tramp-blog/commands/shell/dollar.go

package shell

import (
	"bytes"
	"io"
	"log"
)

type DollarParameters struct {
	ignoreParams *IgnoreFirstCharParameters
	subparsers   []Parser
	lastCreated  *Dollar
}

func (p *DollarParameters) SubParsers() []Parser {
	if p.subparsers == nil {
		if p.ignoreParams == nil {
			p.ignoreParams = &IgnoreFirstCharParameters{}
		}

		p.subparsers = []Parser{
			&BaseParser{
				parameters: p.ignoreParams,
			},
			&BaseParser{
				parameters: &WordParameters{},
			},
			&BaseParser{
				parameters: &SubshellParameters{},
			},
			&BaseParser{
				parameters: &DollarBlockParameters{},
			},
		}
	}

	return p.subparsers
}

func (p *DollarParameters) Enter(_ *CharIterator) error {
	if p.ignoreParams != nil {
		p.ignoreParams.Reset()
	}

	return nil
}

func (p *DollarParameters) Supports(charsBefore []rune, r rune) bool {
	if r == '$' {
		return len(charsBefore) == 0 ||
			countBackslashSuffixes(charsBefore)%2 == 0
	}

	return false
}

func (p *DollarParameters) ShouldLeave(charsBefore []rune, r rune) bool {
	if p.lastCreated != nil {
		if len(p.lastCreated.Tokens()) > 0 {
			if _, isSub := p.lastCreated.Tokens()[0].(*Subshell); isSub {
				return true
			} else if _, isWord := p.lastCreated.Tokens()[0].(*Word); isWord {
				return true
			} else if _, isBlock := p.lastCreated.Tokens()[0].(*Block); isBlock {
				return true
			}

		}
	}

	if isWhitespace(r) || r == ';' || r == ')' {
		return true
	}

	return false
}

func (p *DollarParameters) Leave(i *CharIterator) error {
	return i.Previous()
}

func (p *DollarParameters) MakeToken() Token {
	dollar := &Dollar{}

	p.lastCreated = dollar

	return dollar
}

type Dollar struct {
	BaseToken
}

func (d *Dollar) Expand(state State, stdin io.Reader, stderr io.Writer) ([]string, uint8) {
	if len(d.tokens) > 1 {
		logstr := "Unexpected tokens after dollar sign: " + d.tokens[1].String()
		log.Println(logstr)
		stderr.Write([]byte(logstr))
		return []string{""}, 2
	}

	if word, ok := d.tokens[0].(*Word); ok {
		return []string{state.Variable(word.String())}, 0
	} else if block, ok := d.tokens[0].(*DollarBlock); ok && len(block.Tokens()) > 0 {

		if word, ok := block.Tokens()[0].(*Word); ok {
			return []string{state.Variable(word.String())}, 0
		} else {
			logstr := "Unexpected tokens after dollar sign: " + block.String()
			log.Println(logstr)
			stderr.Write([]byte(logstr))
			return []string{}, 2
		}
	} else if subshell, ok := d.Tokens()[0].(*Subshell); ok {
		stdout := bytes.NewBuffer([]byte{})
		ret := subshell.Evaluate(state, stdin, stdout, stderr)
		return []string{stdout.String()}, ret
	}
	logstr := "Unexpected tokens after dollar sign: " + d.String()
	log.Println(logstr)
	stderr.Write([]byte(logstr))
	return []string{""}, 2
}

type IgnoreFirstCharParameters struct {
	entered bool
}

func (p *IgnoreFirstCharParameters) Reset() {
	p.entered = false
}

func (p *IgnoreFirstCharParameters) Enter(_ *CharIterator) error {
	p.entered = true
	return nil
}

func (p *IgnoreFirstCharParameters) SubParsers() []Parser {
	return []Parser{
		&BaseParser{
			parameters: &CharParserParameters{},
		},
	}
}

func (p *IgnoreFirstCharParameters) MakeToken() Token {
	return nil
}

func (p *IgnoreFirstCharParameters) Supports(_ []rune, r rune) bool {
	if !p.entered {
		return true
	}

	return false
}

func (p *IgnoreFirstCharParameters) ShouldLeave(_ []rune, r rune) bool {
	return true
}