e5d67c6e16
Remove/replace "github.com/pkg/errors" and "errors" with "fmt" or "corteza/server/pkg/errors" Closes #528
112 lines
1.9 KiB
Go
112 lines
1.9 KiB
Go
package jsenv
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import (
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"crypto/md5"
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"encoding/hex"
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"fmt"
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"github.com/dop251/goja"
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)
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const (
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// placeholder for functions in js env
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exportFuncDescriptor = "_expFunc_"
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)
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type (
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Vm struct {
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g *goja.Runtime
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t Transformer
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}
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)
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func New(t Transformer) Vm {
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return Vm{
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g: goja.New(),
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t: t,
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}
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}
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// New creates a goja internal type
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func (ss Vm) New(i interface{}) goja.Value {
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return ss.g.ToValue(i)
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}
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// Register the value in vm
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func (ss Vm) Register(key string, i interface{}) error {
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return ss.g.Set(key, i)
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}
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// Fetch value from vm
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func (ss Vm) Fetch(key string) goja.Value {
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return ss.g.Get(key)
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}
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// RegisterFunction registers the function to the vm and returns the
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// function that can be used in go
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func (ss Vm) RegisterFunction(s string, wrapperFn ...func() string) (f *Fn, err error) {
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if len(wrapperFn) > 0 {
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for _, wfn := range wrapperFn {
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s = fmt.Sprintf(wfn(), s)
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}
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} else {
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s = fmt.Sprintf("function (input) { %s }", s)
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}
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desc := ss.funcDescriptor(s)
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run := fmt.Sprintf("var %s=%s;", desc, s)
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err = ss.Eval(run)
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if err != nil {
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return
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}
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internalF := ss.Fetch(desc)
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if internalF == nil {
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err = fmt.Errorf("could not fetch registered value")
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return
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}
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fnn, ok := goja.AssertFunction(internalF)
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if !ok {
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err = fmt.Errorf("could not assert function")
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return
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}
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return &Fn{
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f: fnn,
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}, nil
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}
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// Eval transforms the input js to the specified
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// version and evals in vm
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func (ss Vm) Eval(p string) (err error) {
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tr, err := ss.t.Transform(p)
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if err != nil {
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return
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}
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_, err = ss.g.RunString(string(tr))
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return
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}
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// Compile is used only when parsing the
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// input evaluation without actually running it
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func (ss Vm) Compile(p string) (err error) {
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_, err = goja.Parse("", p)
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return
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}
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func (ss Vm) genID(s string) string {
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h := md5.Sum([]byte(s))
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return hex.EncodeToString(h[:])
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}
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func (ss Vm) funcDescriptor(s string) string {
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return fmt.Sprintf("%s%s", exportFuncDescriptor, ss.genID(s))
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}
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