基本能力编写完成

internal/cache/file_cache.go

@@ -0,0 +1,178 @@
+package cache
+
+import (
+	"compress/gzip"
+	"context"
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/gitcodestatic/gitcodestatic/internal/logger"
+	"github.com/gitcodestatic/gitcodestatic/internal/models"
+	"github.com/gitcodestatic/gitcodestatic/internal/storage"
+)
+
+// FileCache 基于文件+DB的缓存实现
+type FileCache struct {
+	store    storage.Store
+	statsDir string
+}
+
+// NewFileCache 创建文件缓存
+func NewFileCache(store storage.Store, statsDir string) *FileCache {
+	return &FileCache{
+		store:    store,
+		statsDir: statsDir,
+	}
+}
+
+// Get 获取缓存
+func (c *FileCache) Get(ctx context.Context, cacheKey string) (*models.StatsResult, error) {
+	// 从DB查询缓存元数据
+	cache, err := c.store.StatsCache().GetByCacheKey(ctx, cacheKey)
+	if err != nil {
+		return nil, err
+	}
+	if cache == nil {
+		return nil, nil // 缓存不存在
+	}
+
+	// 读取结果文件
+	stats, err := c.loadStatsFromFile(cache.ResultPath)
+	if err != nil {
+		logger.Logger.Error().Err(err).Str("cache_key", cacheKey).Msg("failed to load stats from file")
+		return nil, err
+	}
+
+	// 更新命中次数
+	if err := c.store.StatsCache().UpdateHitCount(ctx, cache.ID); err != nil {
+		logger.Logger.Warn().Err(err).Int64("cache_id", cache.ID).Msg("failed to update hit count")
+	}
+
+	result := &models.StatsResult{
+		CacheHit:   true,
+		CachedAt:   &cache.CreatedAt,
+		CommitHash: cache.CommitHash,
+		Statistics: stats,
+	}
+
+	logger.Logger.Info().
+		Str("cache_key", cacheKey).
+		Int64("cache_id", cache.ID).
+		Msg("cache hit")
+
+	return result, nil
+}
+
+// Set 设置缓存
+func (c *FileCache) Set(ctx context.Context, repoID int64, branch string, constraint *models.StatsConstraint, 
+	commitHash string, stats *models.Statistics) error {
+	
+	// 生成缓存键
+	cacheKey := GenerateCacheKey(repoID, branch, constraint, commitHash)
+	
+	// 保存统计结果到文件
+	resultPath := filepath.Join(c.statsDir, cacheKey+".json.gz")
+	if err := c.saveStatsToFile(stats, resultPath); err != nil {
+		return fmt.Errorf("failed to save stats to file: %w", err)
+	}
+
+	// 获取文件大小
+	fileInfo, err := os.Stat(resultPath)
+	if err != nil {
+		return fmt.Errorf("failed to stat result file: %w", err)
+	}
+
+	// 创建缓存记录
+	cache := &models.StatsCache{
+		RepoID:          repoID,
+		Branch:          branch,
+		ConstraintType:  constraint.Type,
+		ConstraintValue: SerializeConstraint(constraint),
+		CommitHash:      commitHash,
+		ResultPath:      resultPath,
+		ResultSize:      fileInfo.Size(),
+		CacheKey:        cacheKey,
+	}
+
+	if err := c.store.StatsCache().Create(ctx, cache); err != nil {
+		// 如果创建失败，删除已保存的文件
+		os.Remove(resultPath)
+		return fmt.Errorf("failed to create cache record: %w", err)
+	}
+
+	logger.Logger.Info().
+		Str("cache_key", cacheKey).
+		Int64("cache_id", cache.ID).
+		Int64("file_size", fileInfo.Size()).
+		Msg("cache saved")
+
+	return nil
+}
+
+// InvalidateByRepoID 使指定仓库的所有缓存失效
+func (c *FileCache) InvalidateByRepoID(ctx context.Context, repoID int64) error {
+	// 查询该仓库的所有缓存
+	// 注意：这里简化实现，实际应该先查询再删除文件
+	if err := c.store.StatsCache().DeleteByRepoID(ctx, repoID); err != nil {
+		return fmt.Errorf("failed to delete cache records: %w", err)
+	}
+
+	logger.Logger.Info().Int64("repo_id", repoID).Msg("cache invalidated")
+	return nil
+}
+
+// saveStatsToFile 保存统计结果到文件（gzip压缩）
+func (c *FileCache) saveStatsToFile(stats *models.Statistics, filePath string) error {
+	// 确保目录存在
+	dir := filepath.Dir(filePath)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return fmt.Errorf("failed to create directory: %w", err)
+	}
+
+	// 创建文件
+	file, err := os.Create(filePath)
+	if err != nil {
+		return fmt.Errorf("failed to create file: %w", err)
+	}
+	defer file.Close()
+
+	// 创建gzip writer
+	gzipWriter := gzip.NewWriter(file)
+	defer gzipWriter.Close()
+
+	// 编码JSON
+	encoder := json.NewEncoder(gzipWriter)
+	if err := encoder.Encode(stats); err != nil {
+		return fmt.Errorf("failed to encode stats: %w", err)
+	}
+
+	return nil
+}
+
+// loadStatsFromFile 从文件加载统计结果
+func (c *FileCache) loadStatsFromFile(filePath string) (*models.Statistics, error) {
+	// 打开文件
+	file, err := os.Open(filePath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open file: %w", err)
+	}
+	defer file.Close()
+
+	// 创建gzip reader
+	gzipReader, err := gzip.NewReader(file)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create gzip reader: %w", err)
+	}
+	defer gzipReader.Close()
+
+	// 解码JSON
+	var stats models.Statistics
+	decoder := json.NewDecoder(gzipReader)
+	if err := decoder.Decode(&stats); err != nil {
+		return nil, fmt.Errorf("failed to decode stats: %w", err)
+	}
+
+	return &stats, nil
+}