rustdoc/formats/
renderer.rs

1use rustc_data_structures::profiling::SelfProfilerRef;
2use rustc_middle::ty::TyCtxt;
3
4use crate::clean;
5use crate::config::RenderOptions;
6use crate::error::Error;
7use crate::formats::cache::Cache;
8
9/// Allows for different backends to rustdoc to be used with the `run_format()` function. Each
10/// backend renderer has hooks for initialization, documenting an item, entering and exiting a
11/// module, and cleanup/finalizing output.
12pub(crate) trait FormatRenderer<'tcx>: Sized {
13    /// Gives a description of the renderer. Used for performance profiling.
14    fn descr() -> &'static str;
15
16    /// Whether to call `item` recursively for modules
17    ///
18    /// This is true for html, and false for json. See #80664
19    const RUN_ON_MODULE: bool;
20
21    /// This associated type is the type where the current module information is stored.
22    ///
23    /// For each module, we go through their items by calling for each item:
24    ///
25    /// 1. `save_module_data`
26    /// 2. `item`
27    /// 3. `restore_module_data`
28    ///
29    /// This is because the `item` method might update information in `self` (for example if the child
30    /// is a module). To prevent it from impacting the other children of the current module, we need to
31    /// reset the information between each call to `item` by using `restore_module_data`.
32    type ModuleData;
33
34    /// This method is called right before call [`Self::item`]. This method returns a type
35    /// containing information that needs to be reset after the [`Self::item`] method has been
36    /// called with the [`Self::restore_module_data`] method.
37    ///
38    /// In short it goes like this:
39    ///
40    /// ```ignore (not valid code)
41    /// let reset_data = renderer.save_module_data();
42    /// renderer.item(item)?;
43    /// renderer.restore_module_data(reset_data);
44    /// ```
45    fn save_module_data(&mut self) -> Self::ModuleData;
46    /// Used to reset current module's information.
47    fn restore_module_data(&mut self, info: Self::ModuleData);
48
49    /// Renders a single non-module item. This means no recursive sub-item rendering is required.
50    fn item(&mut self, item: &clean::Item) -> Result<(), Error>;
51
52    /// Renders a module (should not handle recursing into children).
53    fn mod_item_in(&mut self, item: &clean::Item) -> Result<(), Error>;
54
55    /// Runs after recursively rendering all sub-items of a module.
56    fn mod_item_out(&mut self) -> Result<(), Error> {
57        Ok(())
58    }
59
60    /// Post processing hook for cleanup and dumping output to files.
61    fn after_krate(self) -> Result<(), Error>;
62}
63
64fn run_format_inner<'tcx, T: FormatRenderer<'tcx>>(
65    cx: &mut T,
66    item: &clean::Item,
67    prof: &SelfProfilerRef,
68) -> Result<(), Error> {
69    if item.is_mod() && T::RUN_ON_MODULE {
70        // modules are special because they add a namespace. We also need to
71        // recurse into the items of the module as well.
72        let _timer =
73            prof.generic_activity_with_arg("render_mod_item", item.name.unwrap().to_string());
74
75        cx.mod_item_in(item)?;
76        let (clean::StrippedItem(box clean::ModuleItem(ref module))
77        | clean::ModuleItem(ref module)) = item.inner.kind
78        else {
79            unreachable!()
80        };
81        for it in module.items.iter() {
82            let info = cx.save_module_data();
83            run_format_inner(cx, it, prof)?;
84            cx.restore_module_data(info);
85        }
86
87        cx.mod_item_out()?;
88    // FIXME: checking `item.name.is_some()` is very implicit and leads to lots of special
89    // cases. Use an explicit match instead.
90    } else if let Some(item_name) = item.name
91        && !item.is_extern_crate()
92    {
93        prof.generic_activity_with_arg("render_item", item_name.as_str()).run(|| cx.item(item))?;
94    }
95    Ok(())
96}
97
98/// Main method for rendering a crate.
99pub(crate) fn run_format<
100    'tcx,
101    T: FormatRenderer<'tcx>,
102    F: FnOnce(clean::Crate, RenderOptions, Cache, TyCtxt<'tcx>) -> Result<(T, clean::Crate), Error>,
103>(
104    krate: clean::Crate,
105    options: RenderOptions,
106    cache: Cache,
107    tcx: TyCtxt<'tcx>,
108    init: F,
109) -> Result<(), Error> {
110    let prof = &tcx.sess.prof;
111
112    let emit_crate = options.should_emit_crate();
113    let (mut format_renderer, krate) = prof
114        .verbose_generic_activity_with_arg("create_renderer", T::descr())
115        .run(|| init(krate, options, cache, tcx))?;
116
117    if !emit_crate {
118        return Ok(());
119    }
120
121    // Render the crate documentation
122    run_format_inner(&mut format_renderer, &krate.module, prof)?;
123
124    prof.verbose_generic_activity_with_arg("renderer_after_krate", T::descr())
125        .run(|| format_renderer.after_krate())
126}
rustdoc/formats/renderer.rs

rustdoc/formats/
renderer.rs
