Some optimizations.

src/cpp/ripple/Ledger.h

@@ -133,6 +133,7 @@ public:
 	bool isClosed()		{ return mClosed; }
 	bool isAccepted()	{ return mAccepted; }
 	bool isImmutable()	{ return mImmutable; }
+	bool isFixed()		{ return mClosed || mImmutable; }
 
 	// ledger signature operations
 	void addRaw(Serializer &s) const;

src/cpp/ripple/RPCHandler.cpp

@@ -899,6 +899,8 @@ Json::Value RPCHandler::doAccountLines(Json::Value jvRequest)
 	if (!lpLedger)
 		return jvResult;
 
+	ScopedUnlock su(theApp->getMasterLock(), lpLedger->isFixed());
+
 	if (!jvRequest.isMember("account"))
 		return rpcError(rpcINVALID_PARAMS);
 
@@ -926,6 +928,7 @@ Json::Value RPCHandler::doAccountLines(Json::Value jvRequest)
 
 		jvResult["account"]	= raAccount.humanAccountID();
 
+
 		// XXX This is wrong, we do access the current ledger and do need to worry about changes.
 		// We access a committed ledger and need not worry about changes.
 
@@ -977,6 +980,8 @@ Json::Value RPCHandler::doAccountOffers(Json::Value jvRequest)
 	if (!lpLedger)
 		return jvResult;
 
+	ScopedUnlock su(theApp->getMasterLock(), lpLedger->isClosed() || lpLedger->isImmutable());
+
 	if (!jvRequest.isMember("account"))
 		return rpcError(rpcINVALID_PARAMS);
 

src/cpp/ripple/ScopedLock.h

@@ -29,11 +29,39 @@ public:
 class ScopedUnlock
 {
 protected:
+	bool mUnlocked;
 	boost::recursive_mutex& mMutex;
 
 public:
-	ScopedUnlock(boost::recursive_mutex& mutex) : mMutex(mutex)	{ mMutex.unlock(); }
-	~ScopedUnlock()												{ mMutex.lock(); }
+	ScopedUnlock(boost::recursive_mutex& mutex, bool unlock = true) : mUnlocked(unlock), mMutex(mutex)
+	{
+		if (unlock)
+			mMutex.unlock();
+	}
+
+	~ScopedUnlock()
+	{
+		if (mUnlocked)
+			mMutex.lock();
+	}
+
+	void lock()
+	{
+		if (mUnlocked)
+		{
+			mMutex.lock();
+			mUnlocked = false;
+		}
+	}
+
+	void unlock()
+	{
+		if (!mUnlocked)
+		{
+			mUnlocked = true;
+			mMutex.unlock();
+		}
+	}
 
 private:
 	ScopedUnlock(const ScopedUnlock&); // no implementation