Add CLI option to setup favicon

src/librustdoc/config.rs

@@ -198,6 +198,8 @@ pub struct RenderOptions {
     pub generate_search_filter: bool,
     /// Option (disabled by default) to generate files used by RLS and some other tools.
     pub generate_redirect_pages: bool,
+    /// An optional path to to the favicon file to use.
+    pub favicon: Option<PathBuf>,
 }
 
 impl Options {
@@ -429,6 +431,14 @@ impl Options {
             }
         });
 
+        let favicon = matches.opt_str("favicon-path").map(|s| PathBuf::from(&s));
+        if let Some(ref favicon) = favicon {
+            if !favicon.is_file() {
+                diag.struct_err("option `--favicon-path` argument must be a file").emit();
+                return Err(1);
+            }
+        }
+
         let show_coverage = matches.opt_present("show-coverage");
         let document_private = matches.opt_present("document-private-items");
 
@@ -508,6 +518,7 @@ impl Options {
                 markdown_playground_url,
                 generate_search_filter,
                 generate_redirect_pages,
+                favicon,
             }
         })
     }

src/librustdoc/html/layout.rs

@@ -9,6 +9,7 @@ use crate::html::render::SlashChecker;
 pub struct Layout {
     pub logo: String,
     pub favicon: String,
+    pub favicon_path: Option<PathBuf>,
     pub external_html: ExternalHtml,
     pub krate: String,
 }
@@ -197,7 +198,11 @@ pub fn render<T: fmt::Display, S: fmt::Display>(
     title     = page.title,
     description = page.description,
     keywords = page.keywords,
-    favicon   = if layout.favicon.is_empty() {
+    favicon   = if layout.favicon_path.is_some() {
+        format!(r#"<link rel="shortcut icon" href="{static_root_path}{path}">"#,
+                static_root_path=static_root_path,
+                path=layout.favicon)
+    } else if layout.favicon.is_empty() {
         format!(r#"<link rel="shortcut icon" href="{static_root_path}favicon{suffix}.ico">"#,
                 static_root_path=static_root_path,
                 suffix=page.resource_suffix)

src/librustdoc/html/render.rs

@@ -527,6 +527,7 @@ pub fn run(mut krate: clean::Crate,
         static_root_path,
         generate_search_filter,
         generate_redirect_pages,
+        favicon,
         ..
     } = options;
 
@@ -545,7 +546,10 @@ pub fn run(mut krate: clean::Crate,
         issue_tracker_base_url: None,
         layout: layout::Layout {
             logo: String::new(),
-            favicon: String::new(),
+            favicon: favicon.as_ref()
+                            .map(|_| format!("favicon-{}.ico", krate.name))
+                            .unwrap_or_else(String::new),
+            favicon_path: favicon,
             external_html,
             krate: krate.name.clone(),
         },
@@ -572,7 +576,16 @@ pub fn run(mut krate: clean::Crate,
         for attr in attrs.lists("doc") {
             match (attr.name_or_empty().get(), attr.value_str()) {
                 ("html_favicon_url", Some(s)) => {
-                    scx.layout.favicon = s.to_string();
+                    let s = s.to_string();
+                    if scx.layout.favicon_path.is_some() {
+                        if !s.is_empty() {
+                            diag.struct_warn("`favicon-path` option has been passed, ignoring \
+                                              `html_favicon_url` attribute")
+                                .emit();
+                        }
+                    } else {
+                        scx.layout.favicon = s;
+                    }
                 }
                 ("html_logo_url", Some(s)) => {
                     scx.layout.logo = s.to_string();
@@ -816,7 +829,10 @@ fn write_shared(
         write(cx.dst.join(&format!("rust-logo{}.png", cx.shared.resource_suffix)),
               static_files::RUST_LOGO)?;
     }
-    if (*cx.shared).layout.favicon.is_empty() {
+    if let Some(ref favicon) = (*cx.shared).layout.favicon_path {
+        let content = try_err!(fs::read(&favicon), &favicon);
+        write(cx.dst.join(&(*cx.shared).layout.favicon), &content)?;
+    } else if (*cx.shared).layout.favicon.is_empty() {
         write(cx.dst.join(&format!("favicon{}.ico", cx.shared.resource_suffix)),
               static_files::RUST_FAVICON)?;
     }

src/librustdoc/lib.rs

@@ -356,6 +356,12 @@ fn opts() -> Vec<RustcOptGroup> {
                       "show-coverage",
                       "calculate percentage of public items with documentation")
         }),
+        unstable("favicon-path", |o| {
+            o.optopt("",
+                     "favicon-path",
+                     "Path string to the favicon file to be used for this crate",
+                     "PATH")
+        }),
     ]
 }
 

src/test/rustdoc/favicon-path.rs

@@ -0,0 +1,6 @@
+// compile-flags:-Z unstable-options --favicon-path ./src/librustdoc/html/static/favicon.ico
+
+#![crate_name = "foo"]
+
+// @has foo/fn.foo.html '//link/@href' '../favicon-foo.ico'
+pub fn foo() {}