trie: new package (#3729)

This implements a simple trie tree for minio server/tools.
This package borrows idea from
https://godoc.org/golang.org/x/text/internal/triegen.

cmd/commands.go

@@ -16,13 +16,16 @@
 
 package cmd
 
-import "github.com/minio/cli"
+import (
+	"github.com/minio/cli"
+	"github.com/minio/minio/pkg/trie"
+)
 
 // Collection of minio commands currently supported are.
 var commands = []cli.Command{}
 
 // Collection of minio commands currently supported in a trie tree.
-var commandsTree = newTrie()
+var commandsTree = trie.NewTrie()
 
 // registerCommand registers a cli command.
 func registerCommand(command cli.Command) {

cmd/main.go

@@ -94,7 +94,7 @@ func findClosestCommands(command string) []string {
 	sort.Strings(closestCommands)
 	// Suggest other close commands - allow missed, wrongly added and
 	// even transposed characters
-	for _, value := range commandsTree.walk(commandsTree.root) {
+	for _, value := range commandsTree.Walk(commandsTree.Root()) {
 		if sort.SearchStrings(closestCommands, value.(string)) < len(closestCommands) {
 			continue
 		}

pkg/trie/trie.go

@@ -1,5 +1,5 @@
 /*
- * Minio Cloud Storage, (C) 2015 Minio, Inc.
+ * Minio Cloud Storage, (C) 2014, 2015, 2016, 2017 Minio, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,80 +14,78 @@
  * limitations under the License.
  */
 
-package cmd
+// Package trie implements a simple trie tree for minio server/tools borrows
+// idea from - https://godoc.org/golang.org/x/text/internal/triegen.
+package trie
 
-// This package borrows idea from - https://godoc.org/golang.org/x/text/internal/triegen
+// Node trie tree node container carries value and children.
+type Node struct {
+	exists bool
+	value  interface{}
+	child  map[rune]*Node // runes as child.
+}
 
-// Trie trie container
+// newNode create a new trie node.
+func newNode() *Node {
+	return &Node{
+		exists: false,
+		value:  nil,
+		child:  make(map[rune]*Node),
+	}
+}
+
+// Trie is a trie container.
 type Trie struct {
-	root *trieNode
+	root *Node
 	size int
 }
 
-// newTrie get new trie
+// Root returns root node.
-func newTrie() *Trie {
+func (t *Trie) Root() *Node {
-	return &Trie{
+	return t.root
-		root: newTrieNode(),
-		size: 0,
-	}
 }
 
-// trieNode trie tree node container carries value and children
+// Insert insert a key.
-type trieNode struct {
-	exists bool
-	value  interface{}
-	child  map[rune]*trieNode // runes as child
-}
-
-func newTrieNode() *trieNode {
-	return &trieNode{
-		exists: false,
-		value:  nil,
-		child:  make(map[rune]*trieNode),
-	}
-}
-
-// Insert insert a key
 func (t *Trie) Insert(key string) {
 	curNode := t.root
 	for _, v := range key {
 		if curNode.child[v] == nil {
-			curNode.child[v] = newTrieNode()
+			curNode.child[v] = newNode()
 		}
 		curNode = curNode.child[v]
 	}
 
 	if !curNode.exists {
-		// increment when new rune child is added
+		// increment when new rune child is added.
 		t.size++
 		curNode.exists = true
 	}
-	// value is stored for retrieval in future
+	// value is stored for retrieval in future.
 	curNode.value = key
 }
 
-// PrefixMatch - prefix match
+// PrefixMatch - prefix match.
 func (t *Trie) PrefixMatch(key string) []interface{} {
 	node, _ := t.findNode(key)
 	if node != nil {
-		return t.walk(node)
+		return t.Walk(node)
 	}
 	return []interface{}{}
 }
 
-// walk the tree
+// Walk the tree.
-func (t *Trie) walk(node *trieNode) (ret []interface{}) {
+func (t *Trie) Walk(node *Node) (ret []interface{}) {
 	if node.exists {
 		ret = append(ret, node.value)
 	}
 	for _, v := range node.child {
-		ret = append(ret, t.walk(v)...)
+		ret = append(ret, t.Walk(v)...)
 	}
 	return
 }
 
-// find nodes corresponding to key
+// find nodes corresponding to key.
-func (t *Trie) findNode(key string) (node *trieNode, index int) {
+func (t *Trie) findNode(key string) (node *Node, index int) {
 	curNode := t.root
 	f := false
 	for k, v := range key {
@@ -110,3 +108,11 @@ func (t *Trie) findNode(key string) (node *trieNode, index int) {
 
 	return curNode, index
 }
+
+// NewTrie create a new trie.
+func NewTrie() *Trie {
+	return &Trie{
+		root: newNode(),
+		size: 0,
+	}
+}

pkg/trie/trie_test.go

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package cmd
+package trie
 
 import (
 	"testing"
@@ -23,7 +23,7 @@ import (
 // Simply make sure creating a new tree works.
 func TestNewTrie(t *testing.T) {
 	var trie *Trie
-	trie = newTrie()
+	trie = NewTrie()
 
 	if trie.size != 0 {
 		t.Errorf("expected size 0, got: %d", trie.size)
@@ -33,7 +33,7 @@ func TestNewTrie(t *testing.T) {
 // Ensure that we can insert new keys into the tree, then check the size.
 func TestInsert(t *testing.T) {
 	var trie *Trie
-	trie = newTrie()
+	trie = NewTrie()
 
 	// We need to have an empty tree to begin with.
 	if trie.size != 0 {
@@ -52,10 +52,10 @@ func TestInsert(t *testing.T) {
 // Ensure that PrefixMatch gives us the correct two keys in the tree.
 func TestPrefixMatch(t *testing.T) {
 	var trie *Trie
-	trie = newTrie()
+	trie = NewTrie()
 
 	// Feed it some fodder: only 'minio' and 'miny-os' should trip the matcher.
-	trie.Insert(globalMinioDefaultOwnerID)
+	trie.Insert("minio")
 	trie.Insert("amazon")
 	trie.Insert("cheerio")
 	trie.Insert("miny-o's")
@@ -65,7 +65,7 @@ func TestPrefixMatch(t *testing.T) {
 		t.Errorf("expected two matches, got: %d", len(matches))
 	}
 
-	if matches[0] != globalMinioDefaultOwnerID && matches[1] != globalMinioDefaultOwnerID {
+	if matches[0] != "minio" && matches[1] != "minio" {
 		t.Errorf("expected one match to be 'minio', got: '%s' and '%s'", matches[0], matches[1])
 	}
 }