frontend: Show feature flags in topbar and separate page

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 +12,8 @@ impl Feature {
     pub fn new(name: String, subfeatures: Vec<String>) -> Self {
         Feature { name, subfeatures }
     }
+
+    pub fn is_private(&self) -> bool {
+        self.name.starts_with('_')
+    }
 }

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 +744,101 @@ mod tests {
             Ok(())
         });
     }
+
+    #[test]
+    fn feature_flags_report_empty() {
+        wrapper(|env| {
+            env.fake_release()
+                .name("library")
+                .version("0.1.0")
+                .features(HashMap::new())
+                .create()?;
+
+            let page = kuchiki::parse_html().one(
+                env.frontend()
+                    .get("/crate/library/0.1.0/features")
+                    .send()?
+                    .text()?,
+            );
+            assert!(page.select_first(r#"p[data-id="empty-features"]"#).is_ok());
+            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("library")
+                .version("0.1.0")
+                .features(features)
+                .create()?;
+
+            let page = kuchiki::parse_html().one(
+                env.frontend()
+                    .get("/crate/library/0.1.0/features")
+                    .send()?
+                    .text()?,
+            );
+            assert!(page.select_first(r#"p[data-id="empty-features"]"#).is_ok());
+            Ok(())
+        });
+    }
+
+    #[test]
+    fn feature_flags_without_default() {
+        wrapper(|env| {
+            let features = [("feature1".into(), Vec::new())]
+                .iter()
+                .cloned()
+                .collect::<HashMap<String, Vec<String>>>();
+            env.fake_release()
+                .name("library")
+                .version("0.1.0")
+                .features(features)
+                .create()?;
+
+            let page = kuchiki::parse_html().one(
+                env.frontend()
+                    .get("/crate/library/0.1.0/features")
+                    .send()?
+                    .text()?,
+            );
+            assert!(page.select_first(r#"p[data-id="empty-features"]"#).is_err());
+            let def_len = page
+                .select_first(r#"b[data-id="default-feature-len"]"#)
+                .unwrap();
+            assert_eq!(def_len.text_contents(), "0");
+            Ok(())
+        });
+    }
+
+    #[test]
+    fn feature_flags_report_null() {
+        wrapper(|env| {
+            let id = env
+                .fake_release()
+                .name("library")
+                .version("0.1.0")
+                .features(HashMap::new())
+                .create()?;
+
+            env.db()
+                .conn()
+                .query("UPDATE releases SET features = NULL WHERE id = $1", &[&id])?;
+
+            let page = kuchiki::parse_html().one(
+                env.frontend()
+                    .get("/crate/library/0.1.0/features")
+                    .send()?
+                    .text()?,
+            );
+            assert!(page.select_first(r#"p[data-id="null-features"]"#).is_ok());
+            Ok(())
+        });
+    }
 }

src/web/features.rs

@@ -0,0 +1,30 @@
+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,
+}
+
+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()?;
+
+    FeaturesPage {
+        metadata: cexpect!(req, MetaData::from_crate(&mut conn, &name, &version)),
+    }
+    .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;
@@ -520,6 +522,7 @@ 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 {
@@ -533,7 +536,8 @@ 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",
@@ -552,6 +556,7 @@ 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)),
         })
     }
 
@@ -566,6 +571,14 @@ 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)]
@@ -844,6 +857,7 @@ mod test {
                 "arm64-unknown-linux-gnu".to_string(),
             ],
             yanked: false,
+            features: None,
         };
 
         let correct_json = json!({
@@ -858,6 +872,7 @@ mod test {
                 "arm64-unknown-linux-gnu",
             ],
             "yanked": false,
+            "features": null
         });
 
         assert_eq!(correct_json, serde_json::to_value(&metadata).unwrap());
@@ -875,6 +890,7 @@ mod test {
                 "arm64-unknown-linux-gnu",
             ],
             "yanked": false,
+            "features": null,
         });
 
         assert_eq!(correct_json, serde_json::to_value(&metadata).unwrap());
@@ -892,6 +908,7 @@ 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 +1,82 @@
+{%- 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 metadata.features -%}
+                            {%- for feature in metadata.features -%}
+                                <li class="pure-menu-item">
+                                    <a href="#{{ feature.name }}" class="pure-menu-link" style="text-align:center;">
+                                        {{ feature.name }}
+                                    </a>
+                                </li>
+                            {%- endfor -%}
+                        {%- elif metadata.features is iterable -%}
+                            <li class="pure-menu-item">
+                                <span style="font-size: 13px;">This release does not have any feature flags.</span>
+                            </li>
+                        {%- else -%}
+                            <li class="pure-menu-item">
+                                <span style="font-size: 13px;">Feature flags data are not available for this release.</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 metadata.features -%}
+                    <p>This version has <b>{{ metadata.features | length }}</b> feature flags, <b data-id="default-feature-len">
+                        {%- if metadata.features[0].name == 'default' -%}
+                            {{ metadata.features[0].subfeatures | length }}
+                        {%- else -%}
+                            0
+                        {%- endif -%}
+                    </b> of them enabled by <b>default</b>.</p>
+                    {%- for feature in metadata.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 -%}
+                {%- elif metadata.features is iterable  -%}
+                    <p data-id="empty-features">This release does not have any feature flags.</p>
+                {%- else -%}
+                    <p data-id="null-features">Feature flags data are not available for this release.</p>
+                {%- endif -%}
+            </div>
+        </div>
+    </div>
+{%- endblock body -%}