frontend: Show feature flags

So far features were stored only in database.
Show their names in topbar menu with link
to the new features page. Features page will show
all relevant features with their subfeatures.

src/db/types.rs

@@ -1,7 +1,7 @@
 use postgres_types::{FromSql, ToSql};
 use serde::Serialize;
 
-#[derive(Debug, Clone, PartialEq, Serialize, FromSql, ToSql)]
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, FromSql, ToSql)]
 #[postgres(name = "feature")]
 pub struct Feature {
     name: String,
@@ -12,4 +12,16 @@ impl Feature {
     pub fn new(name: String, subfeatures: Vec<String>) -> Self {
         Feature { name, subfeatures }
     }
+
+    pub fn is_private(&self) -> bool {
+        self.name.starts_with('_')
+    }
+
+    pub fn is_default(&self) -> bool {
+        self.name == "default"
+    }
+
+    pub fn subfeature_len(&self) -> usize {
+        self.subfeatures.len()
+    }
 }

src/test/fakes.rs

@@ -210,6 +210,11 @@ impl<'a> FakeRelease<'a> {
         self
     }
 
+    pub(crate) fn features(mut self, features: HashMap<String, Vec<String>>) -> Self {
+        self.package.features = features;
+        self
+    }
+
     /// Returns the release_id
     pub(crate) fn create(self) -> Result<i32, Error> {
         use std::fs;

src/web/crate_details.rs

@@ -103,6 +103,7 @@ impl CrateDetails {
                 releases.license,
                 releases.documentation_url,
                 releases.default_target,
+                releases.features,
                 doc_coverage.total_items,
                 doc_coverage.documented_items,
                 doc_coverage.total_items_needing_examples,
@@ -148,6 +149,7 @@ impl CrateDetails {
             default_target: krate.get("default_target"),
             doc_targets: MetaData::parse_doc_targets(krate.get("doc_targets")),
             yanked: krate.get("yanked"),
+            features: MetaData::parse_features(krate.get("features")),
         };
 
         let documented_items: Option<i32> = krate.get("documented_items");
@@ -325,6 +327,7 @@ mod tests {
     use crate::test::{wrapper, TestDatabase};
     use failure::Error;
     use kuchiki::traits::TendrilSink;
+    use std::collections::HashMap;
 
     fn assert_last_successful_build_equals(
         db: &TestDatabase,
@@ -741,4 +744,42 @@ mod tests {
             Ok(())
         });
     }
+
+    #[test]
+    fn feature_flags_is_hidden_when_empty() {
+        wrapper(|env| {
+            env.fake_release()
+                .name("binary")
+                .version("0.1.0")
+                .binary(true)
+                .features(HashMap::new())
+                .create()?;
+
+            let page = kuchiki::parse_html()
+                .one(env.frontend().get("/crate/binary/0.1.0").send()?.text()?);
+            assert!(page.select_first(r#"a[aria-label="Feature"]"#).is_err());
+            Ok(())
+        });
+    }
+
+    #[test]
+    fn feature_private_feature_flags_are_hidden() {
+        wrapper(|env| {
+            let features = [("_private".into(), Vec::new())]
+                .iter()
+                .cloned()
+                .collect::<HashMap<String, Vec<String>>>();
+            env.fake_release()
+                .name("binary")
+                .version("0.1.0")
+                .binary(true)
+                .features(features)
+                .create()?;
+
+            let page = kuchiki::parse_html()
+                .one(env.frontend().get("/crate/binary/0.1.0").send()?.text()?);
+            assert!(page.select_first(r#"a[aria-label="Feature"]"#).is_err());
+            Ok(())
+        });
+    }
 }

src/web/features.rs

@@ -0,0 +1,63 @@
+use crate::db::types::Feature;
+use crate::{
+    db::Pool,
+    impl_webpage,
+    web::{page::WebPage, MetaData},
+};
+use iron::{IronResult, Request, Response};
+use router::Router;
+use serde::Serialize;
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
+struct FeaturesPage {
+    metadata: MetaData,
+    features: Option<Vec<Feature>>,
+    feature_len: usize,
+    default_feature_len: usize,
+}
+
+impl_webpage! {
+    FeaturesPage = "crate/features.html",
+}
+
+pub fn build_features_handler(req: &mut Request) -> IronResult<Response> {
+    let router = extension!(req, Router);
+    let name = cexpect!(req, router.find("name"));
+    let version = cexpect!(req, router.find("version"));
+
+    let mut conn = extension!(req, Pool).get()?;
+
+    let query = ctry!(
+        req,
+        conn.query(
+            "SELECT crates.name,
+                releases.features
+             FROM builds
+             INNER JOIN releases ON releases.id = builds.rid
+             INNER JOIN crates ON releases.crate_id = crates.id
+             WHERE crates.name = $1 AND releases.version = $2
+             ORDER BY releases.id DESC",
+            &[&name, &version]
+        )
+    );
+    let row = cexpect!(req, query.get(0));
+    let features = MetaData::parse_features(row.get("features"));
+    let mut feature_len = 0;
+    let mut default_feature_len = 0;
+    if let Some(ref feature_list) = features {
+        feature_len = feature_list.len();
+        if let Some(first) = feature_list.first() {
+            if first.is_default() {
+                default_feature_len = first.subfeature_len();
+            }
+        }
+    }
+
+    FeaturesPage {
+        metadata: cexpect!(req, MetaData::from_crate(&mut conn, &name, &version)),
+        features,
+        feature_len,
+        default_feature_len,
+    }
+    .into_response(req)
+}

src/web/mod.rs

@@ -81,6 +81,7 @@ mod builds;
 mod crate_details;
 mod error;
 mod extensions;
+mod features;
 mod file;
 pub(crate) mod metrics;
 mod releases;
@@ -90,6 +91,7 @@ mod sitemap;
 mod source;
 mod statics;
 
+use crate::db::types::Feature;
 use crate::{impl_webpage, Context};
 use chrono::{DateTime, Utc};
 use error::Nope;
@@ -519,6 +521,7 @@ pub(crate) struct MetaData {
     pub(crate) default_target: String,
     pub(crate) doc_targets: Vec<String>,
     pub(crate) yanked: bool,
+    pub(crate) features: Option<Vec<Feature>>,
 }
 
 impl MetaData {
@@ -532,7 +535,8 @@ impl MetaData {
                        releases.rustdoc_status,
                        releases.default_target,
                        releases.doc_targets,
-                       releases.yanked
+                       releases.yanked,
+                       releases.features
                 FROM releases
                 INNER JOIN crates ON crates.id = releases.crate_id
                 WHERE crates.name = $1 AND releases.version = $2",
@@ -551,6 +555,7 @@ impl MetaData {
             default_target: row.get(5),
             doc_targets: MetaData::parse_doc_targets(row.get(6)),
             yanked: row.get(7),
+            features: MetaData::parse_features(row.get(8)),
         })
     }
 
@@ -565,6 +570,14 @@ impl MetaData {
             })
             .unwrap_or_else(Vec::new)
     }
+
+    pub(crate) fn parse_features(features: Option<Vec<Feature>>) -> Option<Vec<Feature>> {
+        features.map(|vec| {
+            vec.into_iter()
+                .filter(|feature| !feature.is_private())
+                .collect()
+        })
+    }
 }
 
 #[derive(Debug, Clone, PartialEq, Serialize)]
@@ -843,6 +856,7 @@ mod test {
                 "arm64-unknown-linux-gnu".to_string(),
             ],
             yanked: false,
+            features: None,
         };
 
         let correct_json = json!({
@@ -857,6 +871,7 @@ mod test {
                 "arm64-unknown-linux-gnu",
             ],
             "yanked": false,
+            "features": null
         });
 
         assert_eq!(correct_json, serde_json::to_value(&metadata).unwrap());
@@ -874,6 +889,7 @@ mod test {
                 "arm64-unknown-linux-gnu",
             ],
             "yanked": false,
+            "features": null,
         });
 
         assert_eq!(correct_json, serde_json::to_value(&metadata).unwrap());
@@ -891,6 +907,7 @@ mod test {
                 "arm64-unknown-linux-gnu",
             ],
             "yanked": false,
+            "features": null,
         });
 
         assert_eq!(correct_json, serde_json::to_value(&metadata).unwrap());

src/web/routes.rs

@@ -87,6 +87,10 @@ pub(super) fn build_routes() -> Routes {
         "/crate/:name/:version/builds/:id",
         super::builds::build_list_handler,
     );
+    routes.internal_page(
+        "/crate/:name/:version/features",
+        super::features::build_features_handler,
+    );
     routes.internal_page(
         "/crate/:name/:version/source",
         SimpleRedirect::new(|url| url.set_path(&format!("{}/", url.path()))),

src/web/source.rs

@@ -58,7 +58,8 @@ impl FileList {
                         releases.files,
                         releases.default_target,
                         releases.doc_targets,
-                        releases.yanked
+                        releases.yanked,
+                        releases.features
                 FROM releases
                 LEFT OUTER JOIN crates ON crates.id = releases.crate_id
                 WHERE crates.name = $1 AND releases.version = $2",
@@ -137,6 +138,7 @@ impl FileList {
                     default_target: rows[0].get(6),
                     doc_targets: MetaData::parse_doc_targets(rows[0].get(7)),
                     yanked: rows[0].get(8),
+                    features: MetaData::parse_features(rows[0].get(9)),
                 },
                 files: file_list,
             })

templates/crate/features.html

@@ -0,0 +1,70 @@
+{%- extends "base.html" -%}
+{%- import "header/package_navigation.html" as navigation -%}
+
+{%- block title -%}
+    {{ macros::doc_title(name=metadata.name, version=metadata.version) }}
+{%- endblock title -%}
+
+{%- block topbar -%}
+  {%- set latest_version = "" -%}
+  {%- set latest_path = "" -%}
+  {%- set target = "" -%}
+  {%- set inner_path = metadata.target_name ~ "/index.html" -%}
+  {%- set is_latest_version = true -%}
+  {%- set is_prerelease = false -%}
+  {%- include "rustdoc/topbar.html" -%}
+{%- endblock topbar -%}
+
+{%- block header -%}
+    {{ navigation::package_navigation(metadata=metadata, active_tab="features") }}
+{%- endblock header -%}
+
+{%- block body -%}
+    <div class="container package-page-container">
+        <div class="pure-g">
+            <div class="pure-u-1 pure-u-sm-7-24 pure-u-md-5-24">
+                <div class="pure-menu package-menu">
+                    <ul class="pure-menu-list">
+                        <li class="pure-menu-heading">Feature flags</li>
+                        {%- if features -%}
+                            {%- for feature in features -%}
+                                <li class="pure-menu-item">
+                                    <a href="#{{ feature.name }}" class="pure-menu-link" style="text-align:center;">
+                                        {{ feature.name }}
+                                    </a>
+                                </li>
+                            {%- endfor -%}
+                        {%- else -%}
+                            <li class="pure-menu-item">
+                                <span style="font-size: 13px;">Feature flags are not available for this version.</span>
+                            </li>
+                        {%- endif -%}
+                    </ul>
+                </div>
+            </div>
+
+            <div class="pure-u-1 pure-u-sm-17-24 pure-u-md-19-24 package-details" id="main">
+                <h1>{{ metadata.name }}</h1>
+                {%- if features -%}
+                    <p>This version has <b>{{ feature_len }}</b> feature flags, <b>{{ default_feature_len }}</b> of them being enabled by <b>default</b>.</p>
+                    {%- for feature in features -%}
+                        <h3 id="{{ feature.name }}">{{ feature.name }}</h3>
+                        <ul class="pure-menu-list">
+                            {%- if feature.subfeatures -%}
+                                {%- for subfeature in feature.subfeatures -%}
+                                    <li class="pure-menu-item">
+                                        <span>{{ subfeature }}</span>
+                                    </li>
+                                {%- endfor -%}
+                            {%- else -%}
+                                <p>This feature flag does not enable additional features.</p>
+                            {%- endif -%}
+                        </ul>
+                    {%- endfor -%}
+                {%- else -%}
+                    <p>Feature flags are not available for this version.</p>
+                {%- endif -%}
+            </div>
+        </div>
+    </div>
+{%- endblock body -%}

templates/header/package_navigation.html

@@ -8,6 +8,7 @@
         * `crate`
         * `source`
         * `builds`
+        * `features`
 
     Note: `false` here is acting as a pseudo-null value since you can't directly construct null values
            and tera requires all parameters without defaults to be filled
@@ -85,6 +86,17 @@ <h1 id="crate-title">
                                 <span class="title"> Builds</span>
                             </a>
                         </li>
+
+                        {# The features tab #}
+                        {%- if metadata.features -%}
+                            <li class="pure-menu-item">
+                                <a href="/crate/{{ crate_path | safe }}/features"
+                                   class="pure-menu-link{% if active_tab == 'features' %} pure-menu-active{% endif %}">
+                                    {{ "flag" | fas }}
+                                    <span class="title">Feature flags</span>
+                                </a>
+                            </li>
+                        {%- endif -%}
                     </ul>
                 </div>
             </div>