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(Hub): split off acceptance call to nett flow without stack depth ove…
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…rflow
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@benjaminbollen
benjaminbollen committed Mar 7, 2024
1 parent d8eabbb commit 96180c5
Showing 1 changed file with 77 additions and 60 deletions.
137 changes: 77 additions & 60 deletions src/hub/Hub.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -549,6 +549,8 @@ contract Hub is Circles, IHubV2 {
int256[] memory verifiedNettedFlow = _verifyFlowMatrix(_flowVertices, _flow, coordinates, closedPath);

_effectPathTransfers(_flowVertices, _flow, _streams, coordinates);

int256[] memory streamNettedFlow = _callAcceptanceChecks(_flowVertices, _flow, _streams, coordinates);
}

// Public functions
Expand Down Expand Up @@ -747,12 +749,11 @@ contract Hub is Circles, IHubV2 {
uint16 index = uint16(0);

for (uint64 i = 0; i < _flow.length; i++) {
// retrieve the flow vertices associated with this flow edge
// index: coordinate of Circles identifier avatar address
// index + 1: sender coordinate
// index + 2: receiver coordinate
address circlesId = _flowVertices[_coordinates[index]];
// uint16 fromIndex = index++;
// uint16 toIndex = index++;
address to = _flowVertices[_coordinates[index + 2]];
// amount is uint240, so no need to check for overflow
int256 flow = int256(uint256(_flow[i].amount));

// check the receiver trusts the Circles being sent
Expand Down Expand Up @@ -782,80 +783,106 @@ contract Hub is Circles, IHubV2 {
Stream[] calldata _streams,
uint16[] memory _coordinates
) internal {
// iterate over the coordinate index
uint16 index = uint16(0);

// Create a counter to track the proper definition of the streams
uint16[] memory streamBatchCounter = new uint16[](_streams.length);
address[] memory streamReceivers = new address[](_streams.length);

for (uint16 i = 0; i < _flow.length; i++) {
// retrieve the flow vertices associated with this flow edge
// address circlesId = _flowVertices[_coordinates[index]];
// uint16 fromIndex = index++;
// uint16 toIndex = index++;
address to = _flowVertices[_coordinates[index + 2]];
// uint256 amount = _flow[i].amount;
{
// iterate over the coordinate index
uint16 index = uint16(0);

(uint256[] memory ids, uint256[] memory amounts) =
_asSingletonArrays(toTokenId(_flowVertices[_coordinates[index]]), uint256(_flow[i].amount));
for (uint16 i = 0; i < _flow.length; i++) {
// index: coordinate of Circles identifier avatar address
// index + 1: sender coordinate
// index + 2: receiver coordinate
address to = _flowVertices[_coordinates[index + 2]];

// check that each stream has listed the actual terminal flow edges in the correct order
// note, we can't do this check in _verifyFlowMatrix, because we run out of stack depth there
if (_flow[i].streamSinkId > 0) {
require(
_streams[_flow[i].streamSinkId].flowEdgeIds[streamBatchCounter[_flow[i].streamSinkId]] == i,
"Invalid stream sink"
);
streamBatchCounter[_flow[i].streamSinkId]++;
if (streamReceivers[_flow[i].streamSinkId] == address(0)) {
streamReceivers[_flow[i].streamSinkId] = to;
(uint256[] memory ids, uint256[] memory amounts) =
_asSingletonArrays(toTokenId(_flowVertices[_coordinates[index]]), uint256(_flow[i].amount));

// check that each stream has listed the actual terminal flow edges in the correct order
// note, we can't do this check in _verifyFlowMatrix, because we run out of stack depth there
if (_flow[i].streamSinkId > 0) {
require(
_streams[_flow[i].streamSinkId].flowEdgeIds[streamBatchCounter[_flow[i].streamSinkId]] == i,
"Invalid stream sink"
);
streamBatchCounter[_flow[i].streamSinkId]++;
if (streamReceivers[_flow[i].streamSinkId] == address(0)) {
streamReceivers[_flow[i].streamSinkId] = to;
} else {
require(streamReceivers[_flow[i].streamSinkId] == to, "Invalid stream receiver");
}
}

// effect the flow edge
if (!isGroup(to)) {
// do a erc1155 single transfer without acceptance check,
// as only nett receivers will get an acceptance call
_update(
_flowVertices[_coordinates[index + 1]], // sender, from coordinate
to,
ids,
amounts
);
} else {
require(streamReceivers[_flow[i].streamSinkId] == to, "Invalid stream receiver");
// do group mint, and the sender receives the minted group Circles
_groupMint(
_flowVertices[_coordinates[index + 1]], // sender, from coordinate
to, // group
ids, // collateral
amounts, // amounts
""
);
}
}

// effect the transfer
if (!isGroup(to)) {
// do a erc1155 single transfer without acceptance check,
// as only nett receivers will get an acceptance call
_update(
_flowVertices[_coordinates[index + 1]], // sender, from coordinate
to,
ids,
amounts
);
} else {
// do group mint, and the sender receives the mintedd group Circles
_groupMint(
_flowVertices[_coordinates[index + 1]], // sender, from coordinate
to, // group
ids, // collateral
amounts, // amounts
""
);
index = index + 3;
}

index = index + 3;
for (uint16 i = 0; i < _streams.length; i++) {
require(streamReceivers[i] != address(0), "Invalid stream receiver");
require(streamBatchCounter[i] == _streams[i].flowEdgeIds.length, "Invalid stream batch");
}
}
}

function _callAcceptanceChecks(
address[] calldata _flowVertices,
FlowEdge[] calldata _flow,
Stream[] calldata _streams,
uint16[] memory _coordinates
) internal returns (int256[] memory) {
// intialiaze netted flow
int256[] memory nettedFlow = new int256[](_flowVertices.length);

// effect the stream transfers with acceptance calls
for (uint16 i = 0; i < _streams.length; i++) {
uint256[] memory ids = new uint256[](_streams[i].flowEdgeIds.length);
uint256[] memory amounts = new uint256[](_streams[i].flowEdgeIds.length);
uint256 streamTotal = uint256(0);
for (uint16 j = 0; j < _streams[i].flowEdgeIds.length; j++) {
ids[j] = toTokenId(_flowVertices[_coordinates[_streams[i].flowEdgeIds[j]]]);
amounts[j] = _flow[_streams[i].flowEdgeIds[j]].amount;
streamTotal += amounts[j];
}
require(streamReceivers[i] != address(0), "Invalid stream receiver");
// use the first sink flow edge to recover the receiver coordinate
uint16 receiverCoordinate = _coordinates[3 * _streams[i].flowEdgeIds[0] + 2];
address receiver = _flowVertices[receiverCoordinate];
require(receiver != address(0), "Invalid stream receiver");
_acceptanceCheck(
_flowVertices[_streams[i].sourceCoordinate], // from
streamReceivers[i], // to
receiver, // to
ids, // batch of Circles identifiers terminating in receiver
amounts, // batch of amounts terminating in receiver
_streams[i].data // user-provided data for stream
);
// require(streamTotal <= uint256(type(int256).max));
nettedFlow[_streams[i].sourceCoordinate] -= int256(streamTotal);
// to recover the receiver coordinate, get the first sink
nettedFlow[receiverCoordinate] += int256(streamTotal);
}

return nettedFlow;
}

/**
Expand Down Expand Up @@ -989,16 +1016,6 @@ contract Hub is Circles, IHubV2 {
avatars[SENTINEL] = _avatar;
}

function _checkClosedPath(int256[] calldata _intendedFlow) internal pure returns (bool closedPath_) {
// start by assuming it is a closed path
closedPath_ = true;
for (uint256 i = 0; i < _intendedFlow.length; i++) {
// then any non-zero intentedFlow value, breaks the closed path open
closedPath_ = closedPath_ && (_intendedFlow[i] == int256(0));
}
return closedPath_;
}

// Private functions

/**
Expand Down

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