Fix #1087 stage preprocessor generated files in temp dir

src/book/mod.rs

@@ -182,9 +182,18 @@ impl MDBook {
 
     /// Run the entire build process for a particular `Renderer`.
     pub fn execute_build_process(&self, renderer: &dyn Renderer) -> Result<()> {
+        // The temporary preprocessor output directory
+        let preproc_out_dir = TempFileBuilder::new()
+            .prefix("mdbook-pre-")
+            .tempdir()
+            .expect("Failed to create temporary output dir for preprocessor");
+
         let mut preprocessed_book = self.book.clone();
         let preprocess_ctx = PreprocessorContext::new(
             self.root.clone(),
+            // TempDir::into_path disables the auto delete option, so we need to
+            // use the long way to get to the path.
+            preproc_out_dir.path().to_path_buf(),
             self.config.clone(),
             renderer.name().to_string(),
         );
@@ -197,12 +206,17 @@ impl MDBook {
         }
 
         info!("Running the {} backend", renderer.name());
-        self.render(&preprocessed_book, renderer)?;
+        self.render(&preprocessed_book, renderer, &preprocess_ctx.output_dir)?;
 
         Ok(())
     }
 
-    fn render(&self, preprocessed_book: &Book, renderer: &dyn Renderer) -> Result<()> {
+    fn render(
+        &self,
+        preprocessed_book: &Book,
+        renderer: &dyn Renderer,
+        preproc_out_dir: &PathBuf,
+    ) -> Result<()> {
         let name = renderer.name();
         let build_dir = self.build_dir_for(name);
 
@@ -211,6 +225,7 @@ impl MDBook {
             preprocessed_book.clone(),
             self.config.clone(),
             build_dir,
+            preproc_out_dir.clone(),
         );
 
         renderer
@@ -241,10 +256,15 @@ impl MDBook {
             .collect();
 
         let temp_dir = TempFileBuilder::new().prefix("mdbook-").tempdir()?;
+        let preproc_out_dir = TempFileBuilder::new().prefix("mdbook-pre-").tempdir()?;
 
         // FIXME: Is "test" the proper renderer name to use here?
-        let preprocess_context =
-            PreprocessorContext::new(self.root.clone(), self.config.clone(), "test".to_string());
+        let preprocess_context = PreprocessorContext::new(
+            self.root.clone(),
+            preproc_out_dir.path().to_path_buf(), //TempDir::into_path disables the auto delete option
+            self.config.clone(),
+            "test".to_string(),
+        );
 
         let book = LinkPreprocessor::new().run(&preprocess_context, self.book.clone())?;
         // Index Preprocessor is disabled so that chapter paths continue to point to the

src/preprocess/cmd.rs

@@ -170,6 +170,7 @@ mod tests {
     use super::*;
     use crate::MDBook;
     use std::path::Path;
+    use std::path::PathBuf;
 
     fn book_example() -> MDBook {
         let example = Path::new(env!("CARGO_MANIFEST_DIR")).join("book-example");
@@ -182,6 +183,7 @@ mod tests {
         let md = book_example();
         let ctx = PreprocessorContext::new(
             md.root.clone(),
+            PathBuf::from(""),
             md.config.clone(),
             "some-renderer".to_string(),
         );

src/preprocess/mod.rs

@@ -20,6 +20,9 @@ use std::path::PathBuf;
 pub struct PreprocessorContext {
     /// The location of the book directory on disk.
     pub root: PathBuf,
+    /// The directory where a preprocessor can write generated files to
+    /// Generated files are copied directly to the book output dir
+    pub output_dir: PathBuf,
     /// The book configuration (`book.toml`).
     pub config: Config,
     /// The `Renderer` this preprocessor is being used with.
@@ -32,9 +35,15 @@ pub struct PreprocessorContext {
 
 impl PreprocessorContext {
     /// Create a new `PreprocessorContext`.
-    pub(crate) fn new(root: PathBuf, config: Config, renderer: String) -> Self {
+    pub(crate) fn new(
+        root: PathBuf,
+        output_dir: PathBuf,
+        config: Config,
+        renderer: String,
+    ) -> Self {
         PreprocessorContext {
             root,
+            output_dir: output_dir,
             config,
             renderer,
             mdbook_version: crate::MDBOOK_VERSION.to_string(),

src/renderer/html_handlebars/hbs_renderer.rs

@@ -541,6 +541,7 @@ impl Renderer for HtmlHandlebars {
 
         // Copy all remaining files, avoid a recursive copy from/to the book build dir
         utils::fs::copy_files_except_ext(&src_dir, &destination, true, Some(&build_dir), &["md"])?;
+        utils::fs::copy_files_except_ext(&ctx.preproc_output_dir, &destination, true, None, &[])?;
 
         Ok(())
     }

src/renderer/mod.rs

@@ -58,6 +58,8 @@ pub struct RenderContext {
     pub version: String,
     /// The book's root directory.
     pub root: PathBuf,
+    /// Location of preprocessor generated output files (e.g. images)
+    preproc_output_dir: PathBuf,
     /// A loaded representation of the book itself.
     pub book: Book,
     /// The loaded configuration file.
@@ -72,7 +74,13 @@ pub struct RenderContext {
 
 impl RenderContext {
     /// Create a new `RenderContext`.
-    pub fn new<P, Q>(root: P, book: Book, config: Config, destination: Q) -> RenderContext
+    pub fn new<P, Q>(
+        root: P,
+        book: Book,
+        config: Config,
+        destination: Q,
+        preproc_output_dir: P,
+    ) -> RenderContext
     where
         P: Into<PathBuf>,
         Q: Into<PathBuf>,
@@ -83,6 +91,7 @@ impl RenderContext {
             version: crate::MDBOOK_VERSION.to_string(),
             root: root.into(),
             destination: destination.into(),
+            preproc_output_dir: preproc_output_dir.into(),
             __non_exhaustive: (),
         }
     }