rustdoc: add cli argument --playground-url

Author: liigo

src/librustdoc/html/render.rs

@@ -469,10 +469,8 @@ pub fn run(mut krate: clean::Crate,
                 clean::NameValue(ref x, ref s)
                         if "html_playground_url" == *x => {
                     markdown::PLAYGROUND.with(|slot| {
-                        if slot.borrow().is_none() {
-                            let name = krate.name.clone();
-                            *slot.borrow_mut() = Some((Some(name), s.clone()));
-                        }
+                        let name = krate.name.clone();
+                        *slot.borrow_mut() = Some((Some(name), s.clone()));
                     });
                 }
                 clean::NameValue(ref x, ref s)

src/librustdoc/lib.rs

@@ -162,6 +162,10 @@ pub fn opts() -> Vec<RustcOptGroup> {
         unstable(optmulti("Z", "",
                           "internal and debugging options (only on nightly build)", "FLAG")),
         stable(optopt("", "sysroot", "Override the system root", "PATH")),
+        stable(optopt("", "playground-url",
+                      "URL to send code snippets to, may be reset by --markdown-playground-url \
+                       or `#![doc(html_playground_url=...)]`",
+                      "URL")),
     ]
 }
 
@@ -230,6 +234,10 @@ pub fn main_args(args: &[String]) -> isize {
         }
     };
 
+    if let Some(playground) = matches.opt_str("playground-url") {
+        html::markdown::PLAYGROUND.with(|s| { *s.borrow_mut() = Some((None, playground)); });
+    }
+
     let test_args = matches.opt_strs("test-args");
     let test_args: Vec<String> = test_args.iter()
                                           .flat_map(|s| s.split_whitespace())