Adding preprocessor for Summary

Author: Mauro Gentile

src/book/book.rs

@@ -7,6 +7,7 @@ use std::path::{Path, PathBuf};
 use super::summary::{parse_summary, Link, SectionNumber, Summary, SummaryItem};
 use crate::config::BuildConfig;
 use crate::errors::*;
+use crate::preprocess::SummaryPreprocessor;
 use crate::utils::bracket_escape;
 use log::debug;
 use serde::{Deserialize, Serialize};
@@ -21,7 +22,9 @@ pub fn load_book<P: AsRef<Path>>(src_dir: P, cfg: &BuildConfig) -> Result<Book>
         .with_context(|| format!("Couldn't open SUMMARY.md in {:?} directory", src_dir))?
         .read_to_string(&mut summary_content)?;
 
-    let summary = parse_summary(&summary_content)
+    let preprocessed_summary_content = SummaryPreprocessor::resolve(src_dir, &summary_content);
+
+    let summary = parse_summary(&preprocessed_summary_content)
         .with_context(|| format!("Summary parsing failed for file={:?}", summary_md))?;
 
     if cfg.create_missing {

src/preprocess/links.rs

@@ -71,7 +71,7 @@ impl Preprocessor for LinkPreprocessor {
     }
 }
 
-fn replace_all<P1, P2>(
+pub(crate) fn replace_all<P1, P2>(
     s: &str,
     path: P1,
     source: P2,

src/preprocess/mod.rs

@@ -3,10 +3,12 @@
 pub use self::cmd::CmdPreprocessor;
 pub use self::index::IndexPreprocessor;
 pub use self::links::LinkPreprocessor;
+pub use self::summary::SummaryPreprocessor;
 
 mod cmd;
 mod index;
 mod links;
+mod summary;
 
 use crate::book::Book;
 use crate::config::Config;

src/preprocess/summary.rs

@@ -0,0 +1,13 @@
+use std::path::Path;
+
+/// A preprocessor dedicated just to the summary to resolve links
+#[derive(Default)]
+pub struct SummaryPreprocessor;
+
+impl SummaryPreprocessor {
+    /// Preprocess Summary to resolve links.
+    pub fn resolve(src_dir: &Path, content: &str) -> String {
+        let mut title = String::from("SUMMARY.md");
+        super::links::replace_all(content, src_dir, src_dir, 0, &mut title)
+    }
+}