From e400a94ffb9ffb935bc38b3d681404242f2e6146 Mon Sep 17 00:00:00 2001
From: John <john@johng.cn>
Date: Sun, 9 Jun 2019 10:33:16 +0800
Subject: [PATCH] improving grpool

---
 g/container/gchan/gchan.go   |  8 +++++---
 g/container/gqueue/gqueue.go |  6 +++---
 g/os/grpool/grpool.go        | 12 +++++++-----
 3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/g/container/gchan/gchan.go b/g/container/gchan/gchan.go
index 6b6be6da3..9e762162f 100644
--- a/g/container/gchan/gchan.go
+++ b/g/container/gchan/gchan.go
@@ -4,7 +4,7 @@
 // If a copy of the MIT was not distributed with this file,
 // You can obtain one at https://github.com/gogf/gf.
 
-// Package gchan provides graceful channel for safe operations.
+// Package gchan provides graceful channel for no panic operations.
 //
 // It's safe to call Chan.Push/Close functions repeatedly.
 package gchan
@@ -14,12 +14,13 @@ import (
     "github.com/gogf/gf/g/container/gtype"
 )
 
+// Graceful channel.
 type Chan struct {
     channel chan interface{}
     closed  *gtype.Bool
 }
 
-// New creates a graceful channel with given limit.
+// New creates a graceful channel with given <limit>.
 func New(limit int) *Chan {
     return &Chan {
 	    channel : make(chan interface{}, limit),
@@ -31,7 +32,7 @@ func New(limit int) *Chan {
 // It is safe to be called repeatedly.
 func (c *Chan) Push(value interface{}) error {
     if c.closed.Val() {
-        return errors.New("closed")
+        return errors.New("channel is closed")
     }
     c.channel <- value
     return nil
@@ -39,6 +40,7 @@ func (c *Chan) Push(value interface{}) error {
 
 // Pop pops value from channel.
 // If there's no value in channel, it would block to wait.
+// If the channel is closed, it will return a nil value immediately.
 func (c *Chan) Pop() interface{} {
     return <- c.channel
 }
diff --git a/g/container/gqueue/gqueue.go b/g/container/gqueue/gqueue.go
index ea99c0c6f..9ec7b12c7 100644
--- a/g/container/gqueue/gqueue.go
+++ b/g/container/gqueue/gqueue.go
@@ -37,8 +37,8 @@ const (
 )
 
 // New returns an empty queue object.
-// Optional parameter <limit> is used to limit the size of the queue, which is unlimited by default.
-// When <limit> is given, the queue will be static and high performance which is comparable with stdlib chan.
+// Optional parameter <limit> is used to limit the size of the queue, which is unlimited in default.
+// When <limit> is given, the queue will be static and high performance which is comparable with stdlib channel.
 func New(limit...int) *Queue {
     q := &Queue {
         closed : make(chan struct{}, 0),
@@ -103,7 +103,7 @@ func (q *Queue) Pop() interface{} {
 
 // Close closes the queue.
 // Notice: It would notify all goroutines return immediately,
-// which are being blocked reading by Pop method.
+// which are being blocked reading using Pop method.
 func (q *Queue) Close() {
     close(q.C)
     close(q.events)
diff --git a/g/os/grpool/grpool.go b/g/os/grpool/grpool.go
index 8d2bf116c..675e15193 100644
--- a/g/os/grpool/grpool.go
+++ b/g/os/grpool/grpool.go
@@ -14,10 +14,11 @@ import (
 
 // Goroutine Pool
 type Pool struct {
-    limit  int         // Max goroutine count limit.
-    count  *gtype.Int  // Current running goroutine count.
-    list   *glist.List // Job list.
-    closed *gtype.Bool // Is pool closed or not.
+    limit   int           // Max goroutine count limit.
+    count   *gtype.Int    // Current running goroutine count.
+    list    *glist.List   // Job list for asynchronous job adding purpose.
+    closed  *gtype.Bool   // Is pool closed or not.
+    workers chan struct{} // Goroutine workers using channel to implements blocking feature.
 }
 
 // Default goroutine pool.
@@ -33,7 +34,7 @@ func New(limit...int) *Pool {
         list   : glist.New(),
         closed : gtype.NewBool(),
     }
-    if len(limit) > 0 {
+    if len(limit) > 0 && limit[0] > 0 {
     	p.limit = limit[0]
     }
     return p
@@ -72,6 +73,7 @@ func (p *Pool) Add(f func()) {
 	p.fork()
 }
 
+
 // Size returns current goroutine count of the pool.
 func (p *Pool) Size() int {
     return p.count.Val()