From 3e4033673eb26f63e1b38b3870afc8e1fdc31469 Mon Sep 17 00:00:00 2001
From: Manu Mtz-Almeida <manu.valladolid@gmail.com>
Date: Sun, 6 Jul 2014 21:09:23 +0200
Subject: [PATCH] Using sync.Pool instead of a channel

---
 gin.go    | 80 ++++++++++++-------------------------------------------
 logger.go |  3 +--
 2 files changed, 18 insertions(+), 65 deletions(-)

diff --git a/gin.go b/gin.go
index 33459cbb..85216544 100644
--- a/gin.go
+++ b/gin.go
@@ -13,6 +13,7 @@ import (
 	"math"
 	"net/http"
 	"path"
+	"sync"
 )
 
 const (
@@ -37,11 +38,6 @@ type (
 
 	ErrorMsgs []ErrorMsg
 
-	Config struct {
-		CacheSize    int
-		Preallocated int
-	}
-
 	// Context is the most important part of gin. It allows us to pass variables between middleware,
 	// manage the flow, validate the JSON of a request and render a JSON response for example.
 	Context struct {
@@ -68,19 +64,12 @@ type (
 	Engine struct {
 		*RouterGroup
 		HTMLTemplates *template.Template
-		cache         chan *Context
+		cache         sync.Pool
 		handlers404   []HandlerFunc
 		router        *httprouter.Router
 	}
 )
 
-var (
-	DefaultConfig = Config{
-		CacheSize:    1024,
-		Preallocated: 512,
-	}
-)
-
 // Allows type H to be used with xml.Marshal
 func (h H) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
 	start.Name = xml.Name{"", "map"}
@@ -112,32 +101,19 @@ func (a ErrorMsgs) String() string {
 	return buffer.String()
 }
 
-func NewWithConfig(config Config) *Engine {
-	if config.CacheSize < 2 {
-		panic("CacheSize must be at least 2")
-	}
-	if config.Preallocated > config.CacheSize {
-		panic("Preallocated must be less or equal to CacheSize")
-	}
+// Returns a new blank Engine instance without any middleware attached.
+// The most basic configuration
+func New() *Engine {
 	engine := &Engine{}
 	engine.RouterGroup = &RouterGroup{nil, "/", nil, engine}
 	engine.router = httprouter.New()
 	engine.router.NotFound = engine.handle404
-	engine.cache = make(chan *Context, config.CacheSize)
-
-	// Fill it with empty contexts
-	for i := 0; i < config.Preallocated; i++ {
-		engine.cache <- &Context{Engine: engine, Writer: &responseWriter{}}
+	engine.cache.New = func() interface{} {
+		return &Context{Engine: engine, Writer: &responseWriter{}}
 	}
 	return engine
 }
 
-// Returns a new blank Engine instance without any middleware attached.
-// The most basic configuration
-func New() *Engine {
-	return NewWithConfig(DefaultConfig)
-}
-
 // Returns a Engine instance with the Logger and Recovery already attached.
 func Default() *Engine {
 	engine := New()
@@ -154,10 +130,6 @@ func (engine *Engine) NotFound404(handlers ...HandlerFunc) {
 	engine.handlers404 = handlers
 }
 
-func (engine *Engine) CacheStress() float32 {
-	return 1.0 - float32(len(engine.cache))/float32(cap(engine.cache))
-}
-
 func (engine *Engine) handle404(w http.ResponseWriter, req *http.Request) {
 	handlers := engine.combineHandlers(engine.handlers404)
 	c := engine.createContext(w, req, nil, handlers)
@@ -166,7 +138,7 @@ func (engine *Engine) handle404(w http.ResponseWriter, req *http.Request) {
 	if !c.Writer.Written() {
 		c.Data(404, MIMEPlain, []byte("404 page not found"))
 	}
-	engine.reuseContext(c)
+	engine.cache.Put(c)
 }
 
 // ServeHTTP makes the router implement the http.Handler interface.
@@ -185,32 +157,14 @@ func (engine *Engine) Run(addr string) {
 /************************************/
 
 func (engine *Engine) createContext(w http.ResponseWriter, req *http.Request, params httprouter.Params, handlers []HandlerFunc) *Context {
-	select {
-	case c := <-engine.cache:
-		c.Writer.reset(w)
-		c.Req = req
-		c.Params = params
-		c.handlers = handlers
-		c.Keys = nil
-		c.index = -1
-		return c
-	default:
-		return &Context{
-			Writer:   &responseWriter{w, -1, false},
-			Req:      req,
-			Params:   params,
-			handlers: handlers,
-			index:    -1,
-			Engine:   engine,
-		}
-	}
-}
-
-func (engine *Engine) reuseContext(c *Context) {
-	select {
-	case engine.cache <- c:
-	default:
-	}
+	c := engine.cache.Get().(*Context)
+	c.Writer.reset(w)
+	c.Req = req
+	c.Params = params
+	c.handlers = handlers
+	c.Keys = nil
+	c.index = -1
+	return c
 }
 
 // Adds middlewares to the group, see example code in github.
@@ -246,7 +200,7 @@ func (group *RouterGroup) Handle(method, p string, handlers []HandlerFunc) {
 	group.engine.router.Handle(method, p, func(w http.ResponseWriter, req *http.Request, params httprouter.Params) {
 		c := group.engine.createContext(w, req, params, handlers)
 		c.Next()
-		group.engine.reuseContext(c)
+		group.engine.cache.Put(c)
 	})
 }
 
diff --git a/logger.go b/logger.go
index 7bd87b70..3120cbe9 100644
--- a/logger.go
+++ b/logger.go
@@ -61,11 +61,10 @@ func Logger() HandlerFunc {
 			color = red
 		}
 		latency := time.Since(start)
-		stdlogger.Printf("[GIN] %v |%s %3d %s| %12v | %3.1f%% | %s %4s %s\n",
+		stdlogger.Printf("[GIN] %v |%s %3d %s| %12v | %s %4s %s\n",
 			time.Now().Format("2006/01/02 - 15:04:05"),
 			color, c.Writer.Status(), reset,
 			latency,
-			c.Engine.CacheStress()*100,
 			requester,
 			c.Req.Method, c.Req.URL.Path,
 		)