rewrite in go

vendor/github.com/spf13/viper/util.go

@@ -0,0 +1,223 @@
+// Copyright © 2014 Steve Francia <spf@spf13.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+// Viper is a application configuration system.
+// It believes that applications can be configured a variety of ways
+// via flags, ENVIRONMENT variables, configuration files retrieved
+// from the file system, or a remote key/value store.
+
+package viper
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"unicode"
+
+	slog "github.com/sagikazarmark/slog-shim"
+	"github.com/spf13/cast"
+)
+
+// ConfigParseError denotes failing to parse configuration file.
+type ConfigParseError struct {
+	err error
+}
+
+// Error returns the formatted configuration error.
+func (pe ConfigParseError) Error() string {
+	return fmt.Sprintf("While parsing config: %s", pe.err.Error())
+}
+
+// Unwrap returns the wrapped error.
+func (pe ConfigParseError) Unwrap() error {
+	return pe.err
+}
+
+// toCaseInsensitiveValue checks if the value is a  map;
+// if so, create a copy and lower-case the keys recursively.
+func toCaseInsensitiveValue(value any) any {
+	switch v := value.(type) {
+	case map[any]any:
+		value = copyAndInsensitiviseMap(cast.ToStringMap(v))
+	case map[string]any:
+		value = copyAndInsensitiviseMap(v)
+	}
+
+	return value
+}
+
+// copyAndInsensitiviseMap behaves like insensitiviseMap, but creates a copy of
+// any map it makes case insensitive.
+func copyAndInsensitiviseMap(m map[string]any) map[string]any {
+	nm := make(map[string]any)
+
+	for key, val := range m {
+		lkey := strings.ToLower(key)
+		switch v := val.(type) {
+		case map[any]any:
+			nm[lkey] = copyAndInsensitiviseMap(cast.ToStringMap(v))
+		case map[string]any:
+			nm[lkey] = copyAndInsensitiviseMap(v)
+		default:
+			nm[lkey] = v
+		}
+	}
+
+	return nm
+}
+
+func insensitiviseVal(val any) any {
+	switch v := val.(type) {
+	case map[any]any:
+		// nested map: cast and recursively insensitivise
+		val = cast.ToStringMap(val)
+		insensitiviseMap(val.(map[string]any))
+	case map[string]any:
+		// nested map: recursively insensitivise
+		insensitiviseMap(v)
+	case []any:
+		// nested array: recursively insensitivise
+		insensitiveArray(v)
+	}
+	return val
+}
+
+func insensitiviseMap(m map[string]any) {
+	for key, val := range m {
+		val = insensitiviseVal(val)
+		lower := strings.ToLower(key)
+		if key != lower {
+			// remove old key (not lower-cased)
+			delete(m, key)
+		}
+		// update map
+		m[lower] = val
+	}
+}
+
+func insensitiveArray(a []any) {
+	for i, val := range a {
+		a[i] = insensitiviseVal(val)
+	}
+}
+
+func absPathify(logger *slog.Logger, inPath string) string {
+	logger.Info("trying to resolve absolute path", "path", inPath)
+
+	if inPath == "$HOME" || strings.HasPrefix(inPath, "$HOME"+string(os.PathSeparator)) {
+		inPath = userHomeDir() + inPath[5:]
+	}
+
+	inPath = os.ExpandEnv(inPath)
+
+	if filepath.IsAbs(inPath) {
+		return filepath.Clean(inPath)
+	}
+
+	p, err := filepath.Abs(inPath)
+	if err == nil {
+		return filepath.Clean(p)
+	}
+
+	logger.Error(fmt.Errorf("could not discover absolute path: %w", err).Error())
+
+	return ""
+}
+
+func stringInSlice(a string, list []string) bool {
+	for _, b := range list {
+		if b == a {
+			return true
+		}
+	}
+	return false
+}
+
+func userHomeDir() string {
+	if runtime.GOOS == "windows" {
+		home := os.Getenv("HOMEDRIVE") + os.Getenv("HOMEPATH")
+		if home == "" {
+			home = os.Getenv("USERPROFILE")
+		}
+		return home
+	}
+	return os.Getenv("HOME")
+}
+
+func safeMul(a, b uint) uint {
+	c := a * b
+	if a > 1 && b > 1 && c/b != a {
+		return 0
+	}
+	return c
+}
+
+// parseSizeInBytes converts strings like 1GB or 12 mb into an unsigned integer number of bytes
+func parseSizeInBytes(sizeStr string) uint {
+	sizeStr = strings.TrimSpace(sizeStr)
+	lastChar := len(sizeStr) - 1
+	multiplier := uint(1)
+
+	if lastChar > 0 {
+		if sizeStr[lastChar] == 'b' || sizeStr[lastChar] == 'B' {
+			if lastChar > 1 {
+				switch unicode.ToLower(rune(sizeStr[lastChar-1])) {
+				case 'k':
+					multiplier = 1 << 10
+					sizeStr = strings.TrimSpace(sizeStr[:lastChar-1])
+				case 'm':
+					multiplier = 1 << 20
+					sizeStr = strings.TrimSpace(sizeStr[:lastChar-1])
+				case 'g':
+					multiplier = 1 << 30
+					sizeStr = strings.TrimSpace(sizeStr[:lastChar-1])
+				default:
+					multiplier = 1
+					sizeStr = strings.TrimSpace(sizeStr[:lastChar])
+				}
+			}
+		}
+	}
+
+	size := cast.ToInt(sizeStr)
+	if size < 0 {
+		size = 0
+	}
+
+	return safeMul(uint(size), multiplier)
+}
+
+// deepSearch scans deep maps, following the key indexes listed in the
+// sequence "path".
+// The last value is expected to be another map, and is returned.
+//
+// In case intermediate keys do not exist, or map to a non-map value,
+// a new map is created and inserted, and the search continues from there:
+// the initial map "m" may be modified!
+func deepSearch(m map[string]any, path []string) map[string]any {
+	for _, k := range path {
+		m2, ok := m[k]
+		if !ok {
+			// intermediate key does not exist
+			// => create it and continue from there
+			m3 := make(map[string]any)
+			m[k] = m3
+			m = m3
+			continue
+		}
+		m3, ok := m2.(map[string]any)
+		if !ok {
+			// intermediate key is a value
+			// => replace with a new map
+			m3 = make(map[string]any)
+			m[k] = m3
+		}
+		// continue search from here
+		m = m3
+	}
+	return m
+}