From ef543b3d2b63f18d1f99e9d35bbcdc1fa11a416a Mon Sep 17 00:00:00 2001
From: Vincent Prouillet <vincent@wearewizards.io>
Date: Mon, 7 May 2018 21:03:51 +0200
Subject: [PATCH] Make co-located asset link permalinks

---
 components/front_matter/Cargo.toml     |  1 -
 components/rendering/src/markdown.rs   | 47 ++++++++++++++++----------
 components/rendering/tests/markdown.rs | 31 +++++++++++++++++
 3 files changed, 61 insertions(+), 18 deletions(-)

diff --git a/components/front_matter/Cargo.toml b/components/front_matter/Cargo.toml
index 7a952330..76c6a9fa 100644
--- a/components/front_matter/Cargo.toml
+++ b/components/front_matter/Cargo.toml
@@ -12,5 +12,4 @@ toml = "0.4"
 regex = "1"
 lazy_static = "1"
 
-
 errors = { path = "../errors" }
diff --git a/components/rendering/src/markdown.rs b/components/rendering/src/markdown.rs
index 4773274e..de580e2f 100644
--- a/components/rendering/src/markdown.rs
+++ b/components/rendering/src/markdown.rs
@@ -30,10 +30,15 @@ fn find_anchor(anchors: &[String], name: String, level: u8) -> String {
     find_anchor(anchors, name, level + 1)
 }
 
+fn is_colocated_asset_link(link: &str) -> bool {
+    !link.contains("/")  // http://, ftp://, ../ etc
+        && !link.starts_with("mailto:")
+}
+
 
 pub fn markdown_to_html(content: &str, context: &RenderContext) -> Result<(String, Vec<Header>)> {
     // the rendered html
-    let mut html = String::new();
+    let mut html = String::with_capacity(content.len());
     // Set while parsing
     let mut error = None;
 
@@ -104,29 +109,37 @@ pub fn markdown_to_html(content: &str, context: &RenderContext) -> Result<(Strin
                     Event::Html(Owned("</pre>".to_string()))
                 },
                 // Need to handle relative links
-                Event::Start(Tag::Link(ref link, ref title)) => {
-                    if in_header {
-                        if !title.is_empty() {
-                            temp_header.push(&format!("<a href=\"{}\" title=\"{}\">", link, title));
-                        } else {
-                            temp_header.push(&format!("<a href=\"{}\">", link));
-                        }
-                        return Event::Html(Owned(String::new()));
-                    }
-
-                    if link.starts_with("./") {
-                        match resolve_internal_link(link, context.permalinks) {
-                            Ok(url) => {
-                                return Event::Start(Tag::Link(Owned(url), title.clone()));
-                            },
+                Event::Start(Tag::Link(link, title)) => {
+                    // A few situations here:
+                    // - it could be a relative link (starting with `./`)
+                    // - it could be a link to a co-located asset
+                    // - it could be a normal link
+                    // - any of those can be in a header or not: if it's in a header we need to append to a string
+                    let fixed_link = if link.starts_with("./") {
+                        match resolve_internal_link(&link, context.permalinks) {
+                            Ok(url) => url,
                             Err(_) => {
                                 error = Some(format!("Relative link {} not found.", link).into());
                                 return Event::Html(Owned(String::new()));
                             }
+                        }
+                    } else if is_colocated_asset_link(&link) {
+                        format!("{}{}", context.current_page_permalink, link)
+                    } else {
+                        link.to_string()
+                    };
+
+                    if in_header {
+                        let html = if title.is_empty() {
+                            format!("<a href=\"{}\">", fixed_link)
+                        } else {
+                            format!("<a href=\"{}\" title=\"{}\">", fixed_link, title)
                         };
+                        temp_header.push(&html);
+                        return Event::Html(Owned(String::new()));
                     }
 
-                    Event::Start(Tag::Link(link.clone(), title.clone()))
+                    Event::Start(Tag::Link(Owned(fixed_link), title))
                 },
                 Event::End(Tag::Link(_, _)) => {
                     if in_header {
diff --git a/components/rendering/tests/markdown.rs b/components/rendering/tests/markdown.rs
index 3c66f02c..f6eb938f 100644
--- a/components/rendering/tests/markdown.rs
+++ b/components/rendering/tests/markdown.rs
@@ -473,3 +473,34 @@ fn can_understand_link_with_title_in_header() {
         "<h1 id=\"rust\"><a href=\"https://rust-lang.org\" title=\"Rust homepage\">Rust</a></h1>\n"
     );
 }
+
+#[test]
+fn can_make_valid_relative_link_in_header() {
+    let mut permalinks = HashMap::new();
+    permalinks.insert("pages/about.md".to_string(), "https://vincent.is/about/".to_string());
+    let tera_ctx = Tera::default();
+    let config = Config::default();
+    let context = RenderContext::new(&tera_ctx, &config, "", &permalinks, InsertAnchor::None);
+    let res = render_content(
+        r#" # [rel link](./pages/about.md)"#,
+        &context
+    ).unwrap();
+
+    assert_eq!(
+        res.0,
+        "<h1 id=\"rel-link\"><a href=\"https://vincent.is/about/\">rel link</a></h1>\n"
+    );
+}
+
+
+#[test]
+fn can_make_permalinks_with_colocated_assets() {
+    let permalinks_ctx = HashMap::new();
+    let config = Config::default();
+    let context = RenderContext::new(&GUTENBERG_TERA, &config, "https://vincent.is/about/", &permalinks_ctx, InsertAnchor::None);
+    let res = render_content("[an image](image.jpg)", &context).unwrap();
+    assert_eq!(
+        res.0,
+        "<p><a href=\"https://vincent.is/about/image.jpg\">an image</a></p>\n"
+    );
+}