Add support for epub-version parameter in mdbook-epub plugin

README.md

@@ -75,6 +75,11 @@ its section number.
 `curly-quotes`: Enable converting straight quotes `'x'` and `"x"` to `‘x’` and
 `“x”` (aka *smart quotes*).
 
+`epub-version`: Specifies the EPUB version to use. If omitted, the epub-builder
+default version is used.
+ - `2` — EPUB 2.0.1
+ - `3` — EPUB 3.0.1
+
 ```toml
 [output.epub]
 additional-css = ["./path/to/main.css"]
@@ -83,6 +88,7 @@ cover-image = "ebook-cover.png"
 additional-resources = ["./assets/Open-Sans-Regular.ttf"]
 no-section-label = true
 curly-quotes = true
+epub-version = 3
 ```
 
 ## Logging, seeing progress

src/config.rs

@@ -23,6 +23,8 @@ pub struct Config {
     pub no_section_label: bool,
     /// Use "smart quotes" instead of the usual `"` character.
     pub curly_quotes: bool,
+    /// EPUB version to use if specified, otherwise defaults to the epub-builder default.
+    pub epub_version: Option<u8>,
 }
 
 impl Config {
@@ -68,6 +70,7 @@ impl Default for Config {
             additional_resources: Vec::new(),
             no_section_label: false,
             curly_quotes: false,
+            epub_version: None,
         }
     }
 }

src/generator.rs

@@ -8,7 +8,7 @@ use std::{
     path::{Path, PathBuf},
 };
 
-use epub_builder::{EpubBuilder, EpubContent, ZipLibrary};
+use epub_builder::{EpubBuilder, EpubContent, EpubVersion, ZipLibrary};
 use handlebars::{Handlebars, RenderError, RenderErrorReason};
 use html_parser::{Dom, Node};
 use mdbook::book::{BookItem, Chapter};
@@ -44,9 +44,20 @@ impl<'a> Generator<'a> {
         handler: impl ContentRetriever + 'static,
     ) -> Result<Generator<'a>, Error> {
         let handler = Box::new(handler);
-        let builder = EpubBuilder::new(ZipLibrary::new()?)?;
         let config = Config::from_render_context(ctx)?;
 
+        let epub_version = match config.epub_version {
+            Some(2) => Some(EpubVersion::V20),
+            Some(3) => Some(EpubVersion::V30),
+            Some(v) => return Err(Error::EpubDocCreate(format!("Unsupported epub version specified in book.toml: {}", v))),
+            None => None,
+        };
+
+        let mut builder = EpubBuilder::new(ZipLibrary::new()?)?;
+        if let Some(version) = epub_version {
+            builder.epub_version(version);
+        }
+
         let mut hbs = Handlebars::new();
         hbs.register_template_string("index", config.template()?)
             .map_err(|_| Error::TemplateParse)?;