wisski-cloud-distillery/internal/phpx/marshal.go
2023-11-15 09:51:35 +01:00

150 lines
3.5 KiB
Go

package phpx
import (
"encoding/json"
"math"
"strconv"
"strings"
"github.com/tkw1536/pkglib/collection"
)
// Marshal marshals data as a PHP expression, so that it can be safely used inside a php expession.
//
// Typically data is marshaled using [json.Marshal] and decoded in PHP using 'json_decode'.
// Special cases may exist for specific datatypes.
func Marshal(data any) (string, error) {
switch d := data.(type) {
case string:
return MarshalString(d), nil
}
bytes, err := json.Marshal(data)
if err != nil {
return "", err
}
return "json_decode(" + MarshalString(string(bytes)) + ")", nil
}
// MarshalJSON marshals a json-value safely as an expression to be used as a php string.
//
// A json value is one returned by calling [json.Unmarshal] on a value of type any.
// These are then marshaled by the appropriate function:
//
// - a nil is turned into [PHPNil]
// - a bool is passed to [MarshalBool]
// - a float64 is passed to [MarshalFloat]
// - a string is passed to [MarshalString]
// - an []any is passed to [MarshalSlice]
// - an map[string]any is passed to [MarshalMap]
//
// All marshaling attempts to minify the length of the returned string, meaning compact encodings
// are prefered over length ones.
//
// If a value is none of these types, an empty string is returned.
// No valid value ever returns the empty string
func MarshalJSON(v any) string {
switch v := v.(type) {
case nil:
return PHPNil
case bool:
return MarshalBool(v)
case float64:
return MarshalFloat(v)
case string:
return MarshalString(v)
case []any:
return MarshalSlice(v)
case map[string]any:
return MarshalMap(v)
}
return ""
}
const (
// PHPNil represents the equivalent of a nil value in php
PHPNil = "null"
phpTrue = "!0"
phpFalse = "!1"
phpNaN = "NAN"
phpPositiveInfinity = "INF"
phpNegativeInfinity = "-INF"
)
// MarshalBool marshals b as a boolean to be used in php code.
// This corresponds to the strings "true" or "false".
func MarshalBool(b bool) string {
if b {
return phpTrue
}
return phpFalse
}
// MarshalFloat marshals a floating point number or integer
func MarshalFloat(f float64) string {
// if we actually have an integer, return it!
if i := int64(f); f == float64(i) {
return MarshalInt(i)
}
// special cases
if math.IsNaN(f) {
return phpNaN
}
if math.IsInf(f, 1) {
return phpPositiveInfinity
}
if math.IsInf(f, -1) {
return phpNegativeInfinity
}
// all other cases
return strconv.FormatFloat(f, 'E', -1, 64)
}
// MarshalInt marshals an integer as a string to be used inside a php literal
func MarshalInt(i int64) string {
return strconv.FormatInt(i, 10)
}
var stringReplacer = strings.NewReplacer("'", "\\'", "\\", "\\\\")
// MarshalString marshals s as a php string that can be used safely as a PHP expression.
func MarshalString(s string) string {
// See [https://www.php.net/manual/en/language.types.string.php#language.types.string.syntax.single]
// we just escape
return "'" + stringReplacer.Replace(s) + "'"
}
func MarshalSlice(slice []any) string {
var builder strings.Builder
builder.WriteRune('[')
{
for _, v := range slice {
builder.WriteString(MarshalJSON(v))
builder.WriteRune(',')
}
}
builder.WriteRune(']')
return builder.String()
}
func MarshalMap(m map[string]any) string {
var builder strings.Builder
builder.WriteString("array(")
collection.IterateSorted(m, func(k string, v any) {
builder.WriteString(MarshalString(k))
builder.WriteString("=>")
builder.WriteString(MarshalJSON(v))
builder.WriteString(",")
})
builder.WriteString(")")
return builder.String()
}