From 6fed9dd0dd62718f78eca11e30a71c2712636fbd Mon Sep 17 00:00:00 2001
From: Mikhail Osipov <mike.osipov@gmail.com>
Date: Wed, 16 Dec 2020 15:27:48 +0300
Subject: hook and socket args check fix, tests

---
 pkg/server/opts/opts.go | 149 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 146 insertions(+), 3 deletions(-)

(limited to 'pkg/server/opts')

diff --git a/pkg/server/opts/opts.go b/pkg/server/opts/opts.go
index 22383d8..c5729a3 100644
--- a/pkg/server/opts/opts.go
+++ b/pkg/server/opts/opts.go
@@ -1,6 +1,19 @@
 package opts
 
-import "strings"
+import (
+	"fmt"
+	"reflect"
+	"strconv"
+	"strings"
+)
+
+type fieldSpec struct {
+	name         string
+	inline       bool
+	required     bool
+	positive     bool
+	defaultValue string
+}
 
 type Opts map[string]string
 
@@ -20,7 +33,137 @@ func Parse(s string) (string, Opts) {
 	return v[0], m
 }
 
-func (m Opts) Bool(key string) bool {
-	_, ok := m[key]
+func (opts Opts) Bool(key string) bool {
+	_, ok := opts[key]
 	return ok
 }
+
+func (opts Opts) Configure(v interface{}) error {
+	rv := reflect.ValueOf(v)
+
+	switch {
+	case rv.Kind() != reflect.Ptr:
+		return fmt.Errorf("opts: configure failed: non-pointer %s", rv.Type().String())
+	case rv.IsNil():
+		return fmt.Errorf("opts: configure failed: nil %s", rv.Type().String())
+	case rv.Elem().Kind() != reflect.Struct:
+		return fmt.Errorf("opts: configure failed: non-struct %s", rv.Elem().Type().String())
+	}
+
+	return opts.configure(rv.Elem())
+}
+
+func getFieldSpec(field reflect.StructField) (fs fieldSpec) {
+	fs.name = strings.ToLower(field.Name)
+
+	for _, s := range strings.Split(field.Tag.Get("opts"), ",") {
+		switch {
+		case s == "inline":
+			fs.inline = true
+		case s == "required":
+			fs.required = true
+		case s == "positive":
+			fs.positive = true
+		case strings.HasPrefix(s, "default:"):
+			fs.defaultValue = s[8:]
+		}
+	}
+
+	return
+}
+
+func (opts Opts) setValue(v reflect.Value, fs fieldSpec) error {
+	s, ok := opts[fs.name]
+	kind := v.Kind()
+
+	if kind == reflect.Bool {
+		if s != "" {
+			return fmt.Errorf("%s: boolean option does not need a value", fs.name)
+		}
+
+		if ok {
+			v.SetBool(true)
+		}
+
+		return nil
+	}
+
+	if s == "" {
+		if fs.required {
+			return fmt.Errorf("%s: expect value", fs.name)
+		}
+
+		s = fs.defaultValue
+	}
+
+	if s == "" {
+		return nil
+	}
+
+	switch kind {
+	case reflect.String:
+		v.SetString(s)
+	case reflect.Int:
+		n, err := strconv.Atoi(s)
+		if err != nil {
+			return fmt.Errorf("%s: %w", fs.name, err)
+		}
+		if n <= 0 {
+			return fmt.Errorf("%s: expect positive", fs.name)
+		}
+		v.SetInt(int64(n))
+	default:
+		return fmt.Errorf("%s: unsupported type '%s'", fs.name, v.Type().String())
+	}
+
+	return nil
+}
+
+func (opts Opts) configure(v reflect.Value) error {
+	m := map[string]bool{}
+
+	for s := range opts {
+		m[s] = true
+	}
+
+	var visit func(v reflect.Value) error
+
+	visit = func(v reflect.Value) error {
+		t := v.Type()
+
+		for n := 0; n < v.NumField(); n++ {
+			fs := getFieldSpec(t.Field(n))
+			fv := v.Field(n)
+
+			if fs.inline {
+				if err := visit(fv); err != nil {
+					return err
+				}
+			} else if fv.CanSet() {
+				if err := opts.setValue(v.Field(n), fs); err != nil {
+					return err
+				}
+
+				delete(m, fs.name)
+			}
+		}
+
+		return nil
+	}
+
+	if err := visit(v); err != nil {
+		return err
+	}
+
+	if len(m) > 0 {
+		var ss []string
+
+		for s := range m {
+			ss = append(ss, s)
+		}
+
+		return fmt.Errorf("unknown options: %s", strings.Join(ss, ","))
+	}
+
+	return nil
+}
-- 
cgit v1.2.3-70-g09d2