feat: multiple search indexes (#2514)

* refactor: abstract search interface

* wip: ~

* fix cycle import

* objs update hook

* wip: ~

* Delete search/none

* auto update index while cache changed

* db searcher

TODO: bleve init issue

cannot open index, metadata missing

* fix size type

why float64??

* fix typo

* fix nil pointer using

* api adapt ui

* bleve: fix clear & change struct

internal/search/bleve/init.go

@@ -0,0 +1,38 @@
+package bleve
+
+import (
+	"github.com/alist-org/alist/v3/internal/conf"
+	"github.com/alist-org/alist/v3/internal/search/searcher"
+	"github.com/blevesearch/bleve/v2"
+	log "github.com/sirupsen/logrus"
+)
+
+var config = searcher.Config{
+	Name: "bleve",
+}
+
+func Init(indexPath *string) (bleve.Index, error) {
+	log.Debugf("bleve path: %s", *indexPath)
+	fileIndex, err := bleve.Open(*indexPath)
+	if err == bleve.ErrorIndexPathDoesNotExist {
+		log.Infof("Creating new index...")
+		indexMapping := bleve.NewIndexMapping()
+		fileIndex, err = bleve.New(*indexPath, indexMapping)
+		if err != nil {
+			return nil, err
+		}
+	} else if err != nil {
+		return nil, err
+	}
+	return fileIndex, nil
+}
+
+func init() {
+	searcher.RegisterSearcher(config, func() (searcher.Searcher, error) {
+		b, err := Init(&conf.Conf.BleveDir)
+		if err != nil {
+			return nil, err
+		}
+		return &Bleve{BIndex: b}, nil
+	})
+}