Added truncating to IPC log buffer queue #4651

When the IPC log buffer is too large, the oldest log line is removed
when a new log line is added.

src/lib/ipc/IpcLogOutputter.cpp

@@ -116,7 +116,12 @@ void
 IpcLogOutputter::appendBuffer(const String& text)
 {
 	ArchMutexLock lock(m_bufferMutex);
-	m_buffer.push(text);
+	if (m_buffer.size() >= m_bufferMaxSize) {
+		// if the queue is exceeds size limit,
+		// throw away the oldest item
+		m_buffer.pop_front();
+	}
+	m_buffer.push_back(text);
 }
 
 void
@@ -182,7 +187,7 @@ IpcLogOutputter::getChunk(size_t count)
 	for (size_t i = 0; i < count; i++) {
 		chunk.append(m_buffer.front());
 		chunk.append("\n");
-		m_buffer.pop();
+		m_buffer.pop_front();
 	}
 	return chunk;
 }

src/lib/ipc/IpcLogOutputter.h

@@ -22,7 +22,7 @@
 #include "arch/IArchMultithread.h"
 #include "base/ILogOutputter.h"
 
-#include <queue>
+#include <deque>
 
 class IpcServer;
 class Event;
@@ -87,7 +87,7 @@ private:
 	void				appendBuffer(const String& text);
 
 private:
-	typedef std::queue<String> Buffer;
+	typedef std::deque<String> Buffer;
 
 	IpcServer&			m_ipcServer;
 	Buffer				m_buffer;