github.com/golazy/golazy@v0.0.7-0.20221012133820-968fe65a0b65/lazyview/nodes/attr.go (about)

     1  package nodes
     2  
     3  import (
     4  	"bytes"
     5  	"io"
     6  	"strings"
     7  )
     8  
     9  // Attr holds information about an attribute for an Element Node
    10  type Attr struct {
    11  	key  string
    12  	prop *string
    13  }
    14  
    15  // NewAttr creates a new attribute.
    16  // If several arguments are given, they are join by a space
    17  func NewAttr(key string, value ...string) Attr {
    18  	if len(value) == 0 {
    19  		return Attr{key: key}
    20  	}
    21  	a := strings.Join(value, " ")
    22  	return Attr{key: key, prop: &a}
    23  }
    24  
    25  // WriteTo writes the current string to the writer w
    26  func (a Attr) WriteTo(w io.Writer) (n int64, err error) {
    27  
    28  	//Otherwise, the quotation marks are really needed only if the attribute
    29  	//value contains a space, a line break, an Ascii quotation mark ("), an
    30  	//Ascii apostrophe ('), a grave accent (`), an equals sign (=), a less than
    31  	//sign (<), or a greater than sign (>)
    32  
    33  	n16, err := w.Write([]byte(a.key))
    34  	if err != nil || a.prop == nil {
    35  		return int64(n16), err
    36  	}
    37  	quote := ""
    38  
    39  	if len(*a.prop) == 0 || strings.ContainsAny(*a.prop, "\"'`=<> ") {
    40  		quote = `"`
    41  	}
    42  	n = int64(n16)
    43  
    44  	n16, err = w.Write([]byte("=" + quote))
    45  	n += int64(n16)
    46  	if err != nil {
    47  		return n, err
    48  	}
    49  
    50  	s := strings.ReplaceAll(*a.prop, "\"", "&quot;")
    51  	s = strings.ReplaceAll(s, "<", "&lt;")
    52  	s = strings.ReplaceAll(s, "\"", "&quot;")
    53  	s = strings.ReplaceAll(s, "&", "&amp;")
    54  
    55  	n16, err = w.Write([]byte(s))
    56  	n += int64(n16)
    57  	if err != nil {
    58  		return n, err
    59  	}
    60  
    61  	n16, err = w.Write([]byte(quote))
    62  	n += int64(n16)
    63  	return n, err
    64  }
    65  
    66  func (a Attr) String() string {
    67  	w := &bytes.Buffer{}
    68  	a.WriteTo(w)
    69  	return w.String()
    70  }