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authorMichael Muré <batolettre@gmail.com>2019-08-07 15:31:38 +0200
committerMichael Muré <batolettre@gmail.com>2019-08-08 19:02:46 +0200
commit2e1a5e246ee3589c2f664a62ebd06be7dc69c229 (patch)
tree03e69d6991fb4b9f9a159ba2d7b74b5f36d5069d /bug/operation.go
parent2c3034a0abe13eb6b07d8dd13041e7be4adc6f93 (diff)
downloadgit-bug-2e1a5e246ee3589c2f664a62ebd06be7dc69c229.tar.gz
bug: compute op's ID based on the serialized data on disk
Diffstat (limited to 'bug/operation.go')
-rw-r--r--bug/operation.go61
1 files changed, 41 insertions, 20 deletions
diff --git a/bug/operation.go b/bug/operation.go
index daef7b8c..2298a008 100644
--- a/bug/operation.go
+++ b/bug/operation.go
@@ -27,12 +27,14 @@ const (
SetMetadataOp
)
+const unsetIDMarker = "unset"
+
// 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)
+ // ID return the identifier of the operation, to be used for back references
+ ID() string
// Time return the time when the operation was added
Time() time.Time
// GetUnixTime return the unix timestamp when the operation was added
@@ -53,32 +55,47 @@ type Operation interface {
GetAuthor() identity.Interface
}
-func hashRaw(data []byte) git.Hash {
+func hashRaw(data []byte) string {
hasher := sha256.New()
// Write can't fail
_, _ = hasher.Write(data)
- return git.Hash(fmt.Sprintf("%x", hasher.Sum(nil)))
+ return 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
-
+func idOperation(op Operation) string {
base := op.base()
- if base.hash != "" {
- return base.hash, nil
+ if base.id == "" {
+ // something went really wrong
+ panic("op's id not set")
}
+ if base.id == "unset" {
+ // 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)
+ }
- data, err := json.Marshal(op)
- if err != nil {
- return "", err
+ base.id = hashRaw(data)
}
+ return base.id
+}
- base.hash = hashRaw(data)
-
- return base.hash, nil
+func IDIsValid(id string) bool {
+ // IDs have the same format as a git hash
+ if len(id) != 40 && len(id) != 64 {
+ return false
+ }
+ for _, r := range id {
+ if (r < 'a' || r > 'z') && (r < '0' || r > '9') {
+ return false
+ }
+ }
+ return true
}
// OpBase implement the common code for all operations
@@ -87,8 +104,8 @@ type OpBase struct {
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 op's id in memory.
+ id string
// Not serialized. Store the extra metadata in memory,
// compiled from SetMetadataOperation.
extraMetadata map[string]string
@@ -100,6 +117,7 @@ func newOpBase(opType OperationType, author identity.Interface, unixTime int64)
OperationType: opType,
Author: author,
UnixTime: unixTime,
+ id: unsetIDMarker,
}
}
@@ -118,6 +136,9 @@ func (op OpBase) MarshalJSON() ([]byte, error) {
}
func (op *OpBase) UnmarshalJSON(data []byte) error {
+ // Compute the ID when loading the op from disk.
+ op.id = hashRaw(data)
+
aux := struct {
OperationType OperationType `json:"type"`
Author json.RawMessage `json:"author"`
@@ -192,7 +213,7 @@ func (op *OpBase) SetMetadata(key string, value string) {
}
op.Metadata[key] = value
- op.hash = ""
+ op.id = unsetIDMarker
}
// GetMetadata retrieve arbitrary metadata about the operation