hugo pageparser 代码
文件路径：/parser/pageparser/pageparser.go
/ Copyright 2019 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 pageparser
import (
"bytes"
"errors"
"fmt"
"io"
"io/ioutil"
"github.com/gohugoio/hugo/parser/metadecoders"
)
/ Result holds the parse result.
type Result interface {
/ Iterator returns a new Iterator positioned at the beginning of the parse tree.
Iterator() *Iterator
/ Input returns the input to Parse.
Input() []byte
}
var _ Result = (*pageLexer)(nil)
/ Parse parses the page in the given reader according to the given Config.
func Parse(r io.Reader, cfg Config) (Result, error) {
return parseSection(r, cfg, lexIntroSection)
}
type ContentFrontMatter struct {
Content []byte
FrontMatter map[string]any
FrontMatterFormat metadecoders.Format
}
/ ParseFrontMatterAndContent is a convenience method to extract front matter
/ and content from a content page.
func ParseFrontMatterAndContent(r io.Reader) (ContentFrontMatter, error) {
var cf ContentFrontMatter
psr, err := Parse(r, Config{})
if err != nil {
return cf, err
}
var frontMatterSource []byte
iter := psr.Iterator()
walkFn := func(item Item) bool {
if frontMatterSource != nil {
/ The rest is content.
cf.Content = psr.Input()[item.low:]
/ Done
return false
} else if item.IsFrontMatter() {
cf.FrontMatterFormat = FormatFromFrontMatterType(item.Type)
frontMatterSource = item.Val(psr.Input())
}
return true
}
iter.PeekWalk(walkFn)
cf.FrontMatter, err = metadecoders.Default.UnmarshalToMap(frontMatterSource, cf.FrontMatterFormat)
return cf, err
}
func FormatFromFrontMatterType(typ ItemType) metadecoders.Format {
switch typ {
case TypeFrontMatterJSON:
return metadecoders.JSON
case TypeFrontMatterORG:
return metadecoders.ORG
case TypeFrontMatterTOML:
return metadecoders.TOML
case TypeFrontMatterYAML:
return metadecoders.YAML
default:
return ""
}
}
/ ParseMain parses starting with the main section. Used in tests.
func ParseMain(r io.Reader, cfg Config) (Result, error) {
return parseSection(r, cfg, lexMainSection)
}
func parseSection(r io.Reader, cfg Config, start stateFunc) (Result, error) {
b, err := ioutil.ReadAll(r)
if err != nil {
return nil, fmt.Errorf("failed to read page content: %w", err)
}
return parseBytes(b, cfg, start)
}
func parseBytes(b []byte, cfg Config, start stateFunc) (Result, error) {
lexer := newPageLexer(b, start, cfg)
lexer.run()
return lexer, nil
}
/ NewIterator creates a new Iterator.
func NewIterator(items Items) *Iterator {
return &Iterator{items: items, lastPos: -1}
}
/ An Iterator has methods to iterate a parsed page with support going back
/ if needed.
type Iterator struct {
items Items
lastPos int / position of the last item returned by nextItem
}
/ consumes and returns the next item
func (t *Iterator) Next() Item {
t.lastPos++
return t.Current()
}
var errIndexOutOfBounds = Item{Type: tError, Err: errors.New("no more tokens")}
/ Current will repeatably return the current item.
func (t *Iterator) Current() Item {
if t.lastPos >= len(t.items) {
return errIndexOutOfBounds
}
return t.items[t.lastPos]
}
/ backs up one token.
func (t *Iterator) Backup() {
if t.lastPos < 0 {
panic("need to go forward before going back")
}
t.lastPos--
}
/ Pos returns the current position in the input.
func (t *Iterator) Pos() int {
return t.lastPos
}
/ check for non-error and non-EOF types coming next
func (t *Iterator) IsValueNext() bool {
i := t.Peek()
return i.Type != tError && i.Type != tEOF
}
/ look at, but do not consume, the next item
/ repeated, sequential calls will return the same item
func (t *Iterator) Peek() Item {
return t.items[t.lastPos+1]
}
/ PeekWalk will feed the next items in the iterator to walkFn
/ until it returns false.
func (t *Iterator) PeekWalk(walkFn func(item Item) bool) {
for i := t.lastPos + 1; i < len(t.items); i++ {
item := t.items[i]
if !walkFn(item) {
break
}
}
}
/ Consume is a convenience method to consume the next n tokens,
/ but back off Errors and EOF.
func (t *Iterator) Consume(cnt int) {
for i := 0; i < cnt; i++ {
token := t.Next()
if token.Type == tError || token.Type == tEOF {
t.Backup()
break
}
}
}
/ LineNumber returns the current line number. Used for logging.
func (t *Iterator) LineNumber(source []byte) int {
return bytes.Count(source[:t.Current().low], lf) + 1
}
/ IsProbablySourceOfItems returns true if the given source looks like original
/ source of the items.
/ There may be some false positives, but that is highly unlikely and good enough
/ for the planned purpose.
/ It will also return false if the last item is not EOF (error situations) and
/ true if both source and items are empty.
func IsProbablySourceOfItems(source []byte, items Items) bool {
if len(source) == 0 && len(items) == 0 {
return false
}
if len(items) == 0 {
return false
}
last := items[len(items)-1]
if last.Type != tEOF {
return false
}
if last.Pos() != len(source) {
return false
}
for _, item := range items {
if item.Type == tError {
return false
}
if item.Type == tEOF {
return true
}
if item.Pos() >= len(source) {
return false
}
if item.firstByte != source[item.Pos()] {
return false
}
}
return true
}