99 lines
2.6 KiB
Go
99 lines
2.6 KiB
Go
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package iavlproofs
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import (
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"fmt"
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ics23 "github.com/confio/ics23/go"
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"github.com/cosmos/iavl"
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)
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// convertExistenceProof will convert the given proof into a valid
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// existence proof, if that's what it is.
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//
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// This is the simplest case of the range proof and we will focus on
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// demoing compatibility here
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func convertExistenceProof(p *iavl.RangeProof, key, value []byte) (*ics23.ExistenceProof, error) {
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if len(p.Leaves) != 1 {
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return nil, fmt.Errorf("Existence proof requires RangeProof to have exactly one leaf")
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}
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return &ics23.ExistenceProof{
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Key: key,
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Value: value,
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Leaf: convertLeafOp(p.Leaves[0].Version),
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Path: convertInnerOps(p.LeftPath),
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}, nil
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}
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func convertLeafOp(version int64) *ics23.LeafOp {
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// this is adapted from iavl/proof.go:proofLeafNode.Hash()
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prefix := aminoVarInt(0)
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prefix = append(prefix, aminoVarInt(1)...)
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prefix = append(prefix, aminoVarInt(version)...)
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return &ics23.LeafOp{
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Hash: ics23.HashOp_SHA256,
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PrehashValue: ics23.HashOp_SHA256,
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Length: ics23.LengthOp_VAR_PROTO,
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Prefix: prefix,
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}
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}
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// we cannot get the proofInnerNode type, so we need to do the whole path in one function
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func convertInnerOps(path iavl.PathToLeaf) []*ics23.InnerOp {
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steps := make([]*ics23.InnerOp, 0, len(path))
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// lengthByte is the length prefix prepended to each of the sha256 sub-hashes
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var lengthByte byte = 0x20
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// we need to go in reverse order, iavl starts from root to leaf,
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// we want to go up from the leaf to the root
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for i := len(path) - 1; i >= 0; i-- {
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// this is adapted from iavl/proof.go:proofInnerNode.Hash()
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prefix := aminoVarInt(int64(path[i].Height))
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prefix = append(prefix, aminoVarInt(path[i].Size)...)
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prefix = append(prefix, aminoVarInt(path[i].Version)...)
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var suffix []byte
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if len(path[i].Left) > 0 {
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// length prefixed left side
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prefix = append(prefix, lengthByte)
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prefix = append(prefix, path[i].Left...)
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// prepend the length prefix for child
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prefix = append(prefix, lengthByte)
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} else {
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// prepend the length prefix for child
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prefix = append(prefix, lengthByte)
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// length-prefixed right side
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suffix = []byte{lengthByte}
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suffix = append(suffix, path[i].Right...)
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}
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op := &ics23.InnerOp{
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Hash: ics23.HashOp_SHA256,
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Prefix: prefix,
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Suffix: suffix,
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}
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steps = append(steps, op)
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}
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return steps
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}
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func aminoVarInt(orig int64) []byte {
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// amino-specific byte swizzling
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i := uint64(orig) << 1
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if orig < 0 {
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i = ^i
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}
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// avoid multiple allocs for normal case
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res := make([]byte, 0, 8)
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// standard protobuf encoding
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for i >= 1<<7 {
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res = append(res, uint8(i&0x7f|0x80))
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i >>= 7
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}
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res = append(res, uint8(i))
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return res
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}
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