1 files changed, 115 insertions, 0 deletions
diff --git a/jsre/jsre.go b/jsre/jsre.go
new file mode 100644
index 000000000..31ea955e6
--- /dev/null
+++ b/jsre/jsre.go
@@ -0,0 +1,115 @@
+package jsre
+
+import (
+	"fmt"
+	"github.com/obscuren/otto"
+	"io/ioutil"
+
+	"github.com/ethereum/go-ethereum/common"
+)
+
+/*
+JSRE is a generic JS runtime environment embedding the otto JS interpreter.
+It provides some helper functions to
+- load code from files
+- run code snippets
+- require libraries
+- bind native go objects
+*/
+type JSRE struct {
+	assetPath string
+	vm        *otto.Otto
+}
+
+func New(assetPath string) *JSRE {
+	re := &JSRE{
+		assetPath,
+		otto.New(),
+	}
+
+	// load prettyprint func definition
+	re.vm.Run(pp_js)
+	re.vm.Set("loadScript", re.loadScript)
+
+	return re
+}
+
+// Exec(file) loads and runs the contents of a file
+// if a relative path is given, the jsre's assetPath is used
+func (self *JSRE) Exec(file string) error {
+	return self.exec(common.AbsolutePath(self.assetPath, file))
+}
+
+func (self *JSRE) exec(path string) error {
+	code, err := ioutil.ReadFile(path)
+	if err != nil {
+		return err
+	}
+	_, err = self.vm.Run(code)
+	return err
+}
+
+func (self *JSRE) Bind(name string, v interface{}) (err error) {
+	self.vm.Set(name, v)
+	return
+}
+
+func (self *JSRE) Run(code string) (otto.Value, error) {
+	return self.vm.Run(code)
+}
+
+func (self *JSRE) Get(ns string) (otto.Value, error) {
+	return self.vm.Get(ns)
+}
+
+func (self *JSRE) Set(ns string, v interface{}) error {
+	return self.vm.Set(ns, v)
+}
+
+func (self *JSRE) loadScript(call otto.FunctionCall) otto.Value {
+	file, err := call.Argument(0).ToString()
+	if err != nil {
+		return otto.FalseValue()
+	}
+	if err := self.Exec(file); err != nil {
+		fmt.Println("err:", err)
+		return otto.FalseValue()
+	}
+
+	return otto.TrueValue()
+}
+
+func (self *JSRE) PrettyPrint(v interface{}) (val otto.Value, err error) {
+	var method otto.Value
+	v, err = self.vm.ToValue(v)
+	if err != nil {
+		return
+	}
+	method, err = self.vm.Get("prettyPrint")
+	if err != nil {
+		return
+	}
+	return method.Call(method, v)
+}
+
+func (self *JSRE) ToVal(v interface{}) otto.Value {
+	result, err := self.vm.ToValue(v)
+	if err != nil {
+		fmt.Println("Value unknown:", err)
+		return otto.UndefinedValue()
+	}
+	return result
+}
+
+func (self *JSRE) Eval(code string) (s string, err error) {
+	var val otto.Value
+	val, err = self.Run(code)
+	if err != nil {
+		return
+	}
+	val, err = self.PrettyPrint(val)
+	if err != nil {
+		return
+	}
+	return fmt.Sprintf("%v", val), nil
+}