From 7800f11e5f0ccf9a735dc58475d2c318c9881e04 Mon Sep 17 00:00:00 2001
From: Tyler Yahn <codingalias@gmail.com>
Date: Mon, 24 Jul 2023 12:17:47 -0700
Subject: [PATCH] Remove duplicate code in Builder

---
 sdk/metric/internal/aggregate/aggregate.go | 45 ++++++++--------------
 1 file changed, 16 insertions(+), 29 deletions(-)

diff --git a/sdk/metric/internal/aggregate/aggregate.go b/sdk/metric/internal/aggregate/aggregate.go
index 4a44b3d4a9d..f2a63be5edb 100644
--- a/sdk/metric/internal/aggregate/aggregate.go
+++ b/sdk/metric/internal/aggregate/aggregate.go
@@ -89,51 +89,38 @@ func (b Builder[N]) LastValue() (Measure[N], ComputeAggregation) {
 // arguments passed to the input are expected to be the precomputed sum values.
 func (b Builder[N]) PrecomputedSum(monotonic bool) (Measure[N], ComputeAggregation) {
 	s := newPrecomputedSum[N]()
-
-	var setData func(dest *[]metricdata.DataPoint[N])
-	switch b.Temporality {
-	case metricdata.DeltaTemporality:
-		setData = s.delta
-	default:
-		setData = s.cumulative
-	}
-	return b.filter(s.measure), func(dest *metricdata.Aggregation) int {
-		// Ignore if dest is not a metricdata.Sum. The chance for memory
-		// reuse of the DataPoints is missed (better luck next time).
-		sData, _ := (*dest).(metricdata.Sum[N])
-		sData.Temporality = b.Temporality
-		sData.IsMonotonic = monotonic
-		setData(&sData.DataPoints)
-		*dest = sData
-
-		return len(sData.DataPoints)
-	}
+	f := b.dPtFunc(s.delta, s.cumulative)
+	return b.filter(s.measure), b.compSumFunc(monotonic, f)
 }
 
 // Sum returns a sum aggregate function input and output.
 func (b Builder[N]) Sum(monotonic bool) (Measure[N], ComputeAggregation) {
 	s := newSum[N]()
+	f := b.dPtFunc(s.delta, s.cumulative)
+	return b.filter(s.measure), b.compSumFunc(monotonic, f)
+}
 
-	var setData func(dest *[]metricdata.DataPoint[N])
-	switch b.Temporality {
-	case metricdata.DeltaTemporality:
-		setData = s.delta
-	default:
-		setData = s.cumulative
-	}
-	return b.filter(s.measure), func(dest *metricdata.Aggregation) int {
+func (b Builder[N]) compSumFunc(mono bool, f func(*[]metricdata.DataPoint[N])) ComputeAggregation {
+	return func(dest *metricdata.Aggregation) int {
 		// Ignore if dest is not a metricdata.Sum. The chance for memory
 		// reuse of the DataPoints is missed (better luck next time).
 		sData, _ := (*dest).(metricdata.Sum[N])
 		sData.Temporality = b.Temporality
-		sData.IsMonotonic = monotonic
-		setData(&sData.DataPoints)
+		sData.IsMonotonic = mono
+		f(&sData.DataPoints)
 		*dest = sData
 
 		return len(sData.DataPoints)
 	}
 }
 
+func (b Builder[N]) dPtFunc(delta, cumulative func(*[]metricdata.DataPoint[N])) func(*[]metricdata.DataPoint[N]) {
+	if b.Temporality == metricdata.DeltaTemporality {
+		return delta
+	}
+	return cumulative
+}
+
 // ExplicitBucketHistogram returns a histogram aggregate function input and
 // output.
 func (b Builder[N]) ExplicitBucketHistogram(cfg aggregation.ExplicitBucketHistogram, noSum bool) (Measure[N], ComputeAggregation) {