From a9684e72e9ec9045c4588ef103e6489868bca394 Mon Sep 17 00:00:00 2001 From: Runxi Yu Date: Wed, 4 Mar 2026 12:43:22 +0800 Subject: objectstore/mix: Rename from objectstore/chain --- objectstore/chain/chain.go | 275 --------------------------------------------- 1 file changed, 275 deletions(-) delete mode 100644 objectstore/chain/chain.go (limited to 'objectstore/chain') diff --git a/objectstore/chain/chain.go b/objectstore/chain/chain.go deleted file mode 100644 index 8e10feb6..00000000 --- a/objectstore/chain/chain.go +++ /dev/null @@ -1,275 +0,0 @@ -// 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 - } -} -- cgit v1.3.1-10-gc9f91