From: Alex Rousskov <rousskov@measurement-factory.com>
Date: Fri, 7 Oct 2016 21:18:05 +0000 (-0600)
Subject: Optimized/simplified buffering: Appending nothing is always possible.
X-Git-Tag: SQUID_4_0_15~3
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1bd998545ba62008fae1d09e367678b960f443b9;p=thirdparty%2Fsquid.git

Optimized/simplified buffering: Appending nothing is always possible.

This change avoids CoW when appending an empty buffer to MemBlob or
SBuf, making "if !empty then append()" caller complications unnecessary.
---

diff --git a/src/sbuf/MemBlob.h b/src/sbuf/MemBlob.h
index a2b670fd76..8d727a6579 100644
--- a/src/sbuf/MemBlob.h
+++ b/src/sbuf/MemBlob.h
@@ -72,7 +72,7 @@ public:
      */
     bool canAppend(const size_type off, const size_type n) const {
         // TODO: ignore offset (and adjust size) when the blob is not shared?
-        return isAppendOffset(off) && willFit(n);
+        return (isAppendOffset(off) && willFit(n)) || !n;
     }
 
     /** adjusts internal object state as if exactly n bytes were append()ed