From 2cd3c3a67b34ac03519b4c151935255ff537f3ae Mon Sep 17 00:00:00 2001
From: Michael Hatherly <michaelhatherly@gmail.com>
Date: Fri, 18 Nov 2016 11:00:12 +0200
Subject: [PATCH] Add version selector dropdown menu

During `deploydocs` we check what documentation folders are currently
available and write a `versions.js` file to the root of the repo that
contains a list, `DOC_VERSIONS`, which is used to populate the
dropdown menu.
---
 assets/html/documenter.css |  9 +++++++++
 assets/html/documenter.js  |  7 +++++++
 src/Documenter.jl          |  4 ++++
 src/Writers/HTMLWriter.jl  | 40 ++++++++++++++++++++++++++++++++++----
 4 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/assets/html/documenter.css b/assets/html/documenter.css
index a5ffee126e..223d44d0e5 100644
--- a/assets/html/documenter.css
+++ b/assets/html/documenter.css
@@ -158,6 +158,15 @@ nav.toc input {
     font-size: smaller;
 }
 
+nav.toc select {
+    display: block;
+    height: 2em;
+    width: calc(100% - 3em);
+    margin: 5px auto;
+    font-size: smaller;
+    text-align: center;
+}
+
 nav.toc > ul * {
     margin: 0;
 }
diff --git a/assets/html/documenter.js b/assets/html/documenter.js
index 354bc680e9..c86aec0251 100644
--- a/assets/html/documenter.js
+++ b/assets/html/documenter.js
@@ -52,6 +52,13 @@ require(['mathjax'], function(MathJax) {
 
 require(['jquery', 'highlight', 'highlight-julia'], function($, hljs) {
     $(document).ready(function() {
+        if (typeof DOC_VERSIONS !== 'undefined') {
+            var version_selector = $("#version-selector");
+            DOC_VERSIONS.forEach(function(each) {
+                var option = $("<option value='" + documenterBaseURL + "/../" + each + "'>" + each + "</option>");
+                version_selector.append(option);
+            });
+        }
         hljs.initHighlighting();
     })
 
diff --git a/src/Documenter.jl b/src/Documenter.jl
index e9410833bd..acda0196ff 100644
--- a/src/Documenter.jl
+++ b/src/Documenter.jl
@@ -444,6 +444,10 @@ function deploydocs(;
                             end
                         end
 
+                        # Create the versions.js file containing a list of all docs
+                        # versions. This must always happen after the folder copying.
+                        Writers.HTMLWriter.generate_version_file(pwd())
+
                         # Add, commit, and push the docs to the remote.
                         run(`git add -A .`)
                         try run(`git commit -m "build based on $sha"`) end
diff --git a/src/Writers/HTMLWriter.jl b/src/Writers/HTMLWriter.jl
index bf558a6bb6..5c939f38ce 100644
--- a/src/Writers/HTMLWriter.jl
+++ b/src/Writers/HTMLWriter.jl
@@ -192,6 +192,8 @@ function render_head(ctx, navnode, additional_scripts)
             Symbol("data-main") => relhref(src, ctx.documenter_js)
         ],
 
+        script[:src => relhref(src, "../versions.js")],
+
         # Additional JS files needed for the search page.
         [script[:src => relhref(src, each)] for each in additional_scripts],
 
@@ -248,12 +250,12 @@ end
 # ------------------------------------------------------------------------------
 
 function render_navmenu(ctx, navnode)
-    @tags a form h1 img input nav
+    @tags a form h1 img input nav div select option
     src = get(navnode.page)
     navmenu = nav[".toc"]
     if !isempty(ctx.logo)
         push!(navmenu.nodes,
-            a[:href => ""]( # TODO: link to github?
+            a[:href => relhref(src, "index.html")](
                 img[
                     ".logo",
                     :src => relhref(src, ctx.logo),
@@ -265,12 +267,22 @@ function render_navmenu(ctx, navnode)
     push!(navmenu.nodes, h1(ctx.doc.user.sitename))
     push!(navmenu.nodes,
         form[".search", :action => relhref(src, "search.html")](
+            select[
+                "#version-selector",
+                :onChange => "window.location.href=this.value",
+            ](
+                option[
+                    :value => "#",
+                    :selected => "selected",
+                    :disabled => "disabled",
+                ]("Version"),
+            ),
             input[
                 "#search-query",
                 :name => "q",
                 :type => "text",
-                :placeholder => "Search docs"
-            ]
+                :placeholder => "Search docs",
+            ],
         )
     )
     push!(navmenu.nodes, navitem(ctx, navnode))
@@ -365,6 +377,26 @@ function render_article(ctx, navnode)
     article["#docs"](art_header, pagenodes, art_footer)
 end
 
+function generate_version_file(dir::AbstractString)
+    local named_folders = []
+    local release_folders = []
+    local tag_folders = []
+    for each in readdir(dir)
+        each in ("stable", "latest")        ? push!(named_folders,   each) :
+        ismatch(r"release\-\d+\.\d+", each) ? push!(release_folders, each) :
+        ismatch(Base.VERSION_REGEX, each)   ? push!(tag_folders,     each) : nothing
+    end
+    open(joinpath(dir, "versions.js"), "w") do buf
+        println(buf, "var DOC_VERSIONS = [")
+        for group in (named_folders, release_folders, tag_folders)
+            for folder in sort!(group, rev = true)
+                println(buf, "  \"", folder, "\",")
+            end
+        end
+        println(buf, "];")
+    end
+end
+
 ## domify(...)
 # ------------