From 535255f37a5651b281dd60fa216b3095211aab55 Mon Sep 17 00:00:00 2001
From: john <john@johng.cn>
Date: Tue, 25 Sep 2018 13:18:43 +0800
Subject: [PATCH] =?UTF-8?q?gfpool=E5=A2=9E=E5=8A=A0=E5=9F=BA=E5=87=86?=
 =?UTF-8?q?=E6=B5=8B=E8=AF=95?=
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---
 g/os/gfpool/gfpool.go      | 11 ++++++++---
 g/os/gfpool/gfpool_test.go | 21 +++++++++++++++++++++
 2 files changed, 29 insertions(+), 3 deletions(-)
 create mode 100644 g/os/gfpool/gfpool_test.go

diff --git a/g/os/gfpool/gfpool.go b/g/os/gfpool/gfpool.go
index 2c47161f7..148babe75 100644
--- a/g/os/gfpool/gfpool.go
+++ b/g/os/gfpool/gfpool.go
@@ -89,6 +89,8 @@ func (p *Pool) File() (*File, error) {
             if _, err := f.Seek(0, 2); err != nil {
                 return nil, err
             }
+        } else {
+            f.Seek(0, 0)
         }
         if f.flag & os.O_CREATE > 0 {
             _, err := f.Stat()
@@ -103,10 +105,13 @@ func (p *Pool) File() (*File, error) {
             }
         }
         if f.flag & os.O_TRUNC > 0 {
-            if err := f.Truncate(0); err != nil {
-                return nil, err
+            if stat, err := f.Stat(); err == nil {
+                if stat.Size() > 0 {
+                    if err := f.Truncate(0); err != nil {
+                        return nil, err
+                    }
+                }
             }
-            f.Seek(0, 0)
         }
         return f, nil
     }
diff --git a/g/os/gfpool/gfpool_test.go b/g/os/gfpool/gfpool_test.go
new file mode 100644
index 000000000..beef6771f
--- /dev/null
+++ b/g/os/gfpool/gfpool_test.go
@@ -0,0 +1,21 @@
+package gfpool
+
+import (
+    "testing"
+    "os"
+)
+
+func Benchmark_os_Open_Close(b *testing.B) {
+    for i := 0; i < b.N; i++ {
+        f, _ := os.OpenFile("/tmp/bench-test", os.O_RDWR|os.O_CREATE|os.O_TRUNC|os.O_APPEND, 0766)
+        f.Close()
+    }
+}
+
+func Benchmark_gfpool_Open_Close(b *testing.B) {
+    for i := 0; i < b.N; i++ {
+        f, _ := Open("/tmp/bench-test", os.O_RDWR|os.O_CREATE|os.O_TRUNC|os.O_APPEND, 0766)
+        f.Close()
+    }
+}
+