Rollup merge of rust-lang#83478 - jyn514:fine-grained-files, r=Mark-Simulacrum

rustdoc: Add unstable option to only emit shared/crate-specific files

The intended use case is for docs.rs, which can now copy exactly the
files it cares about, rather than having to guess based on whether they
have a resource suffix or not. In particular, some files have a resource
suffix but cannot be shared between crates: rust-lang/docs.rs#1312 (comment)

The end goal is to fix rust-lang/docs.rs#1327 by reverting rust-lang/docs.rs#1324.

This obsoletes `--print=unversioned-files`, which I plan to remove as
soon as docs.rs stops using it.

I recommend reviewing this one commit at a time.

r? `@GuillaumeGomez` cc `@Nemo157` `@pietroalbini`

Author: Dylan-DPC

src/librustdoc/config.rs

@@ -3,6 +3,7 @@ use std::convert::TryFrom;
 use std::ffi::OsStr;
 use std::fmt;
 use std::path::PathBuf;
+use std::str::FromStr;
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_session::config::{self, parse_crate_types_from_list, parse_externs, CrateType};
@@ -266,6 +267,34 @@ crate struct RenderOptions {
     /// If `true`, generate a JSON file in the crate folder instead of HTML redirection files.
     crate generate_redirect_map: bool,
     crate unstable_features: rustc_feature::UnstableFeatures,
+    crate emit: Vec<EmitType>,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+crate enum EmitType {
+    Unversioned,
+    Toolchain,
+    InvocationSpecific,
+}
+
+impl FromStr for EmitType {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        use EmitType::*;
+        match s {
+            "unversioned-shared-resources" => Ok(Unversioned),
+            "toolchain-shared-resources" => Ok(Toolchain),
+            "invocation-specific" => Ok(InvocationSpecific),
+            _ => Err(()),
+        }
+    }
+}
+
+impl RenderOptions {
+    crate fn should_emit_crate(&self) -> bool {
+        self.emit.is_empty() || self.emit.contains(&EmitType::InvocationSpecific)
+    }
 }
 
 impl Options {
@@ -334,6 +363,19 @@ impl Options {
         // check for deprecated options
         check_deprecated_options(&matches, &diag);
 
+        let mut emit = Vec::new();
+        for list in matches.opt_strs("emit") {
+            for kind in list.split(',') {
+                match kind.parse() {
+                    Ok(kind) => emit.push(kind),
+                    Err(()) => {
+                        diag.err(&format!("unrecognized emission type: {}", kind));
+                        return Err(1);
+                    }
+                }
+            }
+        }
+
         let to_check = matches.opt_strs("check-theme");
         if !to_check.is_empty() {
             let paths = theme::load_css_paths(static_files::themes::LIGHT.as_bytes());
@@ -641,6 +683,7 @@ impl Options {
                 unstable_features: rustc_feature::UnstableFeatures::from_environment(
                     crate_name.as_deref(),
                 ),
+                emit,
             },
             crate_name,
             output_format,

src/librustdoc/formats/renderer.rs

@@ -63,10 +63,15 @@ crate fn run_format<'tcx, T: FormatRenderer<'tcx>>(
 ) -> Result<(), Error> {
     let prof = &tcx.sess.prof;
 
+    let emit_crate = options.should_emit_crate();
     let (mut format_renderer, krate) = prof
         .extra_verbose_generic_activity("create_renderer", T::descr())
         .run(|| T::init(krate, options, edition, cache, tcx))?;
 
+    if !emit_crate {
+        return Ok(());
+    }
+
     // Render the crate documentation
     let crate_name = krate.name;
     let mut work = vec![(format_renderer.make_child_renderer(), krate.module)];

src/librustdoc/html/render/context.rs

@@ -79,17 +79,6 @@ crate struct Context<'tcx> {
 rustc_data_structures::static_assert_size!(Context<'_>, 152);
 
 impl<'tcx> Context<'tcx> {
-    pub(super) fn path(&self, filename: &str) -> PathBuf {
-        // We use splitn vs Path::extension here because we might get a filename
-        // like `style.min.css` and we want to process that into
-        // `style-suffix.min.css`.  Path::extension would just return `css`
-        // which would result in `style.min-suffix.css` which isn't what we
-        // want.
-        let (base, ext) = filename.split_once('.').unwrap();
-        let filename = format!("{}{}.{}", base, self.shared.resource_suffix, ext);
-        self.dst.join(&filename)
-    }
-
     pub(super) fn tcx(&self) -> TyCtxt<'tcx> {
         self.shared.tcx
     }
@@ -301,6 +290,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
     ) -> Result<(Self, clean::Crate), Error> {
         // need to save a copy of the options for rendering the index page
         let md_opts = options.clone();
+        let emit_crate = options.should_emit_crate();
         let RenderOptions {
             output,
             external_html,
@@ -406,7 +396,9 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
 
         let dst = output;
         scx.ensure_dir(&dst)?;
-        krate = sources::render(&dst, &mut scx, krate)?;
+        if emit_crate {
+            krate = sources::render(&dst, &mut scx, krate)?;
+        }
 
         // Build our search index
         let index = build_index(&krate, &mut cache, tcx);
@@ -489,7 +481,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
             |buf: &mut Buffer| all.print(buf),
             &self.shared.style_files,
         );
-        self.shared.fs.write(&final_file, v.as_bytes())?;
+        self.shared.fs.write(final_file, v.as_bytes())?;
 
         // Generating settings page.
         page.title = "Rustdoc settings";