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    /// Sets up any state required for the renderer. When this is called the cache has already been
35    /// populated.
36    fn init(
37        krate: clean::Crate,
38        options: RenderOptions,
39        cache: Cache,
40        tcx: TyCtxt<'tcx>,
41    ) -> Result<(Self, clean::Crate), Error>;
42
43    /// This method is called right before call [`Self::item`]. This method returns a type
44    /// containing information that needs to be reset after the [`Self::item`] method has been
45    /// called with the [`Self::restore_module_data`] method.
46    ///
47    /// In short it goes like this:
48    ///
49    /// ```ignore (not valid code)
50    /// let reset_data = renderer.save_module_data();
51    /// renderer.item(item)?;
52    /// renderer.restore_module_data(reset_data);
53    /// ```
54    fn save_module_data(&mut self) -> Self::ModuleData;
55    /// Used to reset current module's information.
56    fn restore_module_data(&mut self, info: Self::ModuleData);
57
58    /// Renders a single non-module item. This means no recursive sub-item rendering is required.
59    fn item(&mut self, item: &clean::Item) -> Result<(), Error>;
60
61    /// Renders a module (should not handle recursing into children).
62    fn mod_item_in(&mut self, item: &clean::Item) -> Result<(), Error>;
63
64    /// Runs after recursively rendering all sub-items of a module.
65    fn mod_item_out(&mut self) -> Result<(), Error> {
66        Ok(())
67    }
68
69    /// Post processing hook for cleanup and dumping output to files.
70    fn after_krate(self) -> Result<(), Error>;
71}
72
73fn run_format_inner<'tcx, T: FormatRenderer<'tcx>>(
74    cx: &mut T,
75    item: &clean::Item,
76    prof: &SelfProfilerRef,
77) -> Result<(), Error> {
78    if item.is_mod() && T::RUN_ON_MODULE {
79        // modules are special because they add a namespace. We also need to
80        // recurse into the items of the module as well.
81        let _timer =
82            prof.generic_activity_with_arg("render_mod_item", item.name.unwrap().to_string());
83
84        cx.mod_item_in(&item)?;
85        let (clean::StrippedItem(box clean::ModuleItem(ref module))
86        | clean::ModuleItem(ref module)) = item.inner.kind
87        else {
88            unreachable!()
89        };
90        for it in module.items.iter() {
91            let info = cx.save_module_data();
92            run_format_inner(cx, it, prof)?;
93            cx.restore_module_data(info);
94        }
95
96        cx.mod_item_out()?;
97    // FIXME: checking `item.name.is_some()` is very implicit and leads to lots of special
98    // cases. Use an explicit match instead.
99    } else if let Some(item_name) = item.name
100        && !item.is_extern_crate()
101    {
102        prof.generic_activity_with_arg("render_item", item_name.as_str()).run(|| cx.item(&item))?;
103    }
104    Ok(())
105}
106
107/// Main method for rendering a crate.
108pub(crate) fn run_format<'tcx, T: FormatRenderer<'tcx>>(
109    krate: clean::Crate,
110    options: RenderOptions,
111    cache: Cache,
112    tcx: TyCtxt<'tcx>,
113) -> Result<(), Error> {
114    let prof = &tcx.sess.prof;
115
116    let emit_crate = options.should_emit_crate();
117    let (mut format_renderer, krate) = prof
118        .verbose_generic_activity_with_arg("create_renderer", T::descr())
119        .run(|| T::init(krate, options, cache, tcx))?;
120
121    if !emit_crate {
122        return Ok(());
123    }
124
125    // Render the crate documentation
126    run_format_inner(&mut format_renderer, &krate.module, prof)?;
127
128    prof.verbose_generic_activity_with_arg("renderer_after_krate", T::descr())
129        .run(|| format_renderer.after_krate())
130}
rustdoc/formats/renderer.rs

rustdoc/formats/
renderer.rs
