From c069bfdafadf38cb39fd3b5d81298460b8052d3a Mon Sep 17 00:00:00 2001
From: Thomas Hurst <tom@hur.st>
Date: Wed, 22 Aug 2018 17:34:32 +0100
Subject: [PATCH] Rework summary handling.

Push summary handling into Markdown parsing, identifying the presence
of one by giving its length in the rendered markup.

Hopefully a better fix for #376.
---
 components/content/src/page.rs       | 19 +++++-----------
 components/content/src/section.rs    |  4 ++--
 components/rendering/src/lib.rs      |  2 +-
 components/rendering/src/markdown.rs | 33 ++++++++++++++++++++--------
 4 files changed, 33 insertions(+), 25 deletions(-)

diff --git a/components/content/src/page.rs b/components/content/src/page.rs
index 3a0bf066..4162d6d3 100644
--- a/components/content/src/page.rs
+++ b/components/content/src/page.rs
@@ -185,19 +185,12 @@ impl Page {
 
         context.tera_context.add("page", self);
 
-        let res = render_content(
-            &self.raw_content.replacen("<!-- more -->", "<a name=\"continue-reading\"></a>", 1),
-            &context,
-        ).chain_err(|| format!("Failed to render content of {}", self.file.path.display()))?;
-        self.content = res.0;
-        self.toc = res.1;
-        if self.raw_content.contains("<!-- more -->") {
-            self.summary = Some({
-                let summary = self.raw_content.splitn(2, "<!-- more -->").collect::<Vec<&str>>()[0];
-                render_content(summary, &context)
-                    .chain_err(|| format!("Failed to render content of {}", self.file.path.display()))?.0
-            })
-        }
+        let res = render_content(&self.raw_content, &context)
+            .chain_err(|| format!("Failed to render content of {}", self.file.path.display()))?;
+
+        self.summary = res.summary_len.map(|l| res.body[0..l].to_owned());
+        self.content = res.body;
+        self.toc = res.toc;
 
         Ok(())
     }
diff --git a/components/content/src/section.rs b/components/content/src/section.rs
index dcff1f5c..07ddde2b 100644
--- a/components/content/src/section.rs
+++ b/components/content/src/section.rs
@@ -137,8 +137,8 @@ impl Section {
 
         let res = render_content(&self.raw_content, &context)
             .chain_err(|| format!("Failed to render content of {}", self.file.path.display()))?;
-        self.content = res.0;
-        self.toc = res.1;
+        self.content = res.body;
+        self.toc = res.toc;
         Ok(())
     }
 
diff --git a/components/rendering/src/lib.rs b/components/rendering/src/lib.rs
index 9e6d7257..acc08953 100644
--- a/components/rendering/src/lib.rs
+++ b/components/rendering/src/lib.rs
@@ -32,7 +32,7 @@ pub use table_of_contents::Header;
 pub use shortcode::render_shortcodes;
 pub use context::RenderContext;
 
-pub fn render_content(content: &str, context: &RenderContext) -> Result<(String, Vec<Header>)> {
+pub fn render_content(content: &str, context: &RenderContext) -> Result<markdown::Rendered> {
     // Don't do anything if there is nothing like a shortcode in the content
     if content.contains("{{") || content.contains("{%") {
         let rendered = render_shortcodes(content, context)?;
diff --git a/components/rendering/src/markdown.rs b/components/rendering/src/markdown.rs
index 56bea619..a9c3b3e6 100644
--- a/components/rendering/src/markdown.rs
+++ b/components/rendering/src/markdown.rs
@@ -1,4 +1,4 @@
-use std::borrow::Cow::Owned;
+use std::borrow::Cow::{Owned, Borrowed};
 
 use pulldown_cmark as cmark;
 use self::cmark::{Parser, Event, Tag, Options, OPTION_ENABLE_TABLES, OPTION_ENABLE_FOOTNOTES};
@@ -14,6 +14,14 @@ use link_checker::check_url;
 use table_of_contents::{TempHeader, Header, make_table_of_contents};
 use context::RenderContext;
 
+const CONTINUE_READING: &str = "<p><a name=\"continue-reading\"></a></p>\n";
+
+pub struct Rendered {
+    pub body: String,
+    pub summary_len: Option<usize>,
+    pub toc: Vec<Header>
+}
+
 // We might have cases where the slug is already present in our list of anchor
 // for example an article could have several titles named Example
 // We add a counter after the slug if the slug is already present, which
@@ -36,8 +44,7 @@ fn is_colocated_asset_link(link: &str) -> bool {
         && !link.starts_with("mailto:")
 }
 
-
-pub fn markdown_to_html(content: &str, context: &RenderContext) -> Result<(String, Vec<Header>)> {
+pub fn markdown_to_html(content: &str, context: &RenderContext) -> Result<Rendered> {
     // the rendered html
     let mut html = String::with_capacity(content.len());
     // Set while parsing
@@ -57,6 +64,7 @@ pub fn markdown_to_html(content: &str, context: &RenderContext) -> Result<(Strin
     let mut temp_header = TempHeader::default();
 
     let mut opts = Options::empty();
+    let mut has_summary = false;
     opts.insert(OPTION_ENABLE_TABLES);
     opts.insert(OPTION_ENABLE_FOOTNOTES);
 
@@ -208,6 +216,10 @@ pub fn markdown_to_html(content: &str, context: &RenderContext) -> Result<(Strin
                     temp_header = TempHeader::default();
                     Event::Html(Owned(val))
                 }
+                Event::Html(ref markup) if markup.contains("<!-- more -->") => {
+                    has_summary = true;
+                    Event::Html(Borrowed(CONTINUE_READING))
+                }
                 _ => event,
             }
         });
@@ -215,11 +227,14 @@ pub fn markdown_to_html(content: &str, context: &RenderContext) -> Result<(Strin
         cmark::html::push_html(&mut html, parser);
     }
 
-    match error {
-        Some(e) => Err(e),
-        None => Ok((
-            html.replace("<p></p>", "").replace("</p></p>", "</p>"),
-            make_table_of_contents(&headers)
-        )),
+    if let Some(e) = error {
+        return Err(e)
+    } else {
+        html = html.replace("<p></p>", "").replace("</p></p>", "</p>");
+        Ok(Rendered {
+            summary_len: if has_summary { html.find(CONTINUE_READING) } else { None },
+            body: html,
+            toc: make_table_of_contents(&headers)
+        })
     }
 }