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package events
// Matcher matches events.
type Matcher interface {
Match(event Event) bool
}
// MatcherFunc implements matcher with just a function.
type MatcherFunc func(event Event) bool
// Match calls the wrapped function.
func (fn MatcherFunc) Match(event Event) bool {
return fn(event)
}
// Filter provides an event sink that sends only events that are accepted by a
// Matcher. No methods on filter are goroutine safe.
type Filter struct {
dst Sink
matcher Matcher
closed bool
}
// NewFilter returns a new filter that will send to events to dst that return
// true for Matcher.
func NewFilter(dst Sink, matcher Matcher) Sink {
return &Filter{dst: dst, matcher: matcher}
}
// Write an event to the filter.
func (f *Filter) Write(event Event) error {
if f.closed {
return ErrSinkClosed
}
if f.matcher.Match(event) {
return f.dst.Write(event)
}
return nil
}
// Close the filter and allow no more events to pass through.
func (f *Filter) Close() error {
// TODO(stevvooe): Not all sinks should have Close.
if f.closed {
return nil
}
f.closed = true
return f.dst.Close()
}
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