Recursively apply preprocessor (#682)

Author: AndyGauge

src/preprocess/links.rs

@@ -9,6 +9,7 @@ use super::{Preprocessor, PreprocessorContext};
 use book::{Book, BookItem};
 
 const ESCAPE_CHAR: char = '\\';
+const MAX_LINK_NESTED_DEPTH: usize = 10;
 
 /// A preprocessor for expanding the `{{# playpen}}` and `{{# include}}`
 /// helpers in a chapter.
@@ -36,7 +37,7 @@ impl Preprocessor for LinkPreprocessor {
                     .map(|dir| src_dir.join(dir))
                     .expect("All book items have a parent");
 
-                let content = replace_all(&ch.content, base);
+                let content = replace_all(&ch.content, base, &ch.path, 0);
                 ch.content = content;
             }
         });
@@ -45,11 +46,12 @@ impl Preprocessor for LinkPreprocessor {
     }
 }
 
-fn replace_all<P: AsRef<Path>>(s: &str, path: P) -> String {
+fn replace_all<P: AsRef<Path>>(s: &str, path: P, source: &P, depth: usize) -> String {
     // When replacing one thing in a string by something with a different length,
     // the indices after that will not correspond,
     // we therefore have to store the difference to correct this
     let path = path.as_ref();
+    let source = source.as_ref();
     let mut previous_end_index = 0;
     let mut replaced = String::new();
 
@@ -58,7 +60,15 @@ fn replace_all<P: AsRef<Path>>(s: &str, path: P) -> String {
 
         match playpen.render_with_path(&path) {
             Ok(new_content) => {
-                replaced.push_str(&new_content);
+                if depth < MAX_LINK_NESTED_DEPTH {
+                    if let Some(rel_path) = playpen.link.relative_path(path) {
+                        replaced.push_str(&replace_all(&new_content, rel_path, &source.to_path_buf(), depth + 1));
+                    }
+                }
+                else {
+                    error!("Stack depth exceeded in {}. Check for cyclic includes",
+                            source.display());
+                }
                 previous_end_index = playpen.end_index;
             }
             Err(e) => {
@@ -84,6 +94,27 @@ enum LinkType<'a> {
     Playpen(PathBuf, Vec<&'a str>),
 }
 
+impl<'a> LinkType<'a> {
+    fn relative_path<P: AsRef<Path>>(self, base: P) -> Option<PathBuf> {
+        let base = base.as_ref();
+        match self {
+            LinkType::Escaped => None,
+            LinkType::IncludeRange(p, _) => Some(return_relative_path(base, &p)),
+            LinkType::IncludeRangeFrom(p, _) => Some(return_relative_path(base, &p)),
+            LinkType::IncludeRangeTo(p, _) => Some(return_relative_path(base, &p)),
+            LinkType::IncludeRangeFull(p, _) => Some(return_relative_path(base, &p)),
+            LinkType::Playpen(p,_) => Some(return_relative_path(base, &p))
+        }
+    }
+}
+fn return_relative_path<P: AsRef<Path>>(base: P, relative: P) -> PathBuf {
+    base.as_ref()
+        .join(relative)
+        .parent()
+        .expect("Included file should not be /")
+        .to_path_buf()
+}
+
 fn parse_include_path(path: &str) -> LinkType<'static> {
     let mut parts = path.split(':');
     let path = parts.next().unwrap().into();

tests/dummy_book/src/SUMMARY.md

@@ -5,6 +5,7 @@
 - [First Chapter](first/index.md)
     - [Nested Chapter](first/nested.md)
     - [Includes](first/includes.md)
+    - [Recursive](first/recursive.md)
 - [Second Chapter](second.md)
 
 ---

tests/dummy_book/src/first/recursive.md

@@ -0,0 +1,2 @@
+Around the world, around the world
+{{#include recursive.md}}

tests/rendered_output.rs

@@ -29,7 +29,7 @@ const TOC_TOP_LEVEL: &[&'static str] = &[
     "Conclusion",
     "Introduction",
 ];
-const TOC_SECOND_LEVEL: &[&'static str] = &["1.1. Nested Chapter", "1.2. Includes"];
+const TOC_SECOND_LEVEL: &[&'static str] = &["1.1. Nested Chapter", "1.2. Includes", "1.3. Recursive"];
 
 /// Make sure you can load the dummy book and build it without panicking.
 #[test]
@@ -313,6 +313,20 @@ fn able_to_include_files_in_chapters() {
     assert_doesnt_contain_strings(&includes, &["{{#include ../SUMMARY.md::}}"]);
 }
 
+/// Ensure cyclic includes are capped so that no exceptions occur
+#[test]
+fn recursive_includes_are_capped() {
+    let temp = DummyBook::new().build().unwrap();
+    let md = MDBook::load(temp.path()).unwrap();
+    md.build().unwrap();
+
+    let recursive = temp.path().join("book/first/recursive.html");
+    let content = &["Around the world, around the world
+Around the world, around the world
+Around the world, around the world"];
+    assert_contains_strings(&recursive, content);
+}
+
 #[test]
 fn example_book_can_build() {
     let example_book_dir = dummy_book::new_copy_of_example_book().unwrap();
@@ -424,7 +438,7 @@ mod search {
         assert_eq!(docs["first/index.html#some-section"]["body"], "");
         assert_eq!(
             docs["first/includes.html#summary"]["body"],
-            "Introduction First Chapter Nested Chapter Includes Second Chapter Conclusion"
+            "Introduction First Chapter Nested Chapter Includes Recursive Second Chapter Conclusion"
         );
         assert_eq!(
             docs["first/includes.html#summary"]["breadcrumbs"],
@@ -439,7 +453,7 @@ mod search {
     // Setting this to `true` may cause issues with `cargo watch`,
     // since it may not finish writing the fixture before the tests
     // are run again.
-    const GENERATE_FIXTURE: bool = false;
+    const GENERATE_FIXTURE: bool = true;
 
     fn get_fixture() -> serde_json::Value {
         if GENERATE_FIXTURE {

tests/searchindex_fixture.json

@@ -13,7 +13,7 @@
           "title": 1
         },
         "first/includes.html#summary": {
-          "body": 9,
+          "body": 10,
           "breadcrumbs": 3,
           "title": 1
         },
@@ -62,7 +62,7 @@
           "title": "Includes"
         },
         "first/includes.html#summary": {
-          "body": "Introduction First Chapter Nested Chapter Includes Second Chapter Conclusion",
+          "body": "Introduction First Chapter Nested Chapter Includes Recursive Second Chapter Conclusion",
           "breadcrumbs": "First Chapter » Summary",
           "id": "first/includes.html#summary",
           "title": "Summary"
@@ -742,6 +742,30 @@
           "r": {
             "df": 0,
             "docs": {},
+            "e": {
+              "c": {
+                "df": 0,
+                "docs": {},
+                "u": {
+                  "df": 0,
+                  "docs": {},
+                  "r": {
+                    "df": 0,
+                    "docs": {},
+                    "s": {
+                      "df": 1,
+                      "docs": {
+                        "first/includes.html#summary": {
+                          "tf": 1.0
+                        }
+                      }
+                    }
+                  }
+                }
+              },
+              "df": 0,
+              "docs": {}
+            },
             "u": {
               "df": 0,
               "docs": {},
@@ -1630,6 +1654,30 @@
           "r": {
             "df": 0,
             "docs": {},
+            "e": {
+              "c": {
+                "df": 0,
+                "docs": {},
+                "u": {
+                  "df": 0,
+                  "docs": {},
+                  "r": {
+                    "df": 0,
+                    "docs": {},
+                    "s": {
+                      "df": 1,
+                      "docs": {
+                        "first/includes.html#summary": {
+                          "tf": 1.0
+                        }
+                      }
+                    }
+                  }
+                }
+              },
+              "df": 0,
+              "docs": {}
+            },
             "u": {
               "df": 0,
               "docs": {},