cups: add comprehensive CUPs setting page

- Add printers
- Delete printers
- Use polkit APIs as fallback on auth errors
- Fix ref system to conditionally subscribe to cups when wanted

core/internal/server/cups/pkhelper.go

@@ -0,0 +1,184 @@
+package cups
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/godbus/dbus/v5"
+)
+
+const (
+	pkHelperDest      = "org.opensuse.CupsPkHelper.Mechanism"
+	pkHelperPath      = "/"
+	pkHelperInterface = "org.opensuse.CupsPkHelper.Mechanism"
+)
+
+type PkHelper interface {
+	DevicesGet(timeout, limit int, includeSchemes, excludeSchemes []string) ([]Device, error)
+	PrinterAdd(name, uri, ppd, info, location string) error
+	PrinterDelete(name string) error
+	PrinterSetEnabled(name string, enabled bool) error
+	PrinterSetAcceptJobs(name string, enabled bool, reason string) error
+	PrinterSetInfo(name, info string) error
+	PrinterSetLocation(name, location string) error
+	PrinterSetShared(name string, shared bool) error
+	ClassAddPrinter(className, printerName string) error
+	ClassDeletePrinter(className, printerName string) error
+	ClassDelete(className string) error
+	JobCancelPurge(jobID int, purge bool) error
+	JobRestart(jobID int) error
+	JobSetHoldUntil(jobID int, holdUntil string) error
+}
+
+type DBusPkHelper struct {
+	conn *dbus.Conn
+	obj  dbus.BusObject
+}
+
+func NewPkHelper() (*DBusPkHelper, error) {
+	conn, err := dbus.SystemBus()
+	if err != nil {
+		return nil, fmt.Errorf("failed to connect to system bus: %w", err)
+	}
+
+	return &DBusPkHelper{
+		conn: conn,
+		obj:  conn.Object(pkHelperDest, pkHelperPath),
+	}, nil
+}
+
+func (p *DBusPkHelper) DevicesGet(timeout, limit int, includeSchemes, excludeSchemes []string) ([]Device, error) {
+	if includeSchemes == nil {
+		includeSchemes = []string{}
+	}
+	if excludeSchemes == nil {
+		excludeSchemes = []string{}
+	}
+
+	var errStr string
+	var devicesMap map[string]string
+
+	call := p.obj.Call(pkHelperInterface+".DevicesGet", 0, int32(timeout), int32(limit), includeSchemes, excludeSchemes)
+	if call.Err != nil {
+		return nil, call.Err
+	}
+	if err := call.Store(&errStr, &devicesMap); err != nil {
+		return nil, err
+	}
+	if errStr != "" {
+		return nil, fmt.Errorf("%s", errStr)
+	}
+
+	return parseDevicesMap(devicesMap), nil
+}
+
+func parseDevicesMap(devicesMap map[string]string) []Device {
+	devicesByIndex := make(map[string]*Device)
+
+	for key, value := range devicesMap {
+		idx := strings.LastIndex(key, ":")
+		if idx == -1 {
+			continue
+		}
+
+		attr := key[:idx]
+		index := key[idx+1:]
+
+		dev, ok := devicesByIndex[index]
+		if !ok {
+			dev = &Device{}
+			devicesByIndex[index] = dev
+		}
+
+		switch attr {
+		case "device-uri":
+			dev.URI = value
+		case "device-class":
+			dev.Class = value
+		case "device-info":
+			dev.Info = value
+		case "device-make-and-model":
+			dev.MakeModel = value
+		case "device-id":
+			dev.ID = value
+		case "device-location":
+			dev.Location = value
+		}
+	}
+
+	devices := make([]Device, 0, len(devicesByIndex))
+	for _, dev := range devicesByIndex {
+		if dev.URI != "" {
+			devices = append(devices, *dev)
+		}
+	}
+	return devices
+}
+
+func (p *DBusPkHelper) PrinterAdd(name, uri, ppd, info, location string) error {
+	return p.callSimple("PrinterAdd", name, uri, ppd, info, location)
+}
+
+func (p *DBusPkHelper) PrinterDelete(name string) error {
+	return p.callSimple("PrinterDelete", name)
+}
+
+func (p *DBusPkHelper) PrinterSetEnabled(name string, enabled bool) error {
+	return p.callSimple("PrinterSetEnabled", name, enabled)
+}
+
+func (p *DBusPkHelper) PrinterSetAcceptJobs(name string, enabled bool, reason string) error {
+	return p.callSimple("PrinterSetAcceptJobs", name, enabled, reason)
+}
+
+func (p *DBusPkHelper) PrinterSetInfo(name, info string) error {
+	return p.callSimple("PrinterSetInfo", name, info)
+}
+
+func (p *DBusPkHelper) PrinterSetLocation(name, location string) error {
+	return p.callSimple("PrinterSetLocation", name, location)
+}
+
+func (p *DBusPkHelper) PrinterSetShared(name string, shared bool) error {
+	return p.callSimple("PrinterSetShared", name, shared)
+}
+
+func (p *DBusPkHelper) ClassAddPrinter(className, printerName string) error {
+	return p.callSimple("ClassAddPrinter", className, printerName)
+}
+
+func (p *DBusPkHelper) ClassDeletePrinter(className, printerName string) error {
+	return p.callSimple("ClassDeletePrinter", className, printerName)
+}
+
+func (p *DBusPkHelper) ClassDelete(className string) error {
+	return p.callSimple("ClassDelete", className)
+}
+
+func (p *DBusPkHelper) JobCancelPurge(jobID int, purge bool) error {
+	return p.callSimple("JobCancelPurge", int32(jobID), purge)
+}
+
+func (p *DBusPkHelper) JobRestart(jobID int) error {
+	return p.callSimple("JobRestart", int32(jobID))
+}
+
+func (p *DBusPkHelper) JobSetHoldUntil(jobID int, holdUntil string) error {
+	return p.callSimple("JobSetHoldUntil", int32(jobID), holdUntil)
+}
+
+func (p *DBusPkHelper) callSimple(method string, args ...interface{}) error {
+	var errStr string
+
+	call := p.obj.Call(pkHelperInterface+"."+method, 0, args...)
+	if call.Err != nil {
+		return call.Err
+	}
+	if err := call.Store(&errStr); err != nil {
+		return err
+	}
+	if errStr != "" {
+		return fmt.Errorf("%s", errStr)
+	}
+	return nil
+}