mirror of
https://wget.la/https://github.com/leookun/cursor-byok
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112 lines
3.3 KiB
Go
112 lines
3.3 KiB
Go
// content_blob_store.go 负责持久化 history 引用的内容寻址二进制数据。
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package forwarder
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import (
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"bytes"
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"crypto/sha256"
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"encoding/hex"
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"fmt"
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"os"
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"path/filepath"
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"strings"
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)
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const contentBlobDirectoryName = ".blobs"
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// ContentBlobStore 使用 SHA-256 内容哈希保存不可变二进制数据。
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type ContentBlobStore struct {
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root string
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}
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// NewContentBlobStore 创建独立于 context.json 和 checkpoint 的内容寻址存储。
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func NewContentBlobStore(historyRoot string) *ContentBlobStore {
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historyRoot = strings.TrimSpace(historyRoot)
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if historyRoot == "" {
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return &ContentBlobStore{}
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}
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return &ContentBlobStore{root: filepath.Join(historyRoot, contentBlobDirectoryName, "sha256")}
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}
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// Put 校验内容哈希并幂等保存数据。
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func (store *ContentBlobStore) Put(id []byte, data []byte) error {
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if store == nil || strings.TrimSpace(store.root) == "" {
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return fmt.Errorf("content blob store is not initialized")
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}
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normalizedID, err := normalizeContentBlobID(id)
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if err != nil {
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return err
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}
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digest := sha256.Sum256(data)
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if !bytes.Equal(normalizedID, digest[:]) {
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return fmt.Errorf("content blob id does not match payload sha256")
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}
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path := store.blobPath(normalizedID)
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if existing, err := store.Get(normalizedID); err == nil {
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if bytes.Equal(existing, data) {
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return nil
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}
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return fmt.Errorf("content blob payload conflicts with existing id")
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} else if !os.IsNotExist(err) {
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return err
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}
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if err := os.MkdirAll(store.root, 0o700); err != nil {
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return fmt.Errorf("create content blob directory: %w", err)
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}
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temporary, err := os.CreateTemp(store.root, ".blob-*")
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if err != nil {
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return fmt.Errorf("create content blob temporary file: %w", err)
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}
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temporaryPath := temporary.Name()
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defer os.Remove(temporaryPath)
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if err := temporary.Chmod(0o600); err != nil {
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_ = temporary.Close()
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return fmt.Errorf("set content blob permissions: %w", err)
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}
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if _, err := temporary.Write(data); err != nil {
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_ = temporary.Close()
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return fmt.Errorf("write content blob: %w", err)
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}
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if err := temporary.Sync(); err != nil {
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_ = temporary.Close()
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return fmt.Errorf("sync content blob: %w", err)
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}
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if err := temporary.Close(); err != nil {
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return fmt.Errorf("close content blob: %w", err)
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}
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if err := os.Rename(temporaryPath, path); err != nil {
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return fmt.Errorf("commit content blob: %w", err)
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}
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return nil
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}
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// Get 读取内容并再次校验哈希，避免损坏数据进入模型请求。
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func (store *ContentBlobStore) Get(id []byte) ([]byte, error) {
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if store == nil || strings.TrimSpace(store.root) == "" {
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return nil, fmt.Errorf("content blob store is not initialized")
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}
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normalizedID, err := normalizeContentBlobID(id)
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if err != nil {
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return nil, err
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}
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data, err := os.ReadFile(store.blobPath(normalizedID))
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if err != nil {
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return nil, err
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}
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digest := sha256.Sum256(data)
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if !bytes.Equal(normalizedID, digest[:]) {
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return nil, fmt.Errorf("content blob sha256 verification failed")
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}
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return append([]byte(nil), data...), nil
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}
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func (store *ContentBlobStore) blobPath(id []byte) string {
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return filepath.Join(store.root, hex.EncodeToString(id))
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}
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func normalizeContentBlobID(id []byte) ([]byte, error) {
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if len(id) != sha256.Size {
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return nil, fmt.Errorf("content blob id must be %d bytes", sha256.Size)
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}
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return append([]byte(nil), id...), nil
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}
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