Codechange: [Network] Introduce function to validate the client name

4 files changed, 17 insertions, 3 deletions

diff --git a/src/network/network_client.cpp b/src/network/network_client.cpp
index 5858859cb..a12215bbc 100644
--- a/src/network/network_client.cpp
+++ b/src/network/network_client.cpp
@@ -1251,6 +1251,20 @@ void NetworkClientsToSpectators(CompanyID cid)
 }
 
 /**
+ * Check whether the given client name is deemed valid for use in network games.
+ * An empty name (null or '') is not valid as that is essentially no name at all.
+ * A name starting with white space is not valid for tab completion purposes.
+ * @param client_name The client name to check for validity.
+ * @return True iff the name is valid.
+ */
+bool NetworkIsValidClientName(const char *client_name)
+{
+	if (StrEmpty(client_name)) return false;
+	if (*client_name == ' ') return false;
+	return true;
+}
+
+/**
  * Send the server our name.
  */
 void NetworkUpdateClientName()
diff --git a/src/network/network_func.h b/src/network/network_func.h
index d14dd290f..a7f2e7cb5 100644
--- a/src/network/network_func.h
+++ b/src/network/network_func.h
@@ -36,6 +36,7 @@ extern StringList _network_host_list;
 extern StringList _network_ban_list;
 
 byte NetworkSpectatorCount();
+bool NetworkIsValidClientName(const char *client_name);
 void NetworkUpdateClientName();
 bool NetworkCompanyHasClients(CompanyID company);
 const char *NetworkChangeCompanyPassword(CompanyID company_id, const char *password);
diff --git a/src/network/network_gui.cpp b/src/network/network_gui.cpp
index 1c80f7f3c..15cf24f49 100644
--- a/src/network/network_gui.cpp
+++ b/src/network/network_gui.cpp
@@ -808,8 +808,7 @@ public:
 			}
 
 			case WID_NG_CLIENT:
-				/* Make sure the name does not start with a space, so TAB completion works */
-				if (!StrEmpty(this->name_editbox.text.buf) && this->name_editbox.text.buf[0] != ' ') {
+				if (NetworkIsValidClientName(this->name_editbox.text.buf)) {
 					strecpy(_settings_client.network.client_name, this->name_editbox.text.buf, lastof(_settings_client.network.client_name));
 				} else {
 					strecpy(_settings_client.network.client_name, "Player", lastof(_settings_client.network.client_name));
diff --git a/src/network/network_server.cpp b/src/network/network_server.cpp
index 552171027..321c8aa09 100644
--- a/src/network/network_server.cpp
+++ b/src/network/network_server.cpp
@@ -946,7 +946,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_JOIN(Packet *p)
 	}
 
 	/* We need a valid name.. make it Player */
-	if (StrEmpty(name)) strecpy(name, "Player", lastof(name));
+	if (!NetworkIsValidClientName(name)) strecpy(name, "Player", lastof(name));
 
 	if (!NetworkFindName(name, lastof(name))) { // Change name if duplicate
 		/* We could not create a name for this client */