From e484aaa1f90819312dd7a4d9a1a0db8ef9c3ffdf Mon Sep 17 00:00:00 2001
From: Ge Song <gesong0606@gmail.com>
Date: Fri, 7 Apr 2023 22:41:19 +0800
Subject: [PATCH] add synchelper;

---
 synchelper/bytes_buffer_pool.go | 18 +++++++++++++++++
 synchelper/go.mod               |  3 +++
 synchelper/io_writer.go         | 25 ++++++++++++++++++++++++
 synchelper/pool.go              | 34 +++++++++++++++++++++++++++++++++
 4 files changed, 80 insertions(+)
 create mode 100644 synchelper/bytes_buffer_pool.go
 create mode 100644 synchelper/go.mod
 create mode 100644 synchelper/io_writer.go
 create mode 100644 synchelper/pool.go

diff --git a/synchelper/bytes_buffer_pool.go b/synchelper/bytes_buffer_pool.go
new file mode 100644
index 0000000..56f4405
--- /dev/null
+++ b/synchelper/bytes_buffer_pool.go
@@ -0,0 +1,18 @@
+package synchelper
+
+import "bytes"
+
+// NewBytesBufferPool 返回新的 BytesBufferPool
+func NewBytesBufferPool(initialSize, maximumSize int) BytesBufferPool {
+	return NewPool(
+		func() any {
+			return bytes.NewBuffer(make([]byte, 0, initialSize))
+		},
+		func(v *bytes.Buffer) bool {
+			return v.Cap() <= maximumSize
+		},
+	)
+}
+
+// BytesBufferPool 是 [*bytes.Buffer] 的资源池
+type BytesBufferPool = Pool[*bytes.Buffer]
diff --git a/synchelper/go.mod b/synchelper/go.mod
new file mode 100644
index 0000000..03f664a
--- /dev/null
+++ b/synchelper/go.mod
@@ -0,0 +1,3 @@
+module git.blauwelle.com/go/crate/synchelper
+
+go 1.20
diff --git a/synchelper/io_writer.go b/synchelper/io_writer.go
new file mode 100644
index 0000000..d3ae9f6
--- /dev/null
+++ b/synchelper/io_writer.go
@@ -0,0 +1,25 @@
+package synchelper
+
+import (
+	"io"
+	"sync"
+)
+
+// NewSyncWriter 返回写互斥的 writer
+func NewSyncWriter(writer io.Writer) io.Writer {
+	return &syncWriter{
+		writer: writer,
+		lock:   sync.Mutex{},
+	}
+}
+
+type syncWriter struct {
+	writer io.Writer
+	lock   sync.Mutex
+}
+
+func (w *syncWriter) Write(p []byte) (n int, err error) {
+	w.lock.Lock()
+	defer w.lock.Unlock()
+	return w.writer.Write(p)
+}
diff --git a/synchelper/pool.go b/synchelper/pool.go
new file mode 100644
index 0000000..fba75b8
--- /dev/null
+++ b/synchelper/pool.go
@@ -0,0 +1,34 @@
+package synchelper
+
+import (
+	"sync"
+)
+
+// NewPool 初始化 Pool,
+// newFn 是资源的构造函数,
+// putCond 返回 true 时表示资源可以被放回 Pool 中.
+func NewPool[T any](newFn func() any, putCond func(v T) bool) Pool[T] {
+	return Pool[T]{
+		pool:    &sync.Pool{New: newFn},
+		putCond: putCond,
+	}
+}
+
+// Pool 是通用的资源池
+type Pool[T any] struct {
+	pool    *sync.Pool
+	putCond func(v T) bool
+}
+
+// Get 获取资源
+func (pool Pool[T]) Get() T {
+	return pool.pool.Get().(T)
+}
+
+// Put 放回资源
+func (pool Pool[T]) Put(v T) {
+	if !pool.putCond(v) {
+		return
+	}
+	pool.pool.Put(v)
+}