Rollup merge of #36334 - GuillaumeGomez:run_but, r=steveklabnik

Set run button transparent instead of invisible

r? @steveklabnik

And of course a screenshot:

![screenshot from 2016-09-08 01-15-45](https://cloud.githubusercontent.com/assets/3050060/18331849/31fe1f8c-7562-11e6-9ae9-1dab44089ec6.png)

src/librustdoc/html/highlight.rs

@@ -33,7 +33,8 @@ use syntax::parse;
 use syntax_pos::Span;
 
 /// Highlights `src`, returning the HTML output.
-pub fn render_with_highlighting(src: &str, class: Option<&str>, id: Option<&str>) -> String {
+pub fn render_with_highlighting(src: &str, class: Option<&str>, id: Option<&str>,
+                                extension: Option<&str>) -> String {
     debug!("highlighting: ================\n{}\n==============", src);
     let sess = parse::ParseSess::new();
     let fm = sess.codemap().new_filemap("<stdin>".to_string(), None, src.to_string());
@@ -47,6 +48,9 @@ pub fn render_with_highlighting(src: &str, class: Option<&str>, id: Option<&str>
         return format!("<pre>{}</pre>", src);
     }
 
+    if let Some(extension) = extension {
+        write!(out, "{}", extension).unwrap();
+    }
     write_footer(&mut out).unwrap();
     String::from_utf8_lossy(&out[..]).into_owned()
 }

src/librustdoc/html/markdown.rs

@@ -262,9 +262,11 @@ pub fn render(w: &mut fmt::Formatter, s: &str, print_toc: bool) -> fmt::Result {
                                               &Default::default());
                     s.push_str(&format!("<span class='rusttest'>{}</span>", Escape(&test)));
                 });
-                s.push_str(&highlight::render_with_highlighting(&text,
+                s.push_str(&highlight::render_with_highlighting(
+                               &text,
                                Some("rust-example-rendered"),
-                                                                None));
+                               None,
+                               Some("<a class='test-arrow' target='_blank' href=''>Run</a>")));
                 let output = CString::new(s).unwrap();
                 hoedown_buffer_puts(ob, output.as_ptr());
             })

src/librustdoc/html/render.rs

@@ -2954,7 +2954,7 @@ impl<'a> fmt::Display for Source<'a> {
             write!(fmt, "<span id=\"{0}\">{0:1$}</span>\n", i, cols)?;
         }
         write!(fmt, "</pre>")?;
-        write!(fmt, "{}", highlight::render_with_highlighting(s, None, None))?;
+        write!(fmt, "{}", highlight::render_with_highlighting(s, None, None, None))?;
         Ok(())
     }
 }
@@ -2963,6 +2963,7 @@ fn item_macro(w: &mut fmt::Formatter, cx: &Context, it: &clean::Item,
               t: &clean::Macro) -> fmt::Result {
     w.write_str(&highlight::render_with_highlighting(&t.source,
                                                      Some("macro"),
+                                                     None,
                                                      None))?;
     render_stability_since_raw(w, it.stable_since(), None)?;
     document(w, cx, it)

src/librustdoc/html/static/playpen.js

@@ -27,9 +27,7 @@ document.addEventListener('DOMContentLoaded', function() {
                 return;
             }
 
-            var a = document.createElement('a');
-            a.setAttribute('class', 'test-arrow');
-            a.textContent = 'Run';
+            var a = el.querySelectorAll('a.test-arrow')[0];
 
             var code = el.previousElementSibling.textContent;
 
@@ -40,17 +38,6 @@ document.addEventListener('DOMContentLoaded', function() {
 
             a.setAttribute('href', window.playgroundUrl + '?code=' +
                            encodeURIComponent(code) + channel);
-            a.setAttribute('target', '_blank');
-
-            el.appendChild(a);
-        };
-
-        el.onmouseout = function(e) {
-            if (el.contains(e.relatedTarget)) {
-                return;
-            }
-
-            el.removeChild(el.querySelectorAll('a.test-arrow')[0]);
         };
     });
 });

src/librustdoc/html/static/rustdoc.css

@@ -568,15 +568,18 @@ pre.rust .lifetime { color: #B76514; }
 .rusttest { display: none; }
 pre.rust { position: relative; }
 a.test-arrow {
+    background-color: rgba(78, 139, 202, 0.2);
     display: inline-block;
     position: absolute;
-    background-color: #4e8bca;
     padding: 5px 10px 5px 10px;
     border-radius: 5px;
     font-size: 130%;
     top: 5px;
     right: 5px;
 }
+a.test-arrow:hover{
+    background-color: #4e8bca;
+}
 
 .section-header:hover a:after {
     content: '\2002\00a7\2002';