From 57e517a56bd048c902be1c1e1a0655316a5189a4 Mon Sep 17 00:00:00 2001
From: Stepan Palamarchuk <stepan@fb.com>
Date: Mon, 25 Apr 2016 14:12:21 -0700
Subject: [PATCH] Remove unnecessary construction of IOBuf in Cursor

Summary: This assignment is unnecessary, because in `for` loop we **always** call `cloneOneInto` that would assign another IOBuf to that IOBuf.

Reviewed By: alikhtarov

Differential Revision: D3215861

fb-gh-sync-id: ad87b99848aaae79f0870d49e0474f1abf0f28e5
fbshipit-source-id: ad87b99848aaae79f0870d49e0474f1abf0f28e5
---
 folly/io/Cursor.h                      |  2 --
 folly/io/test/IOBufCursorBenchmark.cpp | 10 ++++++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/folly/io/Cursor.h b/folly/io/Cursor.h
index 74412ea6..3cf369e9 100644
--- a/folly/io/Cursor.h
+++ b/folly/io/Cursor.h
@@ -324,8 +324,6 @@ class CursorBase {
   }
 
   size_t cloneAtMost(folly::IOBuf& buf, size_t len) {
-    buf = folly::IOBuf();
-
     std::unique_ptr<folly::IOBuf> tmp;
     size_t copied = 0;
     for (int loopCount = 0; true; ++loopCount) {
diff --git a/folly/io/test/IOBufCursorBenchmark.cpp b/folly/io/test/IOBufCursorBenchmark.cpp
index e7142d9c..233f800b 100644
--- a/folly/io/test/IOBufCursorBenchmark.cpp
+++ b/folly/io/test/IOBufCursorBenchmark.cpp
@@ -76,6 +76,16 @@ BENCHMARK(skipBenchmark, iters) {
   }
 }
 
+BENCHMARK(cloneBenchmark, iters) {
+  folly::IOBuf out;
+  while (iters--) {
+    Cursor c(iobuf_read_benchmark.get());
+    for (int i = 0; i < benchmark_size; ++i) {
+      c.clone(out, 1);
+    }
+  }
+}
+
 // fbmake opt
 // _bin/folly/experimental/io/test/iobuf_cursor_test -benchmark
 //
-- 
2.34.1