package bug import ( "crypto/sha256" "encoding/json" "fmt" "time" "github.com/MichaelMure/git-bug/identity" "github.com/MichaelMure/git-bug/util/git" "github.com/pkg/errors" ) // 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 { // base return the OpBase of the Operation, for package internal use base() *OpBase // Hash return the hash of the operation, to be used for back references Hash() (git.Hash, error) // Time return the time when the operation was added Time() time.Time // GetUnixTime return the unix timestamp when the operation was added GetUnixTime() int64 // GetFiles return the files needed by this operation GetFiles() []git.Hash // Apply the operation to a Snapshot to create the final state Apply(snapshot *Snapshot) // Validate check if the operation is valid (ex: a title is a single line) Validate() error // 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 // GetAuthor return the author identity GetAuthor() identity.Interface } func hashRaw(data []byte) git.Hash { hasher := sha256.New() // Write can't fail _, _ = hasher.Write(data) return git.Hash(fmt.Sprintf("%x", hasher.Sum(nil))) } // hash compute the hash of the serialized operation func hashOperation(op Operation) (git.Hash, error) { // TODO: this might not be the best idea: if a single bit change in the output of json.Marshal, this will break. // Idea: hash the segment of serialized data (= immutable) instead of the go object in memory base := op.base() if base.hash != "" { return base.hash, nil } data, err := json.Marshal(op) if err != nil { return "", err } base.hash = hashRaw(data) return base.hash, nil } // OpBase implement the common code for all operations type OpBase struct { OperationType OperationType Author identity.Interface UnixTime int64 Metadata map[string]string // Not serialized. Store the op's hash in memory. hash git.Hash // 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, } } func (op OpBase) MarshalJSON() ([]byte, error) { return json.Marshal(struct { OperationType OperationType `json:"type"` Author identity.Interface `json:"author"` UnixTime int64 `json:"timestamp"` Metadata map[string]string `json:"metadata,omitempty"` }{ OperationType: op.OperationType, Author: op.Author, UnixTime: op.UnixTime, Metadata: op.Metadata, }) } func (op *OpBase) UnmarshalJSON(data []byte) error { aux := struct { OperationType OperationType `json:"type"` Author json.RawMessage `json:"author"` UnixTime int64 `json:"timestamp"` Metadata map[string]string `json:"metadata,omitempty"` }{} if err := json.Unmarshal(data, &aux); err != nil { return err } // delegate the decoding of the identity author, err := identity.UnmarshalJSON(aux.Author) if err != nil { return err } op.OperationType = aux.OperationType op.Author = author op.UnixTime = aux.UnixTime op.Metadata = aux.Metadata return nil } // Time return the time when the operation was added func (op *OpBase) Time() time.Time { return time.Unix(op.UnixTime, 0) } // GetUnixTime return the unix timestamp when the operation was added func (op *OpBase) GetUnixTime() int64 { return op.UnixTime } // GetFiles return the files needed by this operation func (op *OpBase) GetFiles() []git.Hash { return nil } // Validate check the OpBase for errors func opBaseValidate(op Operation, opType OperationType) error { if op.base().OperationType != opType { return fmt.Errorf("incorrect operation type (expected: %v, actual: %v)", opType, op.base().OperationType) } if op.GetUnixTime() == 0 { return fmt.Errorf("time not set") } if op.base().Author == nil { return fmt.Errorf("author not set") } if err := op.base().Author.Validate(); err != nil { return errors.Wrap(err, "author") } for _, hash := range op.GetFiles() { if !hash.IsValid() { return fmt.Errorf("file with invalid hash %v", hash) } } return nil } // SetMetadata store arbitrary metadata about the operation func (op *OpBase) SetMetadata(key string, value string) { if op.Metadata == nil { op.Metadata = make(map[string]string) } op.Metadata[key] = value op.hash = "" } // GetMetadata retrieve arbitrary metadata about the operation func (op *OpBase) GetMetadata(key string) (string, bool) { val, ok := op.Metadata[key] if ok { return val, true } // extraMetadata can't replace the original operations value if any val, ok = op.extraMetadata[key] return val, ok } // AllMetadata return all metadata for this operation func (op *OpBase) AllMetadata() map[string]string { result := make(map[string]string) for key, val := range op.extraMetadata { result[key] = val } // Original metadata take precedence for key, val := range op.Metadata { result[key] = val } return result } // GetAuthor return author identity func (op *OpBase) GetAuthor() identity.Interface { return op.Author }