Adding Comments

KVServer.c

@@ -82,13 +82,14 @@ void *worker(void *args) {
     int epollfd;
     int *newfd=malloc(sizeof(int));
     
-    read_pipe = ((int *) args)[0]; //assigned the read end of the pipe    
     epollfd = epoll_create1(0);
     if (epollfd == -1) {
         perror("epoll_create1");
         exit(EXIT_FAILURE);
     }
 
+    /* Add the pipe which we get from main thread */
+    read_pipe = ((int *) args)[0];   
     ev.events = EPOLLIN;
     ev.data.fd = read_pipe;
     if (epoll_ctl(epollfd, EPOLL_CTL_ADD, read_pipe, &ev) == -1) {
@@ -104,7 +105,11 @@ void *worker(void *args) {
         }
         for ( i= 0; i < nfds; ++i ) {
             if (events[i].data.fd == read_pipe) {
-                fflush(stdout);
+                /*  if we get a request from main thread to add new client
+                    ie. events[i].data.fd is equal to the pipe which we use to talk with main thread
+                     - read this newfd from pipe
+                     - add this newfd to epoll instance to monitor for client requests
+                */
                 read(read_pipe, newfd, sizeof(newfd));
                 printf("\nread %d\n", *newfd);
                 ev.data.fd=*newfd;
@@ -114,24 +119,25 @@ void *worker(void *args) {
                     exit(EXIT_FAILURE);
                 }
                
-                fflush(stdout);
-            } 
-            else{
+            } else {
+                /*  if we get a request from client
+                    ie. events[i].data.fd is equal to the client socket fd
+                */
                 int flag = events[i].events;
-                
+
                 if (flag & EPOLLRDHUP) {
                     /* Connection was closed.
-                        Remove socket from epoll instance
-                        Close the socket and dont process more info from this socket
+                        - Remove socket from epoll instance
+                        - Close the socket and dont process more info from this socket
+                        Note: This if block should be before EPOLLIN
                     */
-                    char eof;
-                    read(events[i].data.fd  , &eof, sizeof(char));
                     epoll_ctl( epollfd, EPOLL_CTL_DEL, events[i].data.fd , NULL );
                     close(events[i].data.fd);
                     continue; 
                 }
 
                 if (flag & EPOLLIN) {
+                    /* Parse the actual message from client */
                     struct message *requestMessage= malloc(sizeof(struct message));
                     int readlength=read(events[i].data.fd  , requestMessage, sizeof(struct message)); 
                     printf("\n[Message Received from client]\n[[Status:%c][Key:%s][Value:%s]]",requestMessage->status,requestMessage->key,requestMessage->value);               
@@ -156,7 +162,7 @@ int main (int argc, int argv) {
     struct sockaddr_in serv_addr, cli_addr; 
 
     //int *pipes = (int*) malloc(pool_thread_size * 2 * sizeof(pipes));
-    int pipes[5][2];
+    int pipes[5][2];                                // TODO: initialize pipes dynamically
 
     // initialize thread pool with initial pool size
     threads = malloc(pool_thread_size * sizeof(pthread_t));
@@ -194,7 +200,7 @@ int main (int argc, int argv) {
             perror("ERROR on accept");
 
         write(pipes[next][1], &newsockfd, sizeof(newsockfd));
-        printf("main thread ka fd ka value: %d\n",newsockfd);
+        printf("main thread value: %d\n",newsockfd);
         fflush(stdout);
         
         next = (next+1) % pool_thread_size;