Change: Make a shortened network revision string for use in server qu…

…eries

src/network/core/game.h

@@ -56,6 +56,8 @@ struct NetworkGameInfo : NetworkServerGameInfo {
 	byte map_set;                                   ///< Graphical set
 };
 
+const char * GetNetworkRevisionString();
+
 #endif /* ENABLE_NETWORK */
 
 #endif /* NETWORK_CORE_GAME_H */

src/network/core/tcp_http.cpp

@@ -45,6 +45,7 @@ NetworkHTTPSocketHandler::NetworkHTTPSocketHandler(SOCKET s,
 	redirect_depth(depth),
 	sock(s)
 {
+	/* Not using GetNetworRevisionString() since there are no field length limitations here */
 	size_t bufferSize = strlen(url) + strlen(host) + strlen(_openttd_revision) + (data == NULL ? 0 : strlen(data)) + 128;
 	char *buffer = AllocaM(char, bufferSize);
 

src/network/network.cpp

@@ -1100,13 +1100,53 @@ void NetworkShutDown()
 	NetworkCoreShutdown();
 }
 
+/**
+ * Get the network version string used by this build.
+ * The returned string is guaranteed to be at most NETWORK_REVISON_LENGTH bytes.
+ */
+const char * GetNetworkRevisionString()
+{
+	/* This will be allocated on heap and never free'd, but only once so not a "real" leak. */
+	static char *network_revision = nullptr;
+	/* We want at least this many characters of the git hash, if the base string becomes truncatad. */
+	const uint MIN_GITHASH_LENGTH = 8;
+
+	if (!network_revision) {
+		/* Start by taking a chance on the full revision string. */
+		network_revision = stredup(_openttd_revision);
+		/* If it's too long, truncate it. */
+		if (strlen(network_revision) >= NETWORK_REVISION_LENGTH - 1) {
+			network_revision[NETWORK_REVISION_LENGTH - 1] = '\0';
+
+			/* Prepare a prefix of the git hash.
+			 * Size is length + 1 for terminator, +2 for -g prefix, +1 for optional M suffix. */
+			char githash_prefix[MIN_GITHASH_LENGTH + 4] = "-g";
+			for (uint i = 0; i < MIN_GITHASH_LENGTH; i++) {
+				githash_prefix[i + 2] = _openttd_revision_hash[i];
+			}
+			if (_openttd_revision_modified == 2) {
+				githash_prefix[MIN_GITHASH_LENGTH + 2] = 'M';
+				githash_prefix[MIN_GITHASH_LENGTH + 3] = '\0';
+			}
+
+			if (strstr(network_revision, githash_prefix) == nullptr) {
+				/* The prefix was not found, forcibly replace the last part of the version string with it. */
+				strecpy(network_revision + NETWORK_REVISION_LENGTH - strlen(githash_prefix) - 1, githash_prefix, network_revision + NETWORK_REVISION_LENGTH);
+			}
+		}
+	}
+
+	assert(strlen(network_revision) < NETWORK_REVISION_LENGTH); // strlen does not include terminator, constant does, hence strictly less than
+	return network_revision;
+}
+
 /**
  * Checks whether the given version string is compatible with our version.
  * @param other the version string to compare to
  */
 bool IsNetworkCompatibleVersion(const char *other)
 {
-	return strncmp(_openttd_revision, other, NETWORK_REVISION_LENGTH - 1) == 0;
+	return strncmp(GetNetworkRevisionString(), other, NETWORK_REVISION_LENGTH - 1) == 0;
 }
 
 #endif /* ENABLE_NETWORK */

src/network/network_admin.cpp

@@ -172,7 +172,7 @@ NetworkRecvStatus ServerNetworkAdminSocketHandler::SendWelcome()
 	Packet *p = new Packet(ADMIN_PACKET_SERVER_WELCOME);
 
 	p->Send_string(_settings_client.network.server_name);
-	p->Send_string(_openttd_revision);
+	p->Send_string(_openttd_revision); // Not GetNetworRevisionString() since there is no field length limitation here
 	p->Send_bool  (_network_dedicated);
 
 	p->Send_string(_network_game_info.map_name);

src/network/network_client.cpp

@@ -343,7 +343,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::SendJoin()
 	SetWindowDirty(WC_NETWORK_STATUS_WINDOW, WN_NETWORK_STATUS_WINDOW_JOIN);
 
 	Packet *p = new Packet(PACKET_CLIENT_JOIN);
-	p->Send_string(_openttd_revision);
+	p->Send_string(GetNetworkRevisionString());
 	p->Send_uint32(_openttd_newgrf_version);
 	p->Send_string(_settings_client.network.client_name); // Client name
 	p->Send_uint8 (_network_join_as);     // PlayAs

src/network/network_udp.cpp

@@ -191,7 +191,7 @@ void ServerNetworkUDPSocketHandler::Receive_CLIENT_FIND_SERVER(Packet *p, Networ
 
 	strecpy(ngi.map_name, _network_game_info.map_name, lastof(ngi.map_name));
 	strecpy(ngi.server_name, _settings_client.network.server_name, lastof(ngi.server_name));
-	strecpy(ngi.server_revision, _openttd_revision, lastof(ngi.server_revision));
+	strecpy(ngi.server_revision, GetNetworkRevisionString(), lastof(ngi.server_revision));
 
 	Packet packet(PACKET_UDP_SERVER_RESPONSE);
 	this->SendNetworkGameInfo(&packet, &ngi);