Create stubs for first few functions

util.go

@@ -0,0 +1,63 @@
+package adb
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"log"
+	"os/exec"
+)
+
+var adb string
+
+const killed = 130
+
+func init() {
+	path, err := exec.LookPath("adb")
+	if err != nil {
+		log.Printf("%v", ErrNotInstalled)
+		adb = ""
+		return
+	}
+	adb = path
+}
+
+func execute(ctx context.Context, args []string) (string, string, int, error) {
+	var (
+		err      error
+		stderr   bytes.Buffer
+		stdout   bytes.Buffer
+		code     int
+		output   string
+		warnings string
+	)
+
+	if adb == "" {
+		panic(ErrNotInstalled)
+	}
+	cmd := exec.CommandContext(ctx, adb, args...)
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+	err = cmd.Run()
+	output = stdout.String()
+	warnings = stderr.String()
+	code = cmd.ProcessState.ExitCode()
+
+	customErr := filterErr(warnings)
+	if customErr != nil {
+		err = customErr
+	}
+	if code != 0 && err == nil {
+		err = fmt.Errorf("received error code %d for stderr `%s`: %w", code, warnings, ErrUnspecified)
+	}
+
+	return output, warnings, code, err
+}
+
+// filterErr matches known output strings against the stderr.
+//
+// The inferred error type is then returned.
+// TODO: implement
+func filterErr(stderr string) error {
+	return nil
+}