From 9b58219eb7354bf094273d82382d57cd08def293 Mon Sep 17 00:00:00 2001
From: Gabriele Cimato <gabriele.cimato@gmail.com>
Date: Tue, 8 Aug 2023 08:58:35 -0500
Subject: [PATCH] refactor: fix mem usage returns, update estimation functions

---
 array.go       | 16 ++++++++--------
 builtin_map.go |  2 +-
 object.go      |  4 ++--
 runtime.go     | 42 ++++++++++++++++++++++--------------------
 4 files changed, 33 insertions(+), 31 deletions(-)

diff --git a/array.go b/array.go
index cb35708b..0e7a2a55 100644
--- a/array.go
+++ b/array.go
@@ -562,8 +562,8 @@ var (
 // With this function we sample 10% of the array values,
 // determine their average mem usage and use that to estimate mem
 // usage of the whole array
-func (a *arrayObject) estimateMemUsage(ctx *MemUsageContext) (memUsage uint64, newMemUsage uint64, err error) {
-	var samplesVisited, runningEstimate, newRunningEstimate uint64
+func (a *arrayObject) estimateMemUsage(ctx *MemUsageContext) (estimate uint64, newEstimate uint64, err error) {
+	var samplesVisited, memUsage, newMemUsage uint64
 	sampleSize := len(a.values) / 10
 
 	// grabbing one sample every "sampleSize" to provide consistent
@@ -578,17 +578,17 @@ func (a *arrayObject) estimateMemUsage(ctx *MemUsageContext) (memUsage uint64, n
 		memUsage += inc
 		newMemUsage += newInc
 		// average * number of a.values
-		runningEstimate = uint64((float32(memUsage) / float32(samplesVisited)) * float32(len(a.values)))
-		newRunningEstimate = uint64((float32(newMemUsage) / float32(samplesVisited)) * float32(len(a.values)))
+		estimate = uint64((float32(memUsage) / float32(samplesVisited)) * float32(len(a.values)))
+		newEstimate = uint64((float32(newMemUsage) / float32(samplesVisited)) * float32(len(a.values)))
 		if err != nil {
-			return runningEstimate, newRunningEstimate, err
+			return estimate, newEstimate, err
 		}
-		if exceeded := ctx.MemUsageLimitExceeded(memUsage); exceeded {
-			return memUsage, newMemUsage, nil
+		if exceeded := ctx.MemUsageLimitExceeded(estimate); exceeded {
+			return estimate, newEstimate, nil
 		}
 	}
 
-	return runningEstimate, newRunningEstimate, nil
+	return estimate, newEstimate, nil
 }
 
 func (a *arrayObject) MemUsage(ctx *MemUsageContext) (memUsage uint64, newMemUsage uint64, err error) {
diff --git a/builtin_map.go b/builtin_map.go
index de148662..5d3cecd5 100644
--- a/builtin_map.go
+++ b/builtin_map.go
@@ -101,7 +101,7 @@ func (mo *mapObject) MemUsage(ctx *MemUsageContext) (memUsage uint64, newMemUsag
 	ctx.VisitObj(mo)
 
 	if err := ctx.Descend(); err != nil {
-		return 0, 0, err
+		return memUsage, newMemUsage, err
 	}
 
 	memUsage, newMemUsage, err = mo.baseObject.MemUsage(ctx)
diff --git a/object.go b/object.go
index f4004c29..4b172f13 100644
--- a/object.go
+++ b/object.go
@@ -1932,8 +1932,8 @@ func computeMemUsageEstimate(memUsage, samplesVisited uint64, totalProps int) ui
 // estimateMemUsage helps calculating mem usage for large objects.
 // It will sample the object and use those samples to estimate the
 // mem usage.
-func (o *baseObject) estimateMemUsage(ctx *MemUsageContext) (memUsage uint64, newMemUsage uint64, err error) {
-	var samplesVisited uint64
+func (o *baseObject) estimateMemUsage(ctx *MemUsageContext) (estimate uint64, newEstimate uint64, err error) {
+	var samplesVisited, memUsage, newMemUsage uint64
 	totalProps := len(o.propNames)
 	sampleSize := totalProps / 10
 
diff --git a/runtime.go b/runtime.go
index 48a2ef0d..d5ce876a 100644
--- a/runtime.go
+++ b/runtime.go
@@ -526,34 +526,36 @@ func (r *Runtime) MemUsage(ctx *MemUsageContext) (memUsage uint64, newMemUsage u
 		}
 	}
 
-	if r.vm != nil {
-		if r.vm.callStack != nil {
-			for idx := range r.vm.callStack {
-				inc, newInc, err := r.vm.callStack[idx].MemUsage(ctx)
-				memUsage += inc
-				newMemUsage += newInc
-				if err != nil {
-					return memUsage, newMemUsage, err
-				}
-			}
-		}
+	if r.vm == nil {
+		return memUsage, newMemUsage, nil
+	}
 
-		if r.vm.stash != nil {
-			inc, newInc, err := r.vm.stash.MemUsage(ctx)
+	if r.vm.callStack != nil {
+		for idx := range r.vm.callStack {
+			inc, newInc, err := r.vm.callStack[idx].MemUsage(ctx)
 			memUsage += inc
 			newMemUsage += newInc
 			if err != nil {
 				return memUsage, newMemUsage, err
 			}
 		}
+	}
 
-		if r.vm.stack != nil {
-			inc, newInc, err := r.vm.stack.MemUsage(ctx)
-			memUsage += inc
-			newMemUsage += newInc
-			if err != nil {
-				return memUsage, newMemUsage, err
-			}
+	if r.vm.stash != nil {
+		inc, newInc, err := r.vm.stash.MemUsage(ctx)
+		memUsage += inc
+		newMemUsage += newInc
+		if err != nil {
+			return memUsage, newMemUsage, err
+		}
+	}
+
+	if r.vm.stack != nil {
+		inc, newInc, err := r.vm.stack.MemUsage(ctx)
+		memUsage += inc
+		newMemUsage += newInc
+		if err != nil {
+			return memUsage, newMemUsage, err
 		}
 	}