Add a dependency manager for render-time actions.

This will be used for supporting things like copying static files or rendering code blocks like gnuplot or graphviz.

src/context/dependency_manager.rs

@@ -0,0 +1,19 @@
+use std::path::PathBuf;
+
+pub(crate) type RefDependencyManager = std::sync::Arc<std::sync::Mutex<DependencyManager>>;
+
+#[derive(Debug)]
+pub(crate) struct DependencyManager {
+    /// A stack of paths for the files being visited.
+    ///
+    /// The last entry is the current file being processed. This can be used for handling relative-path links.
+    file_stack: Vec<PathBuf>,
+}
+
+impl DependencyManager {
+    pub(crate) fn new() -> Self {
+        DependencyManager {
+            file_stack: Vec::new(),
+        }
+    }
+}

src/context/mod.rs

@@ -11,6 +11,7 @@ mod clock;
 mod code;
 mod comment;
 mod comment_block;
+mod dependency_manager;
 mod diary_sexp;
 mod document_element;
 mod drawer;
@@ -72,6 +73,7 @@ pub(crate) use blog_post_page::RenderBlogPostPage;
 pub(crate) use blog_post_page::RenderBlogPostPageInput;
 pub(crate) use blog_stream::RenderBlogStream;
 pub(crate) use blog_stream::RenderBlogStreamInput;
+pub(crate) use dependency_manager::DependencyManager;
 pub(crate) use document_element::RenderDocumentElement;
 pub(crate) use element::RenderElement;
 pub(crate) use footnote_definition::RenderRealFootnoteDefinition;

src/context/render_context.rs

@@ -3,6 +3,8 @@ use std::path::Path;
 use crate::config::Config;
 use crate::error::CustomError;
 
+use super::dependency_manager::RefDependencyManager;
+
 /// The supporting information used for converting the intermediate representation into the dust context for rendering.
 #[derive(Debug, Clone)]
 pub(crate) struct RenderContext<'intermediate> {
@@ -16,6 +18,13 @@ pub(crate) struct RenderContext<'intermediate> {
     /// IDs, for example, multiple blog posts with footnotes in a blog
     /// stream.
     pub(crate) id_addition: Option<&'intermediate str>,
+
+    /// Tracks dependencies from rendering Org document(s).
+    ///
+    /// Examples of dependencies would be:
+    ///   - Static files that need to be copied to the output folder
+    ///   - Code blocks that need to be executed (for example, gnuplot graphs)
+    pub(crate) dependency_manager: RefDependencyManager,
 }
 
 impl<'intermediate> RenderContext<'intermediate> {
@@ -24,12 +33,14 @@ impl<'intermediate> RenderContext<'intermediate> {
         output_directory: &'intermediate Path,
         output_file: &'intermediate Path,
         id_addition: Option<&'intermediate str>,
+        dependency_manager: RefDependencyManager,
     ) -> Result<RenderContext<'intermediate>, CustomError> {
         Ok(RenderContext {
             config,
             output_root_directory: output_directory,
             output_file,
             id_addition,
+            dependency_manager,
         })
     }
 }