Only calculate end offset once

Author: benaadams

src/Microsoft.AspNet.Server.Kestrel/Http/SocketInput.cs

@@ -62,10 +62,10 @@ public IncomingBuffer IncomingStart(int minimumSize)
         {
             lock (_sync)
             {
-                if (_tail != null && minimumSize <= _tail.Data.Offset + _tail.Data.Count - _tail.End)
+                if (_tail != null && minimumSize <= _tail.BlockEndOffset - _tail.End)
                 {
                     _pinned = _tail;
-                    var data = new ArraySegment<byte>(_pinned.Data.Array, _pinned.End, _pinned.Data.Offset + _pinned.Data.Count - _pinned.End);
+                    var data = new ArraySegment<byte>(_pinned.Data.Array, _pinned.End, _pinned.BlockEndOffset - _pinned.End);
                     var dataPtr = _pinned.Pin() + _pinned.End;
                     return new IncomingBuffer
                     {

src/Microsoft.AspNet.Server.Kestrel/Http/SocketOutput.cs

@@ -423,7 +423,7 @@ private static void BytesBetween(MemoryPoolIterator2 start, MemoryPoolIterator2
                 return;
             }
 
-            bytes = start.Block.Data.Offset + start.Block.Data.Count - start.Index;
+            bytes = start.Block.BlockEndOffset - start.Index;
             buffers = 1;
 
             for (var block = start.Block.Next; block != end.Block; block = block.Next)

src/Microsoft.AspNet.Server.Kestrel/Infrastructure/MemoryPoolBlock2.cs

@@ -52,6 +52,11 @@ protected MemoryPoolBlock2()
         /// </summary>
         public byte[] Array => Data.Array;
 
+        /// <summary>
+        /// Fixed end offset of the block
+        /// </summary>
+        public int BlockEndOffset { get; private set; }
+
         /// <summary>
         /// The Start represents the offset into Array where the range of "active" bytes begins. At the point when the block is leased
         /// the Start is guaranteed to be equal to Array.Offset. The value of Start may be assigned anywhere between Data.Offset and
@@ -144,6 +149,7 @@ public static MemoryPoolBlock2 Create(
                 Slab = slab,
                 Start = data.Offset,
                 End = data.Offset,
+                BlockEndOffset = data.Offset + data.Count
             };
         }
 

src/Microsoft.AspNet.Server.Kestrel/Infrastructure/MemoryPoolIterator2.cs

@@ -593,7 +593,7 @@ public unsafe void CopyFrom(byte[] data, int offset, int count)
         {
             var block = _block;
             var blockIndex = _index;
-            var bytesLeftInBlock = block.Data.Offset + block.Data.Count - blockIndex;
+            var bytesLeftInBlock = block.BlockEndOffset - blockIndex;
 
             if (bytesLeftInBlock >= count)
             {
@@ -603,15 +603,11 @@ public unsafe void CopyFrom(byte[] data, int offset, int count)
                 return;
             }
 
-            var pool = block.Pool;
-
-            while (count > 0)
+            do
             {
                 if (bytesLeftInBlock == 0)
                 {
-                    block.End = blockIndex;
-
-                    var nextBlock = pool.Lease();
+                    var nextBlock = block.Pool.Lease();
                     blockIndex = nextBlock.Data.Offset;
                     bytesLeftInBlock = nextBlock.Data.Count;
                     block.Next = nextBlock;
@@ -622,9 +618,10 @@ public unsafe void CopyFrom(byte[] data, int offset, int count)
                 {
                     count -= bytesLeftInBlock;
                     Buffer.BlockCopy(data, offset, block.Array, blockIndex, bytesLeftInBlock);
-                    blockIndex += bytesLeftInBlock;
                     offset += bytesLeftInBlock;
+                    block.End = blockIndex + bytesLeftInBlock;
                     bytesLeftInBlock = 0;
+                    continue;
                 }
                 else
                 {
@@ -634,7 +631,7 @@ public unsafe void CopyFrom(byte[] data, int offset, int count)
                     _block = block;
                     return;
                 }
-            }
+            } while (true);
         }
 
         public unsafe void CopyFromAscii(string data)
@@ -649,7 +646,7 @@ public unsafe void CopyFromAscii(string data)
             var blockIndex = _index;
             var length = data.Length;
 
-            var bytesLeftInBlock = block.Data.Offset + block.Data.Count - blockIndex;
+            var bytesLeftInBlock = block.BlockEndOffset - blockIndex;
             var bytesLeftInBlockMinusSpan = bytesLeftInBlock - 3;
 
             fixed (char* pData = data)

src/Microsoft.AspNet.Server.Kestrel/Networking/UvWriteReq.cs

@@ -66,7 +66,7 @@ public unsafe void Write(
                 for (var index = 0; index < nBuffers; index++)
                 {
                     var blockStart = block == start.Block ? start.Index : block.Data.Offset;
-                    var blockEnd = block == end.Block ? end.Index : block.Data.Offset + block.Data.Count;
+                    var blockEnd = block == end.Block ? end.Index : block.BlockEndOffset;
 
                     // create and pin each segment being written
                     pBuffers[index] = Libuv.buf_init(

test/Microsoft.AspNet.Server.KestrelTests/SocketOutputTests.cs

@@ -308,11 +308,11 @@ public void ProducingStartAndProducingCompleteCanBeUsedDirectly()
 
                 // block 1
                 var start = socketOutput.ProducingStart();
-                start.Block.End = start.Block.Data.Offset + start.Block.Data.Count;
+                start.Block.End = start.Block.BlockEndOffset;
 
                 // block 2
                 var block2 = memory.Lease();
-                block2.End = block2.Data.Offset + block2.Data.Count;
+                block2.End = block2.BlockEndOffset;
                 start.Block.Next = block2;
 
                 var end = new MemoryPoolIterator2(block2, block2.End);