Add book.translations to support translation preprocessors

src/book/mod.rs

@@ -190,18 +190,31 @@ impl MDBook {
         info!("Book building has started");
 
         for renderer in &self.renderers {
-            self.execute_build_process(&**renderer)?;
+            // build for the default language
+            self.execute_build_process(&**renderer, None)?;
+            // build for each translation language
+            for translation in &self.config.book.translations {
+                self.execute_build_process(&**renderer, Some(translation))?;
+            }
         }
 
         Ok(())
     }
 
     /// Run the entire build process for a particular [`Renderer`].
-    pub fn execute_build_process(&self, renderer: &dyn Renderer) -> Result<()> {
+    pub fn execute_build_process(
+        &self,
+        renderer: &dyn Renderer,
+        translation: Option<&str>,
+    ) -> Result<()> {
         let mut preprocessed_book = self.book.clone();
+        let mut config = self.config.clone();
+        if let Some(translation) = translation {
+            config.book.language = Some(translation.to_string());
+        }
         let preprocess_ctx = PreprocessorContext::new(
             self.root.clone(),
-            self.config.clone(),
+            config.clone(),
             renderer.name().to_string(),
         );
 
@@ -213,19 +226,27 @@ impl MDBook {
         }
 
         let name = renderer.name();
-        let build_dir = self.build_dir_for(name);
+        let mut build_dir = self.build_dir_for(name);
+        // Use sub-dir for each translation
+        if let Some(translation) = translation {
+            build_dir = build_dir.join(translation);
+        }
 
-        let mut render_context = RenderContext::new(
-            self.root.clone(),
-            preprocessed_book,
-            self.config.clone(),
-            build_dir,
-        );
+        let mut render_context =
+            RenderContext::new(self.root.clone(), preprocessed_book, config, build_dir);
         render_context
             .chapter_titles
             .extend(preprocess_ctx.chapter_titles.borrow_mut().drain());
 
-        info!("Running the {} backend", renderer.name());
+        info!(
+            "Running the {}{} backend",
+            renderer.name(),
+            if let Some(translation) = translation {
+                format!("[{}]", translation)
+            } else {
+                "".to_string()
+            }
+        );
         renderer
             .render(&render_context)
             .with_context(|| "Rendering failed")

src/config.rs

@@ -411,6 +411,8 @@ pub struct BookConfig {
     pub multilingual: bool,
     /// The main language of the book.
     pub language: Option<String>,
+    /// The book's translations.
+    pub translations: Vec<String>,
 }
 
 impl Default for BookConfig {
@@ -422,6 +424,7 @@ impl Default for BookConfig {
             src: PathBuf::from("src"),
             multilingual: false,
             language: Some(String::from("en")),
+            translations: Vec::new(),
         }
     }
 }
@@ -769,6 +772,7 @@ mod tests {
             multilingual: true,
             src: PathBuf::from("source"),
             language: Some(String::from("ja")),
+            ..Default::default()
         };
         let build_should_be = BuildConfig {
             build_dir: PathBuf::from("outputs"),

src/renderer/html_handlebars/hbs_renderer.rs

@@ -94,6 +94,7 @@ impl HtmlHandlebars {
         };
 
         ctx.data.insert("path".to_owned(), json!(path));
+        ctx.data.insert("path_html".to_owned(), json!(filepath));
         ctx.data.insert("content".to_owned(), json!(content));
         ctx.data.insert("chapter_title".to_owned(), json!(ch.name));
         ctx.data.insert("title".to_owned(), json!(title));
@@ -635,6 +636,9 @@ fn make_data(
         "language".to_owned(),
         json!(config.book.language.clone().unwrap_or_default()),
     );
+    if !config.book.translations.is_empty() {
+        data.insert("translations".to_owned(), json!(config.book.translations));
+    }
     data.insert(
         "book_title".to_owned(),
         json!(config.book.title.clone().unwrap_or_default()),

tests/init.rs

@@ -29,7 +29,7 @@ fn base_mdbook_init_should_create_default_content() {
     let contents = fs::read_to_string(temp.path().join("book.toml")).unwrap();
     assert_eq!(
         contents,
-        "[book]\nauthors = []\nlanguage = \"en\"\nmultilingual = false\nsrc = \"src\"\n"
+        "[book]\nauthors = []\nlanguage = \"en\"\nmultilingual = false\nsrc = \"src\"\ntranslations = []\n"
     );
 }
 
@@ -96,7 +96,7 @@ fn run_mdbook_init_with_custom_book_and_src_locations() {
     let contents = fs::read_to_string(temp.path().join("book.toml")).unwrap();
     assert_eq!(
         contents,
-        "[book]\nauthors = []\nlanguage = \"en\"\nmultilingual = false\nsrc = \"in\"\n\n[build]\nbuild-dir = \"out\"\ncreate-missing = true\nextra-watch-dirs = []\nuse-default-preprocessors = true\n"
+        "[book]\nauthors = []\nlanguage = \"en\"\nmultilingual = false\nsrc = \"in\"\ntranslations = []\n\n[build]\nbuild-dir = \"out\"\ncreate-missing = true\nextra-watch-dirs = []\nuse-default-preprocessors = true\n"
     );
 }