ref: 2e8656494d14df5258d6cd7c00672b94074ee1e9
parent: a03e6e14a1e807136b05f28072f37dcf8c030f6b
author: Runxi Yu <me@runxiyu.org>
date: Fri Feb 20 20:42:01 EST 2026
objectdb/chain: Chain belongs separately from objectdb
--- a/objectdb/chain.go
+++ /dev/null
@@ -1,126 +1,0 @@
-package objectdb
-
-import (
- "errors"
- "fmt"
- "io"
-
- "codeberg.org/lindenii/furgit/objectid"
- "codeberg.org/lindenii/furgit/objecttype"
-)
-
-// Chain queries multiple object databases in order.
-type Chain struct {- backends []ObjectDB
-}
-
-// NewChain creates an ordered object database chain.
-func NewChain(backends ...ObjectDB) *Chain {- return &Chain{- backends: append([]ObjectDB(nil), backends...),
- }
-}
-
-// ReadBytesFull reads a full serialized object from the first backend that has it.
-func (chain *Chain) ReadBytesFull(id objectid.ObjectID) ([]byte, error) {- for i, backend := range chain.backends {- if backend == nil {- continue
- }
- full, err := backend.ReadBytesFull(id)
- if err == nil {- return full, nil
- }
- if errors.Is(err, ErrObjectNotFound) {- continue
- }
- return nil, fmt.Errorf("objectdb: backend %d read bytes full: %w", i, err)- }
- return nil, ErrObjectNotFound
-}
-
-// ReadBytesContent reads an object's type and content bytes from the first backend that has it.
-func (chain *Chain) ReadBytesContent(id objectid.ObjectID) (objecttype.Type, []byte, error) {- for i, backend := range chain.backends {- if backend == nil {- continue
- }
- ty, content, err := backend.ReadBytesContent(id)
- if err == nil {- return ty, content, nil
- }
- if errors.Is(err, ErrObjectNotFound) {- continue
- }
- return objecttype.TypeInvalid, nil, fmt.Errorf("objectdb: backend %d read bytes content: %w", i, err)- }
- return objecttype.TypeInvalid, nil, ErrObjectNotFound
-}
-
-// ReadReaderFull reads a full serialized object stream from the first backend that has it.
-func (chain *Chain) ReadReaderFull(id objectid.ObjectID) (io.ReadCloser, error) {- for i, backend := range chain.backends {- if backend == nil {- continue
- }
- reader, err := backend.ReadReaderFull(id)
- if err == nil {- return reader, nil
- }
- if errors.Is(err, ErrObjectNotFound) {- continue
- }
- return nil, fmt.Errorf("objectdb: backend %d read reader full: %w", i, err)- }
- return nil, ErrObjectNotFound
-}
-
-// ReadReaderContent reads an object's type and content stream from the first backend that has it.
-func (chain *Chain) ReadReaderContent(id objectid.ObjectID) (objecttype.Type, io.ReadCloser, error) {- for i, backend := range chain.backends {- if backend == nil {- continue
- }
- ty, reader, err := backend.ReadReaderContent(id)
- if err == nil {- return ty, reader, nil
- }
- if errors.Is(err, ErrObjectNotFound) {- continue
- }
- return objecttype.TypeInvalid, nil, fmt.Errorf("objectdb: backend %d read reader content: %w", i, err)- }
- return objecttype.TypeInvalid, nil, ErrObjectNotFound
-}
-
-// ReadHeader reads object header data from the first backend that has it.
-func (chain *Chain) ReadHeader(id objectid.ObjectID) (objecttype.Type, int64, error) {- for i, backend := range chain.backends {- if backend == nil {- continue
- }
- ty, size, err := backend.ReadHeader(id)
- if err == nil {- return ty, size, nil
- }
- if errors.Is(err, ErrObjectNotFound) {- continue
- }
- return objecttype.TypeInvalid, 0, fmt.Errorf("objectdb: backend %d read header: %w", i, err)- }
- return objecttype.TypeInvalid, 0, ErrObjectNotFound
-}
-
-// Close closes all backends and joins close errors.
-func (chain *Chain) Close() error {- var errs []error
- for _, backend := range chain.backends {- if backend == nil {- continue
- }
- if err := backend.Close(); err != nil {- errs = append(errs, err)
- }
- }
- return errors.Join(errs...)
-}
--- /dev/null
+++ b/objectdb/chain/chain.go
@@ -1,0 +1,128 @@
+// Package chain provides an ordered object database chain implementation.
+package chain
+
+import (
+ "errors"
+ "fmt"
+ "io"
+
+ "codeberg.org/lindenii/furgit/objectdb"
+ "codeberg.org/lindenii/furgit/objectid"
+ "codeberg.org/lindenii/furgit/objecttype"
+)
+
+// Chain queries multiple object databases in order.
+type Chain struct {+ backends []objectdb.ObjectDB
+}
+
+// New creates an ordered object database chain.
+func New(backends ...objectdb.ObjectDB) *Chain {+ return &Chain{+ backends: append([]objectdb.ObjectDB(nil), backends...),
+ }
+}
+
+// ReadBytesFull reads a full serialized object from the first backend that has it.
+func (chain *Chain) ReadBytesFull(id objectid.ObjectID) ([]byte, error) {+ for i, backend := range chain.backends {+ if backend == nil {+ continue
+ }
+ full, err := backend.ReadBytesFull(id)
+ if err == nil {+ return full, nil
+ }
+ if errors.Is(err, objectdb.ErrObjectNotFound) {+ continue
+ }
+ return nil, fmt.Errorf("objectdb: backend %d read bytes full: %w", i, err)+ }
+ return nil, objectdb.ErrObjectNotFound
+}
+
+// ReadBytesContent reads an object's type and content bytes from the first backend that has it.
+func (chain *Chain) ReadBytesContent(id objectid.ObjectID) (objecttype.Type, []byte, error) {+ for i, backend := range chain.backends {+ if backend == nil {+ continue
+ }
+ ty, content, err := backend.ReadBytesContent(id)
+ if err == nil {+ return ty, content, nil
+ }
+ if errors.Is(err, objectdb.ErrObjectNotFound) {+ continue
+ }
+ return objecttype.TypeInvalid, nil, fmt.Errorf("objectdb: backend %d read bytes content: %w", i, err)+ }
+ return objecttype.TypeInvalid, nil, objectdb.ErrObjectNotFound
+}
+
+// ReadReaderFull reads a full serialized object stream from the first backend that has it.
+func (chain *Chain) ReadReaderFull(id objectid.ObjectID) (io.ReadCloser, error) {+ for i, backend := range chain.backends {+ if backend == nil {+ continue
+ }
+ reader, err := backend.ReadReaderFull(id)
+ if err == nil {+ return reader, nil
+ }
+ if errors.Is(err, objectdb.ErrObjectNotFound) {+ continue
+ }
+ return nil, fmt.Errorf("objectdb: backend %d read reader full: %w", i, err)+ }
+ return nil, objectdb.ErrObjectNotFound
+}
+
+// ReadReaderContent reads an object's type and content stream from the first backend that has it.
+func (chain *Chain) ReadReaderContent(id objectid.ObjectID) (objecttype.Type, io.ReadCloser, error) {+ for i, backend := range chain.backends {+ if backend == nil {+ continue
+ }
+ ty, reader, err := backend.ReadReaderContent(id)
+ if err == nil {+ return ty, reader, nil
+ }
+ if errors.Is(err, objectdb.ErrObjectNotFound) {+ continue
+ }
+ return objecttype.TypeInvalid, nil, fmt.Errorf("objectdb: backend %d read reader content: %w", i, err)+ }
+ return objecttype.TypeInvalid, nil, objectdb.ErrObjectNotFound
+}
+
+// ReadHeader reads object header data from the first backend that has it.
+func (chain *Chain) ReadHeader(id objectid.ObjectID) (objecttype.Type, int64, error) {+ for i, backend := range chain.backends {+ if backend == nil {+ continue
+ }
+ ty, size, err := backend.ReadHeader(id)
+ if err == nil {+ return ty, size, nil
+ }
+ if errors.Is(err, objectdb.ErrObjectNotFound) {+ continue
+ }
+ return objecttype.TypeInvalid, 0, fmt.Errorf("objectdb: backend %d read header: %w", i, err)+ }
+ return objecttype.TypeInvalid, 0, objectdb.ErrObjectNotFound
+}
+
+// Close closes all backends and joins close errors.
+func (chain *Chain) Close() error {+ var errs []error
+ for _, backend := range chain.backends {+ if backend == nil {+ continue
+ }
+ if err := backend.Close(); err != nil {+ errs = append(errs, err)
+ }
+ }
+ return errors.Join(errs...)
+}
--
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