README
¶
Predicate
This package contains the predicate data structure and its encoding and helper functions to unpack/pack the data structure.
Encoding
A byte slice of size N is encoded as:
- Slice of N bytes
- Delimiter byte
0xff - Appended 0s to the nearest multiple of 32 bytes
Results
This defines how to encode PredicateResults within the block header's Extra data field.
For more information on the motivation for encoding the results of predicate verification within a block, see here.
Serialization
Results have a maximum size of 1MB enforced by the codec. The actual size depends on how much data the Precompile predicates may put into the results, the gas cost they charge, and the block gas limit. PredicateResults are encoded using the AvalancheGo codec, which serializes a map by serializing the length of the map as a uint32 and then serializes each key-value pair sequentially.
PredicateResults:
| Field | Type | Size |
|---|---|---|
| codecID | uint16 | 2 bytes |
| results | map[[32]byte]TxPredicateResults | 4 + size(results) bytes |
| Total | 6 + size(results) |
codecIDis the codec version used to serialize the payload and is hardcoded to0x0000resultsis a map of transaction hashes to the correspondingTxPredicateResults
TxPredicateResults
| Field | Type | Size |
|---|---|---|
| txPredicateResults | map[[20]byte][]byte | 4 + size(txPredicateResults) bytes |
txPredicateResultsis a map of precompile addresses to the corresponding byte array returned by the predicate
Examples
// codecID
0x00, 0x00,
// results length
0x00, 0x00, 0x00, 0x00
// codecID
0x00, 0x00,
// Results length
0x00, 0x00, 0x00, 0x01,
// txHash (key in results map)
0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
// TxPredicateResults (value in results map)
// TxPredicateResults length
0x00, 0x00, 0x00, 0x01,
// precompile address (key in TxPredicateResults map)
0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
// Byte array results (value in TxPredicateResults map)
// Length of bytes result
0x00, 0x00, 0x00, 0x03,
// bytes
0x01, 0x02, 0x03
// codecID
0x00, 0x00,
// Results length
0x00, 0x00, 0x00, 0x02,
// txHash (key in results map)
0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
// TxPredicateResults (value in results map)
// TxPredicateResults length
0x00, 0x00, 0x00, 0x01,
// precompile address (key in TxPredicateResults map)
0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
// Byte array results (value in TxPredicateResults map)
// Length of bytes result
0x00, 0x00, 0x00, 0x03,
// bytes
0x01, 0x02, 0x03
// txHash2 (key in results map)
0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
// TxPredicateResults (value in results map)
// TxPredicateResults length
0x00, 0x00, 0x00, 0x01,
// precompile address (key in TxPredicateResults map)
0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00,
// Byte array results (value in TxPredicateResults map)
// Length of bytes result
0x00, 0x00, 0x00, 0x03,
// bytes
0x01, 0x02, 0x03
Documentation
¶
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func FromAccessList ¶
func FromAccessList(rules Predicates, list types.AccessList) map[common.Address][]Predicate
FromAccessList extracts predicates from a transaction's access list.
If an address is specified multiple times in the access list, each set of storage keys for that address is considered an individual predicate.
Types ¶
type BlockResults ¶
type BlockResults map[common.Hash]PrecompileResults
BlockResults maps the transactions in a block to their precompile results.
func ParseBlockResults ¶
func ParseBlockResults(b []byte) (BlockResults, error)
ParseBlockResults parses bytes into predicate results.
func (*BlockResults) Bytes ¶
func (b *BlockResults) Bytes() ([]byte, error)
Bytes marshals the predicate results.
func (*BlockResults) Set ¶
func (b *BlockResults) Set(txHash common.Hash, txResults PrecompileResults)
Set sets the predicate results for the given txHash. Results are overwritten, not merged.
type PrecompileResults ¶
PrecompileResults is a map of results for each precompile address to the resulting bitset.
type Predicate ¶
Predicate is a message padded with the delimiter and zeros and chunked into 32-byte chunks.
func New ¶
New constructs a predicate from raw predicate bytes.
It chunks the predicate by appending predicate.Delimiter and zero-padding to a multiple of 32 bytes.
Source Files