Refactor screensaver package into display and lockscreen

display/display.go

@@ -0,0 +1,45 @@
+package display
+
+import (
+	"os/exec"
+	"regexp"
+	"strings"
+)
+
+
+// Suspend the display using xset
+func Suspend() error {
+	cmd := exec.Command("xset",
+		"dpms",
+		"force",
+		"suspend",
+	)
+	return cmd.Run()
+}
+
+// IsOn determines if the display is on
+func IsOn() (bool, error) {
+	cmd := exec.Command("xset", "q")
+	outputBytes, err := cmd.CombinedOutput()
+	if err != nil {
+		return false, err
+	}
+	return determineIfDisplayIsOn(string(outputBytes)), nil
+}
+
+func determineIfDisplayIsOn(xsetOutput string) bool {
+	if ! strings.Contains(xsetOutput, "Monitor") {
+		// after booting xset q is missing this line
+		// lacking better ideas assume display is on
+		return true
+	}
+
+	re := regexp.MustCompile(`Monitor is (\w+)`)
+	matches := re.FindStringSubmatch(xsetOutput)
+	if len(matches) >= 2 {
+		if matches[1] == "On" {
+			return true
+		}
+	}
+	return false
+}