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Optimize votes lookups for recent checkpoints (#3673)

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This commit is contained in:
Francisco
2022-09-04 17:48:26 -03:00
committed by GitHub
parent a60ae0f18b
commit e09ccd1449
9 changed files with 96 additions and 104 deletions
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41
scripts/generate/templates/Checkpoints.js
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@ -70,25 +70,6 @@ function upperLookup(${opts.historyTypeName} storage self, ${opts.keyTypeName} k
uint256 pos = _upperBinaryLookup(self.${opts.checkpointFieldName}, key, 0, length);
return pos == 0 ? 0 : _unsafeAccess(self.${opts.checkpointFieldName}, pos - 1).${opts.valueFieldName};
}
/**
* @dev Returns the value in the most recent checkpoint with key lower or equal than the search key (similarly to
* {upperLookup}), optimized for the case when the search key is known to be recent.
*/
function upperLookupRecent(${opts.historyTypeName} storage self, ${opts.keyTypeName} key) internal view returns (${opts.valueTypeName}) {
uint256 length = self.${opts.checkpointFieldName}.length;
uint256 offset = 1;
while (offset <= length && _unsafeAccess(self.${opts.checkpointFieldName}, length - offset).${opts.keyFieldName} > key) {
offset <<= 1;
}
uint256 low = 0 < offset && offset < length ? length - offset : 0;
uint256 high = length - (offset >> 1);
uint256 pos = _upperBinaryLookup(self.${opts.checkpointFieldName}, key, low, high);
return pos == 0 ? 0 : _unsafeAccess(self.${opts.checkpointFieldName}, pos - 1).${opts.valueFieldName};
}
`;
const legacyOperations = opts => `\
@ -115,22 +96,28 @@ function getAtBlock(${opts.historyTypeName} storage self, uint256 blockNumber) i
/**
* @dev Returns the value at a given block number. If a checkpoint is not available at that block, the closest one
* before it is returned, or zero otherwise. Similarly to {upperLookup} but optimized for the case when the search
* key is known to be recent.
* before it is returned, or zero otherwise. Similar to {upperLookup} but optimized for the case when the searched
* checkpoint is probably "recent", defined as being among the last sqrt(N) checkpoints where N is the number of
* checkpoints.
*/
function getAtRecentBlock(${opts.historyTypeName} storage self, uint256 blockNumber) internal view returns (uint256) {
function getAtProbablyRecentBlock(${opts.historyTypeName} storage self, uint256 blockNumber) internal view returns (uint256) {
require(blockNumber < block.number, "Checkpoints: block not yet mined");
uint32 key = SafeCast.toUint32(blockNumber);
uint256 length = self.${opts.checkpointFieldName}.length;
uint256 offset = 1;
while (offset <= length && _unsafeAccess(self.${opts.checkpointFieldName}, length - offset).${opts.keyFieldName} > key) {
offset <<= 1;
uint256 low = 0;
uint256 high = length;
if (length > 5) {
uint256 mid = length - Math.sqrt(length);
if (key < _unsafeAccess(self.${opts.checkpointFieldName}, mid)._blockNumber) {
high = mid;
} else {
low = mid + 1;
}
}
uint256 low = offset < length ? length - offset : 0;
uint256 high = length - (offset >> 1);
uint256 pos = _upperBinaryLookup(self.${opts.checkpointFieldName}, key, low, high);
return pos == 0 ? 0 : _unsafeAccess(self.${opts.checkpointFieldName}, pos - 1).${opts.valueFieldName};