Rollup merge of rust-lang#40332 - steveklabnik:extract-book, r=alexcrichton

Extract book into a submodule

Part of rust-lang#39588

We probably don't want to land this till after the beta branches on friday, but would still ❤️ a review from @alexcrichton , since I am a rustbuild noob.

This pr:

1. removes the book
2. adds it back in as a submodule
3. the submodule includes both the old book and the new book
4. it also includes an index page explaining the difference in editions
5. it also includes redirect pages for the old book URLs.
6. so we build all that stuff too.

r? @alexcrichton

Author: frewsxcv

.gitmodules

@@ -27,3 +27,6 @@
 [submodule "reference"]
 	path = src/doc/reference
 	url = https://github.com/rust-lang-nursery/reference.git
+[submodule "book"]
+	path = src/doc/book
+	url = https://github.com/rust-lang/book

src/bootstrap/check.rs

@@ -285,6 +285,16 @@ pub fn docs(build: &Build, compiler: &Compiler) {
             continue
         }
 
+        // The nostarch directory in the book is for no starch, and so isn't guaranteed to build.
+        // we don't care if it doesn't build, so skip it.
+        use std::ffi::OsStr;
+        let path: &OsStr = p.as_ref();
+        if let Some(path) = path.to_str() {
+            if path.contains("nostarch") {
+                continue;
+            }
+        }
+
         println!("doc tests for: {}", p.display());
         markdown_test(build, compiler, &p);
     }

src/bootstrap/doc.rs

@@ -53,6 +53,82 @@ pub fn rustbook(build: &Build, target: &str, name: &str) {
                    .arg(out));
 }
 
+/// Build the book and associated stuff.
+///
+/// We need to build:
+///
+/// * Book (first edition)
+/// * Book (second edition)
+/// * Index page
+/// * Redirect pages
+pub fn book(build: &Build, target: &str, name: &str) {
+    // build book first edition
+    rustbook(build, target, &format!("{}/first-edition", name));
+
+    // build book second edition
+    rustbook(build, target, &format!("{}/second-edition", name));
+
+    // build the index page
+    let index = format!("{}/index.md", name);
+    println!("Documenting book index ({})", target);
+    invoke_rustdoc(build, target, &index);
+
+    // build the redirect pages
+    println!("Documenting book redirect pages ({})", target);
+    for file in t!(fs::read_dir(build.src.join("src/doc/book/redirects"))) {
+        let file = t!(file);
+        let path = file.path();
+        let path = path.to_str().unwrap();
+
+        invoke_rustdoc(build, target, path);
+    }
+}
+
+fn invoke_rustdoc(build: &Build, target: &str, markdown: &str) {
+    let out = build.doc_out(target);
+
+    let compiler = Compiler::new(0, &build.config.build);
+
+    let path = build.src.join("src/doc").join(markdown);
+
+    let rustdoc = build.rustdoc(&compiler);
+
+    let favicon = build.src.join("src/doc/favicon.inc");
+    let footer = build.src.join("src/doc/footer.inc");
+
+    let version_input = build.src.join("src/doc/version_info.html.template");
+    let version_info = out.join("version_info.html");
+
+    if !up_to_date(&version_input, &version_info) {
+        let mut info = String::new();
+        t!(t!(File::open(&version_input)).read_to_string(&mut info));
+        let info = info.replace("VERSION", &build.rust_release())
+                       .replace("SHORT_HASH", build.rust_info.sha_short().unwrap_or(""))
+                       .replace("STAMP", build.rust_info.sha().unwrap_or(""));
+        t!(t!(File::create(&version_info)).write_all(info.as_bytes()));
+    }
+
+    let mut cmd = Command::new(&rustdoc);
+
+    build.add_rustc_lib_path(&compiler, &mut cmd);
+
+    let out = out.join("book");
+
+    t!(fs::copy(build.src.join("src/doc/rust.css"), out.join("rust.css")));
+
+    cmd.arg("--html-after-content").arg(&footer)
+        .arg("--html-before-content").arg(&version_info)
+        .arg("--html-in-header").arg(&favicon)
+        .arg("--markdown-playground-url")
+        .arg("https://play.rust-lang.org/")
+        .arg("-o").arg(&out)
+        .arg(&path)
+        .arg("--markdown-css")
+        .arg("rust.css");
+
+    build.run(&mut cmd);
+}
+
 /// Generates all standalone documentation as compiled by the rustdoc in `stage`
 /// for the `target` into `out`.
 ///

src/bootstrap/step.rs

@@ -581,7 +581,7 @@ pub fn build_rules<'a>(build: &'a Build) -> Rules {
               .stage(0)
          })
          .default(build.config.docs)
-         .run(move |s| doc::rustbook(build, s.target, "book"));
+         .run(move |s| doc::book(build, s.target, "book"));
     rules.doc("doc-nomicon", "src/doc/nomicon")
          .dep(move |s| {
              s.name("tool-rustbook")