tree.go

package minima

/**
* Minima is a free and open source software under Mit license

Copyright (c) 2024 gominima

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

* Authors @apoorvcodes @megatank58
* Maintainers @Panquesito7 @savioxavier @Shubhaankar-Sharma @apoorvcodes @megatank58
* Thank you for showing interest in minima and for this beautiful community
*/

import (
	"strings"
	"sync"
)

/**
 * @info the radix tree structure
 * @property {Node} [roots] The roots of the tree
 * @property {int} [len] The lenght of the tree
 * @property {int} [size] The size of the tree
 * @property {bool} [safe] Whether the mutex is enabled or not
 * @property {byte} [placeholder] The regex byte for params
 * @property {byte} [delim] The regex byte for params
 * @property {sync.Mutex} [mu] The synx.Mutex instance
 */
type tree struct {
	root        *Node
	len         int
	size        int
	safe        bool
	placeholder byte
	delim       byte
	mu          *sync.Mutex
}

/**
 * @info Creates a new radix tree
 */
func NewTree() *tree {
	return &tree{
		root:        &Node{},
		len:         1,
		placeholder: ':',
		delim:       '/',
		mu:          &sync.Mutex{},
		safe:        true,
	}
}

/**
 * @info Inserts a new node in the tree
 * @param {string} [key] The route path used as key
 * @param {Handler} [handler] The handler to be used
 * @returns {}
 */
func (tr *tree) InsertNode(key string, handler Handler) {
	if key == "" || handler == nil {
		return
	}
	if tr.safe {
		defer tr.mu.Unlock()
		tr.mu.Lock()
	}
	n := tr.root

	for {
		var next *edge
		var slice string

		for _, edge := range n.edges {
			var found int
			slice = edge.key
			for i := range slice {
				if i < len(key) && slice[i] == key[i] {
					found++
					continue
				}
				break
			}
			if found > 0 {
				key = key[found:]
				slice = slice[found:]
				next = edge
				break
			}
		}
		if next != nil {
			n = next.n
			n.priority++

			if len(key) == 0 {
				if len(slice) == 0 {
					n.handler = handler
					return
				}
				next.key = next.key[:len(next.key)-len(slice)]
				c := n.clone()
				c.priority--
				n.edges = []*edge{
					&edge{
						key: slice,
						n:   c,
					},
				}
				n.handler = handler
				tr.len++
				return
			}
			if len(slice) > 0 {
				c := n.clone()
				c.priority--
				n.edges = []*edge{
					&edge{ // the suffix that is clone into a new node
						key: slice,
						n:   c,
					},
					&edge{ // the new node
						key: key,
						n: &Node{
							handler:  handler,
							depth:    n.depth + 1,
							priority: 1,
						},
					},
				}
				next.key = next.key[:len(next.key)-len(slice)]
				n.handler = nil
				tr.len += 2
				tr.size += len(key)
				return
			}
			continue
		}
		n.edges = append(n.edges, &edge{
			key: key,
			n: &Node{
				handler:  handler,
				depth:    n.depth + 1,
				priority: 1,
			},
		})

		tr.len++
		tr.size += len(key)
		return
	}
}

/**
 * @info Finds a specific node from the tree
 * @param {string} [key] The route path used as key
 * @returns {*Node, map[string]string}
 */
func (tr *tree) GetNode(key string) (*Node, map[string]string) {
	if key == "" {
		return nil, nil
	}
	if tr.safe {
		defer tr.mu.Unlock()
		tr.mu.Lock()
	}
	n := tr.root
	var params map[string]string
	for n != nil && key != "" {
		var next *edge
	Walk:
		for _, edge := range n.edges {
			slice := edge.key

			for {
				pindex := len(slice)
				if i := strings.IndexByte(slice, tr.placeholder); i >= 0 {
					pindex = i
				}
				prefix := slice[:pindex]
				if !strings.HasPrefix(key, prefix) {
					continue Walk
				}
				key = key[len(prefix):]

				if len(prefix) == len(slice) {
					next = edge
					break Walk
				}
				var delimint int
				slice = slice[pindex:]
				if delimint = strings.IndexByte(slice[1:], tr.delim) + 1; delimint <= 0 {
					delimint = len(slice)
				}
				k := slice[1:delimint]
				slice = slice[delimint:]
				if delimint = strings.IndexByte(key[1:], tr.delim) + 1; delimint <= 0 {
					delimint = len(key)
				}
				if params == nil {
					params = make(map[string]string)
				}
				params[k] = key[:delimint]
				key = key[delimint:]
				if slice == "" && key == "" {
					next = edge
					break Walk
				}

			}
		}
		if next != nil {
			n = next.n
			continue
		}
		n = nil
	}
	return n, params
}

/**
 * @info Turns a radix tree into a hash map
 * @param {tree} [tre] The tree to convert
 * @returns {map[string]Handler}
 */
func ToMap(tre *tree) map[string]Handler {
	ma := make(map[string]Handler, tre.len)
	for _, edge := range tre.root.edges {
		ma[edge.key] = edge.n.handler
	}
	return ma
}

/**
 * @info Inserts a hash map to the tree
 * @param {map[string]Handler} [m] The hash map to insert
 * @returns {}
 */
func (tr *tree) InsertMap(m map[string]Handler) {
	for i, v := range m {
		tr.InsertNode(i, v)
	}
}