[release/1.4.6] cmd, console: split off the console into a reusable package

(cherry picked from commit ffaf58f0a9)

internal/jsre/completion.go

@@ -0,0 +1,74 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package jsre
+
+import (
+	"sort"
+	"strings"
+
+	"github.com/robertkrimen/otto"
+)
+
+// CompleteKeywords returns potential continuations for the given line. Since line is
+// evaluated, callers need to make sure that evaluating line does not have side effects.
+func (jsre *JSRE) CompleteKeywords(line string) []string {
+	var results []string
+	jsre.Do(func(vm *otto.Otto) {
+		results = getCompletions(vm, line)
+	})
+	return results
+}
+
+func getCompletions(vm *otto.Otto, line string) (results []string) {
+	parts := strings.Split(line, ".")
+	objRef := "this"
+	prefix := line
+	if len(parts) > 1 {
+		objRef = strings.Join(parts[0:len(parts)-1], ".")
+		prefix = parts[len(parts)-1]
+	}
+
+	obj, _ := vm.Object(objRef)
+	if obj == nil {
+		return nil
+	}
+	iterOwnAndConstructorKeys(vm, obj, func(k string) {
+		if strings.HasPrefix(k, prefix) {
+			if objRef == "this" {
+				results = append(results, k)
+			} else {
+				results = append(results, strings.Join(parts[:len(parts)-1], ".")+"."+k)
+			}
+		}
+	})
+
+	// Append opening parenthesis (for functions) or dot (for objects)
+	// if the line itself is the only completion.
+	if len(results) == 1 && results[0] == line {
+		obj, _ := vm.Object(line)
+		if obj != nil {
+			if obj.Class() == "Function" {
+				results[0] += "("
+			} else {
+				results[0] += "."
+			}
+		}
+	}
+
+	sort.Strings(results)
+	return results
+}