ref: a9684e72e9ec9045c4588ef103e6489868bca394
parent: f31ad11ed0665bfaed90c67890a5fa951301d3f3
author: Runxi Yu <me@runxiyu.org>
date: Wed Mar 4 07:43:22 EST 2026
objectstore/mix: Rename from objectstore/chain
--- a/objectstore/chain/chain.go
+++ /dev/null
@@ -1,275 +1,0 @@
-// Package chain provides an adaptive wrapper over multiple object storage
-// backends.
-package chain
-
-import (
- "errors"
- "fmt"
- "io"
- "sync"
-
- "codeberg.org/lindenii/furgit/objectid"
- "codeberg.org/lindenii/furgit/objectstore"
- "codeberg.org/lindenii/furgit/objecttype"
-)
-
-// Chain queries multiple object databases with an MRU backend preference.
-type Chain struct {- mu sync.RWMutex
-
- backendHead *backendNode
- backendTail *backendNode
- backendNodeByStore map[objectstore.Store]*backendNode
-}
-
-// New creates a Chain from backends.
-func New(backends ...objectstore.Store) *Chain {- nodeByStore := make(map[objectstore.Store]*backendNode, len(backends))
-
- var (
- head *backendNode
- tail *backendNode
- )
-
- for _, backend := range backends {- if backend == nil {- continue
- }
-
- node := &backendNode{- backend: backend,
- prev: tail,
- }
- if tail != nil {- tail.next = node
- }
-
- if head == nil {- head = node
- }
-
- tail = node
- nodeByStore[backend] = node
- }
-
- return &Chain{- backendHead: head,
- backendTail: tail,
- backendNodeByStore: nodeByStore,
- }
-}
-
-// ReadBytesFull reads a full serialized object from one backend that has it.
-func (chain *Chain) ReadBytesFull(id objectid.ObjectID) ([]byte, error) {- for i, backend := 0, chain.firstBackend(); backend != nil; i, backend = i+1, chain.nextBackend(backend) {- full, err := backend.ReadBytesFull(id)
- if err == nil {- chain.touchBackend(backend)
-
- return full, nil
- }
-
- if errors.Is(err, objectstore.ErrObjectNotFound) {- continue
- }
-
- return nil, fmt.Errorf("objectstore: backend %d read bytes full: %w", i, err)- }
-
- return nil, objectstore.ErrObjectNotFound
-}
-
-// ReadBytesContent reads an object's type and content bytes from one backend
-// that has it.
-func (chain *Chain) ReadBytesContent(id objectid.ObjectID) (objecttype.Type, []byte, error) {- for i, backend := 0, chain.firstBackend(); backend != nil; i, backend = i+1, chain.nextBackend(backend) {- ty, content, err := backend.ReadBytesContent(id)
- if err == nil {- chain.touchBackend(backend)
-
- return ty, content, nil
- }
-
- if errors.Is(err, objectstore.ErrObjectNotFound) {- continue
- }
-
- return objecttype.TypeInvalid, nil, fmt.Errorf("objectstore: backend %d read bytes content: %w", i, err)- }
-
- return objecttype.TypeInvalid, nil, objectstore.ErrObjectNotFound
-}
-
-// ReadReaderFull reads a full serialized object stream from one backend that
-// has it.
-func (chain *Chain) ReadReaderFull(id objectid.ObjectID) (io.ReadCloser, error) {- for i, backend := 0, chain.firstBackend(); backend != nil; i, backend = i+1, chain.nextBackend(backend) {- reader, err := backend.ReadReaderFull(id)
- if err == nil {- chain.touchBackend(backend)
-
- return reader, nil
- }
-
- if errors.Is(err, objectstore.ErrObjectNotFound) {- continue
- }
-
- return nil, fmt.Errorf("objectstore: backend %d read reader full: %w", i, err)- }
-
- return nil, objectstore.ErrObjectNotFound
-}
-
-// ReadReaderContent reads an object's type, declared content length, and
-// content stream from one backend that has it.
-func (chain *Chain) ReadReaderContent(id objectid.ObjectID) (objecttype.Type, int64, io.ReadCloser, error) {- for i, backend := 0, chain.firstBackend(); backend != nil; i, backend = i+1, chain.nextBackend(backend) {- ty, size, reader, err := backend.ReadReaderContent(id)
- if err == nil {- chain.touchBackend(backend)
-
- return ty, size, reader, nil
- }
-
- if errors.Is(err, objectstore.ErrObjectNotFound) {- continue
- }
-
- return objecttype.TypeInvalid, 0, nil, fmt.Errorf("objectstore: backend %d read reader content: %w", i, err)- }
-
- return objecttype.TypeInvalid, 0, nil, objectstore.ErrObjectNotFound
-}
-
-// ReadSize reads object content length from one backend that has it.
-func (chain *Chain) ReadSize(id objectid.ObjectID) (int64, error) {- for i, backend := 0, chain.firstBackend(); backend != nil; i, backend = i+1, chain.nextBackend(backend) {- size, err := backend.ReadSize(id)
- if err == nil {- chain.touchBackend(backend)
-
- return size, nil
- }
-
- if errors.Is(err, objectstore.ErrObjectNotFound) {- continue
- }
-
- return 0, fmt.Errorf("objectstore: backend %d read size: %w", i, err)- }
-
- return 0, objectstore.ErrObjectNotFound
-}
-
-// ReadHeader reads object header data from one backend that has it.
-func (chain *Chain) ReadHeader(id objectid.ObjectID) (objecttype.Type, int64, error) {- for i, backend := 0, chain.firstBackend(); backend != nil; i, backend = i+1, chain.nextBackend(backend) {- ty, size, err := backend.ReadHeader(id)
- if err == nil {- chain.touchBackend(backend)
-
- return ty, size, nil
- }
-
- if errors.Is(err, objectstore.ErrObjectNotFound) {- continue
- }
-
- return objecttype.TypeInvalid, 0, fmt.Errorf("objectstore: backend %d read header: %w", i, err)- }
-
- return objecttype.TypeInvalid, 0, objectstore.ErrObjectNotFound
-}
-
-// Close closes all backends and joins close errors.
-func (chain *Chain) Close() error {- chain.mu.RLock()
-
- backends := make([]objectstore.Store, 0, len(chain.backendNodeByStore))
- for node := chain.backendHead; node != nil; node = node.next {- backends = append(backends, node.backend)
- }
-
- chain.mu.RUnlock()
-
- var errs []error
-
- for _, backend := range backends {- err := backend.Close()
- if err != nil {- errs = append(errs, err)
- }
- }
-
- return errors.Join(errs...)
-}
-
-type backendNode struct {- backend objectstore.Store
- prev *backendNode
- next *backendNode
-}
-
-func (chain *Chain) firstBackend() objectstore.Store {- chain.mu.RLock()
- defer chain.mu.RUnlock()
-
- if chain.backendHead == nil {- return nil
- }
-
- return chain.backendHead.backend
-}
-
-func (chain *Chain) nextBackend(current objectstore.Store) objectstore.Store {- chain.mu.RLock()
- defer chain.mu.RUnlock()
-
- node := chain.backendNodeByStore[current]
- if node == nil || node.next == nil {- return nil
- }
-
- return node.next.backend
-}
-
-func (chain *Chain) touchBackend(backend objectstore.Store) {- if backend == nil {- return
- }
-
- if !chain.mu.TryLock() {- return
- }
- defer chain.mu.Unlock()
-
- node := chain.backendNodeByStore[backend]
- if node == nil || node == chain.backendHead {- return
- }
-
- if node.prev != nil {- node.prev.next = node.next
- }
-
- if node.next != nil {- node.next.prev = node.prev
- }
-
- if chain.backendTail == node {- chain.backendTail = node.prev
- }
-
- node.prev = nil
-
- node.next = chain.backendHead
- if chain.backendHead != nil {- chain.backendHead.prev = node
- }
-
- chain.backendHead = node
- if chain.backendTail == nil {- chain.backendTail = node
- }
-}
--- /dev/null
+++ b/objectstore/mix/mix.go
@@ -1,0 +1,275 @@
+// Package mix provides an adaptive wrapper over multiple object storage
+// backends.
+package mix
+
+import (
+ "errors"
+ "fmt"
+ "io"
+ "sync"
+
+ "codeberg.org/lindenii/furgit/objectid"
+ "codeberg.org/lindenii/furgit/objectstore"
+ "codeberg.org/lindenii/furgit/objecttype"
+)
+
+// Mix queries multiple object databases with an MRU backend preference.
+type Mix struct {+ mu sync.RWMutex
+
+ backendHead *backendNode
+ backendTail *backendNode
+ backendNodeByStore map[objectstore.Store]*backendNode
+}
+
+// New creates a Mix from backends.
+func New(backends ...objectstore.Store) *Mix {+ nodeByStore := make(map[objectstore.Store]*backendNode, len(backends))
+
+ var (
+ head *backendNode
+ tail *backendNode
+ )
+
+ for _, backend := range backends {+ if backend == nil {+ continue
+ }
+
+ node := &backendNode{+ backend: backend,
+ prev: tail,
+ }
+ if tail != nil {+ tail.next = node
+ }
+
+ if head == nil {+ head = node
+ }
+
+ tail = node
+ nodeByStore[backend] = node
+ }
+
+ return &Mix{+ backendHead: head,
+ backendTail: tail,
+ backendNodeByStore: nodeByStore,
+ }
+}
+
+// ReadBytesFull reads a full serialized object from one backend that has it.
+func (mix *Mix) ReadBytesFull(id objectid.ObjectID) ([]byte, error) {+ for i, backend := 0, mix.firstBackend(); backend != nil; i, backend = i+1, mix.nextBackend(backend) {+ full, err := backend.ReadBytesFull(id)
+ if err == nil {+ mix.touchBackend(backend)
+
+ return full, nil
+ }
+
+ if errors.Is(err, objectstore.ErrObjectNotFound) {+ continue
+ }
+
+ return nil, fmt.Errorf("objectstore: backend %d read bytes full: %w", i, err)+ }
+
+ return nil, objectstore.ErrObjectNotFound
+}
+
+// ReadBytesContent reads an object's type and content bytes from one backend
+// that has it.
+func (mix *Mix) ReadBytesContent(id objectid.ObjectID) (objecttype.Type, []byte, error) {+ for i, backend := 0, mix.firstBackend(); backend != nil; i, backend = i+1, mix.nextBackend(backend) {+ ty, content, err := backend.ReadBytesContent(id)
+ if err == nil {+ mix.touchBackend(backend)
+
+ return ty, content, nil
+ }
+
+ if errors.Is(err, objectstore.ErrObjectNotFound) {+ continue
+ }
+
+ return objecttype.TypeInvalid, nil, fmt.Errorf("objectstore: backend %d read bytes content: %w", i, err)+ }
+
+ return objecttype.TypeInvalid, nil, objectstore.ErrObjectNotFound
+}
+
+// ReadReaderFull reads a full serialized object stream from one backend that
+// has it.
+func (mix *Mix) ReadReaderFull(id objectid.ObjectID) (io.ReadCloser, error) {+ for i, backend := 0, mix.firstBackend(); backend != nil; i, backend = i+1, mix.nextBackend(backend) {+ reader, err := backend.ReadReaderFull(id)
+ if err == nil {+ mix.touchBackend(backend)
+
+ return reader, nil
+ }
+
+ if errors.Is(err, objectstore.ErrObjectNotFound) {+ continue
+ }
+
+ return nil, fmt.Errorf("objectstore: backend %d read reader full: %w", i, err)+ }
+
+ return nil, objectstore.ErrObjectNotFound
+}
+
+// ReadReaderContent reads an object's type, declared content length, and
+// content stream from one backend that has it.
+func (mix *Mix) ReadReaderContent(id objectid.ObjectID) (objecttype.Type, int64, io.ReadCloser, error) {+ for i, backend := 0, mix.firstBackend(); backend != nil; i, backend = i+1, mix.nextBackend(backend) {+ ty, size, reader, err := backend.ReadReaderContent(id)
+ if err == nil {+ mix.touchBackend(backend)
+
+ return ty, size, reader, nil
+ }
+
+ if errors.Is(err, objectstore.ErrObjectNotFound) {+ continue
+ }
+
+ return objecttype.TypeInvalid, 0, nil, fmt.Errorf("objectstore: backend %d read reader content: %w", i, err)+ }
+
+ return objecttype.TypeInvalid, 0, nil, objectstore.ErrObjectNotFound
+}
+
+// ReadSize reads object content length from one backend that has it.
+func (mix *Mix) ReadSize(id objectid.ObjectID) (int64, error) {+ for i, backend := 0, mix.firstBackend(); backend != nil; i, backend = i+1, mix.nextBackend(backend) {+ size, err := backend.ReadSize(id)
+ if err == nil {+ mix.touchBackend(backend)
+
+ return size, nil
+ }
+
+ if errors.Is(err, objectstore.ErrObjectNotFound) {+ continue
+ }
+
+ return 0, fmt.Errorf("objectstore: backend %d read size: %w", i, err)+ }
+
+ return 0, objectstore.ErrObjectNotFound
+}
+
+// ReadHeader reads object header data from one backend that has it.
+func (mix *Mix) ReadHeader(id objectid.ObjectID) (objecttype.Type, int64, error) {+ for i, backend := 0, mix.firstBackend(); backend != nil; i, backend = i+1, mix.nextBackend(backend) {+ ty, size, err := backend.ReadHeader(id)
+ if err == nil {+ mix.touchBackend(backend)
+
+ return ty, size, nil
+ }
+
+ if errors.Is(err, objectstore.ErrObjectNotFound) {+ continue
+ }
+
+ return objecttype.TypeInvalid, 0, fmt.Errorf("objectstore: backend %d read header: %w", i, err)+ }
+
+ return objecttype.TypeInvalid, 0, objectstore.ErrObjectNotFound
+}
+
+// Close closes all backends and joins close errors.
+func (mix *Mix) Close() error {+ mix.mu.RLock()
+
+ backends := make([]objectstore.Store, 0, len(mix.backendNodeByStore))
+ for node := mix.backendHead; node != nil; node = node.next {+ backends = append(backends, node.backend)
+ }
+
+ mix.mu.RUnlock()
+
+ var errs []error
+
+ for _, backend := range backends {+ err := backend.Close()
+ if err != nil {+ errs = append(errs, err)
+ }
+ }
+
+ return errors.Join(errs...)
+}
+
+type backendNode struct {+ backend objectstore.Store
+ prev *backendNode
+ next *backendNode
+}
+
+func (mix *Mix) firstBackend() objectstore.Store {+ mix.mu.RLock()
+ defer mix.mu.RUnlock()
+
+ if mix.backendHead == nil {+ return nil
+ }
+
+ return mix.backendHead.backend
+}
+
+func (mix *Mix) nextBackend(current objectstore.Store) objectstore.Store {+ mix.mu.RLock()
+ defer mix.mu.RUnlock()
+
+ node := mix.backendNodeByStore[current]
+ if node == nil || node.next == nil {+ return nil
+ }
+
+ return node.next.backend
+}
+
+func (mix *Mix) touchBackend(backend objectstore.Store) {+ if backend == nil {+ return
+ }
+
+ if !mix.mu.TryLock() {+ return
+ }
+ defer mix.mu.Unlock()
+
+ node := mix.backendNodeByStore[backend]
+ if node == nil || node == mix.backendHead {+ return
+ }
+
+ if node.prev != nil {+ node.prev.next = node.next
+ }
+
+ if node.next != nil {+ node.next.prev = node.prev
+ }
+
+ if mix.backendTail == node {+ mix.backendTail = node.prev
+ }
+
+ node.prev = nil
+
+ node.next = mix.backendHead
+ if mix.backendHead != nil {+ mix.backendHead.prev = node
+ }
+
+ mix.backendHead = node
+ if mix.backendTail == nil {+ mix.backendTail = node
+ }
+}
--- a/repository/open.go
+++ b/repository/open.go
@@ -8,8 +8,8 @@
"codeberg.org/lindenii/furgit/config"
"codeberg.org/lindenii/furgit/objectid"
"codeberg.org/lindenii/furgit/objectstore"
- objectchain "codeberg.org/lindenii/furgit/objectstore/chain"
objectloose "codeberg.org/lindenii/furgit/objectstore/loose"
+ objectmix "codeberg.org/lindenii/furgit/objectstore/mix"
objectpacked "codeberg.org/lindenii/furgit/objectstore/packed"
"codeberg.org/lindenii/furgit/refstore"
refchain "codeberg.org/lindenii/furgit/refstore/chain"
@@ -123,7 +123,7 @@
return nil, nil, fmt.Errorf("repository: open objects/pack: %w", err)}
- objectsChain := objectchain.New(backends...)
+ objectsChain := objectmix.New(backends...)
objectsRootForWriting, err := root.OpenRoot("objects") if err != nil {--
⑨