1 files changed, 63 insertions, 0 deletions
diff --git a/common/natspec/natspec.go b/common/natspec/natspec.go
new file mode 100644
index 000000000..793bf59ae
--- /dev/null
+++ b/common/natspec/natspec.go
@@ -0,0 +1,63 @@
+package natspec
+
+import (
+	"fmt"
+	"github.com/obscuren/otto"
+)
+
+type NatSpec struct {
+	jsvm *otto.Otto
+}
+
+// TODO: should initialise with abi and userdoc jsons
+func New() (self *NatSpec, err error) {
+
+	self = new(NatSpec)
+	self.jsvm = otto.New()
+
+	_, err = self.jsvm.Run(natspecJS)
+	if err != nil {
+		return
+	}
+	_, err = self.jsvm.Run("var natspec = require('natspec');")
+	if err != nil {
+		return
+	}
+
+	return
+}
+
+func (self *NatSpec) Notice(transaction, abi, method, expression string) (string, error) {
+	var err error
+	if _, err = self.jsvm.Run("var transaction = " + transaction + ";"); err != nil {
+		return "", fmt.Errorf("natspec.js error setting transaction: %v", err)
+	}
+
+	if _, err = self.jsvm.Run("var abi = " + abi + ";"); err != nil {
+		return "", fmt.Errorf("natspec.js error setting abi: %v", err)
+	}
+
+	if _, err = self.jsvm.Run("var method = '" + method + "';"); err != nil {
+		return "", fmt.Errorf("natspec.js error setting method: %v", err)
+	}
+
+	if _, err = self.jsvm.Run("var expression = \"" + expression + "\";"); err != nil {
+		return "", fmt.Errorf("natspec.js error setting expression: %v", err)
+	}
+
+	self.jsvm.Run("var call = {method: method,abi: abi,transaction: transaction};")
+	value, err := self.jsvm.Run("natspec.evaluateExpression(expression, call);")
+	if err != nil {
+		return "", fmt.Errorf("natspec.js error evaluating expression: %v", err)
+	}
+	evalError := "Natspec evaluation failed, wrong input params"
+	if value.String() == evalError {
+		return "", fmt.Errorf("natspec.js error evaluating expression: wrong input params in expression '%s'", expression)
+	}
+	if len(value.String()) == 0 {
+		return "", fmt.Errorf("natspec.js error evaluating expression")
+	}
+
+	return value.String(), nil
+
+}