package bug
import (
"crypto/rand"
"encoding/json"
"fmt"
"time"
"github.com/pkg/errors"
"github.com/MichaelMure/git-bug/entity"
"github.com/MichaelMure/git-bug/entity/dag"
"github.com/MichaelMure/git-bug/identity"
)
// OperationType is an operation type identifier
type OperationType int
const (
_ OperationType = iota
CreateOp
SetTitleOp
AddCommentOp
SetStatusOp
LabelChangeOp
EditCommentOp
NoOpOp
SetMetadataOp
)
// Operation define the interface to fulfill for an edit operation of a Bug
type Operation interface {
dag.Operation
// Type return the type of the operation
Type() OperationType
// Time return the time when the operation was added
Time() time.Time
// Apply the operation to a Snapshot to create the final state
Apply(snapshot *Snapshot)
// SetMetadata store arbitrary metadata about the operation
SetMetadata(key string, value string)
// GetMetadata retrieve arbitrary metadata about the operation
GetMetadata(key string) (string, bool)
// AllMetadata return all metadata for this operation
AllMetadata() map[string]string
setExtraMetadataImmutable(key string, value string)
}
func idOperation(op Operation, base *OpBase) entity.Id {
if base.id == "" {
// something went really wrong
panic("op's id not set")
}
if base.id == entity.UnsetId {
// This means we are trying to get the op's Id *before* it has been stored, for instance when
// adding multiple ops in one go in an OperationPack.
// As the Id is computed based on the actual bytes written on the disk, we are going to predict
// those and then get the Id. This is safe as it will be the exact same code writing on disk later.
data, err := json.Marshal(op)
if err != nil {
panic(err)
}
base.id = entity.DeriveId(data)
}
return base.id
}
func operationUnmarshaller(author identity.Interface, raw json.RawMessage, resolver identity.Resolver) (dag.Operation, error) {
var t struct {
OperationType OperationType `json:"type"`
}
if err := json.Unmarshal(raw, &t); err != nil {
return nil, err
}
var op Operation
switch t.OperationType {
case AddCommentOp:
op = &AddCommentOperation{}
case CreateOp:
op = &CreateOperation{}
case EditCommentOp:
op = &EditCommentOperation{}
case LabelChangeOp:
op = &LabelChangeOperation{}
case NoOpOp:
op = &NoOpOperation{}
case SetMetadataOp:
op = &SetMetadataOperation{}
case SetStatusOp:
op = &SetStatusOperation{}
case SetTitleOp:
op = &SetTitleOperation{}
default:
panic(fmt.Sprintf("unknown operation type %v", t.OperationType))
}
err := json.Unmarshal(raw, &op)
if err != nil {
return nil, err
}
switch op := op.(type) {
case *AddCommentOperation:
op.Author_ = author
case *CreateOperation:
op.Author_ = author
case *EditCommentOperation:
op.Author_ = author
case *LabelChangeOperation:
op.Author_ = author
case *NoOpOperation:
op.Author_ = author
case *SetMetadataOperation:
op.Author_ = author
case *SetStatusOperation:
op.Author_ = author
case *SetTitleOperation:
op.Author_ = author
default:
panic(fmt.Sprintf("unknown operation type %T", op))
}
return op, nil
}
// OpBase implement the common code for all operations
type OpBase struct {
OperationType OperationType `json:"type"`
Author_ identity.Interface `json:"-"` // not serialized
// TODO: part of the data model upgrade, this should eventually be a timestamp + lamport
UnixTime int64 `json:"timestamp"`
Metadata map[string]string `json:"metadata,omitempty"`
// mandatory random bytes to ensure a better randomness of the data used to later generate the ID
// len(Nonce) should be > 20 and < 64 bytes
// It has no functional purpose and should be ignored.
Nonce []byte `json:"nonce"`
// Not serialized. Store the op's id in memory.
id entity.Id
// Not serialized. Store the extra metadata in memory,
// compiled from SetMetadataOperation.
extraMetadata map[string]string
}
// newOpBase is the constructor for an OpBase
func newOpBase(opType OperationType, author identity.Interface, unixTime int64) OpBase {
return OpBase{
OperationType: opType,
Author_: author,
UnixTime: unixTime,
Nonce: makeNonce(20),
id: entity.UnsetId,
}
}
func makeNonce(len int) []byte {
result := make([]byte, len)
_, err := rand.Read(result)
if err != nil {
panic(err)
}
return result
}
func (base *OpBase) UnmarshalJSON(data []byte) error {
// Compute the Id when loading the op from disk.
base.id = entity.DeriveId(data)
aux := struct {
OperationType OperationType `json:"type"`
UnixTime int64 `json:"timestamp"`
Metadata map[string]string `json:"metadata,omitempty"`
Nonce []byte `json:"nonce"`
}{}
if err := json.Unmarshal(data, &aux); err != nil {
return err
}
base.OperationType = aux.OperationType
base.UnixTime = aux.UnixTime
base.Metadata = aux.Metadata
base.Nonce = aux.Nonce
return nil
}
func (base *OpBase) Type() OperationType {
return base.OperationType
}
// Time return the time when the operation was added
func (base *OpBase) Time() time.Time {
return time.Unix(base.UnixTime, 0)
}
// Validate check the OpBase for errors
func (base *OpBase) Validate(op Operation, opType OperationType) error {
if base.OperationType != opType {
return fmt.Errorf("incorrect operation type (expected: %v, actual: %v)", opType, base.OperationType)
}
if op.Time().Unix() == 0 {
return fmt.Errorf("time not set")
}
if base.Author_ == nil {
return fmt.Errorf("author not set")
}
if err := op.Author().Validate(); err != nil {
return errors.Wrap(err, "author")
}
if op, ok := op.(dag.OperationWithFiles); ok {
for _, hash := range op.GetFiles() {
if !hash.IsValid() {
return fmt.Errorf("file with invalid hash %v", hash)
}
}
}
if len(base.Nonce) > 64 {
return fmt.Errorf("nonce is too big")
}
if len(base.Nonce) < 20 {
return fmt.Errorf("nonce is too small")
}
return nil
}
// SetMetadata store arbitrary metadata about the operation
func (base *OpBase) SetMetadata(key string, value string) {
if base.Metadata == nil {
base.Metadata = make(map[string]string)
}
base.Metadata[key] = value
base.id = entity.UnsetId
}
// GetMetadata retrieve arbitrary metadata about the operation
func (base *OpBase) GetMetadata(key string) (string, bool) {
val, ok := base.Metadata[key]
if ok {
return val, true
}
// extraMetadata can't replace the original operations value if any
val, ok = base.extraMetadata[key]
return val, ok
}
// AllMetadata return all metadata for this operation
func (base *OpBase) AllMetadata() map[string]string {
result := make(map[string]string)
for key, val := range base.extraMetadata {
result[key] = val
}
// Original metadata take precedence
for key, val := range base.Metadata {
result[key] = val
}
return result
}
func (base *OpBase) setExtraMetadataImmutable(key string, value string) {
if base.extraMetadata == nil {
base.extraMetadata = make(map[string]string)
}
if _, exist := base.extraMetadata[key]; !exist {
base.extraMetadata[key] = value
}
}
// Author return author identity
func (base *OpBase) Author() identity.Interface {
return base.Author_
}
