events: support disjunctive filters

While different filters are applied in conjunction, the same filter (but
with different values) should be applied in disjunction.  This allows,
for instance, to query the events of two containers.

Fixes: #10507
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

libpod/events/filters.go

@@ -97,18 +97,41 @@ func parseFilter(filter string) (string, string, error) {
 	return filterSplit[0], filterSplit[1], nil
 }
 
-func generateEventOptions(filters []string, since, until string) ([]EventFilter, error) {
-	options := make([]EventFilter, 0, len(filters))
+// applyFilters applies the EventFilter slices in sequence.  Filters under the
+// same key are disjunctive while each key must match (conjuctive).
+func applyFilters(event *Event, filterMap map[string][]EventFilter) bool {
+	for _, filters := range filterMap {
+		success := false
+		for _, filter := range filters {
+			if filter(event) {
+				success = true
+				break
+			}
+		}
+		if !success {
+			return false
+		}
+	}
+	return true
+}
+
+// generateEventFilter parses the specified filters into a filter map that can
+// later on be used to filter events.  Keys are conjunctive, values are
+// disjunctive.
+func generateEventFilters(filters []string, since, until string) (map[string][]EventFilter, error) {
+	filterMap := make(map[string][]EventFilter)
 	for _, filter := range filters {
 		key, val, err := parseFilter(filter)
 		if err != nil {
 			return nil, err
 		}
-		funcFilter, err := generateEventFilter(key, val)
+		filterFunc, err := generateEventFilter(key, val)
 		if err != nil {
 			return nil, err
 		}
-		options = append(options, funcFilter)
+		filterSlice := filterMap[key]
+		filterSlice = append(filterSlice, filterFunc)
+		filterMap[key] = filterSlice
 	}
 
 	if len(since) > 0 {
@@ -116,7 +139,8 @@ func generateEventOptions(filters []string, since, until string) ([]EventFilter,
 		if err != nil {
 			return nil, errors.Wrapf(err, "unable to convert since time of %s", since)
 		}
-		options = append(options, generateEventSinceOption(timeSince))
+		filterFunc := generateEventSinceOption(timeSince)
+		filterMap["since"] = []EventFilter{filterFunc}
 	}
 
 	if len(until) > 0 {
@@ -124,7 +148,8 @@ func generateEventOptions(filters []string, since, until string) ([]EventFilter,
 		if err != nil {
 			return nil, errors.Wrapf(err, "unable to convert until time of %s", until)
 		}
-		options = append(options, generateEventUntilOption(timeUntil))
+		filterFunc := generateEventUntilOption(timeUntil)
+		filterMap["until"] = []EventFilter{filterFunc}
 	}
-	return options, nil
+	return filterMap, nil
 }