From ed1a216121e1deb16e1cfb900a66bf17ad7f9247 Mon Sep 17 00:00:00 2001
From: CrazyMerlyn <crazy.d.merlyn@gmail.com>
Date: Thu, 23 Mar 2017 23:24:26 +0530
Subject: [PATCH] Fix header links

Header fragment links now use "id" attribute instead of the depreciated
"name" attribute.

Similar headers are given numbered ids to avoid id collisions.
For instance, if there are three headers named "Example", their ids
would be "#example", "#example-1", and "#example-2" respectively.
---
 src/renderer/html_handlebars/hbs_renderer.rs | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/renderer/html_handlebars/hbs_renderer.rs b/src/renderer/html_handlebars/hbs_renderer.rs
index a36fc83a..6d49f21d 100644
--- a/src/renderer/html_handlebars/hbs_renderer.rs
+++ b/src/renderer/html_handlebars/hbs_renderer.rs
@@ -11,6 +11,7 @@ use std::fs::{self, File};
 use std::error::Error;
 use std::io::{self, Read};
 use std::collections::BTreeMap;
+use std::collections::HashMap;
 
 use handlebars::Handlebars;
 
@@ -229,6 +230,7 @@ fn make_data(book: &MDBook) -> Result<serde_json::Map<String, serde_json::Value>
 
 fn build_header_links(html: String, filename: &str) -> String {
     let regex = Regex::new(r"<h(\d)>(.*?)</h\d>").unwrap();
+    let mut id_counter = HashMap::new();
 
     regex.replace_all(&html, |caps: &Captures| {
         let level = &caps[1];
@@ -254,7 +256,16 @@ fn build_header_links(html: String, filename: &str) -> String {
             }
         }).collect::<String>();
 
-        format!("<a class=\"header\" href=\"{filename}#{id}\" name=\"{id}\"><h{level}>{text}</h{level}></a>",
+        let id_count = *id_counter.get(&id).unwrap_or(&0);
+        id_counter.insert(id.clone(), id_count + 1);
+
+        let id = if id_count > 0 {
+            format!("{}-{}", id, id_count)
+        } else {
+            id
+        };
+
+        format!("<a class=\"header\" href=\"{filename}#{id}\" id=\"{id}\"><h{level}>{text}</h{level}></a>",
             level=level, id=id, text=text, filename=filename)
     }).into_owned()
 }