1 files changed, 56 insertions, 0 deletions
diff --git a/models/system/appstate.go b/models/system/appstate.go
new file mode 100644
index 0000000..01faa1a
--- /dev/null
+++ b/models/system/appstate.go
@@ -0,0 +1,56 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package system
+
+import (
+	"context"
+
+	"code.gitea.io/gitea/models/db"
+)
+
+// AppState represents a state record in database
+// if one day we would make Gitea run as a cluster,
+// we can introduce a new field `Scope` here to store different states for different nodes
+type AppState struct {
+	ID       string `xorm:"pk varchar(200)"`
+	Revision int64
+	Content  string `xorm:"LONGTEXT"`
+}
+
+func init() {
+	db.RegisterModel(new(AppState))
+}
+
+// SaveAppStateContent saves the app state item to database
+func SaveAppStateContent(ctx context.Context, key, content string) error {
+	return db.WithTx(ctx, func(ctx context.Context) error {
+		eng := db.GetEngine(ctx)
+		// try to update existing row
+		res, err := eng.Exec("UPDATE app_state SET revision=revision+1, content=? WHERE id=?", content, key)
+		if err != nil {
+			return err
+		}
+		rows, _ := res.RowsAffected()
+		if rows != 0 {
+			// the existing row is updated, so we can return
+			return nil
+		}
+		// if no existing row, insert a new row
+		_, err = eng.Insert(&AppState{ID: key, Content: content})
+		return err
+	})
+}
+
+// GetAppStateContent gets an app state from database
+func GetAppStateContent(ctx context.Context, key string) (content string, err error) {
+	e := db.GetEngine(ctx)
+	appState := &AppState{ID: key}
+	has, err := e.Get(appState)
+	if err != nil {
+		return "", err
+	} else if !has {
+		return "", nil
+	}
+	return appState.Content, nil
+}