From e180185856d758f48f5982d50f6d3b53ab34d004 Mon Sep 17 00:00:00 2001
From: Will Norris <will@willnorris.com>
Date: Tue, 29 Nov 2016 15:30:07 -0800
Subject: [PATCH] add copy of net/http package

this includes an exact copy of the TimeoutHandler func and supporting
types from net/http, modified only to handle minor issues for imported
types.

Ref: #75
---
 third_party/http/LICENSE   |  27 ++++++++
 third_party/http/README    |   1 +
 third_party/http/server.go | 136 +++++++++++++++++++++++++++++++++++++
 3 files changed, 164 insertions(+)
 create mode 100644 third_party/http/LICENSE
 create mode 100644 third_party/http/README
 create mode 100644 third_party/http/server.go

diff --git a/third_party/http/LICENSE b/third_party/http/LICENSE
new file mode 100644
index 0000000..6a66aea
--- /dev/null
+++ b/third_party/http/LICENSE
@@ -0,0 +1,27 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/third_party/http/README b/third_party/http/README
new file mode 100644
index 0000000..893738a
--- /dev/null
+++ b/third_party/http/README
@@ -0,0 +1 @@
+Package http is based on a copy of net/http.
diff --git a/third_party/http/server.go b/third_party/http/server.go
new file mode 100644
index 0000000..133c3c9
--- /dev/null
+++ b/third_party/http/server.go
@@ -0,0 +1,136 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package http provides helpers for HTTP servers.
+package http
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"net/http"
+	"sync"
+	"time"
+)
+
+// TimeoutHandler returns a Handler that runs h with the given time limit.
+//
+// The new Handler calls h.ServeHTTP to handle each request, but if a
+// call runs for longer than its time limit, the handler responds with
+// a 503 Service Unavailable error and the given message in its body.
+// (If msg is empty, a suitable default message will be sent.)
+// After such a timeout, writes by h to its ResponseWriter will return
+// ErrHandlerTimeout.
+//
+// TimeoutHandler buffers all Handler writes to memory and does not
+// support the Hijacker or Flusher interfaces.
+func TimeoutHandler(h http.Handler, dt time.Duration, msg string) http.Handler {
+	return &timeoutHandler{
+		handler: h,
+		body:    msg,
+		dt:      dt,
+	}
+}
+
+// ErrHandlerTimeout is returned on ResponseWriter Write calls
+// in handlers which have timed out.
+var ErrHandlerTimeout = errors.New("http: Handler timeout")
+
+type timeoutHandler struct {
+	handler http.Handler
+	body    string
+	dt      time.Duration
+
+	// When set, no timer will be created and this channel will
+	// be used instead.
+	testTimeout <-chan time.Time
+}
+
+func (h *timeoutHandler) errorBody() string {
+	if h.body != "" {
+		return h.body
+	}
+	return "<html><head><title>Timeout</title></head><body><h1>Timeout</h1></body></html>"
+}
+
+func (h *timeoutHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	var t *time.Timer
+	timeout := h.testTimeout
+	if timeout == nil {
+		t = time.NewTimer(h.dt)
+		timeout = t.C
+	}
+	done := make(chan struct{})
+	tw := &timeoutWriter{
+		w: w,
+		h: make(http.Header),
+	}
+	go func() {
+		h.handler.ServeHTTP(tw, r)
+		close(done)
+	}()
+	select {
+	case <-done:
+		tw.mu.Lock()
+		defer tw.mu.Unlock()
+		dst := w.Header()
+		for k, vv := range tw.h {
+			dst[k] = vv
+		}
+		if !tw.wroteHeader {
+			tw.code = http.StatusOK
+		}
+		w.WriteHeader(tw.code)
+		w.Write(tw.wbuf.Bytes())
+		if t != nil {
+			t.Stop()
+		}
+	case <-timeout:
+		tw.mu.Lock()
+		defer tw.mu.Unlock()
+		w.WriteHeader(http.StatusServiceUnavailable)
+		io.WriteString(w, h.errorBody())
+		tw.timedOut = true
+		return
+	}
+}
+
+type timeoutWriter struct {
+	w    http.ResponseWriter
+	h    http.Header
+	wbuf bytes.Buffer
+
+	mu          sync.Mutex
+	timedOut    bool
+	wroteHeader bool
+	code        int
+}
+
+func (tw *timeoutWriter) Header() http.Header { return tw.h }
+
+func (tw *timeoutWriter) Write(p []byte) (int, error) {
+	tw.mu.Lock()
+	defer tw.mu.Unlock()
+	if tw.timedOut {
+		return 0, ErrHandlerTimeout
+	}
+	if !tw.wroteHeader {
+		tw.writeHeader(http.StatusOK)
+	}
+	return tw.wbuf.Write(p)
+}
+
+func (tw *timeoutWriter) WriteHeader(code int) {
+	tw.mu.Lock()
+	defer tw.mu.Unlock()
+	if tw.timedOut || tw.wroteHeader {
+		return
+	}
+	tw.writeHeader(code)
+}
+
+func (tw *timeoutWriter) writeHeader(code int) {
+	tw.wroteHeader = true
+	tw.code = code
+}