Use timer for resetting buffers

Wiebe Cazemier
1 parent 468ca477
Showing 5 changed files with 26 additions and 37 deletions
cirbuf.cpp
cirbuf.h
client.cpp
client.h
threaddata.cpp
 #include "cirbuf.h"
-#include <time.h>
-
 #include <iostream>
 #include <exception>
 #include <stdexcept>
@@ -140,7 +138,7 @@ void CirBuf::doubleSize(uint factor)
     memset(&buf[head], 5, maxWriteSize() + 2);
 #endif
-    resizedAt = time(NULL);
+    primedForSizeReset = false;
 }
 uint32_t CirBuf::getSize() const
@@ -148,14 +146,25 @@ uint32_t CirBuf::getSize() const
     return size;
 }
-time_t CirBuf::bufferLastResizedSecondsAgo() const
+void CirBuf::resetSizeIfEligable(size_t size)
 {
-    return time(NULL) - resizedAt;
+    // Ensuring the reset will only happen the second time the timer event hits.
+    if (!primedForSizeReset)
+    {
+        primedForSizeReset = true;
+        return;
+    }
+
+    if (usedBytes() > 0)
+        return;
+
+    resetSize(size);
 }
 void CirBuf::resetSize(size_t newSize)
 {
     assert(usedBytes() == 0);
+    primedForSizeReset = false;
     if (this->size == newSize)
         return;
     char *newBuf = (char*)malloc(newSize);
@@ -166,7 +175,6 @@ void CirBuf::resetSize(size_t newSize)
     this->size = newSize;
     head = 0;
     tail = 0;
-    resizedAt = time(NULL);
 #ifndef NDEBUG
     Logger *logger = Logger::getInstance();
     logger->logf(LOG_DEBUG, "Reset buf size: %d", size);
@@ -18,7 +18,7 @@ class CirBuf
     uint32_t tail = 0;
     uint32_t size = 0;
-    time_t resizedAt = 0;
+    bool primedForSizeReset = false;
 public:
     CirBuf(size_t size);
@@ -37,7 +37,7 @@ public:
     void doubleSize(uint factor = 2);
     uint32_t getSize() const;
-    time_t bufferLastResizedSecondsAgo() const;
+    void resetSizeIfEligable(size_t size);
     void resetSize(size_t size);
     void reset();
@@ -228,19 +228,6 @@ bool Client::writeBufIntoFd()
     const bool bufferHasData = writebuf.usedBytes() > 0;
     setReadyForWriting(bufferHasData || error == IoWrapResult::Wouldblock);
-    if (!bufferHasData)
-    {
-        writeBufIsZeroCount++;
-        bool doReset = (writeBufIsZeroCount >= 10 && writebuf.getSize() > (maxPacketSize / 10) && writebuf.bufferLastResizedSecondsAgo() > 30);
-        doReset |= (writeBufIsZeroCount >= 100 && writebuf.bufferLastResizedSecondsAgo() > 300);
-
-        if (doReset)
-        {
-            writeBufIsZeroCount = 0;
-            writebuf.resetSize(initialBufferSize);
-        }
-    }
-
     return true;
 }
@@ -268,6 +255,12 @@ std::string Client::getKeepAliveInfoString() const
     return s;
 }
+void Client::resetBuffersIfEligible()
+{
+    readbuf.resetSizeIfEligable(initialBufferSize);
+    writebuf.resetSizeIfEligable(initialBufferSize);
+}
+
 // Call this from a place you know the writeBufMutex is locked, or we're still only doing SSL accept.
 void Client::setReadyForWriting(bool val)
 {
@@ -353,19 +346,6 @@ bool Client::bufferToMqttPackets(std::vector&lt;MqttPacket&gt; &amp;packetQueueIn, Client_
     setReadyForReading(readbuf.freeSpace() > 0);
-    if (readbuf.usedBytes() == 0)
-    {
-        readBufIsZeroCount++;
-        bool doReset = (readBufIsZeroCount >= 10 && readbuf.getSize() > (maxPacketSize / 10) && readbuf.bufferLastResizedSecondsAgo() > 30);
-        doReset |= (readBufIsZeroCount >= 100 && readbuf.bufferLastResizedSecondsAgo() > 300);
-
-        if (doReset)
-        {
-            readBufIsZeroCount = 0;
-            readbuf.resetSize(initialBufferSize);
-        }
-    }
-
     return true;
 }
@@ -38,10 +38,7 @@ class Client
     IoWrapper ioWrapper;
     CirBuf readbuf;
-    uint8_t readBufIsZeroCount = 0;
-
     CirBuf writebuf;
-    uint8_t writeBufIsZeroCount = 0;
     bool authenticated = false;
     bool connectPacketSeen = false;
@@ -114,6 +111,7 @@ public:
     std::string repr();
     bool keepAliveExpired();
     std::string getKeepAliveInfoString() const;
+    void resetBuffersIfEligible();
 };
@@ -132,7 +132,10 @@ void ThreadData::doKeepAliveCheck()
                 it = clients_by_fd.erase(it);
             }
             else
+            {
+                client->resetBuffersIfEligible();
                 it++;
+            }
         }
     }
     catch (std::exception &ex)