Return true from NpgsqlDataReader.HasRows even after all rows have been read.

jbcooley · jbcooley · commit 179de685bc84 · 2014-03-09T13:16:27.000-05:00
diff --git a/Npgsql/Npgsql/NpgsqlDataReader.cs b/Npgsql/Npgsql/NpgsqlDataReader.cs
@@ -978,6 +978,7 @@ internal class ForwardsOnlyDataReader : NpgsqlDataReader, IStreamOwner
         private long? _lastInsertOID = null;
         private long? _nextInsertOID = null;
         internal bool _cleanedUp = false;
+        private bool _hasRows = false;
         private readonly NpgsqlConnector.NotificationThreadBlock _threadBlock;
 
         //Unfortunately we sometimes don't know we're going to be dealing with
@@ -1247,6 +1248,11 @@ private NpgsqlRow GetNextRow(bool clearPending)
                 {
                     _pendingRow = null;
                 }
+                if (!_hasRows)
+                {
+                    // when rows are found, store that this result has rows.
+                    _hasRows = (ret != null);
+                }
                 return ret;
             }
             CurrentRow = null;
@@ -1260,6 +1266,11 @@ private NpgsqlRow GetNextRow(bool clearPending)
                 _pendingDescription = objNext as NpgsqlRowDescription;
                 return null;
             }
+            if (!_hasRows)
+            {
+                // when rows are found, store that this result has rows.
+                _hasRows = objNext is NpgsqlRow;
+            }
             return objNext as NpgsqlRow;
         }
 
@@ -1302,7 +1313,12 @@ internal override long? LastInsertedOID
         /// </summary>
         public override Boolean HasRows
         {
-            get { return GetNextRow(false) != null; }
+            get
+            {
+                // Return true even after the last row has been read in this result.
+                // the first call to GetNextRow will set _hasRows to true if rows are found.
+                return _hasRows || (GetNextRow(false) != null);
+            }
         }
 
         private void CleanUp(bool finishedMessages)
@@ -1366,6 +1382,7 @@ private Boolean NextResultInternal()
             {
                 CurrentRow = null;
                 _currentResultsetSchema = null;
+                _hasRows = false; // set to false and let the reading code determine if the set has rows.
                 return (_currentDescription = GetNextRowDescription()) != null;
             }
             catch (System.IO.IOException ex)
@@ -1510,6 +1527,7 @@ public long? LastInsertedOID
         private ResultSet _currentResult;
         private DataRow _currentRow;
         private int _lastRecordsAffected;
+        private bool _hasRows;
 
         public CachingDataReader(ForwardsOnlyDataReader reader, CommandBehavior behavior)
             : base(reader._command, behavior)
@@ -1579,21 +1597,7 @@ internal override NpgsqlRowDescription CurrentDescription
 
         public override bool HasRows
         {
-            get
-            {
-                if (_currentRow != null || _currentResult.Count != 0)
-                {
-                    return true;
-                }
-                foreach (ResultSet rs in _results)
-                {
-                    if (rs.Count != 0)
-                    {
-                        return true;
-                    }
-                }
-                return false;
-            }
+            get { return _hasRows; }
         }
 
         public override int RecordsAffected
@@ -1664,9 +1668,14 @@ public override bool NextResult()
             if (_results.Count == 0)
             {
                 _currentResult = null;
+                // clear HasRows after moving past the end of the results.
+                _hasRows = false;
                 return false;
             }
             _lastRecordsAffected = (_currentResult = _results.Dequeue()).RecordsAffected;
+            // HasRows stores if the results has rows even after they have been read for the current results
+            // reset as you move to the next results.
+            _hasRows = _results.Count != 0;
             return true;
         }
 
diff --git a/tests/DataReaderTests.cs b/tests/DataReaderTests.cs
@@ -980,6 +980,7 @@ public void HasRowsGetValue()
             {
                 Assert.IsTrue(dr.HasRows);
                 Assert.IsTrue(dr.Read());
+                Assert.IsTrue(dr.HasRows);
                 Assert.AreEqual(1, dr.GetValue(0));
             }
         }
@@ -996,6 +997,7 @@ public void IntervalAsTimeSpan()
             {
                 Assert.IsTrue(dr.HasRows);
                 Assert.IsTrue(dr.Read());
+                Assert.IsTrue(dr.HasRows);
                 var ts = dr.GetTimeSpan(0);
             }
         }

Original file line number	Diff line number	Diff line change
`@@ -980,6 +980,7 @@ public void HasRowsGetValue()`
`980`	`980`	`{`
`981`	`981`	`Assert.IsTrue(dr.HasRows);`
`982`	`982`	`Assert.IsTrue(dr.Read());`
	`983`	`+ Assert.IsTrue(dr.HasRows);`
`983`	`984`	`Assert.AreEqual(1, dr.GetValue(0));`
`984`	`985`	`}`
`985`	`986`	`}`
`@@ -996,6 +997,7 @@ public void IntervalAsTimeSpan()`
`996`	`997`	`{`
`997`	`998`	`Assert.IsTrue(dr.HasRows);`
`998`	`999`	`Assert.IsTrue(dr.Read());`
	`1000`	`+ Assert.IsTrue(dr.HasRows);`
`999`	`1001`	`var ts = dr.GetTimeSpan(0);`
`1000`	`1002`	`}`
`1001`	`1003`	`}`