bbcode - processor.go

  package bbcode
  
  import (
  	"bytes"
  	"io"
  	"strings"
  
  	"vimagination.zapto.org/parser"
  )
  
  // Processor contains methods necessary for creating custom Handlers.
  type Processor struct {
  	w      io.Writer
  	err    error
  	p      parser.Parser
  	bbCode *BBCode
  }
  
  // Write writes to the underlying writer.
  // The error is stored and does not need to be handled.
  func (p *Processor) Write(b []byte) (int, error) {
  	if p.err != nil {
  		return 0, p.err
  	}
  
  	var n int
  
  	n, p.err = p.w.Write(b)
  
  	return n, p.err
  }
  
  // Process will continue processing the bbCode until it gets to an end tag
  // which matches the tag name given, or until it reaches the end of the input.
  // It returns true if the end tag was found, or false otherwise.
  func (p *Processor) Process(untilTag string) bool {
  	for {
  		switch t := p.Get().(type) {
  		case Text:
  			p.printText(t)
  		case OpenTag:
  			p.ProcessTag(t)
  		case CloseTag:
  			if strings.EqualFold(t.Name, untilTag) {
  				return true
  			}
  
  			p.printCloseTag(t)
  		default:
  			return false
  		}
  	}
  }
  
  // GetContents grabs the raw contents of a tag and returns it as a string.
  func (p *Processor) GetContents(untilTag string) string {
  	if p.err != nil {
  		return ""
  	}
  
  	w := p.w
  	b := bytes.NewBuffer(make([]byte, 0, 1024))
  	p.w = b
  	t := p.bbCode.text
  	p.bbCode.text = PlainText
  
  Loop:
  	for {
  		switch t := p.Get().(type) {
  		case Text:
  			p.printText(t)
  		case OpenTag:
  			p.printOpenTag(t)
  		case CloseTag:
  			if strings.EqualFold(t.Name, untilTag) {
  				break Loop
  			}
  
  			p.printCloseTag(t)
  		default:
  			break Loop
  		}
  	}
  
  	p.bbCode.text = t
  	p.w = w
  
  	return b.String()
  }
  
  // ProcessTag will process the given tag as normal.
  func (p *Processor) ProcessTag(t OpenTag) {
  	h := p.getTagHandler(t.Name)
  
  	if h == nil {
  		p.printOpenTag(t)
  	} else {
  		var attr string
  
  		if t.Attr != nil {
  			attr = *t.Attr
  		}
  
  		h.Handle(p, attr)
  	}
  }
  
  func (p *Processor) getTagHandler(name string) Handler {
  	for _, tag := range p.bbCode.tags {
  		if strings.EqualFold(tag.Name(), name) {
  			return tag
  		}
  	}
  
  	return nil
  }
  
  // Get returns the next token.
  // It will be either a Text, OpenTag or a CloseTag.
  func (p *Processor) Get() any {
  	phrase, _ := p.p.GetPhrase()
  
  	switch phrase.Type {
  	case phraseText:
  		text := make(Text, 0, len(phrase.Data))
  
  		for _, t := range phrase.Data {
  			text = append(text, t.Data)
  		}
  
  		return text
  	case phraseOpen:
  		tag := OpenTag{
  			Name: phrase.Data[0].Data,
  		}
  
  		if len(phrase.Data) > 1 {
  			tag.Attr = &phrase.Data[1].Data
  		}
  
  		return tag
  	case phraseClose:
  		return CloseTag{Name: phrase.Data[0].Data}
  	}
  
  	return nil
  }
  
  // Print writes the textual representation of the given token to the output,
  // using the text Handler.
  func (p *Processor) Print(t any) {
  	switch t := t.(type) {
  	case string:
  		p.bbCode.text.Handle(p, t)
  	case Text:
  		p.printText(t)
  	case OpenTag:
  		p.printOpenTag(t)
  	case CloseTag:
  		p.printCloseTag(t)
  	}
  }
  
  func (p *Processor) printText(t Text) {
  	for _, str := range t {
  		p.bbCode.text.Handle(p, str)
  	}
  }
  
  func (p *Processor) printOpenTag(t OpenTag) {
  	p.bbCode.text.Handle(p, p.bbCode.tks.openTag)
  	p.bbCode.text.Handle(p, t.Name)
  
  	if t.Attr != nil {
  		p.bbCode.text.Handle(p, p.bbCode.tks.attributeSep)
  		p.bbCode.text.Handle(p, *t.Attr)
  	}
  
  	p.bbCode.text.Handle(p, p.bbCode.tks.closeTag)
  }
  
  func (p *Processor) printCloseTag(t CloseTag) {
  	p.bbCode.text.Handle(p, p.bbCode.tks.openTag)
  	p.bbCode.text.Handle(p, p.bbCode.tks.closingTag)
  	p.bbCode.text.Handle(p, t.Name)
  	p.bbCode.text.Handle(p, p.bbCode.tks.closeTag)
  }
  
  // Text is a token containing simple textual data.
  type Text []string
  
  // OpenTag is a token containing the name of the tag and a possible attribute..
  type OpenTag struct {
  	Name string
  	Attr *string
  }
  
  // CloseTag is a token containing the name of the tag.
  type CloseTag struct {
  	Name string
  }