adding send_interface declaring pure virtual function of sendMessage

adding some comments to socket_listener header

headers/constants.h

@@ -2,9 +2,14 @@
 #define __CONSTANTS_H__
 #ifndef TRX_SOCKET_CONSTANTS
 #define TRX_SOCKET_CONSTANTS 1
-
+/**
+ * Values used when attempting to open a socket
+ */
 const int SOCKET_ERROR = -1;
 const int SOCKET_OK = 0;
+/**
+ * Values used when listening for connections to a socket
+ */
 const int WAIT_SOCKET_FAILURE = -1;
 const int WAIT_SOCKET_SUCCESS = 0;
 

headers/listen_interface.h

@@ -4,6 +4,7 @@
 #include <string>
 
 class ListenInterface {
+ public:
   virtual void onMessageReceived(int socket_id, std::string message) = 0;
 };
 

headers/send_interface.h

@@ -0,0 +1,11 @@
+#ifndef __SEND_INTERFACE_H__
+#define __SEND_INTERFACE_H__
+
+#include <string>
+
+class SendInterface {
+ public:
+  virtual void sendMessage(int client_socket_fd, std::string message) = 0;
+};
+
+#endif  // __SEND_INTERFACE_H__

headers/socket_listener.h

@@ -1,17 +1,18 @@
 #ifndef __SOCKET_LISTENER_H__
 #define __SOCKET_LISTENER_H__
+// Project libraries
+#include "listen_interface.h"
+#include "send_interface.h"
 
+// System libraries
 #include <sys/socket.h>
+
+// C++ Libraries
 #include <string>
-#include "listen_interface.h"
 
 #define MAX_BUFFER_SIZE (49152)
 
-// typedef void (*MessageReceivedHandler)(SocketListener* listener, int
-// socketId,
-//                                       std::string msg);
-
-class SocketListener : ListenInterface {
+class SocketListener : public ListenInterface, public SendInterface {
  public:
   // constructor
   SocketListener(std::string ipAddress, int port);
@@ -19,21 +20,29 @@ class SocketListener : ListenInterface {
   // destructor
   ~SocketListener();
 
-  // public methods
-
-  // Send message to client
-  void sendMessage(int socket, std::string msg);
+  /**
+   * Send a message to a client socket described by its file descriptor
+   * @param[in] {int} client_socket_fd The client socket file descriptor
+   * @param[in] {std::string} The message to be sent
+   */
+  virtual void sendMessage(int client_socket_fd, std::string message) override;
 
-  // Initialize
+  /**
+   * Perform intialization work
+   */
   bool init();
 
-  // Main process loop
+  /**
+   * Main message loop
+   */
   void run();
 
-  // Cleanup
+  /**
+   * Perform any cleanup work
+   */
   void cleanup();
 
-  void onMessageReceived(int socket_id, std::string message);
+  virtual void onMessageReceived(int socket_id, std::string message) override;
 
  private:
   // private methods

socket_listener.cpp

@@ -1,5 +1,6 @@
 // Project headers
 #include "headers/socket_listener.h"
+
 #include "headers/constants.h"
 // System libraries
 #include <arpa/inet.h>
@@ -29,10 +30,10 @@ SocketListener::~SocketListener() { cleanup(); }
  * sendMessage
  * @method
  * Send a null-terminated array of characters, supplied as a const char pointer,
- * to a client socket
+ * to a client socket described by its file descriptor
  */
-void SocketListener::sendMessage(int clientSocket, std::string msg) {
-  send(clientSocket, msg.c_str(), msg.size() + 1, 0);
+void SocketListener::sendMessage(int client_socket_fd, std::string msg) {
+  send(client_socket_fd, msg.c_str(), msg.size() + 1, 0);
 }
 
 /**
@@ -65,7 +66,7 @@ void SocketListener::run() {
     // wait for a client connection and get its socket file descriptor
     int client_socket_fd = waitForConnection(listening_socket_fd);
 
-    if (socket != SOCKET_ERROR) {
+    if (client_socket_fd != SOCKET_ERROR) {
       // Destroy listening socket and deallocate its file descriptor. Only use
       // the client socket now.
       close(listening_socket_fd);
@@ -85,7 +86,7 @@ void SocketListener::run() {
           std::cout << "Bytes received: " << bytes_received << "\nData: " << buf
                     << std::endl;
           // Handle incoming message
-          onMessageReceived(socket, std::string(buf));
+          onMessageReceived(client_socket_fd, std::string(buf));
         } else {
           std::cout << "client disconnected" << std::endl;
           break;