Internals cleanup (#9)

acmd.go

@@ -7,27 +7,19 @@ import (
 	"io"
 	"os"
 	"os/signal"
-	"regexp"
 	"sort"
 	"syscall"
 	"text/tabwriter"
 )
 
-var (
-	cmdNameRE = regexp.MustCompile("^[A-Za-z0-9-_]+$")
-
-	nopFunc = func(context.Context, []string) error { return nil }
-)
-
 // Runner of the sub-commands.
 type Runner struct {
 	cfg     Config
 	cmds    []Command
 	errInit error
 
-	ctx     context.Context
-	rootCmd Command
-	args    []string
+	ctx  context.Context
+	args []string
 }
 
 // Command specifies a sub-command for a program's command-line interface.
@@ -128,21 +120,20 @@ func (r *Runner) init() error {
 		r.cfg.Usage = defaultUsage(r.cfg.Output)
 	}
 
-	cmds := r.cmds
-	r.rootCmd = Command{
+	fakeRootCmd := Command{
 		Name:        "root",
-		Subcommands: cmds,
+		Subcommands: r.cmds,
 	}
-	if err := validateCommand(r.rootCmd); err != nil {
+	if err := validateCommand(fakeRootCmd); err != nil {
 		return err
 	}
 
-	cmds = append(cmds,
+	r.cmds = append(r.cmds,
 		Command{
 			Name:        "help",
 			Description: "shows help message",
 			Do: func(ctx context.Context, args []string) error {
-				r.cfg.Usage(r.cfg, cmds)
+				r.cfg.Usage(r.cfg, r.cmds)
 				return nil
 			},
 		},
@@ -156,13 +147,9 @@ func (r *Runner) init() error {
 		},
 	)
 
-	sort.Slice(cmds, func(i, j int) bool {
-		return cmds[i].Name < cmds[j].Name
+	sort.Slice(r.cmds, func(i, j int) bool {
+		return r.cmds[i].Name < r.cmds[j].Name
 	})
-
-	r.rootCmd.Subcommands = cmds
-	r.rootCmd.Do = rootDo(r.cfg, cmds)
-
 	return nil
 }
 
@@ -182,10 +169,10 @@ func validateCommand(cmd Command) error {
 	case cmd.Alias == "help" || cmd.Alias == "version":
 		return fmt.Errorf("command alias %q is reserved", cmd.Alias)
 
-	case !cmdNameRE.MatchString(cmd.Name):
+	case !isStringValid(cmd.Name):
 		return fmt.Errorf("command %q must contains only letters, digits, - and _", cmd.Name)
 
-	case cmd.Alias != "" && !cmdNameRE.MatchString(cmd.Alias):
+	case cmd.Alias != "" && !isStringValid(cmd.Alias):
 		return fmt.Errorf("command alias %q must contains only letters, digits, - and _", cmd.Alias)
 
 	case len(cmds) != 0:
@@ -222,44 +209,58 @@ func validateSubcommands(cmds []Command) error {
 	return nil
 }
 
+func isStringValid(s string) bool {
+	if len(s) == 0 {
+		return false
+	}
+	for _, c := range s {
+		if !(('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z') ||
+			('0' <= c && c <= '9') || c == '-' || c == '_') {
+			return false
+		}
+	}
+	return true
+}
+
 // Run commands.
 func (r *Runner) Run() error {
 	if r.errInit != nil {
 		return fmt.Errorf("cannot init runner: %w", r.errInit)
 	}
-	if err := r.rootCmd.Do(r.ctx, r.args); err != nil {
+	cmd, params, err := findCmd(r.cfg, r.cmds, r.args)
+	if err != nil {
+		return err
+	}
+	if err := cmd(r.ctx, params); err != nil {
 		return fmt.Errorf("cannot run command: %w", err)
 	}
 	return nil
 }
 
-func rootDo(cfg Config, cmds []Command) func(ctx context.Context, args []string) error {
-	return func(ctx context.Context, args []string) error {
-		cmds, args := cmds, args
-		for {
-			selected, params := args[0], args[1:]
+func findCmd(cfg Config, cmds []Command, args []string) (func(ctx context.Context, args []string) error, []string, error) {
+	for {
+		selected, params := args[0], args[1:]
 
-			var found bool
-			for _, c := range cmds {
-				if selected != c.Name && selected != c.Alias {
-					continue
-				}
+		var found bool
+		for _, c := range cmds {
+			if selected != c.Name && selected != c.Alias {
+				continue
+			}
 
-				// go deeper into subcommands
-				if c.Do == nil {
-					if len(params) == 0 {
-						return errors.New("no args for command provided")
-					}
-					cmds, args = c.Subcommands, params
-					found = true
-					break
+			// go deeper into subcommands
+			if c.Do == nil {
+				if len(params) == 0 {
+					return nil, nil, errors.New("no args for command provided")
 				}
-				return c.Do(ctx, params)
+				cmds, args = c.Subcommands, params
+				found = true
+				break
 			}
+			return c.Do, params, nil
+		}
 
-			if !found {
-				return errNotFoundAndSuggest(cfg.Output, cfg.AppName, selected, cmds)
-			}
+		if !found {
+			return nil, nil, errNotFoundAndSuggest(cfg.Output, cfg.AppName, selected, cmds)
 		}
 	}
 }

acmd_test.go

@@ -12,7 +12,10 @@ import (
 	"time"
 )
 
-var nopUsage = func(cfg Config, cmds []Command) {}
+var (
+	nopFunc  = func(context.Context, []string) error { return nil }
+	nopUsage = func(cfg Config, cmds []Command) {}
+)
 
 func TestRunner(t *testing.T) {
 	buf := &bytes.Buffer{}
@@ -67,8 +70,10 @@ func TestRunner(t *testing.T) {
 }
 
 func TestRunnerMustSetDefaults(t *testing.T) {
+	args := append([]string{"runner"}, os.Args[1:]...)
 	cmds := []Command{{Name: "foo", Do: nopFunc}}
 	r := RunnerOf(cmds, Config{
+		Args:   args,
 		Output: io.Discard,
 		Usage:  nopUsage,
 	})
@@ -77,7 +82,7 @@ func TestRunnerMustSetDefaults(t *testing.T) {
 	if err == nil {
 		t.Fatal()
 	}
-	if errStr := err.Error(); !strings.Contains(errStr, "cannot run command: no such command") {
+	if errStr := err.Error(); !strings.Contains(errStr, `no such command "runner"`) {
 		t.Fatal(err)
 	}
 
@@ -92,7 +97,7 @@ func TestRunnerMustSetDefaults(t *testing.T) {
 	}
 
 	gotCmds := map[string]struct{}{}
-	for _, c := range r.rootCmd.Subcommands {
+	for _, c := range r.cmds {
 		gotCmds[c.Name] = struct{}{}
 	}
 	if _, ok := gotCmds["help"]; !ok {