Addressed review comments

Signed-off-by: Kirtana Ashok <kiashok@microsoft.com>

database.go

@@ -17,7 +17,6 @@
 package platforms
 
 import (
-	"regexp"
 	"runtime"
 	"strings"
 )
@@ -60,35 +59,25 @@ func isKnownArch(arch string) bool {
 	return false
 }
 
-// normalizeOSVersion will only include the OSVersion if present.
-// The formart of OS on the platform specifier is <OS>[(<OSVersion>)]
+// normalizeOS will return OS and OSVersion.
+// The formart of OSAndVersion is <OS>[(<OSVersion>)]
 // OSVersion is optional only and is currently used only by windows OS.
 // If OsVersion is not specified, empty string is returned.
-func normalizeOSVersion(OSAndVersion string) string {
+func normalizeOS(OSAndVersion string) (os, osversion string) {
 	if OSAndVersion == "" {
-		return ""
+		os = runtime.GOOS
+		return
 	}
+	parts := strings.SplitAfter(OSAndVersion, "(")
 
-	parts := regexp.MustCompile("[()]").Split(OSAndVersion, -1)
-	if len(parts) > 1 {
-		if parts[1] != "" {
-			return parts[1]
-		}
-	}
-	return ""
-}
-
-func normalizeOS(OSAndVersion string) string {
-	if OSAndVersion == "" {
-		return runtime.GOOS
-	}
-	os := strings.Split(strings.ToLower(OSAndVersion), "(")[0]
-
-	switch os {
-	case "macos":
-		os = "darwin"
+	switch len(parts) {
+	case 2:
+		osversion = strings.ToLower(strings.TrimRight(parts[1], ")"))
+		fallthrough
+	case 1:
+		os = strings.ToLower(parts[0])
 	}
-	return os
+	return
 }
 
 // normalizeArch normalizes the architecture.

platforms.go

@@ -208,8 +208,7 @@ func Parse(specifier string) (specs.Platform, error) {
 		// we have very little information about the platform here, we are
 		// going to be a little more strict if we don't know about the argument
 		// value.
-		p.OS = normalizeOS(parts[0])
-		p.OSVersion = normalizeOSVersion(parts[0])
+		p.OS, p.OSVersion = normalizeOS(parts[0])
 		if isKnownOS(p.OS) {
 			// picks a default architecture
 			p.Architecture = runtime.GOARCH
@@ -233,8 +232,7 @@ func Parse(specifier string) (specs.Platform, error) {
 	case 2:
 		// In this case, we treat as a regular os[(osversion)]/arch pair. We don't care
 		// about whether or not we know of the platform.
-		p.OS = normalizeOS(parts[0])
-		p.OSVersion = normalizeOSVersion(parts[0])
+		p.OS, p.OSVersion = normalizeOS(parts[0])
 		p.Architecture, p.Variant = normalizeArch(parts[1], "")
 		if p.Architecture == "arm" && p.Variant == "v7" {
 			p.Variant = ""
@@ -243,8 +241,7 @@ func Parse(specifier string) (specs.Platform, error) {
 		return p, nil
 	case 3:
 		// we have a fully specified variant, this is rare
-		p.OS = normalizeOS(parts[0])
-		p.OSVersion = normalizeOSVersion(parts[0])
+		p.OS, p.OSVersion = normalizeOS(parts[0])
 		p.Architecture, p.Variant = normalizeArch(parts[1], parts[2])
 		if p.Architecture == "arm64" && p.Variant == "" {
 			p.Variant = "v8"
@@ -285,7 +282,7 @@ func Format(platform specs.Platform) string {
 // For example, if "Aarch64" is encountered, we change it to "arm64" or if
 // "x86_64" is encountered, it becomes "amd64".
 func Normalize(platform specs.Platform) specs.Platform {
-	platform.OS = normalizeOS(platform.OS)
+	platform.OS, platform.OSVersion = normalizeOS(platform.OS)
 	platform.Architecture, platform.Variant = normalizeArch(platform.Architecture, platform.Variant)
 
 	return platform