ABORT implementation successful via double fork demon

- the developed solution matches the classic double fork method to produce daemon processes.
- concept standardization established. Good to go.
- Note - The current implementation is only inside `RETR` command.
- Next steps - Extend it to other commands using same method.

Author: jatin69

src/client/commands/cmd_ABOR.cpp

@@ -28,4 +28,5 @@ void Client::cmd_ABOR(int controlConnectionfd) {
  * so,
  * a design decision has to be made
  * about how this abort implementation should be elegantly incorportated in the main branch.
+ *
 */

src/client/commands/cmd_RETR.cpp

@@ -3,7 +3,14 @@
 // RETR - get/retrive a file from server
 
 void Client::cmd_RETR(int controlConnectionfd, const vector<string>& args) {
-	
+
+	/**Data connection before fork() . why not ?
+	 * 
+	 * Was not working.
+	 * Was giving error : connection reset by peer ; don't know why
+	 * 
+	*/
+
 	string ftpResponse;
 
 	/**Create a child - As per RFC 959
@@ -93,6 +100,11 @@ void Client::cmd_RETR(int controlConnectionfd, const vector<string>& args) {
 		int dataConnectionfd = createDataConnection(controlConnectionfd);
 
 		// send a signal to parent that he is safe to return now
+
+		// the independently developed solution 
+		// matches with the standard solution for daemon production.
+		// ref - https://stackoverflow.com/a/10932710
+
 		int newp = fork();
 		if(newp > 0){
 			string s = executeShellCommand("ps fj");

src/server/commands/cmd_RETR.cpp

@@ -2,6 +2,14 @@
 
 // RETR - get/retrive a file from server
 void Server::cmd_RETR(int controlConnectionfd, const vector<string>& args) {
+
+	/**Data connection before fork() . why not ?
+	 * 
+	 * Was not working.
+	 * Was giving error : connection reset by peer ; don't know why
+	 * 
+	*/
+
 	int pid = fork();
 	if (pid < 0) {  // error
 		printError();
@@ -50,6 +58,10 @@ void Server::cmd_RETR(int controlConnectionfd, const vector<string>& args) {
 		// @abort
 		int dataConnectionfd = createDataConnection(controlConnectionfd);
 
+		// the independently developed solution 
+		// matches with the standard solution for daemon production.
+		// ref - https://stackoverflow.com/a/10932710
+
 		// send a signal to parent that he is safe to return now
 		int newpid = fork();
 		if(newpid > 0){