rustdoc-json: Clean up serialization and printing.

src/librustdoc/json/mod.rs

@@ -39,8 +39,10 @@ pub(crate) struct JsonRenderer<'tcx> {
  /// A mapping of IDs that contains all local items for this crate which gets output as a top
  /// level field of the JSON blob.
  index: Rc<RefCell<FxHashMap<types::Id, types::Item>>>,
- /// The directory where the blob will be written to.
- out_path: Option<PathBuf>,
+ /// The directory where the JSON blob should be written to.
+ ///
+ /// If this is `None`, the blob will be printed to `stdout` instead.
+ out_dir: Option<PathBuf>,
  cache: Rc<Cache>,
  imported_items: DefIdSet,
 }
@@ -101,18 +103,20 @@ impl<'tcx> JsonRenderer<'tcx> {
  .unwrap_or_default()
  }
 
- fn write<T: Write>(
+ fn serialize_and_write<T: Write>(
  &self,
- output: types::Crate,
+ output_crate: types::Crate,
  mut writer: BufWriter<T>,
  path: &str,
  ) -> Result<(), Error> {
- self.tcx
- .sess
- .time("rustdoc_json_serialization", || serde_json::ser::to_writer(&mut writer, &output))
- .unwrap();
- try_err!(writer.flush(), path);
- Ok(())
+ self.sess().time("rustdoc_json_serialize_and_write", || {
+ try_err!(
+ serde_json::ser::to_writer(&mut writer, &output_crate).map_err(|e| e.to_string()),
+ path
+ );
+ try_err!(writer.flush(), path);
+ Ok(())
+ })
  }
 }
 
@@ -137,7 +141,7 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
  JsonRenderer {
  tcx,
  index: Rc::new(RefCell::new(FxHashMap::default())),
- out_path: if options.output_to_stdout { None } else { Some(options.output) },
+ out_dir: if options.output_to_stdout { None } else { Some(options.output) },
  cache: Rc::new(cache),
  imported_items,
  },
@@ -237,7 +241,7 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
  let index = (*self.index).clone().into_inner();
 
  debug!("Constructing Output");
- let output = types::Crate {
+ let output_crate = types::Crate {
  root: types::Id(format!("0:0:{}", e.name(self.tcx).as_u32())),
  crate_version: self.cache.crate_version.clone(),
  includes_private: self.cache.document_private,
@@ -278,20 +282,20 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
  .collect(),
  format_version: types::FORMAT_VERSION,
  };
- if let Some(ref out_path) = self.out_path {
- let out_dir = out_path.clone();
+ if let Some(ref out_dir) = self.out_dir {
  try_err!(create_dir_all(&out_dir), out_dir);
 
- let mut p = out_dir;
- p.push(output.index.get(&output.root).unwrap().name.clone().unwrap());
+ let mut p = out_dir.clone();
+ p.push(output_crate.index.get(&output_crate.root).unwrap().name.clone().unwrap());
  p.set_extension("json");
- self.write(
- output,
+
+ self.serialize_and_write(
+ output_crate,
  BufWriter::new(try_err!(File::create(&p), p)),
  &p.display().to_string(),
  )
  } else {
- self.write(output, BufWriter::new(stdout()), "<stdout>")
+ self.serialize_and_write(output_crate, BufWriter::new(stdout().lock()), "<stdout>")
  }
  }