Counter (#24)

* add counter for node.index

* rm extra comment

counter.go

@@ -0,0 +1,30 @@
+package gtree
+
+import (
+	"sync"
+)
+
+// for Node.index
+type counter struct {
+	n  uint
+	mu sync.Mutex
+}
+
+func newCounter() *counter {
+	return &counter{}
+}
+
+func (c *counter) next() uint {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	c.n += 1
+	return c.n
+}
+
+func (c *counter) reset() {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	c.n = 0
+}

node.go

@@ -68,7 +68,7 @@ func (n *Node) validate() error {
 	return nil
 }
 
-type generateFunc func(row string) *Node
+type generateFunc func(row string, idx uint) *Node
 
 type spaceType string
 
@@ -105,7 +105,7 @@ var (
 	nodeIdxMu sync.Mutex
 )
 
-func generateFuncTab(row string) *Node {
+func generateFuncTab(row string, idx uint) *Node {
 	var (
 		text      = ""
 		hierarchy = rootHierarchyNum
@@ -142,15 +142,10 @@ func generateFuncTab(row string) *Node {
 		hierarchy = 0
 	}
 
-	nodeIdxMu.Lock()
-	defer nodeIdxMu.Unlock()
-
-	nodeIdx++
-
-	return newNode(text, hierarchy, nodeIdx)
+	return newNode(text, hierarchy, idx)
 }
 
-func generateFuncTwoSpaces(row string) *Node {
+func generateFuncTwoSpaces(row string, idx uint) *Node {
 	var (
 		text      = ""
 		hierarchy = rootHierarchyNum
@@ -183,15 +178,10 @@ func generateFuncTwoSpaces(row string) *Node {
 		}
 	}
 
-	nodeIdxMu.Lock()
-	defer nodeIdxMu.Unlock()
-
-	nodeIdx++
-
-	return newNode(text, hierarchy, nodeIdx)
+	return newNode(text, hierarchy, idx)
 }
 
-func generateFuncFourSpaces(row string) *Node {
+func generateFuncFourSpaces(row string, idx uint) *Node {
 	var (
 		text      = ""
 		hierarchy = rootHierarchyNum
@@ -224,10 +214,5 @@ func generateFuncFourSpaces(row string) *Node {
 		}
 	}
 
-	nodeIdxMu.Lock()
-	defer nodeIdxMu.Unlock()
-
-	nodeIdx++
-
-	return newNode(text, hierarchy, nodeIdx)
+	return newNode(text, hierarchy, idx)
 }

programmable.go

@@ -3,7 +3,6 @@ package gtree
 
 import (
 	"io"
-	"sync"
 
 	"github.com/pkg/errors"
 )
@@ -30,24 +29,20 @@ func ExecuteProgrammably(w io.Writer, root *Node, optFns ...OptFn) error {
 		return err
 	}
 
+	idxCounter.reset()
+
 	tree := newTree(conf.encode, conf.formatLastNode, conf.formatIntermedialNode)
 	tree.addRoot(root)
 	return tree.grow().expand(w)
 }
 
 var (
-	programableNodeIdx   uint
-	programableNodeIdxMu sync.Mutex
+	idxCounter = newCounter()
 )
 
 // NewRoot creates a starting node for building tree.
 func NewRoot(text string) *Node {
-	programableNodeIdxMu.Lock()
-	defer programableNodeIdxMu.Unlock()
-
-	programableNodeIdx++
-
-	return newNode(text, rootHierarchyNum, programableNodeIdx)
+	return newNode(text, rootHierarchyNum, idxCounter.next())
 }
 
 // Add adds a node and returns an instance of it.
@@ -59,12 +54,7 @@ func (parent *Node) Add(text string) *Node {
 		}
 	}
 
-	programableNodeIdxMu.Lock()
-	defer programableNodeIdxMu.Unlock()
-
-	programableNodeIdx++
-
-	current := newNode(text, parent.hierarchy+1, programableNodeIdx)
+	current := newNode(text, parent.hierarchy+1, idxCounter.next())
 	current.setParent(parent)
 	parent.addChild(current)
 	return current

tree.go

@@ -63,19 +63,21 @@ func Execute(w io.Writer, r io.Reader, optFns ...OptFn) error {
 func sprout(scanner *bufio.Scanner, conf *config) (treeer, error) {
 	var (
 		stack            *stack
+		counter          = newCounter()
 		generateNodeFunc = decideGenerateFunc(conf.space)
 		tree             = newTree(conf.encode, conf.formatLastNode, conf.formatIntermedialNode)
 	)
 
 	for scanner.Scan() {
 		row := scanner.Text()
-		currentNode := generateNodeFunc(row)
+		currentNode := generateNodeFunc(row, counter.next())
 
 		if err := currentNode.validate(); err != nil {
 			return nil, err
 		}
 
 		if currentNode.isRoot() {
+			counter.reset()
 			tree.addRoot(currentNode)
 			stack = newStack()
 			stack.push(currentNode)