Init V4 community edition (#2265)

* Init V4 community edition

* Init V4 community edition

application/migrator/directlink.go

@@ -0,0 +1,82 @@
+package migrator
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/cloudreve/Cloudreve/v4/application/migrator/model"
+	"github.com/cloudreve/Cloudreve/v4/ent/file"
+	"github.com/cloudreve/Cloudreve/v4/pkg/conf"
+)
+
+func (m *Migrator) migrateDirectLink() error {
+	m.l.Info("Migrating direct links...")
+	batchSize := 1000
+	offset := m.state.DirectLinkOffset
+	ctx := context.Background()
+
+	if m.state.DirectLinkOffset > 0 {
+		m.l.Info("Resuming direct link migration from offset %d", offset)
+	}
+
+	for {
+		m.l.Info("Migrating direct links with offset %d", offset)
+		var directLinks []model.SourceLink
+		if err := model.DB.Limit(batchSize).Offset(offset).Find(&directLinks).Error; err != nil {
+			return fmt.Errorf("failed to list v3 direct links: %w", err)
+		}
+
+		if len(directLinks) == 0 {
+			if m.dep.ConfigProvider().Database().Type == conf.PostgresDB {
+				m.l.Info("Resetting direct link ID sequence for postgres...")
+				m.v4client.DirectLink.ExecContext(ctx, "SELECT SETVAL('direct_links_id_seq',  (SELECT MAX(id) FROM direct_links))")
+			}
+			break
+		}
+
+		tx, err := m.v4client.Tx(ctx)
+		if err != nil {
+			_ = tx.Rollback()
+			return fmt.Errorf("failed to start transaction: %w", err)
+		}
+
+		for _, dl := range directLinks {
+			sourceId := int(dl.FileID) + m.state.LastFolderID
+			// check if file exists
+			_, err = tx.File.Query().Where(file.ID(sourceId)).First(ctx)
+			if err != nil {
+				m.l.Warning("File %d not found, skipping direct link %d", sourceId, dl.ID)
+				continue
+			}
+
+			stm := tx.DirectLink.Create().
+				SetCreatedAt(formatTime(dl.CreatedAt)).
+				SetUpdatedAt(formatTime(dl.UpdatedAt)).
+				SetRawID(int(dl.ID)).
+				SetFileID(sourceId).
+				SetName(dl.Name).
+				SetDownloads(dl.Downloads).
+				SetSpeed(0)
+
+			if _, err := stm.Save(ctx); err != nil {
+				_ = tx.Rollback()
+				return fmt.Errorf("failed to create direct link %d: %w", dl.ID, err)
+			}
+		}
+
+		if err := tx.Commit(); err != nil {
+			return fmt.Errorf("failed to commit transaction: %w", err)
+		}
+
+		offset += batchSize
+		m.state.DirectLinkOffset = offset
+		if err := m.saveState(); err != nil {
+			m.l.Warning("Failed to save state after direct link batch: %s", err)
+		} else {
+			m.l.Info("Saved migration state after processing this batch")
+		}
+	}
+
+	return nil
+
+}