From 582c2758b020c735ebc15381b1a2df3409d30bb1 Mon Sep 17 00:00:00 2001
From: JoelKatz <DavidJoelSchwartz@GMail.com>
Date: Tue, 2 Jul 2013 19:22:28 -0700
Subject: [PATCH] Get a lock acquire out of a critical fast path.

---
 src/cpp/ripple/ripple_InboundLedger.cpp | 16 ++++++++++------
 src/cpp/ripple/ripple_InboundLedger.h   | 20 ++++++++++----------
 2 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/src/cpp/ripple/ripple_InboundLedger.cpp b/src/cpp/ripple/ripple_InboundLedger.cpp
index bd738a295..0eaf36af9 100644
--- a/src/cpp/ripple/ripple_InboundLedger.cpp
+++ b/src/cpp/ripple/ripple_InboundLedger.cpp
@@ -168,15 +168,19 @@ void InboundLedger::onTimer (bool progress)
 
 void InboundLedger::awaitData ()
 {
-    boost::recursive_mutex::scoped_lock sl (mLock);
     ++mWaitCount;
 }
 
 void InboundLedger::noAwaitData ()
-{
-    boost::recursive_mutex::scoped_lock sl (mLock);
-
-    if (mWaitCount > 0 ) --mWaitCount;
+{ // subtract one if mWaitCount is greater than zero
+    do
+    {
+       int j = mWaitCount.get();
+       if (j <= 0)
+           return;
+       if (mWaitCount.compareAndSetBool(j - 1, j))
+           return;
+    } while (1);
 }
 
 void InboundLedger::addPeers ()
@@ -285,7 +289,7 @@ void InboundLedger::trigger (Peer::ref peer)
         return;
     }
 
-    if ((mWaitCount > 0) && peer)
+    if ((mWaitCount.get() > 0) && peer)
     {
         WriteLog (lsTRACE, InboundLedger) << "Skipping peer";
         return;
diff --git a/src/cpp/ripple/ripple_InboundLedger.h b/src/cpp/ripple/ripple_InboundLedger.h
index b5327ffa4..3988b51be 100644
--- a/src/cpp/ripple/ripple_InboundLedger.h
+++ b/src/cpp/ripple/ripple_InboundLedger.h
@@ -102,16 +102,16 @@ private:
     boost::weak_ptr <PeerSet> pmDowncast ();
 
 private:
-    Ledger::pointer mLedger;
-    bool            mHaveBase;
-    bool            mHaveState;
-    bool            mHaveTransactions;
-    bool            mAborted;
-    bool            mSignaled;
-    bool            mAccept;
-    bool            mByHash;
-    int             mWaitCount;
-    uint32          mSeq;
+    Ledger::pointer    mLedger;
+    bool               mHaveBase;
+    bool               mHaveState;
+    bool               mHaveTransactions;
+    bool               mAborted;
+    bool               mSignaled;
+    bool               mAccept;
+    bool               mByHash;
+    beast::Atomic<int> mWaitCount;
+    uint32             mSeq;
 
     std::set <SHAMapNode> mRecentTXNodes;
     std::set <SHAMapNode> mRecentASNodes;