only build crates for default target unless asked

src/docbuilder/chroot_builder.rs

@@ -25,7 +25,7 @@ const TARGETS: [&'static str; 6] = [
     "x86_64-unknown-linux-gnu"
 ];
 
-
+const DEFAULT_TARGET: &'static str = "x86_64-unknown-linux-gnu";
 
 #[derive(Debug)]
 pub struct ChrootBuilderResult {
@@ -86,11 +86,21 @@ impl DocBuilder {
         // copy sources and documentation
         let file_list = try!(self.add_sources_into_database(&conn, &pkg));
         let successfully_targets = if res.have_doc {
+            let default_target = metadata.default_target.as_ref().map(String::as_str);
+            let mut build_targets = metadata.extra_targets.clone().unwrap_or_default();
+            {
+                // FIXME: skip the second build for `default_target` by copying its documentation
+                // in twice
+                let default_target = default_target.unwrap_or(DEFAULT_TARGET);
+                if !build_targets.iter().any(|t| t == default_target) {
+                    build_targets.push(default_target.to_owned());
+                }
+            }
             try!(self.copy_documentation(&pkg,
                                          &res.rustc_version,
-                                         metadata.default_target.as_ref().map(String::as_str),
+                                         default_target,
                                          true));
-            let successfully_targets = self.build_package_for_all_targets(&pkg);
+            let successfully_targets = self.build_package_for_all_targets(&pkg, &build_targets);
             for target in &successfully_targets {
                 try!(self.copy_documentation(&pkg, &res.rustc_version, Some(target), false));
             }
@@ -151,11 +161,16 @@ impl DocBuilder {
 
 
 
-    /// Builds documentation of crate for every target and returns Vec of successfully targets
-    fn build_package_for_all_targets(&self, package: &Package) -> Vec<String> {
+    /// Builds documentation of the given crate for the given targets and returns a Vec of the ones
+    /// that were successful.
+    fn build_package_for_all_targets(&self, package: &Package, targets: &[String]) -> Vec<String> {
         let mut successfuly_targets = Vec::new();
 
-        for target in TARGETS.iter() {
+        for target in targets.iter() {
+            if !TARGETS.contains(&&**target) {
+                // we only support building for win/mac/linux 32-/64-bit
+                continue;
+            }
             debug!("Building {} for {}", canonical_name(&package), target);
             let cmd = format!("cratesfyi doc {} ={} {}",
                               package.manifest().name(),

src/docbuilder/metadata.rs

@@ -21,6 +21,7 @@ use failure::err_msg;
 /// all-features = true
 /// no-default-features = true
 /// default-target = "x86_64-unknown-linux-gnu"
+/// extra-targets = [ "x86_64-apple-darwin", "x86_64-pc-windows-msvc" ]
 /// rustc-args = [ "--example-rustc-arg" ]
 /// rustdoc-args = [ "--example-rustdoc-arg" ]
 /// dependencies = [ "example-system-dependency" ]
@@ -45,6 +46,11 @@ pub struct Metadata {
     /// is always built on this target. You can change default target by setting this.
     pub default_target: Option<String>,
 
+    /// Docs.rs doesn't automatically build extra targets for crates. If you want a crate to build
+    /// for multiple targets, set `extra-targets` to the list of targets to build, in addition to
+    /// `default-target`.
+    pub extra_targets: Option<Vec<String>>,
+
     /// List of command line arguments for `rustc`.
     pub rustc_args: Option<Vec<String>>,
 
@@ -93,6 +99,7 @@ impl Metadata {
             all_features: false,
             no_default_features: false,
             default_target: None,
+            extra_targets: None,
             rustc_args: None,
             rustdoc_args: None,
             dependencies: None,
@@ -120,6 +127,8 @@ impl Metadata {
                         .and_then(|v| v.as_bool()).unwrap_or(metadata.all_features);
                     metadata.default_target = table.get("default-target")
                         .and_then(|v| v.as_str()).map(|v| v.to_owned());
+                    metadata.extra_targets = table.get("extra-targets").and_then(|f| f.as_array())
+                        .and_then(|f| f.iter().map(|v| v.as_str().map(|v| v.to_owned())).collect());
                     metadata.rustc_args = table.get("rustc-args").and_then(|f| f.as_array())
                         .and_then(|f| f.iter().map(|v| v.as_str().map(|v| v.to_owned())).collect());
                     metadata.rustdoc_args = table.get("rustdoc-args").and_then(|f| f.as_array())
@@ -151,6 +160,7 @@ mod test {
             all-features = true
             no-default-features = true
             default-target = "x86_64-unknown-linux-gnu"
+            extra-targets = [ "x86_64-apple-darwin", "x86_64-pc-windows-msvc" ]
             rustc-args = [ "--example-rustc-arg" ]
             rustdoc-args = [ "--example-rustdoc-arg" ]
             dependencies = [ "example-system-dependency" ]
@@ -171,6 +181,11 @@ mod test {
 
         assert_eq!(metadata.default_target.unwrap(), "x86_64-unknown-linux-gnu".to_owned());
 
+        let extra_targets = metadata.extra_targets.unwrap();
+        assert_eq!(extra_targets.len(), 2);
+        assert_eq!(extra_targets[0], "x86_64-apple-darwin".to_owned());
+        assert_eq!(extra_targets[1], "x86_64-pc-windows-msvc".to_owned());
+
         let rustc_args = metadata.rustc_args.unwrap();
         assert_eq!(rustc_args.len(), 1);
         assert_eq!(rustc_args[0], "--example-rustc-arg".to_owned());

templates/about.hbs

@@ -101,21 +101,44 @@
     </tbody>
   </table>
 
-  <h4>Metadata for custom builds</h4>
+  <h4 id="metadata"><a href="#metadata">Metadata for custom builds</a></h4>
 
   <p>You can customize docs.rs builds by defining <code>[package.metadata.docs.rs]</code> table in your crates' `Cargo.toml`.</p>
 
-  <p>An example metadata:</p>
+  <p>The available configuration flags you can customize are:</p>
 
   <pre><code>[package]
 name = "test"
 
 [package.metadata.docs.rs]
+
+# Features to pass to Cargo (default: none)
 features = [ "feature1", "feature2" ]
+
+# Whether to pass `--all-features` to Cargo (default: false)
 all-features = true
+
+# Whether to pass `--no-default-features` to Cargo (default: false)
 no-default-features = true
+
+# Target to test build on, used as the default landing page (default: "x86_64-unknown-linux-gnu")
+#
+# Available targets:
+# - x86_64-unknown-linux-gnu
+# - x86_64-apple-darwin
+# - x86_64-pc-windows-msvc
+# - i686-unknown-linux-gnu
+# - i686-apple-darwin
+# - i686-pc-windows-msvc
 default-target = "x86_64-unknown-linux-gnu"
+
+# Extra targets to build, same available targets as `default-target` (default: none)
+extra-targets = [ "x86_64-apple-darwin", "x86_64-pc-windows-msvc" ]
+
+# Additional `RUSTFLAGS` to set (default: none)
 rustc-args = [ "--example-rustc-arg" ]
+
+# Additional `RUSTDOCFLAGS` to set (default: none)
 rustdoc-args = [ "--example-rustdoc-arg" ]</pre></code>
 
   <h4>Version</h4>