Fix recovery middleware to render gitea style page. (#13857)

* Some changes to fix recovery

* Move Recovery to middlewares

* Remove trace code

* Fix lint

* add session middleware and remove dependent on macaron for sso

* Fix panic 500 page rendering

* Fix bugs

* Fix fmt

* Fix vendor

* recover unnecessary change

* Fix lint and addd some comments about the copied codes.

* Use util.StatDir instead of com.StatDir

Co-authored-by: 6543 <6543@obermui.de>

vendor/github.com/unrolled/render/buffer.go

@@ -0,0 +1,46 @@
+package render
+
+import "bytes"
+
+// bufPool represents a reusable buffer pool for executing templates into.
+var bufPool *BufferPool
+
+// BufferPool implements a pool of bytes.Buffers in the form of a bounded channel.
+// Pulled from the github.com/oxtoacart/bpool package (Apache licensed).
+type BufferPool struct {
+	c chan *bytes.Buffer
+}
+
+// NewBufferPool creates a new BufferPool bounded to the given size.
+func NewBufferPool(size int) (bp *BufferPool) {
+	return &BufferPool{
+		c: make(chan *bytes.Buffer, size),
+	}
+}
+
+// Get gets a Buffer from the BufferPool, or creates a new one if none are
+// available in the pool.
+func (bp *BufferPool) Get() (b *bytes.Buffer) {
+	select {
+	case b = <-bp.c:
+	// reuse existing buffer
+	default:
+		// create new buffer
+		b = bytes.NewBuffer([]byte{})
+	}
+	return
+}
+
+// Put returns the given Buffer to the BufferPool.
+func (bp *BufferPool) Put(b *bytes.Buffer) {
+	b.Reset()
+	select {
+	case bp.c <- b:
+	default: // Discard the buffer if the pool is full.
+	}
+}
+
+// Initialize buffer pool for writing templates into.
+func init() {
+	bufPool = NewBufferPool(64)
+}