internal/dl: move template to lib/godoc

This completes an old TODO and uses the standard site frame
for the download page instead of having a separate copy.

Change-Id: Id647a6bb03d563b007b16cab51f40083d071c944
Reviewed-on: https://go-review.googlesource.com/c/website/+/317658
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

8 files changed, 245 insertions, 316 deletions

diff --git a/_content/lib/godoc/dl.html b/_content/lib/godoc/dl.html
new file mode 100644
index 00000000..11a893a8
--- /dev/null
+++ b/_content/lib/godoc/dl.html
@@ -0,0 +1,159 @@
+{{with .Data}}
+<p>
+After downloading a binary release suitable for your system,
+please follow the <a href="/doc/install">installation instructions</a>.
+</p>
+
+<p>
+If you are building from source,
+follow the <a href="/doc/install/source">source installation instructions</a>.
+</p>
+
+<p>
+See the <a href="/doc/devel/release.html">release history</a> for more
+information about Go releases.
+</p>
+
+<p>
+  As of Go 1.13, the go command by default downloads and authenticates
+  modules using the Go module mirror and Go checksum database run by Google. See
+  <a href="https://proxy.golang.org/privacy">https://proxy.golang.org/privacy</a>
+  for privacy information about these services and the
+  <a href="/cmd/go/">go command documentation</a>
+  for configuration details including how to disable the use of these servers or use
+  different ones.
+</p>
+
+{{with .Featured}}
+<h3 id="featured">Featured downloads</h3>
+{{range .}}
+{{template "download" .}}
+{{end}}
+{{end}}
+
+<div style="clear: both;"></div>
+
+{{with .Stable}}
+<h3 id="stable">Stable versions</h3>
+{{template "download-releases" .}}
+{{end}}
+
+{{with .Unstable}}
+<h3 id="unstable">Unstable version</h3>
+{{template "download-releases" .}}
+{{end}}
+
+{{with .Archive}}
+<div class="toggle" id="archive">
+  <div class="collapsed">
+    <h3 class="toggleButton" title="Click to show versions">Archived versions ▹</h3>
+  </div>
+  <div class="expanded">
+    <h3 class="toggleButton" title="Click to hide versions">Archived versions ▾</h3>
+    {{template "download-releases" .}}
+  </div>
+</div>
+{{end}}
+
+<script>
+$(document).ready(function() {
+  $('a.download').click(function(e) {
+    // Try using the link text as the file name,
+    // unless there's a child element of class 'filename'.
+    var filename = $(this).text();
+    var child = $(this).find('.filename');
+    if (child.length > 0) {
+      filename = child.text();
+    }
+
+    // This must be kept in sync with the filenameRE in godocs.js.
+    var filenameRE = /^go1\.\d+(\.\d+)?([a-z0-9]+)?\.([a-z0-9]+)(-[a-z0-9]+)?(-osx10\.[68])?\.([a-z.]+)$/;
+    var m = filenameRE.exec(filename);
+    if (!m) {
+      // Don't redirect to the download page if it won't recognize this file.
+      // (Should not happen.)
+      return;
+    }
+
+    var dest = "/doc/install";
+    if (filename.indexOf(".src.") != -1) {
+      dest += "/source";
+    }
+    dest += "?download=" + filename;
+
+    e.preventDefault();
+    e.stopPropagation();
+    window.location = dest;
+  });
+});
+</script>
+{{end}}
+
+{{define "download-releases"}}
+{{range .}}
+<div class="toggle{{if .Visible}}Visible{{end}}" id="{{.Version}}">
+	<div class="collapsed">
+		<h2 class="toggleButton" title="Click to show downloads for this version">{{.Version}} ▹</h2>
+	</div>
+	<div class="expanded">
+		<h2 class="toggleButton" title="Click to hide downloads for this version">{{.Version}} ▾</h2>
+		{{if .Stable}}{{else}}
+			<p>This is an <b>unstable</b> version of Go. Use with caution.</p>
+			<p>If you already have Go installed, you can install this version by running:</p>
+<pre>
+go get golang.org/dl/{{.Version}}
+</pre>
+			<p>Then, use the <code>{{.Version}}</code> command instead of the <code>go</code> command to use {{.Version}}.</p>
+		{{end}}
+		{{template "download-files" .}}
+	</div>
+</div>
+{{end}}
+{{end}}
+
+{{define "download-files"}}
+<table class="downloadtable">
+<thead>
+<tr class="first">
+  <th>File name</th>
+  <th>Kind</th>
+  <th>OS</th>
+  <th>Arch</th>
+  <th>Size</th>
+  {{/* Use the checksum type of the first file for the column heading. */}}
+  <th>{{(index .Files 0).ChecksumType}} Checksum</th>
+</tr>
+</thead>
+{{if .SplitPortTable}}
+  {{range .Files}}{{if .PrimaryPort}}{{template "download-file" .}}{{end}}{{end}}
+
+  {{/* TODO(cbro): add a link to an explanatory doc page */}}
+  <tr class="first"><th colspan="6" class="first">Other Ports</th></tr>
+  {{range .Files}}{{if not .PrimaryPort}}{{template "download-file" .}}{{end}}{{end}}
+{{else}}
+  {{range .Files}}{{template "download-file" .}}{{end}}
+{{end}}
+</table>
+{{end}}
+
+{{define "download-file"}}
+<tr{{if .Highlight}} class="highlight"{{end}}>
+  <td class="filename"><a class="download" href="{{.URL}}">{{.Filename}}</a></td>
+  <td>{{.PrettyKind}}</td>
+  <td>{{.PrettyOS}}</td>
+  <td>{{.PrettyArch}}</td>
+  <td>{{.PrettySize}}</td>
+  <td><tt>{{.PrettyChecksum}}</tt></td>
+</tr>
+{{end}}
+
+{{define "download"}}
+<a class="download downloadBox" href="{{.URL}}">
+<div class="platform">{{.Platform}}</div>
+{{with .Requirements}}<div class="reqs">{{.}}</div>{{end}}
+<div>
+  <span class="filename">{{.Filename}}</span>
+  {{if .Size}}<span class="size">({{.PrettySize}})</span>{{end}}
+</div>
+</a>
+{{end}}
diff --git a/_content/lib/godoc/style.css b/_content/lib/godoc/style.css
index 7e5008d7..b83700f3 100644
--- a/_content/lib/godoc/style.css
+++ b/_content/lib/godoc/style.css
@@ -1070,4 +1070,62 @@ a.error {
     white-space: pre-wrap;
     page-break-inside: avoid;
   }
-}
\ No newline at end of file
+}
+table.downloadtable {
+  margin-left: 20px;
+  margin-right: 20px;
+  border-collapse: collapse;
+}
+table.downloadtable tr {
+  background-color: #f0f0f0;
+}
+table.downloadtable tr:nth-child(2n), table.downloadtable tr.first {
+  background-color: white;
+}
+table.downloadtable td, table.downloadtable th {
+  white-space: nowrap;
+  padding: 6px 10px;
+}
+table.downloadtable tt {
+  font-size: xx-small;
+}
+table.downloadtable tr.highlight td {
+  font-weight: bold;
+}
+a.downloadBox {
+  display: block;
+  color: #222;
+  border: 1px solid #375EAB;
+  border-radius: 5px;
+  background: #E0EBF5;
+  width: 280px;
+  float: left;
+  margin-left: 10px;
+  margin-bottom: 10px;
+  padding: 10px;
+}
+a.downloadBox:hover {
+  text-decoration: none;
+}
+.downloadBox .platform {
+  font-size: large;
+}
+.downloadBox .filename {
+  color: #007d9c;
+  font-weight: bold;
+  line-height: 1.5em;
+}
+a.downloadBox:hover .filename {
+  text-decoration: underline;
+}
+.downloadBox .size {
+  font-size: small;
+  font-weight: normal;
+}
+.downloadBox .reqs {
+  font-size: small;
+  font-style: italic;
+}
+.downloadBox .checksum {
+  font-size: 5pt;
+}
diff --git a/cmd/golangorg/prod.go b/cmd/golangorg/prod.go
index b156bfce..e6e3a548 100644
--- a/cmd/golangorg/prod.go
+++ b/cmd/golangorg/prod.go
@@ -40,7 +40,7 @@ func lateSetup(mux *http.ServeMux) {
 
 	datastoreClient, memcacheClient := getClients()
 
-	dl.RegisterHandlers(mux, datastoreClient, memcacheClient)
+	dl.RegisterHandlers(mux, site, datastoreClient, memcacheClient)
 	short.RegisterHandlers(mux, datastoreClient, memcacheClient)
 
 	// Register /compile and /share handlers against the default serve mux
diff --git a/internal/dl/dl.go b/internal/dl/dl.go
index d9864218..2a3a7da0 100644
--- a/internal/dl/dl.go
+++ b/internal/dl/dl.go
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build go1.16
+// +build go1.16
+
 // Package dl implements a simple downloads frontend server.
 //
 // It accepts HTTP POST requests to create a new download metadata entity, and
@@ -24,7 +27,6 @@ package dl
 
 import (
 	"fmt"
-	"html/template"
 	"regexp"
 	"sort"
 	"strconv"
@@ -33,7 +35,7 @@ import (
 )
 
 const (
-	cacheKey      = "download_list_4" // increment if listTemplateData changes
+	cacheKey      = "download_list_5" // increment if listTemplateData changes
 	cacheDuration = time.Hour
 )
 
@@ -58,6 +60,9 @@ func (f File) ChecksumType() string {
 	return "SHA1"
 }
 
+func (f File) PrettyArch() string { return pretty(f.Arch) }
+func (f File) PrettyKind() string { return pretty(f.Kind) }
+
 func (f File) PrettyChecksum() string {
 	if f.ChecksumSHA256 != "" {
 		return f.ChecksumSHA256
@@ -177,14 +182,8 @@ var featuredFiles = []Feature{
 type listTemplateData struct {
 	Featured                  []Feature
 	Stable, Unstable, Archive []Release
-	GoogleCN                  bool
 }
 
-var (
-	listTemplate  = template.Must(template.New("").Funcs(templateFuncs).Parse(templateHTML))
-	templateFuncs = template.FuncMap{"pretty": pretty}
-)
-
 func filesToFeatured(fs []File) (featured []Feature) {
 	for _, feature := range featuredFiles {
 		for _, file := range fs {
diff --git a/internal/dl/dl_test.go b/internal/dl/dl_test.go
index 1e562b3f..1a1e6326 100644
--- a/internal/dl/dl_test.go
+++ b/internal/dl/dl_test.go
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build go1.16
+// +build go1.16
+
 package dl
 
 import (
diff --git a/internal/dl/server.go b/internal/dl/server.go
index 7ec45a60..3f8efd41 100644
--- a/internal/dl/server.go
+++ b/internal/dl/server.go
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build go1.16
+// +build go1.16
+
 package dl
 
 import (
@@ -21,15 +24,17 @@ import (
 	"cloud.google.com/go/datastore"
 	"golang.org/x/website/internal/env"
 	"golang.org/x/website/internal/memcache"
+	"golang.org/x/website/internal/web"
 )
 
 type server struct {
+	site      *web.Site
 	datastore *datastore.Client
 	memcache  *memcache.CodecClient
 }
 
-func RegisterHandlers(mux *http.ServeMux, dc *datastore.Client, mc *memcache.Client) {
-	s := server{dc, mc.WithCodec(memcache.Gob)}
+func RegisterHandlers(mux *http.ServeMux, site *web.Site, dc *datastore.Client, mc *memcache.Client) {
+	s := server{site, dc, mc.WithCodec(memcache.Gob)}
 	mux.HandleFunc("/dl", s.getHandler)
 	mux.HandleFunc("/dl/", s.getHandler) // also serves listHandler
 	mux.HandleFunc("/dl/upload", s.uploadHandler)
@@ -49,9 +54,7 @@ func (h server) listHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	ctx := r.Context()
-	d := listTemplateData{
-		GoogleCN: googleCN(r),
-	}
+	d := listTemplateData{}
 
 	if err := h.memcache.Get(ctx, cacheKey, &d); err != nil {
 		if err != memcache.ErrCacheMiss {
@@ -82,9 +85,11 @@ func (h server) listHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if err := listTemplate.ExecuteTemplate(w, "root", d); err != nil {
-		log.Printf("ERROR executing template: %v", err)
-	}
+	h.site.ServePage(w, r, web.Page{
+		Title:    "Downloads",
+		Template: "dl.html",
+		Data:     d,
+	})
 }
 
 // serveJSON serves a JSON representation of d. It assumes that requests are
diff --git a/internal/dl/server_test.go b/internal/dl/server_test.go
index 2cff8d79..8aa52054 100644
--- a/internal/dl/server_test.go
+++ b/internal/dl/server_test.go
@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build go1.16
+// +build go1.16
+
 package dl
 
 import (
diff --git a/internal/dl/tmpl.go b/internal/dl/tmpl.go
deleted file mode 100644
index d0005f21..00000000
--- a/internal/dl/tmpl.go
+++ /dev/null
@@ -1,298 +0,0 @@
-// Copyright 2015 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 dl
-
-// TODO(adg): refactor this to use the tools/godoc/static template.
-
-const templateHTML = `
-{{define "root"}}
-<!DOCTYPE html>
-<html lang="en">
-<meta charset="utf-8">
-<meta name="description" content="Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.">
-<meta name="viewport" content="width=device-width, initial-scale=1">
-<meta name="theme-color" content="#00ADD8">
-<title>Downloads - The Go Programming Language</title>
-<link href="https://fonts.googleapis.com/css?family=Work+Sans:600|Roboto:400,700" rel="stylesheet">
-<link href="https://fonts.googleapis.com/css?family=Product+Sans&text=Supported%20by%20Google&display=swap" rel="stylesheet">
-<link type="text/css" rel="stylesheet" href="/lib/godoc/style.css">
-<script>window.initFuncs = [];</script>
-<style>
-  table.codetable {
-    margin-left: 20px;
-    margin-right: 20px;
-    border-collapse: collapse;
-  }
-  table.codetable tr {
-    background-color: #f0f0f0;
-  }
-  table.codetable tr:nth-child(2n), table.codetable tr.first {
-    background-color: white;
-  }
-  table.codetable td, table.codetable th {
-    white-space: nowrap;
-    padding: 6px 10px;
-  }
-  table.codetable tt {
-    font-size: xx-small;
-  }
-  table.codetable tr.highlight td {
-    font-weight: bold;
-  }
-  a.downloadBox {
-    display: block;
-    color: #222;
-    border: 1px solid #375EAB;
-    border-radius: 5px;
-    background: #E0EBF5;
-    width: 280px;
-    float: left;
-    margin-left: 10px;
-    margin-bottom: 10px;
-    padding: 10px;
-  }
-  a.downloadBox:hover {
-    text-decoration: none;
-  }
-  .downloadBox .platform {
-    font-size: large;
-  }
-  .downloadBox .filename {
-    color: #007d9c;
-    font-weight: bold;
-    line-height: 1.5em;
-  }
-  a.downloadBox:hover .filename {
-    text-decoration: underline;
-  }
-  .downloadBox .size {
-    font-size: small;
-    font-weight: normal;
-  }
-  .downloadBox .reqs {
-    font-size: small;
-    font-style: italic;
-  }
-  .downloadBox .checksum {
-    font-size: 5pt;
-  }
-</style>
-<body class="Site">
-<header class="Header js-header">
-  <div class="Header-banner">
-    Black Lives Matter.
-    <a href="https://support.eji.org/give/153413/#!/donation/checkout"
-       target="_blank"
-       rel="noopener">Support the Equal Justice Initiative.</a>
-  </div>
-  <nav class="Header-nav">
-    <a href="/"><img class="Header-logo" src="/lib/godoc/images/go-logo-blue.svg" alt="Go"></a>
-    <button class="Header-menuButton js-headerMenuButton" aria-label="Main menu" aria-expanded="false">
-      <div class="Header-menuButtonInner"></div>
-    </button>
-    <ul class="Header-menu">
-      <li class="Header-menuItem"><a href="/doc/">Documents</a></li>
-      <li class="Header-menuItem"><a href="/pkg/">Packages</a></li>
-      <li class="Header-menuItem"><a href="/project/">The Project</a></li>
-      <li class="Header-menuItem"><a href="/help/">Help</a></li>
-      {{if not .GoogleCN}}
-        <li class="Header-menuItem"><a href="/blog/">Blog</a></li>
-        <li class="Header-menuItem"><a href="https://play.golang.org/">Play</a></li>
-      {{end}}
-    </ul>
-  </nav>
-</header>
-
-<main id="page" class="Site-content">
-<div class="container">
-
-<h1>Downloads</h1>
-
-<p>
-After downloading a binary release suitable for your system,
-please follow the <a href="/doc/install">installation instructions</a>.
-</p>
-
-<p>
-If you are building from source,
-follow the <a href="/doc/install/source">source installation instructions</a>.
-</p>
-
-<p>
-See the <a href="/doc/devel/release.html">release history</a> for more
-information about Go releases.
-</p>
-
-<p>
-  As of Go 1.13, the go command by default downloads and authenticates
-  modules using the Go module mirror and Go checksum database run by Google. See
-  <a href="https://proxy.golang.org/privacy">https://proxy.golang.org/privacy</a>
-  for privacy information about these services and the
-  <a href="/cmd/go/">go command documentation</a>
-  for configuration details including how to disable the use of these servers or use
-  different ones.
-</p>
-
-{{with .Featured}}
-<h3 id="featured">Featured downloads</h3>
-{{range .}}
-{{template "download" .}}
-{{end}}
-{{end}}
-
-<div style="clear: both;"></div>
-
-{{with .Stable}}
-<h3 id="stable">Stable versions</h3>
-{{template "releases" .}}
-{{end}}
-
-{{with .Unstable}}
-<h3 id="unstable">Unstable version</h3>
-{{template "releases" .}}
-{{end}}
-
-{{with .Archive}}
-<div class="toggle" id="archive">
-  <div class="collapsed">
-    <h3 class="toggleButton" title="Click to show versions">Archived versions ▹</h3>
-  </div>
-  <div class="expanded">
-    <h3 class="toggleButton" title="Click to hide versions">Archived versions ▾</h3>
-    {{template "releases" .}}
-  </div>
-</div>
-{{end}}
-
-</div><!-- .container -->
-</main><!-- #page -->
-<footer>
-  <div class="Footer">
-    <img class="Footer-gopher" src="/lib/godoc/images/footer-gopher.jpg" alt="The Go Gopher">
-    <ul class="Footer-links">
-      <li class="Footer-link"><a href="/doc/copyright.html">Copyright</a></li>
-      <li class="Footer-link"><a href="/doc/tos.html">Terms of Service</a></li>
-      <li class="Footer-link"><a href="http://www.google.com/intl/en/policies/privacy/">Privacy Policy</a></li>
-      <li class="Footer-link"><a href="http://golang.org/issues/new?title=x/website:" target="_blank" rel="noopener">Report a website issue</a></li>
-    </ul>
-    <a class="Footer-supportedBy" href="https://google.com">Supported by Google</a>
-  </div>
-</footer>
-<script>
-  (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
-  (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
-  m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
-  })(window,document,'script','//www.google-analytics.com/analytics.js','ga');
-
-  ga('create', 'UA-11222381-2', 'auto');
-  ga('send', 'pageview');
-
-</script>
-</body>
-<script src="/lib/godoc/jquery.js"></script>
-<script src="/lib/godoc/godocs.js"></script>
-<script>
-$(document).ready(function() {
-  $('a.download').click(function(e) {
-    // Try using the link text as the file name,
-    // unless there's a child element of class 'filename'.
-    var filename = $(this).text();
-    var child = $(this).find('.filename');
-    if (child.length > 0) {
-      filename = child.text();
-    }
-
-    // This must be kept in sync with the filenameRE in godocs.js.
-    var filenameRE = /^go1\.\d+(\.\d+)?([a-z0-9]+)?\.([a-z0-9]+)(-[a-z0-9]+)?(-osx10\.[68])?\.([a-z.]+)$/;
-    var m = filenameRE.exec(filename);
-    if (!m) {
-      // Don't redirect to the download page if it won't recognize this file.
-      // (Should not happen.)
-      return;
-    }
-
-    var dest = "/doc/install";
-    if (filename.indexOf(".src.") != -1) {
-      dest += "/source";
-    }
-    dest += "?download=" + filename;
-
-    e.preventDefault();
-    e.stopPropagation();
-    window.location = dest;
-  });
-});
-</script>
-{{end}}
-
-{{define "releases"}}
-{{range .}}
-<div class="toggle{{if .Visible}}Visible{{end}}" id="{{.Version}}">
-	<div class="collapsed">
-		<h2 class="toggleButton" title="Click to show downloads for this version">{{.Version}} ▹</h2>
-	</div>
-	<div class="expanded">
-		<h2 class="toggleButton" title="Click to hide downloads for this version">{{.Version}} ▾</h2>
-		{{if .Stable}}{{else}}
-			<p>This is an <b>unstable</b> version of Go. Use with caution.</p>
-			<p>If you already have Go installed, you can install this version by running:</p>
-<pre>
-go get golang.org/dl/{{.Version}}
-</pre>
-			<p>Then, use the <code>{{.Version}}</code> command instead of the <code>go</code> command to use {{.Version}}.</p>
-		{{end}}
-		{{template "files" .}}
-	</div>
-</div>
-{{end}}
-{{end}}
-
-{{define "files"}}
-<table class="codetable">
-<thead>
-<tr class="first">
-  <th>File name</th>
-  <th>Kind</th>
-  <th>OS</th>
-  <th>Arch</th>
-  <th>Size</th>
-  {{/* Use the checksum type of the first file for the column heading. */}}
-  <th>{{(index .Files 0).ChecksumType}} Checksum</th>
-</tr>
-</thead>
-{{if .SplitPortTable}}
-  {{range .Files}}{{if .PrimaryPort}}{{template "file" .}}{{end}}{{end}}
-
-  {{/* TODO(cbro): add a link to an explanatory doc page */}}
-  <tr class="first"><th colspan="6" class="first">Other Ports</th></tr>
-  {{range .Files}}{{if not .PrimaryPort}}{{template "file" .}}{{end}}{{end}}
-{{else}}
-  {{range .Files}}{{template "file" .}}{{end}}
-{{end}}
-</table>
-{{end}}
-
-{{define "file"}}
-<tr{{if .Highlight}} class="highlight"{{end}}>
-  <td class="filename"><a class="download" href="{{.URL}}">{{.Filename}}</a></td>
-  <td>{{pretty .Kind}}</td>
-  <td>{{.PrettyOS}}</td>
-  <td>{{pretty .Arch}}</td>
-  <td>{{.PrettySize}}</td>
-  <td><tt>{{.PrettyChecksum}}</tt></td>
-</tr>
-{{end}}
-
-{{define "download"}}
-<a class="download downloadBox" href="{{.URL}}">
-<div class="platform">{{.Platform}}</div>
-{{with .Requirements}}<div class="reqs">{{.}}</div>{{end}}
-<div>
-  <span class="filename">{{.Filename}}</span>
-  {{if .Size}}<span class="size">({{.PrettySize}})</span>{{end}}
-</div>
-</a>
-{{end}}
-`