From bccaca82fa4040d404423ef51b58da0211473094 Mon Sep 17 00:00:00 2001
From: Saturneric <eric.bktu@gmail.com>
Date: Wed, 25 Nov 2020 03:14:32 +0800
Subject: [PATCH] Try to add comments and fix some bugs.

---
 include/communicate/tcp_server.h | 30 ++++++++++++++++++++++--------
 src/communicate/tcp_server.cpp   | 23 ++++++++++++++++-------
 2 files changed, 38 insertions(+), 15 deletions(-)

diff --git a/include/communicate/tcp_server.h b/include/communicate/tcp_server.h
index 83234ca..9c8e3df 100644
--- a/include/communicate/tcp_server.h
+++ b/include/communicate/tcp_server.h
@@ -13,13 +13,21 @@
 
 namespace Net {
 
-/**
- * TCP Server using 
- *
-*/
+// 
+// Provide stable, reliable, easy-to-use, many-to-one TCP communication.
+// Requirement:
+//  1. It must be bound to an available port before use.
+// Features:
+//  1. Support communication concurrency based on multithreading.
+//
 class TCPServer {
 public:
-  TCPServer(int port, int max_connection);
+
+  // 
+  // Please provide an avaliable port(1~65535) first
+  // The default maximum connection limit is 1024
+  //
+  TCPServer(uint16_t port, uint32_t max_connection);
 
   ~TCPServer() {
     stop();
@@ -27,8 +35,8 @@ public:
   }
 
   void stop() {
-    if (p_accept_manager_thread != nullptr)
-      p_accept_manager_thread->interrupt();
+    if (p_conn_mgr_thrd != nullptr)
+      p_conn_mgr_thrd->interrupt();
     this->status = -1;
   }
 
@@ -40,7 +48,7 @@ private:
   struct sockaddr_in server_addr;
   std::queue<uint8_t> recv_buff;
   boost::mutex buff_mutex;
-  boost::thread *p_accept_manager_thread;
+  boost::thread *p_conn_mgr_thrd;
 
   void cycle();
 
@@ -49,6 +57,12 @@ private:
   static void accept(int fd, boost::mutex *buff_mutex,
                      std::queue<uint8_t> *recv_buff, const int *status);
 
+  // 
+  // Using the standard UNIX way to create a new socket
+  // Requirement:
+  //  the given  port need to be free for the binding
+  // Return:
+  //  a new and initialized socket which can be given to listen()
   void create_socket(int port);
 };
 
diff --git a/src/communicate/tcp_server.cpp b/src/communicate/tcp_server.cpp
index 5e90441..7e0fc9f 100644
--- a/src/communicate/tcp_server.cpp
+++ b/src/communicate/tcp_server.cpp
@@ -9,7 +9,7 @@ extern int errno;
 
 void Net::TCPServer::cycle() {
   boost::thread accept_manager_thread(TCPServer::connection_manager, this);
-  this->p_accept_manager_thread = &accept_manager_thread;
+  this->p_conn_mgr_thrd = &accept_manager_thread;
   accept_manager_thread.detach();
 }
 
@@ -59,19 +59,28 @@ void Net::TCPServer::create_socket(int port) {
   this->server_addr.sin_family = AF_INET;
   this->server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
   this->server_addr.sin_port = htons(port);
+
+  // Try binding the socket to the given port
+  if (bind(fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0){
+    // Close the socket created
+    close(fd);
+    throw std::runtime_error(strerror(errno));
+  }
+
 }
 
-Net::TCPServer::TCPServer(int port, int max_connection) {
+Net::TCPServer::TCPServer(uint16_t port, uint32_t max_connection=1024) {
 
-  // 创建 socket
+  // Create a new socket binding certain port
   create_socket(port);
 
-  if (bind(fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0)
-    throw std::runtime_error(strerror(errno));
-
-  if (listen(fd, max_connection) < 0)
+  if (listen(fd, max_connection) < 0) {
+    // Close the socket created
+    close(fd);
     throw std::runtime_error(strerror(errno));
+  }
 
+  // Start running the engine cycle
   cycle();
 }