 
@@ -103,10 +124,11 @@ void trrep::client_context::state(
     assert(lock.owns_lock());
     static const char allowed[state_max_][state_max_] =
         {
-            /* idle exec quit */
-            {  0,   1,   1}, /* idle */
-            {  1,   0,   1}, /* exec */
-            {  0,   0,   0}
+            /* idle exec result quit */
+            {  0,   1,   0,     1}, /* idle */
+            {  0,   0,   1,     0}, /* exec */
+            {  1,   0,   0,     1}, /* result */
+            {  0,   0,   0,     0}  /* quit */
         };
     if (allowed[state_][state])
     {

src/client_context_test.cpp

@@ -25,5 +25,6 @@ BOOST_AUTO_TEST_CASE(client_context_test_error_codes)
     trrep_mock::bf_abort_unordered(cc);
 
     cc.after_statement();
-    cc.after_command();
+    cc.after_command_before_result();
+    cc.after_command_after_result();
 }

src/dbms_simulator.cpp

@@ -392,7 +392,8 @@ private:
             }
             after_statement();
         }
-        after_command();
+        after_command_before_result();
+        after_command_after_result();
         return err;
     }
 

src/server_context.cpp

@@ -323,7 +323,8 @@ int trrep::server_context::on_apply(
         if (not_replaying)
         {
             client_context.after_statement();
-            client_context.after_command();
+            client_context.after_command_before_result();
+            client_context.after_command_after_result();
         }
         assert(ret ||
                txc.state() == trrep::transaction_context::s_committed);