feat: implement caldav search

vendor/github.com/dolanor/caldav-go/caldav/values/component_name.go

@@ -0,0 +1,8 @@
+package values
+
+type ComponentName string
+
+const (
+	CalendarComponentName ComponentName = "VCALENDAR"
+	EventComponentName                  = "VEVENT"
+)

vendor/github.com/dolanor/caldav-go/caldav/values/datetime.go

@@ -0,0 +1,31 @@
+package values
+
+import (
+	"encoding/xml"
+	"errors"
+	"github.com/dolanor/caldav-go/icalendar/values"
+	"time"
+)
+
+// a representation of a date and time for iCalendar
+type DateTime struct {
+	name string
+	t    time.Time
+}
+
+// creates a new caldav datetime representation, must be in UTC
+func NewDateTime(name string, t time.Time) (*DateTime, error) {
+	if t.Location() != time.UTC {
+		return nil, errors.New("CalDAV datetime must be in UTC")
+	} else {
+		return &DateTime{name: name, t: t.Truncate(time.Second)}, nil
+	}
+}
+
+// encodes the datetime value for the iCalendar specification
+func (d *DateTime) MarshalXMLAttr(name xml.Name) (xml.Attr, error) {
+	layout := values.UTCDateTimeFormatString
+	value := d.t.Format(layout)
+	attr := xml.Attr{Name: name, Value: value}
+	return attr, nil
+}

vendor/github.com/dolanor/caldav-go/caldav/values/human_boolean.go

@@ -0,0 +1,8 @@
+package values
+
+type HumanBoolean string
+
+const (
+	YesHumanBoolean HumanBoolean = "yes"
+	NoHumanBoolean               = "no"
+)

vendor/github.com/dolanor/caldav-go/caldav/values/text_collation.go

@@ -0,0 +1,8 @@
+package values
+
+type TextCollation string
+
+const (
+	OctetTextCollation    TextCollation = "i;octet"
+	ASCIICaseMapCollation               = "i;ascii-casemap"
+)