Merge pull request #2759 from ethereum/accurategas

Accurate gas estimation in Transact dialog.

alethzero/Transact.cpp

@@ -323,6 +323,54 @@ string Transact::natspecNotice(Address _to, bytes const& _data)
 		return "Destination not a contract.";
 }
 
+Address Transact::toAccount()
+{
+	return isCreation() ? Address() : m_context->fromString(ui->destination->currentText().toStdString()).first;
+}
+
+GasRequirements Transact::determineGasRequirements()
+{
+	// Determine the minimum amount of gas we need to play...
+	qint64 baseGas = (qint64)Transaction::gasRequired(m_data, 0);
+
+	Address from = fromAccount();
+	Address to = toAccount();
+	ExecutionResult lastGood;
+
+	bool haveUpperBound = false;
+	qint64 lowerBound = baseGas;
+	qint64 upperBound = (qint64)ethereum()->gasLimitRemaining();
+	for (unsigned i = 0; i < 20 && ((haveUpperBound && upperBound - lowerBound > 100) || !haveUpperBound); ++i)	// get to with 100.
+	{
+		qint64 mid = haveUpperBound ? (lowerBound + upperBound) / 2 : upperBound;
+		cdebug << "Trying" << mid;
+		ExecutionResult er;
+		if (isCreation())
+			er = ethereum()->create(from, value(), m_data, mid, gasPrice(), ethereum()->getDefault(), FudgeFactor::Lenient);
+		else
+			er = ethereum()->call(from, value(), to, m_data, mid, gasPrice(), ethereum()->getDefault(), FudgeFactor::Lenient);
+		cdebug << toString(er.excepted);
+		if (er.excepted == TransactionException::OutOfGas || er.excepted == TransactionException::OutOfGasBase || er.excepted == TransactionException::OutOfGasIntrinsic || er.codeDeposit == CodeDeposit::Failed)
+		{
+			lowerBound = mid;
+			if (!haveUpperBound)
+				upperBound *= 2;
+		}
+		else
+		{
+			lastGood = er;
+			if (haveUpperBound)
+				upperBound = mid;
+			else
+				haveUpperBound = true;
+		}
+	}
+
+	// Dry-run execution to determine gas requirement and any execution errors
+//	(qint64)(er.gasUsed + er.gasRefunded + c_callStipend);
+	return GasRequirements{upperBound, baseGas, upperBound - baseGas, (qint64)lastGood.gasRefunded, lastGood};
+}
+
 void Transact::rejigData()
 {
 	if (!ethereum())
@@ -370,56 +418,44 @@ void Transact::rejigData()
 
 	htmlInfo += "<h4>Hex</h4>" + QString(ETH_HTML_DIV(ETH_HTML_MONO)) + QString::fromStdString(toHex(m_data)) + "</div>";
 
-	// Determine the minimum amount of gas we need to play...
-	qint64 baseGas = (qint64)Transaction::gasRequired(m_data, 0);
-	qint64 gasNeeded = 0;
+	auto gasReq = determineGasRequirements();
+	htmlInfo = QString("<div class=\"info\"><span class=\"icon\">INFO</span> Gas required: %1 total = %2 base, %3 exec [%4 refunded later]</div>").arg(gasReq.neededGas).arg(gasReq.baseGas).arg(gasReq.executionGas).arg(gasReq.refundedGas) + htmlInfo;
 
-	if (b < value() + baseGas * gasPrice())
+	if (b < value() + gasReq.baseGas * gasPrice())
 	{
 		// Not enough - bail.
 		bail("<div class=\"error\"><span class=\"icon\">ERROR</span> Account doesn't contain enough for paying even the basic amount of gas required.</div>");
 		return;
 	}
-	else
-		gasNeeded = (qint64)min<bigint>(ethereum()->gasLimitRemaining(), ((b - value()) / max<u256>(gasPrice(), 1)));
-
-	// Dry-run execution to determine gas requirement and any execution errors
-	Address to;
-	ExecutionResult er;
-	if (isCreation())
-		er = ethereum()->create(s, value(), m_data, gasNeeded, gasPrice());
-	else
+	if (gasReq.neededGas > m_ethereum->gasLimitRemaining())
 	{
-		// TODO: cache like m_data.
-		to = m_context->fromString(ui->destination->currentText().toStdString()).first;
-		er = ethereum()->call(s, value(), to, m_data, gasNeeded, gasPrice());
+		// Not enough - bail.
+		bail("<div class=\"error\"><span class=\"icon\">ERROR</span> Gas remaining in block isn't enough to allow the gas required.</div>");
+		return;
 	}
-	gasNeeded = (qint64)(er.gasUsed + er.gasRefunded + c_callStipend);
-	htmlInfo = QString("<div class=\"info\"><span class=\"icon\">INFO</span> Gas required: %1 total = %2 base, %3 exec [%4 refunded later]</div>").arg(gasNeeded).arg(baseGas).arg(gasNeeded - baseGas).arg((qint64)er.gasRefunded) + htmlInfo;
-
-	if (er.excepted != TransactionException::None)
+	if (gasReq.er.excepted != TransactionException::None)
 	{
-		bail("<div class=\"error\"><span class=\"icon\">ERROR</span> " + QString::fromStdString(toString(er.excepted)) + "</div>");
+		bail("<div class=\"error\"><span class=\"icon\">ERROR</span> " + QString::fromStdString(toString(gasReq.er.excepted)) + "</div>");
 		return;
 	}
-	if (er.codeDeposit == CodeDeposit::Failed)
+	if (gasReq.er.codeDeposit == CodeDeposit::Failed)
 	{
-		bail("<div class=\"error\"><span class=\"icon\">ERROR</span> Code deposit failed due to insufficient gas; " + QString::fromStdString(toString(er.gasForDeposit)) + " GAS &lt; " + QString::fromStdString(toString(er.depositSize)) + " bytes * " + QString::fromStdString(toString(c_createDataGas)) + "GAS/byte</div>");
+		bail("<div class=\"error\"><span class=\"icon\">ERROR</span> Code deposit failed due to insufficient gas; " + QString::fromStdString(toString(gasReq.er.gasForDeposit)) + " GAS &lt; " + QString::fromStdString(toString(gasReq.er.depositSize)) + " bytes * " + QString::fromStdString(toString(c_createDataGas)) + "GAS/byte</div>");
 		return;
 	}
 
 	// Add Natspec information
 	if (!isCreation())
-		htmlInfo = "<div class=\"info\"><span class=\"icon\">INFO</span> " + QString::fromStdString(natspecNotice(to, m_data)).toHtmlEscaped() + "</div>" + htmlInfo;
+		htmlInfo = "<div class=\"info\"><span class=\"icon\">INFO</span> " + QString::fromStdString(natspecNotice(toAccount(), m_data)).toHtmlEscaped() + "</div>" + htmlInfo;
 
 	// Update gas
 	if (ui->gas->value() == ui->gas->minimum())
 	{
-		ui->gas->setMinimum(gasNeeded);
-		ui->gas->setValue(gasNeeded);
+		ui->gas->setMinimum(gasReq.neededGas);
+		ui->gas->setValue(gasReq.neededGas);
 	}
 	else
-		ui->gas->setMinimum(gasNeeded);
+		ui->gas->setMinimum(gasReq.neededGas);
 
 	updateFee();
 

alethzero/Transact.h

@@ -33,6 +33,15 @@ namespace Ui { class Transact; }
 namespace dev { namespace eth { class Client; } }
 namespace dev { namespace solidity { class CompilerStack; } }
 
+struct GasRequirements
+{
+	qint64 neededGas;
+	qint64 baseGas;
+	qint64 executionGas;
+	qint64 refundedGas;
+	dev::eth::ExecutionResult er;
+};
+
 class Transact: public QDialog
 {
 	Q_OBJECT
@@ -65,6 +74,7 @@ private:
 	void updateNonce();
 
 	dev::Address fromAccount();
+	dev::Address toAccount();
 	void updateDestination();
 	void updateFee();
 	bool isCreation() const;
@@ -73,6 +83,7 @@ private:
 	dev::u256 value() const;
 	dev::u256 gasPrice() const;
 	dev::Address to() const;
+	GasRequirements determineGasRequirements();
 
 	std::string natspecNotice(dev::Address _to, dev::bytes const& _data);
 	dev::Secret findSecret(dev::u256 _totalReq) const;

libethereum/BlockChain.cpp

@@ -394,7 +394,7 @@ tuple<ImportRoute, bool, unsigned> BlockChain::sync(BlockQueue& _bq, OverlayDB c
 				// Nonce & uncle nonces already verified in verification thread at this point.
 				ImportRoute r;
 				DEV_TIMED_ABOVE("Block import " + toString(block.verified.info.number()), 500)
-					r = import(block.verified, _stateDB, ImportRequirements::Everything & ~ImportRequirements::ValidSeal & ~ImportRequirements::CheckUncles != 0);
+					r = import(block.verified, _stateDB, (ImportRequirements::Everything & ~ImportRequirements::ValidSeal & ~ImportRequirements::CheckUncles) != 0);
 				fresh += r.liveBlocks;
 				dead += r.deadBlocks;
 				goodTransactions.reserve(goodTransactions.size() + r.goodTranactions.size());

libethereum/ClientBase.cpp

@@ -94,7 +94,7 @@ ExecutionResult ClientBase::create(Address const& _from, u256 _value, bytes cons
 		Transaction t(_value, _gasPrice, _gas, _data, n);
 		t.forceSender(_from);
 		if (_ff == FudgeFactor::Lenient)
-			temp.mutableState().addBalance(_from, (u256)(t.gasRequired() * t.gasPrice() + t.value()));
+			temp.mutableState().addBalance(_from, (u256)(t.gas() * t.gasPrice() + t.value()));
 		ret = temp.execute(bc().lastHashes(), t, Permanence::Reverted);
 	}
 	catch (...)

libethereum/Executive.cpp

@@ -383,7 +383,7 @@ bool Executive::go(OnOpFunc const& _onOp)
 		}
 		catch (VMException const& _e)
 		{
-			clog(StateSafeExceptions) << "Safe VM Exception. " << diagnostic_information(_e);
+			cnote/*clog(StateSafeExceptions)*/ << "Safe VM Exception. " << diagnostic_information(_e);
 			m_gas = 0;
 			m_excepted = toTransactionException(_e);
 			m_ext->revert();

libethereum/State.cpp

@@ -485,7 +485,7 @@ std::pair<ExecutionResult, TransactionReceipt> State::execute(EnvInfo const& _en
 	else
 	{
 		commit();
-	
+
 #if ETH_PARANOIA && !ETH_FATDB
 		ctrace << "Executed; now" << rootHash();
 		ctrace << old.diff(*this);