Change GUId generator based on feedback.

doc/lua_api.md

@@ -7614,16 +7614,20 @@ child will follow movement and rotation of that bone.
           -- Default: false
       }
       ```
+* `get_guid()`: returns a global unique identifier (a string)
+    * For players a global unique identiticator is a player name.
+    * For non-player objects, it is unique generated string.
 
 #### Lua entity only (no-op for other objects)
 
 * `remove()`: remove object
     * The object is removed after returning from Lua. However the `ObjectRef`
       itself instantly becomes unusable with all further method calls having
       no effect and returning `nil`.
-* `get_guid()`: returns a global unique identifier (a string)
-    * An object keeps its guid forever, even over server restarts.
-    * The same guid will never be reused for a different object.
+* `set_guid(guid)`: 
+    * Set a global unique identifier string of entity.
+    * Is valid to be called only in `on_activate` callback.
+    * Should be used ONLY for restoring saved guid from staticdata!!!
 * `set_velocity(vel)`
     * Sets the velocity
     * `vel` is a vector, e.g. `{x=0.0, y=2.3, z=1.0}`

games/devtest/mods/unittests/entity.lua

@@ -141,5 +141,5 @@ local function test_entity_guid(_, pos)
 
 	obj:remove()
 end
-unittests.register("test_guid", test_entity_guid, {map=true})
+unittests.register("test_entity_guid", test_entity_guid, {map=true})
 

games/devtest/mods/unittests/player.lua

@@ -84,3 +84,10 @@ local function run_player_add_pos_tests(player)
 end
 unittests.register("test_player_add_pos", run_player_add_pos_tests, {player=true})
 
+--
+-- Player get uuid
+--
+local function test_player_guid_tests(player)
+	assert(player:get_guid()==player:get_player_name())
+end
+unittests.register("test_player_guid", test_player_guid_tests, {player=true})

src/guid.cpp

@@ -20,90 +20,16 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "guid.h"
 #include <sstream>
 
-#define DIGITS_PER_U64 19
-#define MAX_NUM_IN_U64 9999999999999999999ul
+#include "serverenvironment.h"
 
-GUIdGenerator::Validity GUIdGenerator::seed(const GUId &first)
+GUId GUIdGenerator::next(const std::string &prefix)
 {
-	Validity v = getValidity(first);
-	if (v != Valid)
-		return v;
+	std::stringstream s_guid;
 
-	m_next_v.clear();
+	s_guid << prefix << std::hex << m_next << '-' << std::hex << m_env->getGameTime();
 
-	size_t num_len = first.size() - 6;
+	m_next++;
 
-	while (num_len > DIGITS_PER_U64) {
-		num_len -= DIGITS_PER_U64;
-		m_next_v.push_back(std::stoull(first.substr(6 + num_len, DIGITS_PER_U64)));
-	}
-
-	m_next_v.push_back(std::stoull(first.substr(6, num_len)));
-
-	return Valid;
-}
-
-GUId GUIdGenerator::generateNext()
-{
-	if (m_next_v.empty())
-		return "";
-
-	GUId ret = peekNext();
-
-	// increment m_next_v
-
-	if (m_next_v[0] < MAX_NUM_IN_U64) {
-		m_next_v[0] += 1ul;
-
-	} else { // very unlikely
-		m_next_v[0] = 0ul;
-		size_t s = m_next_v.size();
-		for (size_t i = 1; true; i++) {
-			if (i == s) {
-				m_next_v.push_back(1ul);
-				break;
-			}
-			if (m_next_v[i] < MAX_NUM_IN_U64) {
-				m_next_v[i] += 1ul;
-				break;
-			}
-			// very unlikely
-			m_next_v[i] = 0ul;
-			continue;
-		}
-	}
-
-	return ret;
+	return s_guid.str();
 }
 
-GUId GUIdGenerator::peekNext() const
-{
-	if (m_next_v.empty())
-		return "";
-
-	std::ostringstream id_strm;
-
-	id_strm << "v1guid";
-
-	for (auto it = m_next_v.rbegin(); it != m_next_v.rend(); it++)
-		id_strm << *it;
-
-	return id_strm.str();
-}
-
-GUIdGenerator::Validity GUIdGenerator::getValidity(const GUId &id)
-{
-	if (id.empty())
-		return Old;
-
-	size_t s = id.size();
-
-	if (s < 7 || id.substr(0, 6) != "v1guid" || id[6] == '0')
-		return Invalid;
-
-	for (size_t i = 7; i < s; i++)
-		if (!isdigit(id[i]))
-			return Invalid;
-
-	return Valid;
-}

src/guid.h

@@ -20,24 +20,16 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #pragma once
 
 #include "irrlichttypes.h"
+#include "util/basic_macros.h"
 #include <vector>
 #include <string>
 
+class ServerEnvironment;
+
 /**
  * A global unique identifier.
  * It is global because it stays valid in a world forever.
  * It is unique because there are no collisions.
- *
- * It is a string of the following form:
- * "v1guid<deci_num>"
- * where <deci_num> should be replaced by a number of decimal digits, with the
- * first digit != 0 ("0" and "" are invalid).
- * The number after the v is the version number (currently always 1).
- *
- * There is a partial order for guids:
- * guid A is newer than guid B iff
- * A's version number is higher than B's and B's version number is 1 or
- * A and B both have version number 1 and A's deci_num is higher
  */
 typedef std::string GUId;
 
@@ -48,59 +40,41 @@ class GUIdGenerator {
 public:
 	/**
 	 * Creates a new uninitialized generator.
+	 * @param env ServerEnvironment where generator is running
+	 * @param prefix Prefix of generated GUId
+	 * @param next next value getted from loadMeta
 	 */
 	GUIdGenerator() = default;
 
 	~GUIdGenerator() = default;
-
-	/**
-	 * The validity of a guid.
-	 * Old means that it was a valid guid in an older version, this includes
-	 * the empty string.
-	 * Invalid guids are strings that have an invalid form, eg. "v1guid1a23", but
-	 * also guids of newer versions.
-	 * Everything else is valid.
-	 */
-	enum Validity {
-		Valid,
-		Old,
-		Invalid,
-	};
-
-	/**
-	 * Seeds the generator with the first guid to return next.
-	 * Can fail for invalid seeds.
-	 * Do only seed with guids of which you know that itself and newer guids are
-	 * not used yet.
-	 * @param first the first guid that should be returned by generateNext
-	 * @return the validity of the given id; Valid iff the generator is seeded
-	 */
-	Validity seed(const GUId &first);
+	DISABLE_CLASS_COPY(GUIdGenerator)
 
 	/**
 	 * Generates the next guid, which it will never return again.
 	 * @return the new guid, or "" if the generator is not yet initialized
 	 */
-	GUId generateNext();
+	GUId next(const std::string &prefix);
 
+private:
 	/**
-	 * Returns the guid that would be generated next.
-	 * @return the next guid
+	 * Set ServerEnvironment,
+	 * @param env ServerEnvironment.
 	 */
-	GUId peekNext() const;
-
+	void setServerEnvironment(ServerEnvironment *env) { m_env = env; };
 	/**
-	 * Returns the validity for a guid.
-	 * @param id the guid
-	 * @return the validity of id
+	 * Set state to defined/known state,
+	 * @param next New state value.
 	 */
-	static Validity getValidity(const GUId &id);
-
-private:
+	void setState(u32 state) { m_next = state; };
 	/**
-	 * Internal representation of the next guid.
-	 * Each u64 stores 19 decimal digits of the next deci_num.
-	 * The u64s are ordered little-endian-wise.
+	 * Get state,
+	 * @return Return aactual state value.
 	 */
-	std::vector<u64> m_next_v;
+	u32 getState() const { return m_next; };
+
+private:
+	ServerEnvironment *m_env;
+	u32 m_next;
+
+	friend class ServerEnvironment;
 };

src/script/lua_api/l_object.cpp

@@ -1132,6 +1132,25 @@ int ObjectRef::l_set_sprite(lua_State *L)
 	return 0;
 }
 
+// set_guid(self, guid)
+int ObjectRef::l_set_guid(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+	ObjectRef *ref = checkObject<ObjectRef>(L, 1);
+	LuaEntitySAO *entitysao = getluaobject(ref);
+	if (entitysao == nullptr)
+		return 0;
+
+	std::string guid = readParam<std::string>(L, 2, "");
+
+	if (!guid.empty())
+		lua_pushboolean(L, entitysao->setGuid(guid));
+	else
+		lua_pushboolean(L, false);
+
+	return 1;
+}
+
 // DEPRECATED
 // get_entity_name(self)
 int ObjectRef::l_get_entity_name(lua_State *L)

src/script/lua_api/l_object.h

@@ -203,6 +203,9 @@ class ObjectRef : public ModApiBase {
 
 	// set_sprite(self, start_frame, num_frames, framelength, select_x_by_camera)
 	static int l_set_sprite(lua_State *L);
+
+	// set_guid(self, guid)
+	static int l_set_guid(lua_State *L);
 
 	// DEPRECATED
 	// get_entity_name(self)

src/server/luaentity_sao.cpp

@@ -36,7 +36,6 @@ LuaEntitySAO::LuaEntitySAO(ServerEnvironment *env, v3f pos, const std::string &d
 	u16 hp = 1;
 	v3f velocity;
 	v3f rotation;
-	std::string guid;
 
 	while (!data.empty()) { // breakable, run for one iteration
 		std::istringstream is(data, std::ios::binary);
@@ -66,11 +65,7 @@ LuaEntitySAO::LuaEntitySAO(ServerEnvironment *env, v3f pos, const std::string &d
 		rotation.X = readF1000(is);
 		rotation.Z = readF1000(is);
 
-		if (version2 < 2)
-			break;
-		guid = deSerializeString32(is);
-
-		// if (version2 < 3)
+		// if (version2 < 2)
 		//     break;
 		// <read new values>
 		break;
@@ -88,20 +83,13 @@ LuaEntitySAO::LuaEntitySAO(ServerEnvironment *env, v3f pos, const std::string &d
 	m_hp = hp;
 	m_velocity = velocity;
 	m_rotation = rotation;
-	if (!guid.empty()) {
-		m_guid = guid;
-	} else {
-		m_guid = env->generateNextLuaentGUId();
-		m_force_write_staticdata = true;
-	}
 }
 
 LuaEntitySAO::LuaEntitySAO(ServerEnvironment *env, v3f pos, const std::string &name,
 		const std::string &state) :
 		UnitSAO(env, pos),
 		m_init_name(name), m_init_state(state)
 {
-	m_guid = env->generateNextLuaentGUId();
 }
 
 LuaEntitySAO::~LuaEntitySAO()
@@ -132,6 +120,10 @@ void LuaEntitySAO::addedToEnvironment(u32 dtime_s)
 		// Activate entity, supplying serialized state
 		m_env->getScriptIface()->
 			luaentity_Activate(m_id, m_init_state, dtime_s);
+		// if Activate callback does not set guid, set it. 
+		if (m_guid.empty()) {
+			getGuid();
+		}
 	} else {
 		// It's an unknown object
 		// Use entitystring as infotext for debugging
@@ -323,13 +315,11 @@ void LuaEntitySAO::getStaticData(std::string *result) const
 	writeF1000(os, m_rotation.Y);
 
 	// version2. Increase this variable for new values
-	writeU8(os, 2); // PROTOCOL_VERSION >= 37
+	writeU8(os, 1); // PROTOCOL_VERSION >= 37
 
 	writeF1000(os, m_rotation.X);
 	writeF1000(os, m_rotation.Z);
 
-	os << serializeString32(m_guid);
-
 	// <write new values>
 
 	*result = os.str();
@@ -443,6 +433,22 @@ u16 LuaEntitySAO::getHP() const
 	return m_hp;
 }
 
+bool LuaEntitySAO::setGuid(std::string &guid)
+{
+	if (m_guid.empty()) {
+		m_guid = guid;
+		return true;
+	}
+	return false;
+}
+std::string LuaEntitySAO::getGuid()
+{
+	if (m_guid.empty()) {
+		m_guid = m_env->getGUIdGenerator().next(std::string("@"));
+	}
+	return m_guid;
+}
+
 void LuaEntitySAO::setVelocity(v3f velocity)
 {
 	m_velocity = velocity;

src/server/luaentity_sao.h

@@ -59,7 +59,8 @@ class LuaEntitySAO : public UnitSAO
 
 	void setHP(s32 hp, const PlayerHPChangeReason &reason);
 	u16 getHP() const;
-	std::string getGuid() const override { return m_guid; }
+	bool setGuid(std::string &guid);
+	std::string getGuid() override;
 
 	/* LuaEntitySAO-specific */
 	void setVelocity(v3f velocity);

src/server/player_sao.cpp

@@ -414,9 +414,9 @@ void PlayerSAO::setPlayerYaw(const float yaw)
 	UnitSAO::setRotation(rotation);
 }
 
-std::string PlayerSAO::getGuid() const
+std::string PlayerSAO::getGuid()
 {
-	return std::string("vpguid") + m_player->getName();
+	return m_player->getName();
 }
 
 void PlayerSAO::setFov(const float fov)