rustdoc/formats/
renderer.rs

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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(&mut self) -> Result<(), Error>;
71
72    fn cache(&self) -> &Cache;
73}
74
75fn run_format_inner<'tcx, T: FormatRenderer<'tcx>>(
76    cx: &mut T,
77    item: clean::Item,
78    prof: &SelfProfilerRef,
79) -> Result<(), Error> {
80    if item.is_mod() && T::RUN_ON_MODULE {
81        // modules are special because they add a namespace. We also need to
82        // recurse into the items of the module as well.
83        let _timer =
84            prof.generic_activity_with_arg("render_mod_item", item.name.unwrap().to_string());
85
86        cx.mod_item_in(&item)?;
87        let (clean::StrippedItem(box clean::ModuleItem(module)) | clean::ModuleItem(module)) =
88            item.inner.kind
89        else {
90            unreachable!()
91        };
92        for it in module.items {
93            let info = cx.save_module_data();
94            run_format_inner(cx, it, prof)?;
95            cx.restore_module_data(info);
96        }
97
98        cx.mod_item_out()?;
99    // FIXME: checking `item.name.is_some()` is very implicit and leads to lots of special
100    // cases. Use an explicit match instead.
101    } else if let Some(item_name) = item.name
102        && !item.is_extern_crate()
103    {
104        prof.generic_activity_with_arg("render_item", item_name.as_str()).run(|| cx.item(item))?;
105    }
106    Ok(())
107}
108
109/// Main method for rendering a crate.
110pub(crate) fn run_format<'tcx, T: FormatRenderer<'tcx>>(
111    krate: clean::Crate,
112    options: RenderOptions,
113    cache: Cache,
114    tcx: TyCtxt<'tcx>,
115) -> Result<(), Error> {
116    let prof = &tcx.sess.prof;
117
118    let emit_crate = options.should_emit_crate();
119    let (mut format_renderer, krate) = prof
120        .verbose_generic_activity_with_arg("create_renderer", T::descr())
121        .run(|| T::init(krate, options, cache, tcx))?;
122
123    if !emit_crate {
124        return Ok(());
125    }
126
127    // Render the crate documentation
128    run_format_inner(&mut format_renderer, krate.module, prof)?;
129
130    prof.verbose_generic_activity_with_arg("renderer_after_krate", T::descr())
131        .run(|| format_renderer.after_krate())
132}
rustdoc/formats/renderer.rs

rustdoc/formats/
renderer.rs
