add HookExitCb for OnExitCb

sysgo/UI/page_stack.go

@@ -0,0 +1,62 @@
+package UI
+
+import (
+	"sync"
+)
+
+type element struct {
+        data interface{}
+        next *element
+}
+
+type PageStack struct {
+	lock     *sync.Mutex
+	head     *element
+	Size     int
+}
+
+func (stk *PageStack) Push(data interface{}) {
+	stk.lock.Lock()
+
+	element := new(element)
+	element.data = data
+	temp := stk.head
+	element.next = temp
+	stk.head = element
+	stk.Size++
+
+	stk.lock.Unlock()
+}
+
+func (stk *PageStack) Pop() interface{} {
+	if stk.head == nil {
+		return nil
+	}
+	stk.lock.Lock()
+	r := stk.head.data
+	stk.head = stk.head.next
+	stk.Size--
+
+	stk.lock.Unlock()
+
+	return r
+}
+
+func (stk *PageStack) Length() int {
+	return stk.Size
+}
+
+func (stk *PageStack) Last() interface{} {
+	idx := stk.Length() - 1
+	if idx < 0 {
+		return nil
+	} else {
+		return stk.head.data
+	}
+}
+
+func NewPageStack() *PageStack {
+	stk := new(PageStack)
+	stk.lock = &sync.Mutex{}
+	return stk
+}