cross-link by section number if TOC are structurally the same

src/book/mod.rs

@@ -430,11 +430,11 @@ impl MDBook {
                 .map(|item| {
                     match *item {
                         TocItem::Numbered(ref i) =>
-                            TocItem::Numbered(self.set_translation_links(i)),
+                            TocItem::Numbered(self.set_translation_links(i, key.to_owned())),
                         TocItem::Unnumbered(ref i) =>
-                            TocItem::Unnumbered(self.set_translation_links(i)),
+                            TocItem::Unnumbered(self.set_translation_links(i, key.to_owned())),
                         TocItem::Unlisted(ref i) =>
-                            TocItem::Unlisted(self.set_translation_links(i)),
+                            TocItem::Unlisted(self.set_translation_links(i, key.to_owned())),
                         TocItem::Spacer =>
                             TocItem::Spacer,
                     }
@@ -475,7 +475,7 @@ impl MDBook {
         Some(default_links)
     }
 
-    fn set_translation_links(&mut self, content: &TocContent) -> TocContent {
+    fn set_translation_links(&mut self, content: &TocContent, key: String) -> TocContent {
         let mut final_links: BTreeMap<String, TranslationLink> = BTreeMap::new();
         let mut newcontent: TocContent = content.clone();
 
@@ -498,6 +498,9 @@ impl MDBook {
 
         // Find a translation for the links that are still None
 
+        let orig_book: &Book = self.translations.get(&key).unwrap();
+        let orig_toc_id = toc::toc_node_count_id(&orig_book.toc);
+
         for (key, trl) in final_links.clone().iter() {
             match trl.link {
                 Some(_) => { continue; },
@@ -507,6 +510,8 @@ impl MDBook {
             let b: &Book = self.translations.get(key).unwrap();
             let flat_toc = toc::flat_toc(&b.toc);
 
+            let by_section: bool = toc::toc_node_count_id(&b.toc) == orig_toc_id;
+
             for item in flat_toc.iter() {
                 match *item {
                     TocItem::Numbered(ref i) |
@@ -515,7 +520,7 @@ impl MDBook {
 
                         // Note that this will also add a link to itself, which is good.
 
-                        if content.is_it_a_translation_of(i) {
+                        if content.is_it_a_translation_of(i, true, true, by_section) {
                             if let Some(mut a) = i.chapter.get_dest_path() {
                                 // Join the path to the language code, i.e. en/tears.html
                                 a = PathBuf::from(key.to_string()).join(a);

src/book/toc.rs

@@ -55,21 +55,45 @@ impl TocContent {
         }
     }
 
-    pub fn is_it_a_translation_of(&self, checking: &TocContent) -> bool {
+    pub fn is_it_a_translation_of(&self,
+                                  checking: &TocContent,
+                                  by_tr_id: bool,
+                                  by_src_path: bool,
+                                  by_section: bool) -> bool {
+
         // if the user has set the same translation_id on them
-        if let Some(ref a) = self.chapter.translation_id {
+        if by_tr_id {
-            if let Some(ref b) = checking.chapter.translation_id {
+            if let Some(ref a) = self.chapter.translation_id {
-                if a == b {
+                if let Some(ref b) = checking.chapter.translation_id {
-                    return true;
+                    if a == b {
+                        return true;
+                    }
                 }
             }
         }
 
         // if src_path matches
-        if let Some(ref a) = self.chapter.get_src_path() {
+        if by_src_path {
-            if let Some(ref b) = checking.chapter.get_src_path() {
+            if let Some(ref a) = self.chapter.get_src_path() {
-                if a == b {
+                if let Some(ref b) = checking.chapter.get_src_path() {
-                    return true;
+                    if a == b {
+                        return true;
+                    }
+                }
+            }
+        }
+
+        // if section string matches, useful when TOC structure matches but
+        // titles and paths are translated. Can test that with
+        // toc_node_count_id().
+        if by_section {
+            if let Some(_) = self.section {
+                let a = self.section_as_string();
+                if let Some(_) = checking.section {
+                    let b = checking.section_as_string();
+                    if a == b {
+                        return true;
+                    }
                 }
             }
         }
@@ -115,3 +139,34 @@ pub fn flat_toc(toc: &Vec<TocItem>) -> Vec<TocItem> {
     }
     flattened
 }
+
+/// Produces a String that can be used to check if two TOCs have the same
+/// structure. It recursively counts the items at each level, ignoring Spacer
+/// items.
+pub fn toc_node_count_id(toc: &Vec<TocItem>) -> String {
+    let mut counters = String::new();
+
+    let c = toc.iter().filter(|x| {
+        match **x {
+            TocItem::Spacer => { false },
+            _ => { true },
+        }}).count();
+
+    counters.push_str(&format!("{}", c));
+
+    for i in toc.iter() {
+        match *i {
+            TocItem::Numbered(ref x) |
+            TocItem::Unnumbered(ref x) |
+            TocItem::Unlisted(ref x) => {
+                if let Some(ref subs) = x.sub_items {
+                    let a = toc_node_count_id(subs);
+                    counters.push_str(&a);
+                }
+            },
+            TocItem::Spacer => {},
+        }
+    }
+
+    counters
+}

src/tests/hbs_renderer_multilang.rs

@@ -64,32 +64,28 @@ fn it_renders_multilanguage_book() {
     assert!(s.contains("<a href=\"hu/index.html\">hu</a>"));
     assert!(s.contains("<a href=\"fr/index.html\">fr</a>"));
 
-    // Test if translation links given in the TOML header were rendered
+    // Test if translation links are found
 
     book_path = proj.translations.get("en").unwrap().config.get_dest();
+
     chapter_path = book_path.join("rabbit-hole.html");
     s = utils::fs::file_to_string(&chapter_path).unwrap();
+    assert!(s.contains("<a href=\"en/rabbit-hole.html\">en</a>"));
     assert!(s.contains("<a href=\"hu/nyuszi.html\">hu</a>"));
     assert!(s.contains("<a href=\"fr/terrier.html\">fr</a>"));
 
-    // Test if translation links by translation_id were found
-
-    book_path = proj.translations.get("en").unwrap().config.get_dest();
-    chapter_path = book_path.join("long-tale.html");
-    s = utils::fs::file_to_string(&chapter_path).unwrap();
-    assert!(s.contains("<a href=\"en/long-tale.html\">en</a>"));
-    assert!(s.contains("<span>fr</span>"));
-    assert!(s.contains("<a href=\"hu/tarka-farka.html\">hu</a>"));
-
-    // Test if translation links by src_path were found
-
-    book_path = proj.translations.get("en").unwrap().config.get_dest();
     chapter_path = book_path.join("tears.html");
     s = utils::fs::file_to_string(&chapter_path).unwrap();
     assert!(s.contains("<a href=\"en/tears.html\">en</a>"));
     assert!(s.contains("<a href=\"fr/tears.html\">fr</a>"));
     assert!(s.contains("<a href=\"hu/tears.html\">hu</a>"));
 
+    chapter_path = book_path.join("long-tale.html");
+    s = utils::fs::file_to_string(&chapter_path).unwrap();
+    assert!(s.contains("<a href=\"en/long-tale.html\">en</a>"));
+    assert!(s.contains("<a href=\"fr/cocasse.html\">fr</a>"));
+    assert!(s.contains("<a href=\"hu/tarka-farka.html\">hu</a>"));
+
     // Test if print.html is produced for each translations
 
     book_path = proj.translations.get("en").unwrap().config.get_dest();

src/tests/toc_test.rs

@@ -1,7 +1,7 @@
 #[cfg(test)]
 
 use book::chapter::Chapter;
-use book::toc::{TocItem, TocContent, flat_toc};
+use book::toc::{TocItem, TocContent, flat_toc, toc_node_count_id};
 use parse::summary::parse_level;
 
 #[test]
@@ -77,3 +77,37 @@ fn it_flattens_toc() {
 
     assert_eq!(format!("{:#?}", result), expected);
 }
+
+#[test]
+fn it_counts_toc_id_string() {
+    let text = r#"
+# Summary
+
+[Introduction](misc/introduction.md)
+
+- [mdBook](README.md)
+- [Command Line Tool](cli/cli-tool.md)
+    - [init](cli/init.md)
+    - [build](cli/build.md)
+    - [watch](cli/watch.md)
+    - [serve](cli/serve.md)
+    - [test](cli/test.md)
+- [Format](format/format.md)
+    - [SUMMARY.md](format/summary.md)
+    - [Configuration](format/config.md)
+    - [Theme](format/theme/theme.md)
+        - [index.hbs](format/theme/index-hbs.md)
+        - [Syntax highlighting](format/theme/syntax-highlighting.md)
+    - [MathJax Support](format/mathjax.md)
+    - [Rust code specific features](format/rust.md)
+- [Rust Library](lib/lib.md)
+-----------
+[Contributors](misc/contributors.md)
+"#;
+
+    let toc = parse_level(&mut text.split('\n').collect(), 0, vec![0], true).unwrap();
+
+    let counters = toc_node_count_id(&toc);
+
+    assert_eq!(counters, "6552".to_string());
+}