1 files changed, 399 insertions, 0 deletions
diff --git a/common/paths/path.go b/common/paths/path.go
new file mode 100644
index 000000000..906270cae
--- /dev/null
+++ b/common/paths/path.go
@@ -0,0 +1,399 @@
+// Copyright 2021 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package paths
+
+import (
+	"errors"
+	"fmt"
+	"net/url"
+	"path"
+	"path/filepath"
+	"strings"
+	"unicode"
+)
+
+// FilePathSeparator as defined by os.Separator.
+const (
+	FilePathSeparator = string(filepath.Separator)
+	slash             = "/"
+)
+
+// filepathPathBridge is a bridge for common functionality in filepath vs path
+type filepathPathBridge interface {
+	Base(in string) string
+	Clean(in string) string
+	Dir(in string) string
+	Ext(in string) string
+	Join(elem ...string) string
+	Separator() string
+}
+
+type filepathBridge struct{}
+
+func (filepathBridge) Base(in string) string {
+	return filepath.Base(in)
+}
+
+func (filepathBridge) Clean(in string) string {
+	return filepath.Clean(in)
+}
+
+func (filepathBridge) Dir(in string) string {
+	return filepath.Dir(in)
+}
+
+func (filepathBridge) Ext(in string) string {
+	return filepath.Ext(in)
+}
+
+func (filepathBridge) Join(elem ...string) string {
+	return filepath.Join(elem...)
+}
+
+func (filepathBridge) Separator() string {
+	return FilePathSeparator
+}
+
+var fpb filepathBridge
+
+// AbsPathify creates an absolute path if given a working dir and a relative path.
+// If already absolute, the path is just cleaned.
+func AbsPathify(workingDir, inPath string) string {
+	if filepath.IsAbs(inPath) {
+		return filepath.Clean(inPath)
+	}
+	return filepath.Join(workingDir, inPath)
+}
+
+// AddTrailingSlash adds a trailing Unix styled slash (/) if not already
+// there.
+func AddTrailingSlash(path string) string {
+	if !strings.HasSuffix(path, "/") {
+		path += "/"
+	}
+	return path
+}
+
+// AddLeadingSlash adds a leading Unix styled slash (/) if not already
+// there.
+func AddLeadingSlash(path string) string {
+	if !strings.HasPrefix(path, "/") {
+		path = "/" + path
+	}
+	return path
+}
+
+// AddTrailingAndLeadingSlash adds a leading and trailing Unix styled slash (/) if not already
+// there.
+func AddLeadingAndTrailingSlash(path string) string {
+	return AddTrailingSlash(AddLeadingSlash(path))
+}
+
+// MakeTitle converts the path given to a suitable title, trimming whitespace
+// and replacing hyphens with whitespace.
+func MakeTitle(inpath string) string {
+	return strings.Replace(strings.TrimSpace(inpath), "-", " ", -1)
+}
+
+// ReplaceExtension takes a path and an extension, strips the old extension
+// and returns the path with the new extension.
+func ReplaceExtension(path string, newExt string) string {
+	f, _ := fileAndExt(path, fpb)
+	return f + "." + newExt
+}
+
+func makePathRelative(inPath string, possibleDirectories ...string) (string, error) {
+	for _, currentPath := range possibleDirectories {
+		if strings.HasPrefix(inPath, currentPath) {
+			return strings.TrimPrefix(inPath, currentPath), nil
+		}
+	}
+	return inPath, errors.New("can't extract relative path, unknown prefix")
+}
+
+// ExtNoDelimiter takes a path and returns the extension, excluding the delimiter, i.e. "md".
+func ExtNoDelimiter(in string) string {
+	return strings.TrimPrefix(Ext(in), ".")
+}
+
+// Ext takes a path and returns the extension, including the delimiter, i.e. ".md".
+func Ext(in string) string {
+	_, ext := fileAndExt(in, fpb)
+	return ext
+}
+
+// PathAndExt is the same as FileAndExt, but it uses the path package.
+func PathAndExt(in string) (string, string) {
+	return fileAndExt(in, pb)
+}
+
+// FileAndExt takes a path and returns the file and extension separated,
+// the extension including the delimiter, i.e. ".md".
+func FileAndExt(in string) (string, string) {
+	return fileAndExt(in, fpb)
+}
+
+// FileAndExtNoDelimiter takes a path and returns the file and extension separated,
+// the extension excluding the delimiter, e.g "md".
+func FileAndExtNoDelimiter(in string) (string, string) {
+	file, ext := fileAndExt(in, fpb)
+	return file, strings.TrimPrefix(ext, ".")
+}
+
+// Filename takes a file path, strips out the extension,
+// and returns the name of the file.
+func Filename(in string) (name string) {
+	name, _ = fileAndExt(in, fpb)
+	return
+}
+
+// FileAndExt returns the filename and any extension of a file path as
+// two separate strings.
+//
+// If the path, in, contains a directory name ending in a slash,
+// then both name and ext will be empty strings.
+//
+// If the path, in, is either the current directory, the parent
+// directory or the root directory, or an empty string,
+// then both name and ext will be empty strings.
+//
+// If the path, in, represents the path of a file without an extension,
+// then name will be the name of the file and ext will be an empty string.
+//
+// If the path, in, represents a filename with an extension,
+// then name will be the filename minus any extension - including the dot
+// and ext will contain the extension - minus the dot.
+func fileAndExt(in string, b filepathPathBridge) (name string, ext string) {
+	ext = b.Ext(in)
+	base := b.Base(in)
+
+	return extractFilename(in, ext, base, b.Separator()), ext
+}
+
+func extractFilename(in, ext, base, pathSeparator string) (name string) {
+	// No file name cases. These are defined as:
+	// 1. any "in" path that ends in a pathSeparator
+	// 2. any "base" consisting of just an pathSeparator
+	// 3. any "base" consisting of just an empty string
+	// 4. any "base" consisting of just the current directory i.e. "."
+	// 5. any "base" consisting of just the parent directory i.e. ".."
+	if (strings.LastIndex(in, pathSeparator) == len(in)-1) || base == "" || base == "." || base == ".." || base == pathSeparator {
+		name = "" // there is NO filename
+	} else if ext != "" { // there was an Extension
+		// return the filename minus the extension (and the ".")
+		name = base[:strings.LastIndex(base, ".")]
+	} else {
+		// no extension case so just return base, which will
+		// be the filename
+		name = base
+	}
+	return
+}
+
+// GetRelativePath returns the relative path of a given path.
+func GetRelativePath(path, base string) (final string, err error) {
+	if filepath.IsAbs(path) && base == "" {
+		return "", errors.New("source: missing base directory")
+	}
+	name := filepath.Clean(path)
+	base = filepath.Clean(base)
+
+	name, err = filepath.Rel(base, name)
+	if err != nil {
+		return "", err
+	}
+
+	if strings.HasSuffix(filepath.FromSlash(path), FilePathSeparator) && !strings.HasSuffix(name, FilePathSeparator) {
+		name += FilePathSeparator
+	}
+	return name, nil
+}
+
+func prettifyPath(in string, b filepathPathBridge) string {
+	if filepath.Ext(in) == "" {
+		// /section/name/  -> /section/name/index.html
+		if len(in) < 2 {
+			return b.Separator()
+		}
+		return b.Join(in, "index.html")
+	}
+	name, ext := fileAndExt(in, b)
+	if name == "index" {
+		// /section/name/index.html -> /section/name/index.html
+		return b.Clean(in)
+	}
+	// /section/name.html -> /section/name/index.html
+	return b.Join(b.Dir(in), name, "index"+ext)
+}
+
+// CommonDir returns the common directory of the given paths.
+func CommonDir(path1, path2 string) string {
+	if path1 == "" || path2 == "" {
+		return ""
+	}
+
+	p1 := strings.Split(path1, "/")
+	p2 := strings.Split(path2, "/")
+
+	var common []string
+
+	for i := 0; i < len(p1) && i < len(p2); i++ {
+		if p1[i] == p2[i] {
+			common = append(common, p1[i])
+		} else {
+			break
+		}
+	}
+
+	return strings.Join(common, "/")
+}
+
+// Sanitize sanitizes string to be used in Hugo's file paths and URLs, allowing only
+// a predefined set of special Unicode characters.
+//
+// Spaces will be replaced with a single hyphen.
+//
+// This function is the core function used to normalize paths in Hugo.
+//
+// Note that this is the first common step for URL/path sanitation,
+// the final URL/path may end up looking differently  if the user has stricter rules defined (e.g. removePathAccents=true).
+func Sanitize(s string) string {
+	var willChange bool
+	for i, r := range s {
+		willChange = !isAllowedPathCharacter(s, i, r)
+		if willChange {
+			break
+		}
+	}
+
+	if !willChange {
+		// Prevent allocation when nothing changes.
+		return s
+	}
+
+	target := make([]rune, 0, len(s))
+	var (
+		prependHyphen bool
+		wasHyphen     bool
+	)
+
+	for i, r := range s {
+		isAllowed := isAllowedPathCharacter(s, i, r)
+
+		if isAllowed {
+			// track explicit hyphen in input; no need to add a new hyphen if
+			// we just saw one.
+			wasHyphen = r == '-'
+
+			if prependHyphen {
+				// if currently have a hyphen, don't prepend an extra one
+				if !wasHyphen {
+					target = append(target, '-')
+				}
+				prependHyphen = false
+			}
+			target = append(target, r)
+		} else if len(target) > 0 && !wasHyphen && unicode.IsSpace(r) {
+			prependHyphen = true
+		}
+	}
+
+	return string(target)
+}
+
+func isAllowedPathCharacter(s string, i int, r rune) bool {
+	if r == ' ' {
+		return false
+	}
+	// Check for the most likely first (faster).
+	isAllowed := unicode.IsLetter(r) || unicode.IsDigit(r)
+	isAllowed = isAllowed || r == '.' || r == '/' || r == '\\' || r == '_' || r == '#' || r == '+' || r == '~' || r == '-' || r == '@'
+	isAllowed = isAllowed || unicode.IsMark(r)
+	isAllowed = isAllowed || (r == '%' && i+2 < len(s) && ishex(s[i+1]) && ishex(s[i+2]))
+	return isAllowed
+}
+
+// From https://golang.org/src/net/url/url.go
+func ishex(c byte) bool {
+	switch {
+	case '0' <= c && c <= '9':
+		return true
+	case 'a' <= c && c <= 'f':
+		return true
+	case 'A' <= c && c <= 'F':
+		return true
+	}
+	return false
+}
+
+var slashFunc = func(r rune) bool {
+	return r == '/'
+}
+
+// Dir behaves like path.Dir without the path.Clean step.
+//
+//	The returned path ends in a slash only if it is the root "/".
+func Dir(s string) string {
+	dir, _ := path.Split(s)
+	if len(dir) > 1 && dir[len(dir)-1] == '/' {
+		return dir[:len(dir)-1]
+	}
+	return dir
+}
+
+// FieldsSlash cuts s into fields separated with '/'.
+func FieldsSlash(s string) []string {
+	f := strings.FieldsFunc(s, slashFunc)
+	return f
+}
+
+// DirFile holds the result from path.Split.
+type DirFile struct {
+	Dir  string
+	File string
+}
+
+// Used in test.
+func (df DirFile) String() string {
+	return fmt.Sprintf("%s|%s", df.Dir, df.File)
+}
+
+// PathEscape escapes unicode letters in pth.
+// Use URLEscape to escape full URLs including scheme, query etc.
+// This is slightly faster for the common case.
+// Note, there is a url.PathEscape function, but that also
+// escapes /.
+func PathEscape(pth string) string {
+	u, err := url.Parse(pth)
+	if err != nil {
+		panic(err)
+	}
+	return u.EscapedPath()
+}
+
+// ToSlashTrimLeading is just a filepath.ToSlash with an added / prefix trimmer.
+func ToSlashTrimLeading(s string) string {
+	return strings.TrimPrefix(filepath.ToSlash(s), "/")
+}
+
+// ToSlashTrimTrailing is just a filepath.ToSlash with an added / suffix trimmer.
+func ToSlashTrimTrailing(s string) string {
+	return strings.TrimSuffix(filepath.ToSlash(s), "/")
+}
+
+// ToSlashPreserveLeading converts the path given to a forward slash separated path
+// and preserves the leading slash if present trimming any trailing slash.
+func ToSlashPreserveLeading(s string) string {
+	return "/" + strings.Trim(filepath.ToSlash(s), "/")
+}