gax_writers.go

package gax

import "unicode/utf8"

/*
Short for "non-escaping writer". Mostly for internal use. Similar to
`bytes.Buffer` or `strings.Builder`, but simpler and more flexible,
because it's just a typedef of `[]byte`.
*/
type NonEscWri []byte

// Implement `io.Writer`. Similar to `strings.Builder.Write`.
func (self *NonEscWri) Write(val []byte) (int, error) {
	*self = append(*self, val...)
	return len(val), nil
}

// Implement `io.StringWriter`. Similar to `strings.Builder.WriteString`.
func (self *NonEscWri) WriteString(val string) (int, error) {
	*self = append(*self, val...)
	return len(val), nil
}

// Similar to `strings.Builder.WriteRune`.
func (self *NonEscWri) WriteRune(val rune) (int, error) {
	if uint32(val) < utf8.RuneSelf {
		*self = append(*self, byte(val))
		return 1, nil
	}

	self.grow(utf8.UTFMax)

	len := len(*self)
	wid := utf8.EncodeRune((*self)[len:len+utf8.UTFMax], val)
	*self = (*self)[:len+wid]
	return wid, nil
}

// Similar to `strings.Builder.String`. Free cast with no allocation.
func (self NonEscWri) String() string { return bytesString(self) }

// TODO make public.
func (self *NonEscWri) grow(size int) { *self = grow(*self, size) }

/*
Short for "attribute writer". Mostly for internal use. Writes text as if it were
inside an HTML/XML attribute, without enclosing quotes, escaping as necessary.
For escaping rules, see:

	https://www.w3.org/TR/html52/syntax.html#escaping-a-string
*/
type AttrWri []byte

/*
Implement `io.Writer`. Similar to `strings.Builder.Write`, but escapes special
chars. Technically not compliant with `io.Writer`: the returned count of
written bytes may exceed the size of the provided chunk.
*/
func (self *AttrWri) Write(val []byte) (int, error) {
	return self.WriteString(bytesString(val))
}

// Implement `io.StringWriter`. Similar to `strings.Builder.WriteString`, but
// escapes special chars.
func (self *AttrWri) WriteString(val string) (size int, _ error) {
	for _, char := range val {
		delta, _ := self.WriteRune(char)
		size += delta
	}
	return
}

// Similar to `strings.Builder.WriteRune`, but escapes special chars.
func (self *AttrWri) WriteRune(val rune) (int, error) {
	wri := (*NonEscWri)(self)

	switch val {
	case '&':
		return wri.WriteString(`&amp;`)
	case '\u00a0':
		return wri.WriteString(`&nbsp;`)
	case '"':
		return wri.WriteString(`&quot;`)
	default:
		return wri.WriteRune(val)
	}
}

// Similar to `strings.Builder.String`. Free cast with no allocation.
func (self AttrWri) String() string { return bytesString(self) }

/*
Short for "text writer". Mostly for internal use. Writes text as if it were
inside an HTML/XML element, escaping as necessary. For escaping rules, see:

	https://www.w3.org/TR/html52/syntax.html#escaping-a-string
*/
type TextWri []byte

/*
Implement `io.Writer`. Similar to `strings.Builder.Write`, but escapes special
chars. Technically not compliant with `io.Writer`: the returned count of
written bytes may exceed the size of the provided chunk.
*/
func (self *TextWri) Write(val []byte) (int, error) {
	return self.WriteString(bytesString(val))
}

// Implement `io.StringWriter`. Similar to `strings.Builder.WriteString`, but
// escapes special chars.
func (self *TextWri) WriteString(val string) (size int, _ error) {
	for _, char := range val {
		delta, _ := self.WriteRune(char)
		size += delta
	}
	return
}

// Similar to `strings.Builder.WriteRune`, but escapes special chars.
func (self *TextWri) WriteRune(val rune) (int, error) {
	wri := (*NonEscWri)(self)

	switch val {
	case '&':
		return wri.WriteString(`&amp;`)
	case '\u00a0':
		return wri.WriteString(`&nbsp;`)
	case '<':
		return wri.WriteString(`&lt;`)
	case '>':
		return wri.WriteString(`&gt;`)
	default:
		return wri.WriteRune(val)
	}
}

// Similar to `strings.Builder.String`. Free cast with no allocation.
func (self TextWri) String() string { return bytesString(self) }