Merge branch 'algorithm-optimization'

README.md

@@ -40,7 +40,7 @@ $ go get -u github.com/mauricioklein/go-spacetree/spacetree
 
   // Generate the tree
   // Returns a *spacetree.Node, holding the tree's root node
-  root := spacetree.New(scanner, indentationSymbol)
+  root, err := spacetree.New(scanner, indentationSymbol)
 ```
 
 Runnable examples can be found [here](examples/).

examples/main.go

@@ -20,7 +20,7 @@ func main() {
 	scanner := bufio.NewScanner(file)
 	indentationSymbol := "  " // File is indented by two consecutive spaces
 
-	root := spacetree.New(scanner, indentationSymbol)
+	root, err := spacetree.New(scanner, indentationSymbol)
 
-	fmt.Printf("Root: %+v\n", root)
+	fmt.Printf("Root: %+v (error: %+v)\n", root, err)
 }

go.mod

@@ -1,6 +1,3 @@
 module github.com/mauricioklein/go-spacetree
 
-require (
-	github.com/golang-collections/collections v0.0.0-20130729185459-604e922904d3
-	github.com/stretchr/testify v1.3.0
-)
+require github.com/stretchr/testify v1.3.0

go.sum

@@ -1,7 +1,5 @@
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/golang-collections/collections v0.0.0-20130729185459-604e922904d3 h1:zN2lZNZRflqFyxVaTIU61KNKQ9C0055u9CAfpmqUvo4=
-github.com/golang-collections/collections v0.0.0-20130729185459-604e922904d3/go.mod h1:nPpo7qLxd6XL3hWJG/O60sR8ZKfMCiIoNap5GvD12KU=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=

spacetree/doc.go

@@ -31,7 +31,9 @@ Spacetree expects two attributes as input:
   - the content buffer (*bufio.Scanner), holding the indented content
   - the indentation symbol (string)
 
-The result is a *spacetree.Node representing the root of the tree.
+The result is:
+  - a *spacetree.Node, representing the root of the tree
+  - an error, set in case of a processing error (broken indentation, for example)
 
 Example:
 
@@ -40,6 +42,6 @@ Example:
 	scanner := [your *bufio.Scanner containing the indented content]
 	indentationSymbol := " " // single space
 
-	root := spacetree.New(scanner, indentationSymbol)
+	root, err := spacetree.New(scanner, indentationSymbol)
 */
 package spacetree

spacetree/line_test.go

@@ -16,10 +16,11 @@ func Test_toLines_OneLevelWithSpaces(t *testing.T) {
 
 	lines := toLines(scanner, indentationSymbol)
 
-	assert.Equal(t, len(lines), 3)
-	assert.Equal(t, lines[0], line{Value: "1", Level: 0})
-	assert.Equal(t, lines[1], line{Value: "2", Level: 0})
-	assert.Equal(t, lines[2], line{Value: "3", Level: 0})
+	assert.Equal(t, lines, []line{
+		{Value: "1", Level: 0},
+		{Value: "2", Level: 0},
+		{Value: "3", Level: 0},
+	})
 }
 
 func Test_toLines_TwoLevelsWithSpaces(t *testing.T) {
@@ -30,7 +31,6 @@ func Test_toLines_TwoLevelsWithSpaces(t *testing.T) {
 
 	lines := toLines(scanner, indentationSymbol)
 
-	assert.Equal(t, len(lines), 6)
 	assert.Equal(t, lines, []line{
 		{Value: "1", Level: 0},
 		{Value: "1.1", Level: 1},
@@ -49,7 +49,6 @@ func Test_toLines_MultipleLevelsWithSpaces(t *testing.T) {
 
 	lines := toLines(scanner, indentationSymbol)
 
-	assert.Equal(t, len(lines), 8)
 	assert.Equal(t, lines, []line{
 		{Value: "1", Level: 0},
 		{Value: "1.1", Level: 1},
@@ -70,7 +69,6 @@ func Test_toLines_MultipleLevelsWithTabs(t *testing.T) {
 
 	lines := toLines(scanner, indentationSymbol)
 
-	assert.Equal(t, len(lines), 8)
 	assert.Equal(t, lines, []line{
 		{Value: "1", Level: 0},
 		{Value: "1.1", Level: 1},
@@ -91,7 +89,6 @@ func Test_toLines_MultipleLevelsWithDashes(t *testing.T) {
 
 	lines := toLines(scanner, indentationSymbol)
 
-	assert.Equal(t, len(lines), 8)
 	assert.Equal(t, lines, []line{
 		{Value: "1", Level: 0},
 		{Value: "1.1", Level: 1},
@@ -104,6 +101,24 @@ func Test_toLines_MultipleLevelsWithDashes(t *testing.T) {
 	})
 }
 
+func Test_toLines_IndentationBrokenWithSpaces(t *testing.T) {
+	scanner, closeFile := toScanner("indentation_broken_with_spaces.txt")
+	indentationSymbol := "  "
+
+	defer closeFile()
+
+	lines := toLines(scanner, indentationSymbol)
+
+	assert.Equal(t, lines, []line{
+		{Value: "1", Level: 0},
+		{Value: "1.1", Level: 1},
+		{Value: "1.2", Level: 1},
+		{Value: "2", Level: 0},
+		{Value: "3", Level: 0},
+		{Value: "3.1", Level: 4}, // Indentation broken here!
+	})
+}
+
 func toScanner(filename string) (*bufio.Scanner, func() error) {
 	file, err := os.Open("../test_input/" + filename)
 

spacetree/spacetree.go

@@ -4,7 +4,7 @@ import "bufio"
 
 // New returns the root node of the tree generated processing
 // the provided scanner
-func New(scanner *bufio.Scanner, indentationSymbol string) *Node {
+func New(scanner *bufio.Scanner, indentationSymbol string) (*Node, error) {
 	return newTree(
 		toLines(scanner, indentationSymbol),
 	)

spacetree/spacetree_test.go

@@ -12,7 +12,9 @@ func Test_New(t *testing.T) {
 
 	defer closeFile()
 
-	root := New(scanner, indentationSymbol)
+	root, err := New(scanner, indentationSymbol)
+
+	assert.NoError(t, err)
 
 	assert.Equal(t, root, &Node{
 		Value: "",

spacetree/tree.go

@@ -1,50 +1,34 @@
 package spacetree
 
 import (
-	"github.com/golang-collections/collections/stack"
+	"fmt"
 )
 
-func newTree(lines []line) *Node {
+func newTree(lines []line) (*Node, error) {
 	root := newNode("")
-	lastNode := root
 
-	stk := stack.New()
-	stk.Push(root)
+	levelNodeMapping := map[int]*Node{-1: root}
+	level := -1
 
-	currentLevel := -1
-
-	for _, line := range lines {
-		levelDiff := line.Level - currentLevel
-
-		node := newNode(line.Value)
+	for lineNumber, line := range lines {
+		levelDiff := line.Level - level
 
 		if levelDiff > 1 {
-			// Entry is a child of the last node
-			stk.Push(lastNode)
-			currentLevel++
-		} else if levelDiff < 1 {
-			// Entry is in a higher (or same level) than last node.
-			// So, unstack by the level diff
-			for i := 0; i < abs(levelDiff)+1; i++ {
-				stk.Pop()
-				currentLevel--
-			}
+			return nil, newIndentationBrokenError(lineNumber)
 		}
 
-		// Add the new node to the tree
-		stk.Peek().(*Node).addChild(node)
+		parentNode := levelNodeMapping[line.Level-1]
+		n := newNode(line.Value)
+
+		parentNode.addChild(n)
 
-		// Update the last node
-		lastNode = node
+		levelNodeMapping[line.Level] = n
+		level = line.Level
 	}
 
-	return root
+	return root, nil
 }
 
-func abs(x int) int {
-	if x < 0 {
-		return -x
-	}
-
-	return x
+func newIndentationBrokenError(lineNumber int) error {
+	return fmt.Errorf("indentation broken at line %d", lineNumber)
 }

spacetree/tree_test.go

@@ -13,7 +13,9 @@ func Test_newTree_OneLevelIndentation(t *testing.T) {
 		{Value: "3", Level: 0},
 	}
 
-	root := newTree(lines)
+	root, err := newTree(lines)
+
+	assert.NoError(t, err)
 
 	assert.Equal(t, root.Children[0], newNode("1"))
 	assert.Equal(t, root.Children[1], newNode("2"))
@@ -29,7 +31,10 @@ func Test_newTree_TwoLevelIndentation(t *testing.T) {
 		{Value: "2.1", Level: 1},
 	}
 
-	root := newTree(lines)
+	root, err := newTree(lines)
+
+	assert.NoError(t, err)
+
 	var n *Node
 
 	// Node "1"
@@ -54,7 +59,10 @@ func Test_newTree_MultiLevelIndentation(t *testing.T) {
 		{Value: "3.1", Level: 1},
 	}
 
-	root := newTree(lines)
+	root, err := newTree(lines)
+
+	assert.NoError(t, err)
+
 	var n *Node
 
 	// Node "1"
@@ -80,7 +88,23 @@ func Test_newTree_MultiLevelIndentation(t *testing.T) {
 func Test_newTree_Empty(t *testing.T) {
 	lines := []line{}
 
-	root := newTree(lines)
+	root, err := newTree(lines)
 
+	assert.NoError(t, err)
 	assert.Equal(t, root, newNode(""))
 }
+
+func Test_newTree_IndentationBroken(t *testing.T) {
+	lines := []line{
+		{Value: "1", Level: 0},
+		{Value: "1.1", Level: 1},
+		{Value: "1.2", Level: 1},
+		{Value: "2", Level: 0},
+		{Value: "2.1.1", Level: 2}, // Indentation broken here!
+	}
+
+	root, err := newTree(lines)
+
+	assert.Nil(t, root)
+	assert.Errorf(t, err, "indentation broken at line 4")
+}

test_input/indentation_broken_with_spaces.txt

@@ -0,0 +1,6 @@
+1
+  1.1
+  1.2
+2
+3
+        3.1