Moved ethutil => common

1 files changed, 81 insertions, 0 deletions

diff --git a/common/list.go b/common/list.go
new file mode 100644
index 000000000..594a8a24b
--- /dev/null
+++ b/common/list.go
@@ -0,0 +1,81 @@
+package common
+
+import (
+	"encoding/json"
+	"reflect"
+	"sync"
+)
+
+// The list type is an anonymous slice handler which can be used
+// for containing any slice type to use in an environment which
+// does not support slice types (e.g., JavaScript, QML)
+type List struct {
+	mut    sync.Mutex
+	val    interface{}
+	list   reflect.Value
+	Length int
+}
+
+// Initialise a new list. Panics if non-slice type is given.
+func NewList(t interface{}) *List {
+	list := reflect.ValueOf(t)
+	if list.Kind() != reflect.Slice {
+		panic("list container initialized with a non-slice type")
+	}
+
+	return &List{sync.Mutex{}, t, list, list.Len()}
+}
+
+func EmptyList() *List {
+	return NewList([]interface{}{})
+}
+
+// Get N element from the embedded slice. Returns nil if OOB.
+func (self *List) Get(i int) interface{} {
+	if self.list.Len() > i {
+		self.mut.Lock()
+		defer self.mut.Unlock()
+
+		i := self.list.Index(i).Interface()
+
+		return i
+	}
+
+	return nil
+}
+
+func (self *List) GetAsJson(i int) interface{} {
+	e := self.Get(i)
+
+	r, _ := json.Marshal(e)
+
+	return string(r)
+}
+
+// Appends value at the end of the slice. Panics when incompatible value
+// is given.
+func (self *List) Append(v interface{}) {
+	self.mut.Lock()
+	defer self.mut.Unlock()
+
+	self.list = reflect.Append(self.list, reflect.ValueOf(v))
+	self.Length = self.list.Len()
+}
+
+// Returns the underlying slice as interface.
+func (self *List) Interface() interface{} {
+	return self.list.Interface()
+}
+
+// For JavaScript <3
+func (self *List) ToJSON() string {
+	// make(T, 0) != nil
+	list := make([]interface{}, 0)
+	for i := 0; i < self.Length; i++ {
+		list = append(list, self.Get(i))
+	}
+
+	data, _ := json.Marshal(list)
+
+	return string(data)
+}