GarbageCollector.cpp

#include "GarbageCollector.h"
// Constructor sets head and tail to NULL
GarbageCollector::GarbageCollector(){ head= tail =NULL; }

// Add a new connection
void GarbageCollector::addConnection(Connection * connection) {
    if ( head == NULL )	// If head is null (List empty) point head and tail to the connection
        head=tail=connection;
    else { //else add to the end and advance tail
        tail->setNextConnection(connection);
        tail = connection;
    }
}
// Clean up all finished threads
void GarbageCollector::cleanup() {
    Connection * cur = head; // set cur to head
    // Loop and delete all finished connection from the front of the list
    for ( ; cur!= NULL && !cur->isRunning(); )
    {
	cur->waitForRunToFinish(); // Wait for the thread
       	Connection * cur1 = cur;	// get a pointer to it
        cur = cur->getNextConnection(); // Advance cur
	delete (cur1); // Delete finished thread
    }
    head = cur; // Set head to cur
    if ( head == NULL) tail=NULL; // If list is empty set tail to NULL
}
// Invoked upon program termination to Gracefully wait for all running threads to finish
void GarbageCollector::terminate() {
    Connection * cur = head; //set cur to jead
    for ( ; cur!= NULL; ) // Loop on all connections
    {
        cur->waitForRunToFinish(); // wait for the current connection to finish
        Connection * cur1 = cur; // get a pointer to it
        cur = cur->getNextConnection(); // advance cur
        delete (cur1); // delete the current connection
    }
    head = tail=NULL; // set head and tail to NULL as the list should be empty
}
GarbageCollector::~GarbageCollector()
{
    terminate(); // Invoke terminate to dispose all connections
}