Server class code cleanups (#9769)

* Server::overrideDayNightRatio doesn't require to return bool
There is no sense to sending null player, the caller should send a valid object

* Server::init: make private & cleanup
This function is always called before start() and loads some variables which can be loaded in constructor directly.
Make it private and call it directly in start

* Split Server inventory responsibility to a dedicated object

This splits permit to found various historical issues:
* duplicate lookups on player connection
* sending inventory to non related player when a player connects
* non friendly lookups on detached inventories ownership

This reduce the detached inventory complexity and also increased the
lookup performance in a quite interesting way for servers with thousands
of inventories.

src/server/serverinventorymgr.cpp

@@ -0,0 +1,192 @@
+/*
+Minetest
+Copyright (C) 2010-2020 Minetest core development team
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "serverinventorymgr.h"
+#include "map.h"
+#include "nodemetadata.h"
+#include "player_sao.h"
+#include "remoteplayer.h"
+#include "server.h"
+#include "serverenvironment.h"
+
+ServerInventoryManager::ServerInventoryManager() : InventoryManager()
+{
+}
+
+ServerInventoryManager::~ServerInventoryManager()
+{
+	// Delete detached inventories
+	for (auto &detached_inventory : m_detached_inventories) {
+		delete detached_inventory.second.inventory;
+	}
+}
+
+Inventory *ServerInventoryManager::getInventory(const InventoryLocation &loc)
+{
+	switch (loc.type) {
+	case InventoryLocation::UNDEFINED:
+	case InventoryLocation::CURRENT_PLAYER:
+		break;
+	case InventoryLocation::PLAYER: {
+		RemotePlayer *player = m_env->getPlayer(loc.name.c_str());
+		if (!player)
+			return NULL;
+		PlayerSAO *playersao = player->getPlayerSAO();
+		if (!playersao)
+			return NULL;
+		return playersao->getInventory();
+	} break;
+	case InventoryLocation::NODEMETA: {
+		NodeMetadata *meta = m_env->getMap().getNodeMetadata(loc.p);
+		if (!meta)
+			return NULL;
+		return meta->getInventory();
+	} break;
+	case InventoryLocation::DETACHED: {
+		auto it = m_detached_inventories.find(loc.name);
+		if (it == m_detached_inventories.end())
+			return nullptr;
+		return it->second.inventory;
+	} break;
+	default:
+		sanity_check(false); // abort
+		break;
+	}
+	return NULL;
+}
+
+void ServerInventoryManager::setInventoryModified(const InventoryLocation &loc)
+{
+	switch (loc.type) {
+	case InventoryLocation::UNDEFINED:
+		break;
+	case InventoryLocation::PLAYER: {
+
+		RemotePlayer *player = m_env->getPlayer(loc.name.c_str());
+
+		if (!player)
+			return;
+
+		player->setModified(true);
+		player->inventory.setModified(true);
+		// Updates are sent in ServerEnvironment::step()
+	} break;
+	case InventoryLocation::NODEMETA: {
+		MapEditEvent event;
+		event.type = MEET_BLOCK_NODE_METADATA_CHANGED;
+		event.p = loc.p;
+		m_env->getMap().dispatchEvent(event);
+	} break;
+	case InventoryLocation::DETACHED: {
+		// Updates are sent in ServerEnvironment::step()
+	} break;
+	default:
+		sanity_check(false); // abort
+		break;
+	}
+}
+
+Inventory *ServerInventoryManager::createDetachedInventory(
+		const std::string &name, IItemDefManager *idef, const std::string &player)
+{
+	if (m_detached_inventories.count(name) > 0) {
+		infostream << "Server clearing detached inventory \"" << name << "\""
+			   << std::endl;
+		delete m_detached_inventories[name].inventory;
+	} else {
+		infostream << "Server creating detached inventory \"" << name << "\""
+			   << std::endl;
+	}
+
+	Inventory *inv = new Inventory(idef);
+	sanity_check(inv);
+	m_detached_inventories[name].inventory = inv;
+	if (!player.empty()) {
+		m_detached_inventories[name].owner = player;
+
+		if (!m_env)
+			return inv; // Mods are not loaded yet, ignore
+
+		RemotePlayer *p = m_env->getPlayer(name.c_str());
+
+		// if player is connected, send him the inventory
+		if (p && p->getPeerId() != PEER_ID_INEXISTENT) {
+			m_env->getGameDef()->sendDetachedInventory(
+					inv, name, p->getPeerId());
+		}
+	} else {
+		if (!m_env)
+			return inv; // Mods are not loaded yet, don't send
+
+		// Inventory is for everybody, broadcast
+		m_env->getGameDef()->sendDetachedInventory(inv, name, PEER_ID_INEXISTENT);
+	}
+
+	return inv;
+}
+
+bool ServerInventoryManager::removeDetachedInventory(const std::string &name)
+{
+	const auto &inv_it = m_detached_inventories.find(name);
+	if (inv_it == m_detached_inventories.end())
+		return false;
+
+	delete inv_it->second.inventory;
+	const std::string &owner = inv_it->second.owner;
+
+	if (!owner.empty()) {
+		RemotePlayer *player = m_env->getPlayer(owner.c_str());
+
+		if (player && player->getPeerId() != PEER_ID_INEXISTENT)
+			m_env->getGameDef()->sendDetachedInventory(
+					nullptr, name, player->getPeerId());
+
+	} else {
+		// Notify all players about the change
+		m_env->getGameDef()->sendDetachedInventory(
+				nullptr, name, PEER_ID_INEXISTENT);
+	}
+
+	m_detached_inventories.erase(inv_it);
+
+	return true;
+}
+
+void ServerInventoryManager::sendDetachedInventories(const std::string &peer_name,
+		bool incremental,
+		std::function<void(const std::string &, Inventory *)> apply_cb)
+{
+	for (const auto &detached_inventory : m_detached_inventories) {
+		const DetachedInventory &dinv = detached_inventory.second;
+		if (incremental) {
+			if (!dinv.inventory || !dinv.inventory->checkModified())
+				continue;
+		}
+
+		// if we are pushing inventories to a specific player
+		// we should filter to send only the right inventories
+		if (!peer_name.empty()) {
+			const std::string &attached_player = dinv.owner;
+			if (!attached_player.empty() && peer_name != attached_player)
+				continue;
+		}
+
+		apply_cb(detached_inventory.first, detached_inventory.second.inventory);
+	}
+}