caldav: extend query filter types

The basic types related to queries and filtering are missing some
features specified in the RFC (as also noted in the TODO comments). This
adds several of the missing elements, working towards being able to
handle all RFC-compliant queries.

The work is not fully done, e.g. the collation for text-match is still
not handled, but it's getting pretty close.

caldav/caldav.go

@@ -28,18 +28,29 @@ type CalendarCompRequest struct {
 
 type CompFilter struct {
 	Name         string
+	IsNotDefined bool
 	Start, End   time.Time
 	Props        []PropFilter
 	Comps        []CompFilter
 }
 
+type ParamFilter struct {
+	Name         string
+	IsNotDefined bool
+	TextMatch    *TextMatch
+}
+
 type PropFilter struct {
 	Name         string
+	IsNotDefined bool
+	Start, End   time.Time
 	TextMatch    *TextMatch
+	ParamFilter  []ParamFilter
 }
 
 type TextMatch struct {
 	Text            string
+	NegateCondition bool
 }
 
 type CalendarQuery struct {

caldav/elements.go

@@ -22,6 +22,7 @@ var (
 	calendarMultigetName = xml.Name{namespace, "calendar-multiget"}
 
 	calendarName     = xml.Name{namespace, "calendar"}
+	calendarDataName = xml.Name{namespace, "calendar-data"}
 )
 
 // https://tools.ietf.org/html/rfc4791#section-6.2.1
@@ -103,14 +104,44 @@ type propFilter struct {
 	IsNotDefined *struct{}     `xml:"is-not-defined,omitempty"`
 	TimeRange    *timeRange    `xml:"time-range,omitempty"`
 	TextMatch    *textMatch    `xml:"text-match,omitempty"`
-	// TODO: param-filter
+	ParamFilter  []paramFilter `xml:"param-filter,omitempty"`
+}
+
+// https://tools.ietf.org/html/rfc4791#section-9.7.3
+type paramFilter struct {
+	XMLName      xml.Name   `xml:"urn:ietf:params:xml:ns:caldav param-filter"`
+	Name         string     `xml:"name,attr"`
+	IsNotDefined *struct{}  `xml:"is-not-defined,omitempty"`
+	TextMatch    *textMatch `xml:"text-match,omitempty"`
 }
 
 // https://tools.ietf.org/html/rfc4791#section-9.7.5
 type textMatch struct {
 	XMLName         xml.Name        `xml:"urn:ietf:params:xml:ns:caldav text-match"`
 	Text            string          `xml:",chardata"`
-	// TODO: collation, negate-condition
+	Collation       string          `xml:"collation,attr,omitempty"`
+	NegateCondition negateCondition `xml:"negate-condition,attr,omitempty"`
+}
+
+type negateCondition bool
+
+func (nc *negateCondition) UnmarshalText(b []byte) error {
+	switch s := string(b); s {
+	case "yes":
+		*nc = true
+	case "no":
+		*nc = false
+	default:
+		return fmt.Errorf("caldav: invalid negate-condition value: %q", s)
+	}
+	return nil
+}
+
+func (nc negateCondition) MarshalText() ([]byte, error) {
+	if nc {
+		return []byte("yes"), nil
+	}
+	return nil, nil
 }
 
 // https://tools.ietf.org/html/rfc4791#section-9.9

caldav/server.go

@@ -69,17 +69,53 @@ func (h *Handler) handleReport(w http.ResponseWriter, r *http.Request) error {
 	return internal.HTTPErrorf(http.StatusBadRequest, "caldav: expected calendar-query or calendar-multiget element in REPORT request")
 }
 
-func decodePropFilter(el *propFilter) (*PropFilter, error) {
-	pf := &PropFilter{Name: el.Name}
+func decodeParamFilter(el *paramFilter) (*ParamFilter, error) {
+	pf := &ParamFilter{Name: el.Name}
+	if el.IsNotDefined != nil {
+		if el.TextMatch != nil {
+			return nil, fmt.Errorf("caldav: failed to parse param-filter: if is-not-defined is provided, text-match can't be provided")
+		}
+		pf.IsNotDefined = true
+	}
 	if el.TextMatch != nil {
 		pf.TextMatch = &TextMatch{Text: el.TextMatch.Text}
 	}
-	// TODO: IsNotDefined, TimeRange
+	return pf, nil
+}
+
+func decodePropFilter(el *propFilter) (*PropFilter, error) {
+	pf := &PropFilter{Name: el.Name}
+	if el.IsNotDefined != nil {
+		if el.TextMatch != nil || el.TimeRange != nil || len(el.ParamFilter) > 0 {
+			return nil, fmt.Errorf("caldav: failed to parse prop-filter: if is-not-defined is provided, text-match, time-range, or param-filter can't be provided")
+		}
+		pf.IsNotDefined = true
+	}
+	if el.TextMatch != nil {
+		pf.TextMatch = &TextMatch{Text: el.TextMatch.Text}
+	}
+	if el.TimeRange != nil {
+		pf.Start = time.Time(el.TimeRange.Start)
+		pf.End = time.Time(el.TimeRange.End)
+	}
+	for _, paramEl := range el.ParamFilter {
+		paramFi, err := decodeParamFilter(&paramEl)
+		if err != nil {
+			return nil, err
+		}
+		pf.ParamFilter = append(pf.ParamFilter, *paramFi)
+	}
 	return pf, nil
 }
 
 func decodeCompFilter(el *compFilter) (*CompFilter, error) {
 	cf := &CompFilter{Name: el.Name}
+	if el.IsNotDefined != nil {
+		if el.TimeRange != nil || len(el.PropFilters) > 0 || len(el.CompFilters) > 0 {
+			return nil, fmt.Errorf("caldav: failed to parse comp-filter: if is-not-defined is provided, time-range, prop-filter, or comp-filter can't be provided")
+		}
+		cf.IsNotDefined = true
+	}
 	if el.TimeRange != nil {
 		cf.Start = time.Time(el.TimeRange.Start)
 		cf.End = time.Time(el.TimeRange.End)
@@ -98,7 +134,6 @@ func decodeCompFilter(el *compFilter) (*CompFilter, error) {
 		}
 		cf.Comps = append(cf.Comps, *child)
 	}
-	// TODO: IsNotDefined
 	return cf, nil
 }