Major plugin updates

v3/plugins/experimental/single_instance/plugin.go

@@ -0,0 +1,82 @@
+package single_instance
+
+import (
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+
+	"github.com/wailsapp/wails/v3/pkg/application"
+)
+
+type Config struct {
+	// Add any configuration options here
+	LockFileName                  string
+	LockFilePath                  string
+	ActivateAppOnSubsequentLaunch bool
+}
+
+type Plugin struct {
+	config   *Config
+	lockfile *os.File
+}
+
+func (p *Plugin) CallableByJS() []string {
+	return []string{}
+}
+
+func (p *Plugin) Assets() fs.FS {
+	return nil
+}
+
+func NewPlugin(config *Config) *Plugin {
+	if config.LockFilePath == "" {
+		// Use the system default temp directory
+		config.LockFilePath = os.TempDir()
+	}
+	if config.LockFileName == "" {
+		// Use the executable name
+		config.LockFileName = filepath.Base(os.Args[0]) + ".lock"
+	}
+	return &Plugin{
+		config: config,
+	}
+}
+
+// Shutdown is called when the app is shutting down
+func (p *Plugin) Shutdown() error {
+	return p.lockfile.Close()
+}
+
+// Name returns the name of the plugin.
+func (p *Plugin) Name() string {
+	return "github.com/wailsapp/wails/v3/plugins/single-instance"
+}
+
+// Init is called when the app is starting up. You can use this to
+// initialise any resources you need. You can also access the application
+// instance via the app property.
+func (p *Plugin) Init(api application.PluginAPI) error {
+	var err error
+	lockfileName := p.config.LockFilePath + "/" + p.config.LockFileName
+	p.lockfile, err = CreateLockFile(lockfileName, application.Get().GetPID())
+	if err != nil {
+		if p.config.ActivateAppOnSubsequentLaunch {
+			pid, err := GetLockFilePid(lockfileName)
+			if err != nil {
+				return err
+			}
+			err = p.activeInstance(pid)
+			if err != nil {
+				return err
+			}
+		}
+		return fmt.Errorf("another instance of this application is already running")
+	}
+	return nil
+}
+
+// Exported returns a list of exported methods that can be called from the frontend
+func (p *Plugin) Exported() []string {
+	return []string{}
+}