精简后的项目：仅保留 api/ui 源码、文档、构建依赖

api/scanner/scanner_task/scanner_task.go

@@ -0,0 +1,90 @@
+package scanner_task
+
+import (
+	"context"
+	"database/sql"
+	"flag"
+	"io/fs"
+
+	"github.com/photoview/photoview/api/graphql/models"
+	"github.com/photoview/photoview/api/scanner/media_encoding"
+	"github.com/photoview/photoview/api/scanner/scanner_cache"
+	"gorm.io/gorm"
+)
+
+// ScannerTask is an interface for a task to be performed as a part of the scanner pipeline
+type ScannerTask interface {
+	// BeforeScanAlbum will run at the beginning of the scan task.
+	// New values can be stored in the returned TaskContext that will live throughout the lifetime of the task.
+	BeforeScanAlbum(ctx TaskContext) (TaskContext, error)
+
+	// AfterScanAlbum will run at the end of the scan task.
+	AfterScanAlbum(ctx TaskContext, changedMedia []*models.Media, albumMedia []*models.Media) error
+
+	// MediaFound will run for each media file found on the filesystem.
+	// It will run even when the media is already present in the database.
+	// If the returned skip value is true, the media will be skipped and further steps will not be executed for the given file.
+	MediaFound(ctx TaskContext, fileInfo fs.FileInfo, mediaPath string) (skip bool, err error)
+
+	// AfterMediaFound will run each media file after is has been saved to the database, but not processed yet.
+	// It will run even when the media is already present in the database, in that case `newMedia` will be true.
+	AfterMediaFound(ctx TaskContext, media *models.Media, newMedia bool) error
+
+	BeforeProcessMedia(ctx TaskContext, mediaData *media_encoding.EncodeMediaData) (TaskContext, error)
+	ProcessMedia(ctx TaskContext, mediaData *media_encoding.EncodeMediaData, mediaCachePath string) (updatedURLs []*models.MediaURL, err error)
+	AfterProcessMedia(ctx TaskContext, mediaData *media_encoding.EncodeMediaData, updatedURLs []*models.MediaURL, mediaIndex int, mediaTotal int) error
+}
+
+type TaskContext struct {
+	context.Context
+}
+
+func NewTaskContext(parent context.Context, db *gorm.DB, album *models.Album, cache *scanner_cache.AlbumScannerCache) TaskContext {
+	ctx := TaskContext{Context: parent}
+	ctx = ctx.WithValue(taskCtxKeyAlbum, album)
+	ctx = ctx.WithValue(taskCtxKeyAlbumCache, cache)
+	ctx = ctx.WithDB(db)
+
+	return ctx
+}
+
+type taskCtxKeyType string
+
+const (
+	taskCtxKeyAlbum      taskCtxKeyType = "task_album"
+	taskCtxKeyAlbumCache taskCtxKeyType = "task_album_cache"
+	taskCtxKeyDatabase   taskCtxKeyType = "task_database"
+)
+
+func (c TaskContext) GetAlbum() *models.Album {
+	return c.Context.Value(taskCtxKeyAlbum).(*models.Album)
+}
+
+func (c TaskContext) GetCache() *scanner_cache.AlbumScannerCache {
+	return c.Context.Value(taskCtxKeyAlbumCache).(*scanner_cache.AlbumScannerCache)
+}
+
+func (c TaskContext) GetDB() *gorm.DB {
+	return c.Context.Value(taskCtxKeyDatabase).(*gorm.DB)
+}
+
+func (c TaskContext) DatabaseTransaction(transFunc func(ctx TaskContext) error, opts ...*sql.TxOptions) error {
+	return c.GetDB().Transaction(func(tx *gorm.DB) error {
+		return transFunc(c.WithDB(tx))
+	}, opts...)
+}
+
+func (c TaskContext) WithValue(key, val interface{}) TaskContext {
+	return TaskContext{
+		Context: context.WithValue(c.Context, key, val),
+	}
+}
+
+func (c TaskContext) WithDB(db *gorm.DB) TaskContext {
+	// Allow db to be nil in tests
+	if db == nil && flag.Lookup("test.v") != nil {
+		return c
+	}
+
+	return c.WithValue(taskCtxKeyDatabase, db.WithContext(c.Context))
+}