@0x/utils
Version:
89 lines • 4.86 kB
TypeScript
import { EncodingRules } from '../utils/rules';
import { CalldataBlock } from './calldata_block';
export declare class Calldata {
private readonly _rules;
private _selector;
private _root;
constructor(rules: EncodingRules);
/**
* Sets the root calldata block. This block usually corresponds to a Method.
*/
setRoot(block: CalldataBlock): void;
/**
* Sets the selector to be prepended onto the calldata.
* If the root block was created by a Method then a selector will likely be set.
*/
setSelector(selector: string): void;
/**
* Iterates through the calldata blocks, starting from the root block, to construct calldata as a hex string.
* If the `optimize` flag is set then this calldata will be condensed, to save gas.
* If the `annotate` flag is set then this will return human-readable calldata.
* If the `annotate` flag is *not* set then this will return EVM-compatible calldata.
*/
toString(): string;
/**
* There are three types of calldata blocks: Blob, Set and Pointer.
* Scenarios arise where distinct pointers resolve to identical values.
* We optimize by keeping only one such instance of the identical value, and redirecting all pointers here.
* We keep the last such duplicate value because pointers can only be positive (they cannot point backwards).
*
* Example #1:
* function f(string[], string[])
* f(["foo", "bar", "blitz"], ["foo", "bar", "blitz"])
* The array ["foo", "bar", "blitz"] will only be included in the calldata once.
*
* Example #2:
* function f(string[], string)
* f(["foo", "bar", "blitz"], "foo")
* The string "foo" will only be included in the calldata once.
*
* Example #3:
* function f((string, uint, bytes), string, uint, bytes)
* f(("foo", 5, "0x05"), "foo", 5, "0x05")
* The string "foo" and bytes "0x05" will only be included in the calldata once.
* The duplicate `uint 5` values cannot be optimized out because they are static values (no pointer points to them).
*
* @TODO #1:
* This optimization strategy handles blocks that are exact duplicates of one another.
* But what if some block is a combination of two other blocks? Or a subset of another block?
* This optimization problem is not much different from the current implemetation.
* Instead of tracking "observed" hashes, at each node we would simply do pattern-matching on the calldata.
* This strategy would be applied after assigning offsets to the tree, rather than before (as in this strategy).
* Note that one consequence of this strategy is pointers may resolve to offsets that are not word-aligned.
* This shouldn't be a problem but further investigation should be done.
*
* @TODO #2:
* To be done as a follow-up to @TODO #1.
* Since we optimize from the bottom-up, we could be affecting the outcome of a later potential optimization.
* For example, what if by removing one duplicate value we miss out on optimizing another block higher in the tree.
* To handle this case, at each node we can store a candidate optimization in a priority queue (sorted by calldata size).
* At the end of traversing the tree, the candidate at the front of the queue will be the most optimal output.
*
*/
private _optimize;
private _toEvmCompatibeCallDataHex;
/**
* Returns human-readable calldata.
*
* Example:
* simpleFunction(string[], string[])
* strings = ["Hello", "World"]
* simpleFunction(strings, strings)
*
* Output:
* 0xbb4f12e3
* ### simpleFunction
* 0x0 0000000000000000000000000000000000000000000000000000000000000040 ptr<array1> (alias for array2)
* 0x20 0000000000000000000000000000000000000000000000000000000000000040 ptr<array2>
*
* 0x40 0000000000000000000000000000000000000000000000000000000000000002 ### array2
* 0x60 0000000000000000000000000000000000000000000000000000000000000040 ptr<array2[0]>
* 0x80 0000000000000000000000000000000000000000000000000000000000000080 ptr<array2[1]>
* 0xa0 0000000000000000000000000000000000000000000000000000000000000005 array2[0]
* 0xc0 48656c6c6f000000000000000000000000000000000000000000000000000000
* 0xe0 0000000000000000000000000000000000000000000000000000000000000005 array2[1]
* 0x100 576f726c64000000000000000000000000000000000000000000000000000000
*/
private _toHumanReadableCallData;
}
//# sourceMappingURL=calldata.d.ts.map