From 9acd36bf9981cf9cb8e82785508d6eb7f010cc77 Mon Sep 17 00:00:00 2001
From: SmallJoker <mk939@ymail.com>
Date: Tue, 10 Sep 2019 21:18:42 +0200
Subject: [PATCH] Formspecs: Introduce formspec_version to mods

---
 builtin/game/features.lua           |  1 +
 doc/lua_api.txt                     | 14 ++++++++++++++
 src/client/client.cpp               |  3 ++-
 src/client/game.cpp                 |  2 +-
 src/gui/guiFormSpecMenu.cpp         |  9 ++++++++-
 src/gui/guiFormSpecMenu.h           |  4 ++--
 src/network/networkprotocol.h       | 12 +++++++++++-
 src/network/serverpackethandler.cpp |  3 +++
 src/remoteplayer.h                  |  3 +++
 src/script/lua_api/l_server.cpp     |  4 ++++
 src/server.cpp                      |  9 +++++----
 11 files changed, 54 insertions(+), 10 deletions(-)

diff --git a/builtin/game/features.lua b/builtin/game/features.lua
index cf21303c7..51d21e86c 100644
--- a/builtin/game/features.lua
+++ b/builtin/game/features.lua
@@ -13,6 +13,7 @@ core.features = {
 	object_use_texture_alpha = true,
 	object_independent_selectionbox = true,
 	httpfetch_binary_data = true,
+	formspec_version_element = true,
 }
 
 function core.has_feature(arg)
diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index 7fae20603..b809e18c3 100644
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -1959,6 +1959,15 @@ Examples
 Elements
 --------
 
+### `formspec_version[<version>]`
+
+* Set the formspec version to a certain number. If not specified,
+  version 1 is assumed.
+* Must be specified before `size` element.
+* Clients older than this version can neither show newer elements nor display
+  elements with new arguments correctly.
+* Available since feature `formspec_version_element`.
+
 ### `size[<W>,<H>,<fixed_size>]`
 
 * Define the size of the menu in inventory slots
@@ -1995,6 +2004,7 @@ Elements
 
 ### `real_coordinates[<bool>]`
 
+* INFORMATION: Enable it automatically using `formspec_version` version 2 or newer.
 * When set to true, all following formspec elements will use the new coordinate system.
 * If used immediately after `size`, `position`, `anchor`, and `no_prepend` elements
   (if present), the form size will use the new coordinate system.
@@ -2114,6 +2124,7 @@ Elements
   image shall be sized 8 times 16px  times  4 times 16px
 * If `auto_clip` is `true`, the background is clipped to the formspec size
   (`x` and `y` are used as offset values, `w` and `h` are ignored)
+* Available since formspec version 2
 
 ### `pwdfield[<X>,<Y>;<W>,<H>;<name>;<label>]`
 
@@ -3788,6 +3799,8 @@ Utilities
           -- Specifies whether binary data can be uploaded or downloaded using
           -- the HTTP API (5.1.0)
           httpfetch_binary_data = true,
+          -- Whether formspec_version[<version>] may be used (5.1.0)
+          formspec_version_element = true,
       }
 
 * `minetest.has_feature(arg)`: returns `boolean, missing_features`
@@ -3807,6 +3820,7 @@ Utilities
           avg_jitter = 0.03,         -- average packet time jitter
           connection_uptime = 200,   -- seconds since client connected
           protocol_version = 32,     -- protocol version used by client
+          formspec_version = 2,      -- supported formspec version
           -- following information is available on debug build only!!!
           -- DO NOT USE IN MODS
           --ser_vers = 26,             -- serialization version used by client
diff --git a/src/client/client.cpp b/src/client/client.cpp
index 9535acc8e..f6be3186f 100644
--- a/src/client/client.cpp
+++ b/src/client/client.cpp
@@ -1222,12 +1222,13 @@ void Client::sendRespawn()
 void Client::sendReady()
 {
 	NetworkPacket pkt(TOSERVER_CLIENT_READY,
-			1 + 1 + 1 + 1 + 2 + sizeof(char) * strlen(g_version_hash));
+			1 + 1 + 1 + 1 + 2 + sizeof(char) * strlen(g_version_hash) + 2);
 
 	pkt << (u8) VERSION_MAJOR << (u8) VERSION_MINOR << (u8) VERSION_PATCH
 		<< (u8) 0 << (u16) strlen(g_version_hash);
 
 	pkt.putRawString(g_version_hash, (u16) strlen(g_version_hash));
+	pkt << (u16)FORMSPEC_API_VERSION;
 	Send(&pkt);
 }
 
diff --git a/src/client/game.cpp b/src/client/game.cpp
index b5508f2cb..bc35ade85 100644
--- a/src/client/game.cpp
+++ b/src/client/game.cpp
@@ -4055,7 +4055,7 @@ void Game::showPauseMenu()
 	float ypos = simple_singleplayer_mode ? 0.7f : 0.1f;
 	std::ostringstream os;
 
-	os << FORMSPEC_VERSION_STRING  << SIZE_TAG
+	os << FORMSPEC_VERSION_STRING << SIZE_TAG
 		<< "button_exit[4," << (ypos++) << ";3,0.5;btn_continue;"
 		<< strgettext("Continue") << "]";
 
diff --git a/src/gui/guiFormSpecMenu.cpp b/src/gui/guiFormSpecMenu.cpp
index e02abf018..f291b4e87 100644
--- a/src/gui/guiFormSpecMenu.cpp
+++ b/src/gui/guiFormSpecMenu.cpp
@@ -2167,6 +2167,9 @@ void GUIFormSpecMenu::parseElement(parserData* data, const std::string &element)
 	if (element.empty())
 		return;
 
+	if (parseVersionDirect(element))
+		return;
+
 	std::vector<std::string> parts = split(element,'[');
 
 	// ugly workaround to keep compatibility
@@ -2503,7 +2506,7 @@ void GUIFormSpecMenu::regenerateGui(v2u32 screensize)
 	}
 
 	/* Copy of the "real_coordinates" element for after the form size. */
-	mydata.real_coordinates = false;
+	mydata.real_coordinates = m_formspec_version >= 2;
 	for (; i < elements.size(); i++) {
 		std::vector<std::string> parts = split(elements[i], '[');
 		std::string name = trim(parts[0]);
@@ -2648,10 +2651,14 @@ void GUIFormSpecMenu::regenerateGui(v2u32 screensize)
 	if (enable_prepends) {
 		// Backup the coordinates so that prepends can use the coordinates of choice.
 		bool rc_backup = mydata.real_coordinates;
+		bool version_backup = m_formspec_version;
 		mydata.real_coordinates = false; // Old coordinates by default.
+
 		std::vector<std::string> prepend_elements = split(m_formspec_prepend, ']');
 		for (const auto &element : prepend_elements)
 			parseElement(&mydata, element);
+
+		m_formspec_version = version_backup;
 		mydata.real_coordinates = rc_backup; // Restore coordinates
 	}
 
diff --git a/src/gui/guiFormSpecMenu.h b/src/gui/guiFormSpecMenu.h
index e4dc66151..46df0930c 100644
--- a/src/gui/guiFormSpecMenu.h
+++ b/src/gui/guiFormSpecMenu.h
@@ -472,7 +472,7 @@ protected:
 private:
 	IFormSource        *m_form_src;
 	TextDest           *m_text_dst;
-	u32                 m_formspec_version = 0;
+	u16                 m_formspec_version = 1;
 	std::string         m_focused_element = "";
 	JoystickController *m_joystick;
 
@@ -591,7 +591,7 @@ public:
 
 	void setForm(const std::string &formspec)
 	{
-		m_formspec = FORMSPEC_VERSION_STRING + formspec;
+		m_formspec = formspec;
 	}
 
 	const std::string &getForm() const
diff --git a/src/network/networkprotocol.h b/src/network/networkprotocol.h
index 05737d0a9..f603ed6c5 100644
--- a/src/network/networkprotocol.h
+++ b/src/network/networkprotocol.h
@@ -198,6 +198,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 	PROTOCOL VERSION 38:
 		Incremental inventory sending mode
 		Unknown inventory serialization fields no longer throw an error
+		Mod-specific formspec version
 */
 
 #define LATEST_PROTOCOL_VERSION 38
@@ -219,7 +220,16 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #define PASSWORD_SIZE 28       // Maximum password length. Allows for
                                // base64-encoded SHA-1 (27+\0).
 
-#define FORMSPEC_API_VERSION 1
+/*
+	Changes by FORMSPEC_API_VERSION:
+
+	FORMSPEC VERSION 1:
+		(too much)
+	FORMSPEC VERSION 2:
+		Forced real coordinates
+		background[]: 9-slice scaling parameters
+*/
+#define FORMSPEC_API_VERSION 2
 #define FORMSPEC_VERSION_STRING "formspec_version[" TOSTRING(FORMSPEC_API_VERSION) "]"
 
 #define TEXTURENAME_ALLOWED_CHARS "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_.-"
diff --git a/src/network/serverpackethandler.cpp b/src/network/serverpackethandler.cpp
index 6cb3b3520..9999a1690 100644
--- a/src/network/serverpackethandler.cpp
+++ b/src/network/serverpackethandler.cpp
@@ -386,6 +386,9 @@ void Server::handleCommand_ClientReady(NetworkPacket* pkt)
 			peer_id, major_ver, minor_ver, patch_ver,
 			full_ver);
 
+	if (pkt->getRemainingBytes() >= 2)
+		*pkt >> playersao->getPlayer()->formspec_version;
+
 	const std::vector<std::string> &players = m_clients.getPlayerNames();
 	NetworkPacket list_pkt(TOCLIENT_UPDATE_PLAYER_LIST, 0, peer_id);
 	list_pkt << (u8) PLAYER_LIST_INIT << (u16) players.size();
diff --git a/src/remoteplayer.h b/src/remoteplayer.h
index 260504fb4..831bfe956 100644
--- a/src/remoteplayer.h
+++ b/src/remoteplayer.h
@@ -130,6 +130,9 @@ public:
 
 	u16 protocol_version = 0;
 
+	// v1 for clients older than 5.1.0-dev
+	u16 formspec_version = 1;
+
 	session_t getPeerId() const { return m_peer_id; }
 
 	void setPeerId(session_t peer_id) { m_peer_id = peer_id; }
diff --git a/src/script/lua_api/l_server.cpp b/src/script/lua_api/l_server.cpp
index 6017a5475..7c083e652 100644
--- a/src/script/lua_api/l_server.cpp
+++ b/src/script/lua_api/l_server.cpp
@@ -233,6 +233,10 @@ int ModApiServer::l_get_player_information(lua_State *L)
 	lua_pushnumber(L, prot_vers);
 	lua_settable(L, table);
 
+	lua_pushstring(L, "formspec_version");
+	lua_pushnumber(L, player->formspec_version);
+	lua_settable(L, table);
+
 #ifndef NDEBUG
 	lua_pushstring(L,"serialization_version");
 	lua_pushnumber(L, ser_vers);
diff --git a/src/server.cpp b/src/server.cpp
index f6bf491be..6a51139d9 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -1568,7 +1568,7 @@ void Server::SendChatMessage(session_t peer_id, const ChatMessage &message)
 void Server::SendShowFormspecMessage(session_t peer_id, const std::string &formspec,
 	const std::string &formname)
 {
-	NetworkPacket pkt(TOCLIENT_SHOW_FORMSPEC, 0 , peer_id);
+	NetworkPacket pkt(TOCLIENT_SHOW_FORMSPEC, 0, peer_id);
 	if (formspec.empty()){
 		//the client should close the formspec
 		//but make sure there wasn't another one open in meantime
@@ -1579,7 +1579,7 @@ void Server::SendShowFormspecMessage(session_t peer_id, const std::string &forms
 		pkt.putLongString("");
 	} else {
 		m_formspec_state_data[peer_id] = formname;
-		pkt.putLongString(FORMSPEC_VERSION_STRING + formspec);
+		pkt.putLongString(formspec);
 	}
 	pkt << formname;
 
@@ -1908,7 +1908,8 @@ void Server::SendPlayerInventoryFormspec(session_t peer_id)
 		return;
 
 	NetworkPacket pkt(TOCLIENT_INVENTORY_FORMSPEC, 0, peer_id);
-	pkt.putLongString(FORMSPEC_VERSION_STRING + player->inventory_formspec);
+	pkt.putLongString(player->inventory_formspec);
+
 	Send(&pkt);
 }
 
@@ -1920,7 +1921,7 @@ void Server::SendPlayerFormspecPrepend(session_t peer_id)
 		return;
 
 	NetworkPacket pkt(TOCLIENT_FORMSPEC_PREPEND, 0, peer_id);
-	pkt << FORMSPEC_VERSION_STRING + player->formspec_prepend;
+	pkt << player->formspec_prepend;
 	Send(&pkt);
 }