econmanager.cpp

#include "econmanager.h"

#include <IGameConfigs.h>

#include <map>

#ifdef PLATFORM_64BITS
	#define OFFS_M_ATTRIBUTES 0x250
#else
	#define OFFS_M_ATTRIBUTES 0x1BC
#endif

CEconManager g_EconManager;

// pointer to item schema attribute map singleton
using AttributeMap = CUtlMap<int, CEconItemAttributeDefinition, int>;
AttributeMap *g_SchemaAttributes;

size_t g_nAutoAttributeBase = 4000;
std::map<std::string, int> g_AutoNumberedAttributes{};

typedef uintptr_t (*GetEconItemSchema_fn)(void);
GetEconItemSchema_fn fnGetEconItemSchema = nullptr;

// https://www.unknowncheats.me/wiki/Calling_Functions_From_Injected_Library_Using_Function_Pointers_in_C%2B%2B
#ifdef WIN32
typedef bool (__thiscall *CEconItemAttributeInitFromKV_fn)(CEconItemAttributeDefinition* pThis, KeyValues* pAttributeKeys, CUtlVector<CUtlString>* pErrors);
#elif defined(_LINUX)
typedef bool (__cdecl *CEconItemAttributeInitFromKV_fn)(CEconItemAttributeDefinition* pThis, KeyValues* pAttributeKeys, CUtlVector<CUtlString>* pErrors);
#endif
CEconItemAttributeInitFromKV_fn fnItemAttributeInitFromKV = nullptr;

bool CEconManager::Init(char *error, size_t maxlength) {
	// get the base address of the server
	
	SourceMod::IGameConfig *conf;
	if (!gameconfs->LoadGameConfigFile("tf2.econ_dynamic", &conf, error, maxlength)) {
		return false;
	}
	
	if (!conf->GetMemSig("GEconItemSchema()", (void**) &fnGetEconItemSchema)) {
		snprintf(error, maxlength, "Failed to setup call to GetEconItemSchema()");
		return false;
	} else if (!conf->GetMemSig("CEconItemAttributeDefinition::BInitFromKV()", (void**) &fnItemAttributeInitFromKV)) {
		snprintf(error, maxlength, "Failed to setup call to CEconItemAttributeDefinition::BInitFromKV");
		return false;
	}
	
	gameconfs->CloseGameConfigFile(conf);
	
	// is this late enough in the MM:S load stage?  we might just have to hold the function
	g_SchemaAttributes = reinterpret_cast<AttributeMap*>(fnGetEconItemSchema() + OFFS_M_ATTRIBUTES);
	return true;
}

/**
 * Initializes a CEconItemAttributeDefinition from a KeyValues definition, then inserts or
 * replaces the appropriate entry in the schema.
 */
bool CEconManager::InsertOrReplaceAttribute(KeyValues *pAttribKV) {
	KeyValues::AutoDelete attribute{pAttribKV->MakeCopy()};
	const char* attrID = attribute->GetName();
	const char* attrName = attribute->GetString("name");
	
	int attrdef;
	if (strcmp(attrID, "auto") == 0) {
		/**
		 * Have the plugin automatically allocate an attribute ID.
		 * - if the name is already mapped to an ID, then use that
		 * - otherwise, continue to increment our counter until we find an unused one
		 */
		auto search = g_AutoNumberedAttributes.find(attrName);
		if (search != g_AutoNumberedAttributes.end()) {
			attrdef = search->second;
		} else {
			while (g_SchemaAttributes->Find(g_nAutoAttributeBase) != g_SchemaAttributes->InvalidIndex()) {
				g_nAutoAttributeBase++;
			}
			attrdef = g_nAutoAttributeBase;
			g_AutoNumberedAttributes[attrName] = attrdef;
		}
	} else {
		attrdef = atoi(attrID);
		if (attrdef <= 0) {
			META_CONPRINTF("Attribute '%s' has invalid index string '%s'\n", attrName, attrID);
			return false;
		}
	}
	
	attribute->SetName(std::to_string(attrdef).c_str());
	
	// only replace existing injected attributes; fail on schema attributes
	auto existingIndex = g_SchemaAttributes->Find(attrdef);
	if (existingIndex != g_SchemaAttributes->InvalidIndex()) {
		auto &existingAttr = g_SchemaAttributes->Element(existingIndex);
		if (!existingAttr.m_KeyValues->GetBool("injected")) {
			META_CONPRINTF("WARN: Not overriding native attribute '%s'\n",
					existingAttr.m_pszName);
			return false;
		}
	}
	
	// embed additional custom data into attribute KV; econdata and the like can deal with this
	// one could also add this data into the file itself, but this leaves less room for error
	attribute->SetBool("injected", true);
	
	CEconItemAttributeDefinition def;
	fnItemAttributeInitFromKV(&def, attribute, nullptr);
	
	// TODO verify that this doesn't leak, or just shrug it off
	g_SchemaAttributes->InsertOrReplace(attrdef, def);
	return true;
}

bool CEconManager::RegisterAttribute(KeyValues* pAttribKV) {
	AutoKeyValues kv{pAttribKV};
	std::string attrName = kv->GetString("name");
	if (attrName.empty()) {
		attrName = kv->GetString("attribute_class");
		if (attrName.empty()) {
			return false;
		}
		kv->SetString("name", attrName.c_str());
	}
	
	this->m_RegisteredAttributes[attrName] = std::move(kv);
	return true;
}

void CEconManager::InstallAttributes() {
	for (const auto& pair : m_RegisteredAttributes) {
		InsertOrReplaceAttribute(pair.second);
	}
}

KeyValues *CEconManager::GetAttributeDefinitionKeyValuesByName(const char *name) {
	if (!name) {
		return nullptr;
	}
	
	FOR_EACH_MAP_FAST( (*g_SchemaAttributes), i ) {
		if (!(*g_SchemaAttributes)[i].m_pszName) {
			continue;
		}
		if (stricmp((*g_SchemaAttributes)[i].m_pszName, name) == 0) {
			return (*g_SchemaAttributes)[i].m_KeyValues;
		}
	}
	return nullptr;
}