use theme_path key in book.json when given

book-example/src/format/config.md

@@ -15,9 +15,14 @@ Here is an example of what a ***book.json*** file might look like:
 
 #### Supported variables
 
-- **title:** title of the book
-- **author:** author of the book
-- **description:** description, which is added as meta in the html head of each page.
-- **dest:** path to the directory where you want your book to be rendered. If a relative path is given it will be relative to the parent directory of the source directory
+If relative paths are given, they will be relative to the book's root, i.e. the
+parent directory of the source directory.
+
+- **title:** The title of the book.
+- **author:** The author of the book.
+- **description:** The description, which is added as meta in the html head of each page.
+- **src:** The path to the book's source files (chapters in Markdown, SUMMARY.md, etc.). Defaults to `root/src`.
+- **dest:** The path to the directory where you want your book to be rendered. Defaults to `root/book`.
+- **theme_path:** The path to a custom theme directory. Defaults to `root/theme`.
 
 ***note:*** *the supported configurable parameters are scarce at the moment, but more will be added in the future*

src/book/bookconfig.rs

@@ -5,12 +5,15 @@ use std::path::{Path, PathBuf};
 
 #[derive(Debug, Clone)]
 pub struct BookConfig {
-    pub title: String,
-    pub author: String,
-    pub description: String,
     root: PathBuf,
     pub dest: PathBuf,
     pub src: PathBuf,
+    pub theme_path: PathBuf,
+
+    pub title: String,
+    pub author: String,
+    pub description: String,
+
     pub indent_spaces: i32,
     multilingual: bool,
 }
@@ -19,12 +22,15 @@ pub struct BookConfig {
 impl BookConfig {
     pub fn new(root: &Path) -> Self {
         BookConfig {
-            title: String::new(),
-            author: String::new(),
-            description: String::new(),
             root: root.to_owned(),
             dest: root.join("book"),
             src: root.join("src"),
+            theme_path: root.join("theme"),
+
+            title: String::new(),
+            author: String::new(),
+            description: String::new(),
+
             indent_spaces: 4, // indentation used for SUMMARY.md
             multilingual: false,
         }
@@ -72,33 +78,33 @@ impl BookConfig {
 
             // Destination folder
             if let Some(a) = config.get("dest") {
-                let dest = PathBuf::from(&a.to_string().replace("\"", ""));
+                let mut dest = PathBuf::from(&a.to_string().replace("\"", ""));
 
                 // If path is relative make it absolute from the parent directory of src
-                match dest.is_relative() {
-                    true => {
-                        let dest = self.get_root().join(&dest).to_owned();
-                        self.set_dest(&dest);
-                    },
-                    false => {
-                        self.set_dest(&dest);
-                    },
+                if dest.is_relative() {
+                    dest = self.get_root().join(&dest);
                 }
+                self.set_dest(&dest);
             }
 
             // Source folder
             if let Some(a) = config.get("src") {
-                let src = PathBuf::from(&a.to_string().replace("\"", ""));
-                match src.is_relative() {
-                    true => {
-                        let src = self.get_root().join(&src).to_owned();
-                        self.set_src(&src);
-                    },
-                    false => {
-                        self.set_src(&src);
-                    }
+                let mut src = PathBuf::from(&a.to_string().replace("\"", ""));
+                if src.is_relative() {
+                    src = self.get_root().join(&src);
                 }
+                self.set_src(&src);
             }
+
+            // Theme path folder
+            if let Some(a) = config.get("theme_path") {
+                let mut theme_path = PathBuf::from(&a.to_string().replace("\"", ""));
+                if theme_path.is_relative() {
+                    theme_path = self.get_root().join(&theme_path);
+                }
+                self.set_theme_path(&theme_path);
+            }
+
         }
 
         self
@@ -130,4 +136,13 @@ impl BookConfig {
         self.src = src.to_owned();
         self
     }
+
+    pub fn get_theme_path(&self) -> &Path {
+        &self.theme_path
+    }
+
+    pub fn set_theme_path(&mut self, theme_path: &Path) -> &mut Self {
+        self.theme_path = theme_path.to_owned();
+        self
+    }
 }

src/book/mod.rs

@@ -20,6 +20,7 @@ pub struct MDBook {
     root: PathBuf,
     dest: PathBuf,
     src: PathBuf,
+    theme_path: PathBuf,
 
     pub title: String,
     pub author: String,
@@ -34,8 +35,11 @@ pub struct MDBook {
 impl MDBook {
     /// Create a new `MDBook` struct with root directory `root`
     ///
-    /// - The default source directory is set to `root/src`
-    /// - The default output directory is set to `root/book`
+    /// Default directory paths:
+    ///
+    /// - source: `root/src`
+    /// - output: `root/book`
+    /// - theme: `root/theme`
     ///
     /// They can both be changed by using [`set_src()`](#method.set_src) and [`set_dest()`](#method.set_dest)
 
@@ -49,6 +53,7 @@ impl MDBook {
             root: root.to_owned(),
             dest: root.join("book"),
             src: root.join("src"),
+            theme_path: root.join("theme"),
 
             title: String::new(),
             author: String::new(),
@@ -294,6 +299,7 @@ impl MDBook {
 
         self.dest = config.dest;
         self.src = config.src;
+        self.theme_path = config.theme_path;
 
         self
     }
@@ -444,6 +450,18 @@ impl MDBook {
         }
     }
 
+    pub fn set_theme_path(mut self, theme_path: &Path) -> Self {
+        self.theme_path = match theme_path.is_absolute() {
+            true => theme_path.to_owned(),
+            false => self.root.join(theme_path).to_owned(),
+        };
+        self
+    }
+
+    pub fn get_theme_path(&self) -> &Path {
+        &self.theme_path
+    }
+
     // Construct book
     fn parse_summary(&mut self) -> Result<(), Box<Error>> {
         // When append becomes stable, use self.content.append() ...

src/renderer/html_handlebars/hbs_renderer.rs

@@ -30,7 +30,7 @@ impl Renderer for HtmlHandlebars {
         let mut handlebars = Handlebars::new();
 
         // Load theme
-        let theme = theme::Theme::new(book.get_src());
+        let theme = theme::Theme::new(book.get_theme_path());
 
         // Register template
         debug!("[*]: Register handlebars template");

src/theme/mod.rs

@@ -56,12 +56,6 @@ impl Theme {
             return theme;
         }
 
-        let src = src.join("theme");
-        // If src does exist, check if there is a theme directory in it
-        if !src.exists() || !src.is_dir() {
-            return theme;
-        }
-
         // Check for individual files if they exist
 
         // index.hbs