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Diffstat (limited to 'object/store/objectstore.go')
| -rw-r--r-- | object/store/objectstore.go | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/object/store/objectstore.go b/object/store/objectstore.go new file mode 100644 index 00000000..d43dbccd --- /dev/null +++ b/object/store/objectstore.go @@ -0,0 +1,92 @@ +// Package objectstore provides interfaces for object storage backends. +package objectstore + +import ( + "errors" + "io" + + objectid "codeberg.org/lindenii/furgit/object/id" + objecttype "codeberg.org/lindenii/furgit/object/type" +) + +// ErrObjectNotFound indicates that an object does not exist in a backend. +// This error MUST only be used in situations where the object store has +// no specified object ID, but no other unexpected conditions were +// encountered. In particular, it is not suitable for situations where one +// object references another (such as a tree referencing a blob) but +// the latter does not exist; these situations should use a separate +// error (TODO). +var ErrObjectNotFound = errors.New("objectstore: object not found") + +// Store reads Git objects by object ID. +// +// Unless an implementation explicitly documents otherwise, values returned by +// Store methods are only valid until the store is closed. +type Store interface { + // ReadBytesFull reads a full serialized object as "type size\0content". + // + // In a valid repository, hashing this payload with the same algorithm yields + // the requested object ID. Readers should treat this as a repository + // invariant and should not re-verify it on every read. + // + // Any read-time integrity verification beyond producing this payload is + // implementation-defined. + ReadBytesFull(id objectid.ObjectID) ([]byte, error) + + // ReadBytesContent reads an object's type and content bytes. + // + // Any read-time integrity verification beyond producing this payload is + // implementation-defined. + ReadBytesContent(id objectid.ObjectID) (objecttype.Type, []byte, error) + + // ReadReaderFull reads a full serialized object stream as "type size\0content". + // + // Caller must close the returned reader. + // The returned reader is only valid until the store is closed. + // + // Any read-time integrity verification performed while producing the stream + // is implementation-defined. + ReadReaderFull(id objectid.ObjectID) (io.ReadCloser, error) + + // ReadReaderContent reads an object's type, declared content length, + // and content stream. + // + // Caller must close the returned reader. + // The returned reader is only valid until the store is closed. + // + // Any read-time integrity verification performed while producing the stream + // is implementation-defined. + ReadReaderContent(id objectid.ObjectID) (objecttype.Type, int64, io.ReadCloser, error) + + // ReadSize reads an object's declared content length. + // + // This is equivalent to ReadHeader(...).size and may be cheaper than + // ReadHeader when callers do not need object type. + // + // Any read-time integrity verification performed to produce the size is + // implementation-defined. + ReadSize(id objectid.ObjectID) (int64, error) + + // ReadHeader reads an object's type and declared content length. + // + // Any read-time integrity verification performed to produce the header is + // implementation-defined. + ReadHeader(id objectid.ObjectID) (objecttype.Type, int64, error) + + // Refresh updates any backend-local discovery/cache view of on-disk objects. + // + // Backends without dynamic discovery should return nil. + Refresh() error + + // Close releases resources associated with the backend. + // + // Repeated calls to Close are undefined behavior unless the implementation + // explicitly documents otherwise. + Close() error +} + +// type Cursor any +// +// Then make all read functions accept and provide a Cursor +// nil must always be accepted and would exhibit the same behavior as right now +// Non-nil behavior is implementation-defined: e.g., pack selection |