lotus/chain/events/state/diff_adt.go

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package state
import (
"bytes"
"github.com/filecoin-project/go-state-types/abi"
"github.com/filecoin-project/specs-actors/actors/util/adt"
typegen "github.com/whyrusleeping/cbor-gen"
)
// AdtArrayDiff generalizes adt.Array diffing by accepting a Deferred type that can unmarshalled to its corresponding struct
// in an interface implantation.
// Add should be called when a new k,v is added to the array
// Modify should be called when a value is modified in the array
// Remove should be called when a value is removed from the array
type AdtArrayDiff interface {
Add(key uint64, val *typegen.Deferred) error
Modify(key uint64, from, to *typegen.Deferred) error
Remove(key uint64, val *typegen.Deferred) error
}
// TODO Performance can be improved by diffing the underlying IPLD graph, e.g. https://github.com/ipfs/go-merkledag/blob/749fd8717d46b4f34c9ce08253070079c89bc56d/dagutils/diff.go#L104
// CBOR Marshaling will likely be the largest performance bottleneck here.
// DiffAdtArray accepts two *adt.Array's and an AdtArrayDiff implementation. It does the following:
// - All values that exist in preArr and not in curArr are passed to AdtArrayDiff.Remove()
// - All values that exist in curArr nnd not in prevArr are passed to adtArrayDiff.Add()
// - All values that exist in preArr and in curArr are passed to AdtArrayDiff.Modify()
// - It is the responsibility of AdtArrayDiff.Modify() to determine if the values it was passed have been modified.
func DiffAdtArray(preArr, curArr *adt.Array, out AdtArrayDiff) error {
prevVal := new(typegen.Deferred)
if err := preArr.ForEach(prevVal, func(i int64) error {
curVal := new(typegen.Deferred)
found, err := curArr.Get(uint64(i), curVal)
if err != nil {
return err
}
if !found {
if err := out.Remove(uint64(i), prevVal); err != nil {
return err
}
return nil
}
// no modification
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if !bytes.Equal(prevVal.Raw, curVal.Raw) {
if err := out.Modify(uint64(i), prevVal, curVal); err != nil {
return err
}
}
return curArr.Delete(uint64(i))
}); err != nil {
return err
}
curVal := new(typegen.Deferred)
return curArr.ForEach(curVal, func(i int64) error {
return out.Add(uint64(i), curVal)
})
}
// TODO Performance can be improved by diffing the underlying IPLD graph, e.g. https://github.com/ipfs/go-merkledag/blob/749fd8717d46b4f34c9ce08253070079c89bc56d/dagutils/diff.go#L104
// CBOR Marshaling will likely be the largest performance bottleneck here.
// AdtMapDiff generalizes adt.Map diffing by accepting a Deferred type that can unmarshalled to its corresponding struct
// in an interface implantation.
// AsKey should return the Keyer implementation specific to the map
// Add should be called when a new k,v is added to the map
// Modify should be called when a value is modified in the map
// Remove should be called when a value is removed from the map
type AdtMapDiff interface {
AsKey(key string) (abi.Keyer, error)
Add(key string, val *typegen.Deferred) error
Modify(key string, from, to *typegen.Deferred) error
Remove(key string, val *typegen.Deferred) error
}
func DiffAdtMap(preMap, curMap *adt.Map, out AdtMapDiff) error {
prevVal := new(typegen.Deferred)
if err := preMap.ForEach(prevVal, func(key string) error {
curVal := new(typegen.Deferred)
k, err := out.AsKey(key)
if err != nil {
return err
}
found, err := curMap.Get(k, curVal)
if err != nil {
return err
}
if !found {
if err := out.Remove(key, prevVal); err != nil {
return err
}
return nil
}
// no modification
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if !bytes.Equal(prevVal.Raw, curVal.Raw) {
if err := out.Modify(key, prevVal, curVal); err != nil {
return err
}
}
return curMap.Delete(k)
}); err != nil {
return err
}
curVal := new(typegen.Deferred)
return curMap.ForEach(curVal, func(key string) error {
return out.Add(key, curVal)
})
}