first version

internal/backlight/backlight.go

@@ -0,0 +1,71 @@
+package backlight
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"git.trj.tw/golang/utils"
+)
+
+type Backlight struct {
+	Directory string
+}
+
+const currentValueFile = "brightness"
+const maxValueFile = "max_brightness"
+
+func NewInstance(path string) (*Backlight, error) {
+	bl := &Backlight{Directory: path}
+
+	if !utils.CheckExists(path, true) {
+		return nil, fmt.Errorf("backlight class directory check fail")
+	}
+
+	// check brightness and max_brightness file exists
+	brightnessFile := filepath.Join(path, currentValueFile)
+	maxBrightnessFile := filepath.Join(path, maxValueFile)
+
+	if !utils.CheckExists(brightnessFile, false) {
+		return nil, fmt.Errorf("brightness file check fail")
+	}
+	if !utils.CheckExists(maxBrightnessFile, false) {
+		return nil, fmt.Errorf("max_brightness file check fail")
+	}
+
+	return bl, nil
+}
+
+func readBrightnessValue(file string) (val int, err error) {
+	cnt, err := os.ReadFile(file)
+	if err != nil {
+		return 0, err
+	}
+
+	val, err = strconv.Atoi(strings.TrimSpace(string(cnt)))
+	if err != nil {
+		return 0, err
+	}
+
+	return
+}
+
+func (b *Backlight) GetCurrent() (val int, err error) {
+	return readBrightnessValue(filepath.Join(b.Directory, currentValueFile))
+}
+
+func (b *Backlight) GetMax() (val int, err error) {
+	return readBrightnessValue(filepath.Join(b.Directory, maxValueFile))
+}
+
+func (b *Backlight) SetValue(val int) (err error) {
+	brightness := filepath.Join(b.Directory, "brightness")
+
+	if err := os.WriteFile(brightness, []byte(fmt.Sprintf("%d", val)), 0644); err != nil {
+		return err
+	}
+
+	return
+}