From abf39f788609f65d1b2b3ac1548f7146aa5c8584 Mon Sep 17 00:00:00 2001
From: Leslie Linden <leslie@lindenlab.com>
Date: Mon, 21 Nov 2011 15:15:26 -0800
Subject: Greatly reduced the number of memcpy operations done on the media
 plug-in message output pipe by removing 's = s.substr()' type operations. 
 The output string is now cleared via 's.clear()' when its entire contents
 have been pumped and the beginning of the data is stored as an index when
 necessary, rather than modifying the initial string.

Reviewed by davep.
---
 indra/llplugin/llpluginmessagepipe.cpp | 51 ++++++++++++++++++++++------------
 indra/llplugin/llpluginmessagepipe.h   |  1 +
 2 files changed, 35 insertions(+), 17 deletions(-)

(limited to 'indra/llplugin')

diff --git a/indra/llplugin/llpluginmessagepipe.cpp b/indra/llplugin/llpluginmessagepipe.cpp
index 8d13e38ad5..091e93ea4b 100644
--- a/indra/llplugin/llpluginmessagepipe.cpp
+++ b/indra/llplugin/llpluginmessagepipe.cpp
@@ -94,10 +94,10 @@ void LLPluginMessagePipeOwner::killMessagePipe(void)
 LLPluginMessagePipe::LLPluginMessagePipe(LLPluginMessagePipeOwner *owner, LLSocket::ptr_t socket):
 	mInputMutex(gAPRPoolp),
 	mOutputMutex(gAPRPoolp),
+	mOutputStartIndex(0),
 	mOwner(owner),
 	mSocket(socket)
 {
-	
 	mOwner->setMessagePipe(this);
 }
 
@@ -113,6 +113,14 @@ bool LLPluginMessagePipe::addMessage(const std::string &message)
 {
 	// queue the message for later output
 	LLMutexLock lock(&mOutputMutex);
+
+	// If we're starting to use up too much memory, clear
+	if (mOutputStartIndex > 1024 * 1024)
+	{
+		mOutput = mOutput.substr(mOutputStartIndex);
+		mOutputStartIndex = 0;
+	}
+		
 	mOutput += message;
 	mOutput += MESSAGE_DELIMITER;	// message separator
 	
@@ -165,35 +173,44 @@ bool LLPluginMessagePipe::pumpOutput()
 	if(mSocket)
 	{
 		apr_status_t status;
-		apr_size_t size;
+		apr_size_t in_size, out_size;
 		
 		LLMutexLock lock(&mOutputMutex);
-		if(!mOutput.empty())
+
+		const char * output_data = &(mOutput.data()[mOutputStartIndex]);
+		if(*output_data != '\0')
 		{
 			// write any outgoing messages
-			size = (apr_size_t)mOutput.size();
+			in_size = (apr_size_t) (mOutput.size() - mOutputStartIndex);
+			out_size = in_size;
 			
 			setSocketTimeout(0);
 			
 //			LL_INFOS("Plugin") << "before apr_socket_send, size = " << size << LL_ENDL;
 
-			status = apr_socket_send(
-					mSocket->getSocket(),
-					(const char*)mOutput.data(),
-					&size);
+			status = apr_socket_send(mSocket->getSocket(),
+									 output_data,
+									 &out_size);
 
 //			LL_INFOS("Plugin") << "after apr_socket_send, size = " << size << LL_ENDL;
 			
-			if(status == APR_SUCCESS)
+			if((status == APR_SUCCESS) || APR_STATUS_IS_EAGAIN(status))
 			{
-				// success
-				mOutput = mOutput.substr(size);
-			}
-			else if(APR_STATUS_IS_EAGAIN(status))
-			{
-				// Socket buffer is full... 
-				// remove the written part from the buffer and try again later.
-				mOutput = mOutput.substr(size);
+				// Success or Socket buffer is full... 
+				
+				// If we've pumped the entire string, clear it
+				if (out_size == in_size)
+				{
+					mOutputStartIndex = 0;
+					mOutput.clear();
+				}
+				else
+				{
+					llassert(in_size > out_size);
+					
+					// Remove the written part from the buffer and try again later.
+					mOutputStartIndex += out_size;
+				}
 			}
 			else if(APR_STATUS_IS_EOF(status))
 			{
diff --git a/indra/llplugin/llpluginmessagepipe.h b/indra/llplugin/llpluginmessagepipe.h
index beb942c0fe..059943cc90 100644
--- a/indra/llplugin/llpluginmessagepipe.h
+++ b/indra/llplugin/llpluginmessagepipe.h
@@ -86,6 +86,7 @@ protected:
 	std::string mInput;
 	LLMutex mOutputMutex;
 	std::string mOutput;
+	std::string::size_type mOutputStartIndex;
 
 	LLPluginMessagePipeOwner *mOwner;
 	LLSocket::ptr_t mSocket;
-- 
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