firebird-mirror/src/jrd/ExtEngineManager.cpp

/*
 *  The contents of this file are subject to the Initial
 *  Developer's Public License Version 1.0 (the "License");
 *  you may not use this file except in compliance with the
 *  License. You may obtain a copy of the License at
 *  http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_idpl.
 *
 *  Software distributed under the License is distributed AS IS,
 *  WITHOUT WARRANTY OF ANY KIND, either express or implied.
 *  See the License for the specific language governing rights
 *  and limitations under the License.
 *
 *  The Original Code was created by Adriano dos Santos Fernandes
 *  for the Firebird Open Source RDBMS project.
 *
 *  Copyright (c) 2008 Adriano dos Santos Fernandes <adrianosf@uol.com.br>
 *  and all contributors signed below.
 *
 *  All Rights Reserved.
 *  Contributor(s): ______________________________________.
 */

#include "firebird.h"
#include "consts_pub.h"
#include "iberror.h"
#include "inf_pub.h"
#include "../jrd/ExtEngineManager.h"
#include "../jrd/ErrorImpl.h"
#include "../jrd/ValueImpl.h"
#include "../jrd/ValuesImpl.h"
#include "../dsql/sqlda_pub.h"
#include "../common/dsc.h"
#include "../jrd/jrd.h"
#include "../jrd/exe.h"
#include "../jrd/req.h"
#include "../jrd/status.h"
#include "../jrd/tra.h"
#include "../jrd/ibase.h"
#include "../common/os/path_utils.h"
#include "../jrd/cvt_proto.h"
#include "../jrd/evl_proto.h"
#include "../jrd/intl_proto.h"
#include "../jrd/met_proto.h"
#include "../jrd/mov_proto.h"
#include "../jrd/thread_proto.h"
#include "../jrd/Function.h"
#include "../common/isc_proto.h"
#include "../common/classes/auto.h"
#include "../common/classes/fb_string.h"
#include "../common/classes/init.h"
#include "../common/classes/objects_array.h"
#include "../common/config/config.h"
#include "../common/ScanDir.h"
#include "../common/utils_proto.h"
#include "../common/classes/GetPlugins.h"

using namespace Firebird;


namespace Jrd {


class ExtEngineManager::AttachmentImpl : public Firebird::Attachment
{
public:
	AttachmentImpl(ExternalContextImpl* aContext, Handle aHandle, Jrd::Attachment* aAttachment);
	virtual ~AttachmentImpl();

public:
	virtual void FB_CALL dispose(Error* error);

	virtual Handle FB_CALL getHandle(Error* error) const;
	virtual const char* FB_CALL getUserName() const;
	virtual const char* FB_CALL getDatabaseName() const;

private:
	ExternalContextImpl* context;
	FB_API_HANDLE handle;
	Jrd::Attachment* attachment;
};


class ExtEngineManager::TransactionImpl : public Firebird::Transaction
{
public:
	TransactionImpl(Handle aHandle);
	virtual ~TransactionImpl();

public:
	virtual Handle FB_CALL getHandle(Error* error) const;

private:
	FB_API_HANDLE handle;
};


template <typename T> class ExtEngineManager::ContextManager
{
public:
	ContextManager(thread_db* tdbb, EngineAttachmentInfo* aAttInfo, T* obj,
				CallerName aCallerName = CallerName())
		: attInfo(aAttInfo),
		  attachment(tdbb->getAttachment()),
		  transaction(tdbb->getTransaction()),
		  charSet(attachment->att_charset),
		  attInUse(attachment->att_in_use),
		  traInUse(transaction ? transaction->tra_in_use : false)
	{
		attachment->att_in_use = true;

		if (transaction)
		{
			callerName = transaction->tra_caller_name;
			transaction->tra_caller_name = aCallerName;
			++transaction->tra_callback_count;
			transaction->tra_in_use = true;
		}

		attInfo->context->setTransaction(tdbb);

		setCharSet(tdbb, attInfo, obj);
	}

	ContextManager(thread_db* tdbb, EngineAttachmentInfo* aAttInfo, USHORT aCharSet,
				CallerName aCallerName = CallerName())
		: attInfo(aAttInfo),
		  attachment(tdbb->getAttachment()),
		  transaction(tdbb->getTransaction()),
		  charSet(attachment->att_charset),
		  attInUse(attachment->att_in_use),
		  traInUse(transaction ? transaction->tra_in_use : false)
	{
		attachment->att_charset = aCharSet;
		attachment->att_in_use = true;

		if (transaction)
		{
			callerName = transaction->tra_caller_name;
			transaction->tra_caller_name = aCallerName;
			++transaction->tra_callback_count;
			transaction->tra_in_use = true;
		}

		attInfo->context->setTransaction(tdbb);
	}

	~ContextManager()
	{
		if (transaction)
		{
			--transaction->tra_callback_count;
			transaction->tra_in_use = traInUse;
			transaction->tra_caller_name = callerName;
		}

		attachment->att_in_use = attInUse;
		attachment->att_charset = charSet;
	}

private:
	void setCharSet(thread_db* tdbb, EngineAttachmentInfo* attInfo, T* obj)
	{
		attachment->att_charset = attInfo->adminCharSet;

		if (!obj)
			return;

		Utf8 charSetName[MAX_SQL_IDENTIFIER_SIZE];

		{	// scope
			Database::Checkout dcoHolder(tdbb->getDatabase());

			obj->getCharSet(RaiseError(), attInfo->context, charSetName, MAX_SQL_IDENTIFIER_LEN);
			charSetName[MAX_SQL_IDENTIFIER_LEN] = '\0';
		}

		USHORT charSetId;

		if (!MET_get_char_coll_subtype(tdbb, &charSetId,
				reinterpret_cast<const UCHAR*>(charSetName), strlen(charSetName)))
		{
			status_exception::raise(Arg::Gds(isc_charset_not_found) << Arg::Str(charSetName));
		}

		attachment->att_charset = charSetId;
	}

private:
	EngineAttachmentInfo* attInfo;
	Jrd::Attachment* attachment;
	jrd_tra* transaction;
	// These data members are to restore the original information.
	const USHORT charSet;
	const bool attInUse;
	const bool traInUse;
	CallerName callerName;
};


//---------------------


ExtEngineManager::AttachmentImpl::AttachmentImpl(ExternalContextImpl* aContext, Handle aHandle,
		Jrd::Attachment* aAttachment)
	: context(aContext),
	  handle(aHandle),
	  attachment(aAttachment)
{
}

ExtEngineManager::AttachmentImpl::~AttachmentImpl()
{
	context->attachment.release();
	handle = 0;
	dispose(LogError());
}

void FB_CALL ExtEngineManager::AttachmentImpl::dispose(Error* error)
{
	ISC_STATUS_ARRAY statusVector;

	if (handle)
	{
		if (isc_detach_database(statusVector, &handle) != 0)
		{
			ErrorImpl::statusVectorToError(statusVector, error);
			return;
		}
	}

	context->attachment = NULL;
}

Handle FB_CALL ExtEngineManager::AttachmentImpl::getHandle(Error* /*error*/) const
{
	return handle;
}


const char* FB_CALL ExtEngineManager::AttachmentImpl::getUserName() const
{
	return attachment->att_user->usr_user_name.c_str();
}


const char* FB_CALL ExtEngineManager::AttachmentImpl::getDatabaseName() const
{
	return attachment->att_database->dbb_database_name.c_str();
}


//---------------------


ExtEngineManager::TransactionImpl::TransactionImpl(Handle aHandle)
	: handle(aHandle)
{
}

ExtEngineManager::TransactionImpl::~TransactionImpl()
{
}

Handle FB_CALL ExtEngineManager::TransactionImpl::getHandle(Error* /*error*/) const
{
	return handle;
}


//---------------------


ExtEngineManager::ExternalContextImpl::ExternalContextImpl(thread_db* tdbb,
		ExternalEngine* aEngine)
	: engine(aEngine),
	  internalAttachment(tdbb->getAttachment()),
	  miscInfo(*internalAttachment->att_pool),
	  traHandle(0)
{
	//// TODO: admin rights

	attHandle = internalAttachment->att_public_handle;
	clientCharSet = INTL_charset_lookup(tdbb, internalAttachment->att_client_charset)->getName();

	setTransaction(tdbb);
}

ExtEngineManager::ExternalContextImpl::~ExternalContextImpl()
{
	releaseTransaction();
}

void ExtEngineManager::ExternalContextImpl::releaseTransaction()
{
	if (traHandle)
	{
		traHandle = 0;
		transaction = NULL;
	}
}

void ExtEngineManager::ExternalContextImpl::setTransaction(thread_db* tdbb)
{
	releaseTransaction();

	jrd_tra* tra = tdbb->getTransaction();
	traHandle = tra ? tra->tra_public_handle : 0;

	transaction = FB_NEW(*internalAttachment->att_pool) TransactionImpl(traHandle);
}

ExternalEngine* ExtEngineManager::ExternalContextImpl::getEngine(Error* /*error*/)
{
	return engine;
}

Firebird::Attachment* FB_CALL ExtEngineManager::ExternalContextImpl::getAttachment(Error* /*error*/)
{
	if (!this->attachment)
	{
		thread_db* tdbb = JRD_get_thread_data();
		attachment = FB_NEW(*internalAttachment->att_pool) AttachmentImpl(this, attHandle,
			tdbb->getAttachment());
	}

	return attachment;
}

Firebird::Transaction* FB_CALL ExtEngineManager::ExternalContextImpl::getTransaction(Error* /*error*/)
{
	return transaction;
}


const Utf8* FB_CALL ExtEngineManager::ExternalContextImpl::getClientCharSet()
{
	return clientCharSet.c_str();
}


int FB_CALL ExtEngineManager::ExternalContextImpl::obtainInfoCode()
{
	static AtomicCounter counter;
	return ++counter;
}


void* FB_CALL ExtEngineManager::ExternalContextImpl::getInfo(int code)
{
	void* value = NULL;
	miscInfo.get(code, value);
	return value;
}


void* FB_CALL ExtEngineManager::ExternalContextImpl::setInfo(int code, void* value)
{
	void* oldValue = getInfo(code);
	miscInfo.put(code, value);
	return oldValue;
}


//---------------------


ExtEngineManager::Function::Function(thread_db* tdbb, ExtEngineManager* aExtManager,
		ExternalEngine* aEngine, ExternalFunction* aFunction,
		const Jrd::Function* aUdf)
	: extManager(aExtManager),
	  engine(aEngine),
	  function(aFunction),
	  udf(aUdf),
	  database(tdbb->getDatabase())
{
}


ExtEngineManager::Function::~Function()
{
	Database::Checkout dcoHolder(database);
	function->dispose(LogError());
}


void ExtEngineManager::Function::execute(thread_db* tdbb, const NestValueArray& args,
	impure_value* impure) const
{
	EngineAttachmentInfo* attInfo = extManager->getEngineAttachment(tdbb, engine);
	ContextManager<ExternalFunction> ctxManager(tdbb, attInfo, function,
		(udf->getName().package.isEmpty() ?
			CallerName(obj_udf, udf->getName().identifier) :
			CallerName(obj_package_header, udf->getName().package)));

	impure->vlu_desc.dsc_flags = DSC_null;
	MemoryPool& pool = *tdbb->getDefaultPool();
	ValueImpl result(pool, &impure->vlu_desc, "", true);

	HalfStaticArray<impure_value, 32> impureArgs;

	jrd_req* request = tdbb->getRequest();
	impure_value* impureArgsPtr = impureArgs.getBuffer(args.getCount());

	try
	{
		ValuesImpl params(pool, args.getCount());

		for (size_t i = 0; i < args.getCount(); ++i)
		{
			impureArgsPtr->vlu_desc = udf->fun_args[i + 1].fun_parameter->prm_desc;

			if (impureArgsPtr->vlu_desc.isText())
			{
				impureArgsPtr->vlu_string =
					FB_NEW_RPT(pool, impureArgsPtr->vlu_desc.getStringLength()) VaryingString();
				impureArgsPtr->vlu_desc.dsc_address = (UCHAR*) impureArgsPtr->vlu_string;
			}
			else
			{
				impureArgsPtr->vlu_string = NULL;
				impureArgsPtr->vlu_desc.dsc_address = (UCHAR*) &impureArgsPtr->vlu_misc;
			}

			dsc* arg = EVL_expr(tdbb, request, args[i]);

			if (request->req_flags & req_null)
				impureArgsPtr->vlu_desc.dsc_flags = DSC_null;
			else
			{
				MOV_move(tdbb, arg, &impureArgsPtr->vlu_desc);
				INTL_adjust_text_descriptor(tdbb, &impureArgsPtr->vlu_desc);
			}

			params.getValue(i + 1)->make(&impureArgsPtr->vlu_desc, "", true);

			++impureArgsPtr;
		}

		{	// scope
			Database::Checkout dcoHolder(tdbb->getDatabase());
			function->execute(RaiseError(), attInfo->context, &params, &result);
		}
	}
	catch (...)
	{
		for (size_t i = 0; i < args.getCount(); ++i)
			delete impureArgs[i].vlu_string;

		throw;
	}

	for (size_t i = 0; i < args.getCount(); ++i)
		delete impureArgs[i].vlu_string;

	if (result.isNull())
		request->req_flags |= req_null;
	else
		request->req_flags &= ~req_null;
}


//---------------------


ExtEngineManager::Procedure::Procedure(thread_db* tdbb, ExtEngineManager* aExtManager,
	    ExternalEngine* aEngine, ExternalProcedure* aProcedure,
		const jrd_prc* aPrc)
	: extManager(aExtManager),
	  engine(aEngine),
	  procedure(aProcedure),
	  prc(aPrc),
	  database(tdbb->getDatabase())
{
}


ExtEngineManager::Procedure::~Procedure()
{
	Database::Checkout dcoHolder(database);
	procedure->dispose(LogError());
}


ExtEngineManager::ResultSet* ExtEngineManager::Procedure::open(thread_db* tdbb,
	ValuesImpl* inputParams, ValuesImpl* outputParams) const
{
	return FB_NEW(*tdbb->getDefaultPool()) ResultSet(tdbb, inputParams, outputParams, this);
}


//---------------------


ExtEngineManager::ResultSet::ResultSet(thread_db* tdbb, ValuesImpl* inputParams,
		ValuesImpl* outputParams, const ExtEngineManager::Procedure* aProcedure)
	: procedure(aProcedure),
	  database(tdbb->getDatabase()),
	  firstFetch(true)
{
	attInfo = procedure->extManager->getEngineAttachment(tdbb, procedure->engine);
	ContextManager<ExternalProcedure> ctxManager(tdbb, attInfo, procedure->procedure,
		(procedure->prc->getName().package.isEmpty() ?
			CallerName(obj_procedure, procedure->prc->getName().identifier) :
			CallerName(obj_package_header, procedure->prc->getName().package)));
	Attachment* attachment = tdbb->getAttachment();

	charSet = attachment->att_charset;

	Database::Checkout dcoHolder(tdbb->getDatabase());

	resultSet = procedure->procedure->open(RaiseError(), attInfo->context, inputParams,
		outputParams);
}


ExtEngineManager::ResultSet::~ResultSet()
{
	if (resultSet)
	{
		Database::Checkout dcoHolder(database);
		resultSet->dispose(LogError());
	}
}


bool ExtEngineManager::ResultSet::fetch(thread_db* tdbb)
{
	bool wasFirstFetch = firstFetch;
	firstFetch = false;

	if (!resultSet)
		return wasFirstFetch;

	ContextManager<ExternalProcedure> ctxManager(tdbb, attInfo, charSet,
		(procedure->prc->getName().package.isEmpty() ?
			CallerName(obj_procedure, procedure->prc->getName().identifier) :
			CallerName(obj_package_header, procedure->prc->getName().package)));

	Database::Checkout dcoHolder(tdbb->getDatabase());
	return resultSet->fetch(RaiseError());
}


//---------------------


ExtEngineManager::Trigger::Trigger(thread_db* tdbb, ExtEngineManager* aExtManager,
			ExternalEngine* aEngine, ExternalTrigger* aTrigger,
			const Jrd::Trigger* aTrg)
	: extManager(aExtManager),
	  engine(aEngine),
	  trigger(aTrigger),
	  trg(aTrg),
	  database(tdbb->getDatabase())
{
}


ExtEngineManager::Trigger::~Trigger()
{
}


void ExtEngineManager::Trigger::execute(thread_db* tdbb, ExternalTrigger::Action action,
	record_param* oldRpb, record_param* newRpb) const
{
	EngineAttachmentInfo* attInfo = extManager->getEngineAttachment(tdbb, engine);
	ContextManager<ExternalTrigger> ctxManager(tdbb, attInfo, trigger,
		CallerName(obj_trigger, trg->name));

	Array<dsc*> descs;
	try
	{
		MemoryPool& pool = *tdbb->getDefaultPool();
		AutoPtr<ValuesImpl> oldValues, newValues;
		int valueOldCount = 0;
		int valueNewCount = 0;

		if (oldRpb)
			valueOldCount = setValues(tdbb, pool, oldValues, descs, oldRpb);

		if (newRpb)
			valueNewCount = setValues(tdbb, pool, newValues, descs, newRpb);

		{	// scope
			Database::Checkout dcoHolder(tdbb->getDatabase());

			trigger->execute(RaiseError(), attInfo->context, action, oldValues, newValues);

			for (int i = 1; i <= valueNewCount; ++i)
			{
				ValueImpl* val = newValues->getValue(i);

				if (val->isNull())
					SET_NULL(newRpb->rpb_record, val->getFieldNumber());
				else
					CLEAR_NULL(newRpb->rpb_record, val->getFieldNumber());
			}
		}
	}
	catch (...)
	{
		for (size_t i = 0; i < descs.getCount(); ++i)
			delete descs[i];
		throw;
	}

	for (size_t i = 0; i < descs.getCount(); ++i)
		delete descs[i];
}


int ExtEngineManager::Trigger::setValues(thread_db* /*tdbb*/, MemoryPool& pool,
	AutoPtr<ValuesImpl>& values, Array<dsc*>& descs,
	record_param* rpb) const
{
	if (!rpb || !rpb->rpb_record)
		return 0;

	Record* record = rpb->rpb_record;
	const Format* format = record->rec_format;

	values = FB_NEW(pool) ValuesImpl(pool, format->fmt_count);

	int start = descs.getCount();
	descs.resize(start + format->fmt_count);

	int j = 0;

	for (int i = 0; i < format->fmt_count; ++i)
	{
		descs[start + i] = FB_NEW(pool) dsc;

		if (format->fmt_desc[i].dsc_dtype != dtype_unknown)
		{
			EVL_field(rpb->rpb_relation, record, i, descs[start + i]);

			jrd_fld* field = (*rpb->rpb_relation->rel_fields)[i];
			fb_assert(field);

			values->getValue(j + 1)->make(descs[start + i], field->fld_name, true, i);
			++j;
		}
	}

	return j;
}


//---------------------


ExtEngineManager::~ExtEngineManager()
{
	fb_assert(enginesAttachments.count() == 0);
/*
AP: Commented out this code due to later AV.

When engine is released, it does dlclose() plugin module (libudr_engine.so),
but that module is not actually unloaded - because UDR module (libudrcpp_example.so) is using
symbols from plugin module, therefore raising plugin module's reference count.
UDR module can be unloaded only from plugin module's global variable (ModuleMap modules) dtor,
which is not called as long as plugin module is not unloaded. As the result all this will be
unloaded only on program exit, causing at that moment AV if this code is active: it happens that
~ModuleMap dlcloses itself.

	PluginInterface pi;

	EnginesMap::Accessor accessor(&engines);
	for (bool found = accessor.getFirst(); found; found = accessor.getNext())
	{
		ExternalEngine* engine = accessor.current()->second;
		pi->releasePlugin(engine);
	}
 */
}


//---------------------


void ExtEngineManager::initialize()
{
}


void ExtEngineManager::closeAttachment(thread_db* tdbb, Attachment* /*attachment*/)
{
	Array<ExternalEngine*> enginesCopy;

	{	// scope
		ReadLockGuard readGuard(enginesLock);

		EnginesMap::Accessor accessor(&engines);
		for (bool found = accessor.getFirst(); found; found = accessor.getNext())
			enginesCopy.add(accessor.current()->second);
	}

	Database::Checkout dcoHolder(tdbb->getDatabase());

	for (Array<ExternalEngine*>::iterator i = enginesCopy.begin(); i != enginesCopy.end(); ++i)
	{
		ExternalEngine* engine = *i;
		EngineAttachmentInfo* attInfo = getEngineAttachment(tdbb, engine, true);

		if (attInfo)
		{
			ContextManager<ExternalFunction> ctxManager(tdbb, attInfo, attInfo->adminCharSet);
			engine->closeAttachment(LogError(), attInfo->context);
			delete attInfo;
		}
	}
}


ExtEngineManager::Function* ExtEngineManager::makeFunction(thread_db* tdbb, const Jrd::Function* udf,
	const MetaName& engine, const string& entryPoint, const string& body)
{
	string entryPointTrimmed = entryPoint;
	entryPointTrimmed.trim();

	EngineAttachmentInfo* attInfo = getEngineAttachment(tdbb, engine);
	ContextManager<ExternalFunction> ctxManager(tdbb, attInfo, attInfo->adminCharSet,
		(udf->getName().package.isEmpty() ?
			CallerName(obj_udf, udf->getName().identifier) :
			CallerName(obj_package_header, udf->getName().package)));

	ExternalFunction* externalFunction;

	{	// scope
		Database::Checkout dcoHolder(tdbb->getDatabase());

		externalFunction = attInfo->engine->makeFunction(RaiseError(),
			attInfo->context, udf->getName().package.nullStr(), udf->getName().identifier.c_str(),
			entryPointTrimmed.nullStr(), body.nullStr());

		if (!externalFunction)
		{
			status_exception::raise(
				Arg::Gds(isc_eem_func_not_returned) <<
					udf->getName().toString() << engine);
		}
	}

	try
	{
		return FB_NEW(getPool()) Function(tdbb, this, attInfo->engine, externalFunction, udf);
	}
	catch (...)
	{
		Database::Checkout dcoHolder(tdbb->getDatabase());
		externalFunction->dispose(LogError());
		throw;
	}
}


ExtEngineManager::Procedure* ExtEngineManager::makeProcedure(thread_db* tdbb, const jrd_prc* prc,
	const MetaName& engine, const string& entryPoint, const string& body)
{
	string entryPointTrimmed = entryPoint;
	entryPointTrimmed.trim();

	EngineAttachmentInfo* attInfo = getEngineAttachment(tdbb, engine);
	ContextManager<ExternalProcedure> ctxManager(tdbb, attInfo, attInfo->adminCharSet,
		(prc->getName().package.isEmpty() ?
			CallerName(obj_procedure, prc->getName().identifier) :
			CallerName(obj_package_header, prc->getName().package)));

	ExternalProcedure* externalProcedure;

	{	// scope
		Database::Checkout dcoHolder(tdbb->getDatabase());

		externalProcedure = attInfo->engine->makeProcedure(RaiseError(),
			attInfo->context, prc->getName().package.nullStr(), prc->getName().identifier.c_str(),
			entryPointTrimmed.nullStr(), body.nullStr());

		if (!externalProcedure)
		{
			status_exception::raise(
				Arg::Gds(isc_eem_proc_not_returned) <<
					prc->getName().toString() << engine);
		}
	}

	try
	{
		return FB_NEW(getPool()) Procedure(tdbb, this, attInfo->engine, externalProcedure, prc);
	}
	catch (...)
	{
		Database::Checkout dcoHolder(tdbb->getDatabase());
		externalProcedure->dispose(LogError());
		throw;
	}
}


ExtEngineManager::Trigger* ExtEngineManager::makeTrigger(thread_db* tdbb, const Jrd::Trigger* trg,
	const MetaName& engine, const string& entryPoint, const string& body, ExternalTrigger::Type type)
{
	string entryPointTrimmed = entryPoint;
	entryPointTrimmed.trim();

	MetaName relationNameTrimmed;
	if (trg->relation)
		relationNameTrimmed = trg->relation->rel_name;

	EngineAttachmentInfo* attInfo = getEngineAttachment(tdbb, engine);
	ContextManager<ExternalTrigger> ctxManager(tdbb, attInfo, attInfo->adminCharSet,
		CallerName(obj_trigger, trg->name));

	ExternalTrigger* externalTrigger;

	{	// scope
		Database::Checkout dcoHolder(tdbb->getDatabase());

		externalTrigger = attInfo->engine->makeTrigger(RaiseError(), attInfo->context,
			trg->name.c_str(), entryPointTrimmed.nullStr(), body.nullStr(),
			relationNameTrimmed.c_str(), type);

		if (!externalTrigger)
		{
			status_exception::raise(
				Arg::Gds(isc_eem_trig_not_returned) << trg->name << engine);
		}
	}

	try
	{
		return FB_NEW(getPool()) Trigger(tdbb, this, attInfo->engine, externalTrigger, trg);
	}
	catch (...)
	{
		Database::Checkout dcoHolder(tdbb->getDatabase());
		externalTrigger->dispose(LogError());
		throw;
	}
}


ExternalEngine* ExtEngineManager::getEngine(thread_db* tdbb, const MetaName& name)
{
	ReadLockGuard readGuard(enginesLock);
	ExternalEngine* engine = NULL;

	if (!engines.get(name, engine))
	{
		readGuard.release();
		WriteLockGuard writeGuard(enginesLock);

		if (!engines.get(name, engine))
		{
			GetPlugins<ExternalEngine> engineControl(PluginType::ExternalEngine, FB_EXTERNAL_ENGINE_VERSION, name.c_str());

			if (engineControl.hasData())
			{
				EngineAttachment key(NULL, NULL);
				AutoPtr<EngineAttachmentInfo> attInfo;

				try
				{
					Database::Checkout dcoHolder(tdbb->getDatabase());

					engine = engineControl.plugin();
					if (engine)
					{
						int version = engine->getVersion(RaiseError());
						if (version != EXTERNAL_VERSION_1)
						{
							status_exception::raise(
								Arg::Gds(isc_eem_bad_plugin_ver) <<
									Arg::Num(version) << name);
						}

						Database::SyncGuard dsGuard(tdbb->getDatabase());

						key = EngineAttachment(engine, tdbb->getAttachment());
						attInfo = FB_NEW(getPool()) EngineAttachmentInfo();
						attInfo->engine = engine;
						attInfo->context = FB_NEW(getPool()) ExternalContextImpl(tdbb, engine);

						setupAdminCharSet(tdbb, engine, attInfo);

						ContextManager<ExternalFunction> ctxManager(tdbb, attInfo, attInfo->adminCharSet);
						engine->openAttachment(LogError(), attInfo->context);
					}
				}
				catch (...)
				{
					if (engine)
					{
						PluginInterface pi;
						pi->releasePlugin(engine);
					}

					throw;
				}

				if (engine)
				{
					engine->addRef();
					engines.put(name, engine);
					enginesAttachments.put(key, attInfo);
					attInfo.release();
				}
			}
		}
	}

	if (!engine)
	{
		status_exception::raise(Arg::Gds(isc_eem_engine_notfound) << name);
	}

	return engine;
}


ExtEngineManager::EngineAttachmentInfo* ExtEngineManager::getEngineAttachment(
	thread_db* tdbb, const MetaName& name)
{
	ExternalEngine* engine = getEngine(tdbb, name);
	return getEngineAttachment(tdbb, engine);
}


ExtEngineManager::EngineAttachmentInfo* ExtEngineManager::getEngineAttachment(
	thread_db* tdbb, ExternalEngine* engine, bool closing)
{
	EngineAttachment key(engine, tdbb->getAttachment());
	EngineAttachmentInfo* attInfo = NULL;

	ReadLockGuard readGuard(&enginesLock);

	if (!enginesAttachments.get(key, attInfo) && !closing)
	{
		readGuard.release();
		WriteLockGuard writeGuard(enginesLock);

		if (!enginesAttachments.get(key, attInfo))
		{
			attInfo = FB_NEW(getPool()) EngineAttachmentInfo();
			attInfo->engine = engine;
			attInfo->context = FB_NEW(getPool()) ExternalContextImpl(tdbb, engine);

			setupAdminCharSet(tdbb, engine, attInfo);

			enginesAttachments.put(key, attInfo);

			ContextManager<ExternalFunction> ctxManager(tdbb, attInfo, attInfo->adminCharSet);
			Database::Checkout dcoHolder(tdbb->getDatabase());
			engine->openAttachment(LogError(), attInfo->context);
		}

		return attInfo;
	}

	if (closing && attInfo)
	{
		readGuard.release();
		WriteLockGuard writeGuard(enginesLock);
		enginesAttachments.remove(key);
	}

	return attInfo;
}


void ExtEngineManager::setupAdminCharSet(thread_db* tdbb, ExternalEngine* engine,
	EngineAttachmentInfo* attInfo)
{
	ContextManager<ExternalFunction> ctxManager(tdbb, attInfo, CS_UTF8);

	Utf8 charSetName[MAX_SQL_IDENTIFIER_SIZE] = "NONE";
	engine->open(RaiseError(), attInfo->context, charSetName,
		MAX_SQL_IDENTIFIER_LEN);
	charSetName[MAX_SQL_IDENTIFIER_LEN] = '\0';

	if (!MET_get_char_coll_subtype(tdbb, &attInfo->adminCharSet,
			reinterpret_cast<const UCHAR*>(charSetName),
			strlen(charSetName)))
	{
		status_exception::raise(
			Arg::Gds(isc_charset_not_found) <<
			Arg::Str(charSetName));
	}
}


}	// namespace Jrd