Merge pull request #187 from JPWatson/erb-capacity

Fix bug in ExpandableRingBuffer
real-logic · Oct 28, 2019 · 170a221 · 170a221
2 parents 0544ade + 8951d95
commit 170a221
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Showing 2 changed files with 31 additions and 8 deletions.
diff --git a/agrona/src/main/java/org/agrona/ExpandableRingBuffer.java b/agrona/src/main/java/org/agrona/ExpandableRingBuffer.java
@@ -386,15 +386,19 @@ public boolean append(final DirectBuffer srcBuffer, final int srcOffset, final i
         else if (tailOffset >= headOffset)
         {
             final int toEndRemaining = capacity - tailOffset;
-            if (alignedLength > toEndRemaining && alignedLength <= (totalRemaining - toEndRemaining))
-            {
-                buffer.putInt(tailOffset + MESSAGE_LENGTH_OFFSET, toEndRemaining);
-                buffer.putInt(tailOffset + MESSAGE_TYPE_OFFSET, MESSAGE_TYPE_PADDING);
-                tail += toEndRemaining;
-            }
-            else
+
+            if (alignedLength > toEndRemaining)
             {
-                resize(alignedLength);
+                if (alignedLength <= (totalRemaining - toEndRemaining))
+                {
+                    buffer.putInt(tailOffset + MESSAGE_LENGTH_OFFSET, toEndRemaining);
+                    buffer.putInt(tailOffset + MESSAGE_TYPE_OFFSET, MESSAGE_TYPE_PADDING);
+                    tail += toEndRemaining;
+                }
+                else
+                {
+                    resize(alignedLength);
+                }
             }
         }
 

diff --git a/agrona/src/test/java/org/agrona/ExpandableRingBufferTest.java b/agrona/src/test/java/org/agrona/ExpandableRingBufferTest.java
@@ -181,6 +181,25 @@ public void shouldAppendThenIterateMessagesInOrder()
         inOrder.verify(mockConsumer).onMessage(any(MutableDirectBuffer.class), anyInt(), eq(MSG_LENGTH_TWO), anyInt());
     }
 
+    @Test
+    public void shouldAppendMessagesWithinCapacityWithoutExpanding()
+    {
+        final int initialCapacity = 1024;
+        final int maxCapacity = 2048;
+
+        final ExpandableRingBuffer ringBuffer = new ExpandableRingBuffer(initialCapacity, maxCapacity, false);
+
+        final ExpandableRingBuffer.MessageConsumer mockConsumer = mock(ExpandableRingBuffer.MessageConsumer.class);
+        when(mockConsumer.onMessage(any(), anyInt(), anyInt(), anyInt())).thenReturn(Boolean.TRUE);
+
+        assertThat(ringBuffer.capacity(), is(initialCapacity));
+
+        final int messageLength = 32;
+        ringBuffer.append(TEST_MSG, 0, messageLength);
+
+        assertThat(ringBuffer.capacity(), is(initialCapacity));
+    }
+
     @Test
     public void shouldAppendMessagesWithPaddingWithoutExpanding()
     {