From 9d10273f2781be62c56214a35c0539a1661723d5 Mon Sep 17 00:00:00 2001
From: Shai Nagar <sha1n@users.noreply.github.com>
Date: Sat, 12 Jun 2021 18:53:30 +0300
Subject: [PATCH] added build constraints to hide unix specific code from win
 builds (#107)

---
 pkg/cpu_timer_unix.go    | 43 +++++++++++++++++++++++++++++++++
 pkg/cpu_timer_windows.go | 25 +++++++++++++++++++
 pkg/trace.go             | 52 ++++++++++++++++++----------------------
 3 files changed, 91 insertions(+), 29 deletions(-)
 create mode 100644 pkg/cpu_timer_unix.go
 create mode 100644 pkg/cpu_timer_windows.go

diff --git a/pkg/cpu_timer_unix.go b/pkg/cpu_timer_unix.go
new file mode 100644
index 0000000..fb32b08
--- /dev/null
+++ b/pkg/cpu_timer_unix.go
@@ -0,0 +1,43 @@
+// +build linux darwin
+// +build amd64 arm64
+
+package pkg
+
+import (
+	"syscall"
+	"time"
+)
+
+type unixChildrenCPUTimer struct {
+	r            syscall.Rusage
+	sysTimeStart time.Time
+	usrTimeStart time.Time
+}
+
+func newChildrenCPUTimer() CPUTimer {
+	return &unixChildrenCPUTimer{}
+}
+
+func (t *unixChildrenCPUTimer) Start() func() (time.Duration, time.Duration) {
+	err := syscall.Getrusage(syscall.RUSAGE_CHILDREN, &t.r)
+	if err != nil {
+		panic(err)
+	}
+
+	t.sysTimeStart = time.Unix(t.r.Stime.Unix())
+	t.usrTimeStart = time.Unix(t.r.Utime.Unix())
+
+	return t.Elapsed
+}
+
+func (t *unixChildrenCPUTimer) Elapsed() (usr time.Duration, sys time.Duration) {
+	err := syscall.Getrusage(syscall.RUSAGE_CHILDREN, &t.r)
+	if err != nil {
+		panic(err)
+	}
+
+	sysTimeEnd := time.Unix(t.r.Stime.Unix())
+	usrTimeEnd := time.Unix(t.r.Utime.Unix())
+
+	return usrTimeEnd.Sub(t.usrTimeStart), sysTimeEnd.Sub(t.sysTimeStart)
+}
diff --git a/pkg/cpu_timer_windows.go b/pkg/cpu_timer_windows.go
new file mode 100644
index 0000000..5f67dad
--- /dev/null
+++ b/pkg/cpu_timer_windows.go
@@ -0,0 +1,25 @@
+// +build windows
+// +build amd64 arm
+
+package pkg
+
+import (
+	"time"
+)
+
+// NoopCPUTimer NOOP implementation of CPUTimer
+type NoopCPUTimer struct{}
+
+func newChildrenCPUTimer() CPUTimer {
+	return NoopCPUTimer{}
+}
+
+// Start ...
+func (t NoopCPUTimer) Start() func() (time.Duration, time.Duration) {
+	return t.Elapsed
+}
+
+// Elapsed return 0, 0
+func (t NoopCPUTimer) Elapsed() (usr time.Duration, sys time.Duration) {
+	return time.Nanosecond * 0, time.Nanosecond * 0
+}
diff --git a/pkg/trace.go b/pkg/trace.go
index 70de037..ba1a9df 100644
--- a/pkg/trace.go
+++ b/pkg/trace.go
@@ -1,7 +1,6 @@
 package pkg
 
 import (
-	"syscall"
 	"time"
 
 	"github.com/sha1n/benchy/api"
@@ -13,7 +12,7 @@ type tracer struct {
 
 type trace struct {
 	id            string
-	cpuTimer      *childrenCPUTimer
+	cpuTimer      CPUTimer
 	start         time.Time
 	perceivedTime time.Duration
 	usrTime       time.Duration
@@ -77,36 +76,31 @@ func (tr *tracer) Stream() chan api.Trace {
 	return tr.stream
 }
 
-type childrenCPUTimer struct {
-	r            syscall.Rusage
-	sysTimeStart time.Time
-	usrTimeStart time.Time
+// CPUTimer an abstraction for a platform system CPU timer
+type CPUTimer interface {
+	Start() func() (time.Duration, time.Duration)
+	Elapsed() (usr time.Duration, sys time.Duration)
 }
 
-func newChildrenCPUTimer() *childrenCPUTimer {
-	return &childrenCPUTimer{}
-}
+// func newChildrenCPUTimer() CPUTimer {
+// 	switch runtime.GOOS {
+// 	case "windows":
+// 		return NoopCPUTimer{}
+// 	default:
 
-func (t *childrenCPUTimer) Start() func() (time.Duration, time.Duration) {
-	err := syscall.Getrusage(syscall.RUSAGE_CHILDREN, &t.r)
-	if err != nil {
-		panic(err)
-	}
+// 		return newUnixChildrenCPUTimer()
+// 	}
+// }
 
-	t.sysTimeStart = time.Unix(t.r.Stime.Unix())
-	t.usrTimeStart = time.Unix(t.r.Utime.Unix())
+// // NoopCPUTimer NOOP implementation of CPUTimer
+// type NoopCPUTimer struct{}
 
-	return t.Elapsed
-}
+// // Start ...
+// func (t NoopCPUTimer) Start() func() (time.Duration, time.Duration) {
+// 	return t.Elapsed
+// }
 
-func (t *childrenCPUTimer) Elapsed() (usr time.Duration, sys time.Duration) {
-	err := syscall.Getrusage(syscall.RUSAGE_CHILDREN, &t.r)
-	if err != nil {
-		panic(err)
-	}
-
-	sysTimeEnd := time.Unix(t.r.Stime.Unix())
-	usrTimeEnd := time.Unix(t.r.Utime.Unix())
-
-	return usrTimeEnd.Sub(t.usrTimeStart), sysTimeEnd.Sub(t.sysTimeStart)
-}
+// // Elapsed return 0, 0
+// func (t NoopCPUTimer) Elapsed() (usr time.Duration, sys time.Duration) {
+// 	return time.Nanosecond * 0, time.Nanosecond * 0
+// }