internal/lsp: make event directly implement TagMap

Makes Event implement TagMap directly, instead of
having to build an entirely new object.

Change-Id: I0c1e8638de3dc3347f60fd93af3df6b7f8387751
Reviewed-on: https://go-review.googlesource.com/c/tools/+/227300
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>

internal/lsp/debug/rpc.go

@@ -158,8 +158,7 @@ func (r *rpcs) getRPCSpan(ctx context.Context, ev event.Event) (*export.Span, *r
 	}
 	// use the span start event look up the correct stats block
 	// we do this because it prevents us matching a sub span
-	startMap := span.Start().Map()
-	return span, r.getRPCStats(startMap)
+	return span, r.getRPCStats(span.Start())
 }
 
 func (r *rpcs) getRPCStats(tagMap event.TagMap) *rpcStats {
@@ -201,7 +200,7 @@ func (h *rpcTimeHistogram) Mean() timeUnits { return h.Sum / timeUnits(h.Count)
 
 func getStatusCode(span *export.Span) string {
 	for _, ev := range span.Events() {
-		if status := tag.StatusCode.Get(ev.Map()); status != "" {
+		if status := tag.StatusCode.Get(ev); status != "" {
 			return status
 		}
 	}

internal/lsp/debug/serve.go

@@ -547,7 +547,7 @@ func makeGlobalExporter(stderr io.Writer) event.Exporter {
 
 		if ev.IsLog() {
 			// Don't log context cancellation errors.
-			if err := event.Err.Get(ev.Map()); xerrors.Is(err, context.Canceled) {
+			if err := event.Err.Get(ev); xerrors.Is(err, context.Canceled) {
 				return ctx
 			}
 			// Make sure any log messages without an instance go to stderr.

internal/telemetry/event/event.go

@@ -54,7 +54,7 @@ func (ev Event) IsDetach() bool    { return ev.typ == DetachType }
 func (ev Event) IsRecord() bool    { return ev.typ == RecordType }
 
 func (ev Event) Format(f fmt.State, r rune) {
-	tagMap := ev.Map()
+	tagMap := TagMap(ev)
 	if !ev.At.IsZero() {
 		fmt.Fprint(f, ev.At.Format("2006/01/02 15:04:05 "))
 	}
@@ -85,17 +85,13 @@ func (ev Event) Tags() TagIterator {
 		NewTagIterator(ev.dynamic...))
 }
 
-func (ev Event) Map() TagMap {
-	return &eventTagMap{event: ev}
-}
-
-func (m *eventTagMap) Find(key interface{}) Tag {
-	for _, tag := range m.event.static {
+func (ev Event) Find(key interface{}) Tag {
+	for _, tag := range ev.static {
 		if tag.Key == key {
 			return tag
 		}
 	}
-	for _, tag := range m.event.dynamic {
+	for _, tag := range ev.dynamic {
 		if tag.Key == key {
 			return tag
 		}

internal/telemetry/event/export.go

@@ -40,7 +40,7 @@ func deliver(ctx context.Context, exporter Exporter, ev Event) context.Context {
 	// add the current time to the event
 	ev.At = time.Now()
 	// hand the event off to the current exporter
-	return exporter(ctx, ev, ev.Map())
+	return exporter(ctx, ev, ev)
 }
 
 // dispatch is called to deliver an event to the global exporter if set.

internal/telemetry/export/ocagent/ocagent.go

@@ -299,7 +299,7 @@ func convertAnnotation(ev event.Event) *wire.Annotation {
 	if !tags.Valid() {
 		return nil
 	}
-	tagMap := ev.Map()
+	tagMap := event.TagMap(ev)
 	description := event.Msg.Get(tagMap)
 	tags = event.Filter(tags, event.Msg)
 	if description == "" {

internal/telemetry/export/tag.go

@@ -20,7 +20,7 @@ func Labels(output event.Exporter) event.Exporter {
 		stored, _ := ctx.Value(labelContextKey).(event.TagMap)
 		if ev.IsLabel() || ev.IsStartSpan() {
 			// update the tag source stored in the context
-			fromEvent := ev.Map()
+			fromEvent := event.TagMap(ev)
 			if stored == nil {
 				stored = fromEvent
 			} else {