snapshot of https://github.com/cortezaproject/corteza.git (2024.9.x, 2026-09-18; blobs > 131072B omitted)

server/pkg/jsenv/vm.go

@@ -0,0 +1,111 @@
+package jsenv
+
+import (
+	"crypto/md5"
+	"encoding/hex"
+	"fmt"
+
+	"github.com/dop251/goja"
+)
+
+const (
+	// placeholder for functions in js env
+	exportFuncDescriptor = "_expFunc_"
+)
+
+type (
+	Vm struct {
+		g *goja.Runtime
+		t Transformer
+	}
+)
+
+func New(t Transformer) Vm {
+	return Vm{
+		g: goja.New(),
+		t: t,
+	}
+}
+
+// New creates a goja internal type
+func (ss Vm) New(i interface{}) goja.Value {
+	return ss.g.ToValue(i)
+}
+
+// Register the value in vm
+func (ss Vm) Register(key string, i interface{}) error {
+	return ss.g.Set(key, i)
+}
+
+// Fetch value from vm
+func (ss Vm) Fetch(key string) goja.Value {
+	return ss.g.Get(key)
+}
+
+// RegisterFunction registers the function to the vm and returns the
+// function that can be used in go
+func (ss Vm) RegisterFunction(s string, wrapperFn ...func() string) (f *Fn, err error) {
+	if len(wrapperFn) > 0 {
+		for _, wfn := range wrapperFn {
+			s = fmt.Sprintf(wfn(), s)
+		}
+	} else {
+		s = fmt.Sprintf("function (input) { %s }", s)
+	}
+
+	desc := ss.funcDescriptor(s)
+	run := fmt.Sprintf("var %s=%s;", desc, s)
+
+	err = ss.Eval(run)
+
+	if err != nil {
+		return
+	}
+
+	internalF := ss.Fetch(desc)
+
+	if internalF == nil {
+		err = fmt.Errorf("could not fetch registered value")
+		return
+	}
+
+	fnn, ok := goja.AssertFunction(internalF)
+
+	if !ok {
+		err = fmt.Errorf("could not assert function")
+		return
+	}
+
+	return &Fn{
+		f: fnn,
+	}, nil
+}
+
+// Eval transforms the input js to the specified
+// version and evals in vm
+func (ss Vm) Eval(p string) (err error) {
+	tr, err := ss.t.Transform(p)
+
+	if err != nil {
+		return
+	}
+
+	_, err = ss.g.RunString(string(tr))
+	return
+}
+
+// Compile is used only when parsing the
+// input evaluation without actually running it
+func (ss Vm) Compile(p string) (err error) {
+	_, err = goja.Parse("", p)
+	return
+}
+
+func (ss Vm) genID(s string) string {
+	h := md5.Sum([]byte(s))
+	return hex.EncodeToString(h[:])
+}
+
+func (ss Vm) funcDescriptor(s string) string {
+	return fmt.Sprintf("%s%s", exportFuncDescriptor, ss.genID(s))
+}