feat! generate foo/index.html for foo.mdwn (ikiwiki usedirs)

Implement the ikiwiki "usedirs" functionality in riki, so that riki
generates compatible URLs with ikiwiki. This means that for an input
page foo.mdwn, riki generates an output page of foo/index.html.

ikiwiki has its "usedirs" setting enabled by default, with the
following justification:

  There are several advantages to `usedirs`, including simpler URLs, URLs that
  aren't dependent on the underlying implementation (`.html`), and being able to
  use URLs as tags as described in the [rel-tag
  microformat](http://microformats.org/wiki/rel-tag).

  The main disadvantage is that it is harder to browse using `file://` URIs,
  since `file:///dir/` doesn't automatically translate to `dir/index.html`. This
  is something one could fix in the browser though.

For riki it's enough to be compatible with ikiwiki.

Sponsored-by: author

2 files changed, 74 insertions, 37 deletions

diff --git a/riki.md b/riki.md
index f74f7a0..de4e08a 100644
--- a/riki.md
+++ b/riki.md
@@ -27,7 +27,7 @@ be an empty HTML file._
 given an installed riki
 given file site/empty.mdwn from empty
 when I run riki build --plain-body site output
-then AST of site/empty.mdwn matches that of output/empty.html
+then AST of site/empty.mdwn matches that of output/empty/index.html
 ~~~
 
 
@@ -43,7 +43,7 @@ be an HTML file with the same text, without extra elements._
 given an installed riki
 given file site/page.mdwn from para
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -63,7 +63,7 @@ output must have a blockquote element.
 given an installed riki
 given file site/page.mdwn from blockquote
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -81,7 +81,7 @@ output must have a pre element.
 given an installed riki
 given file site/page.mdwn from indented-code
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -99,7 +99,7 @@ output must have a pre element.
 given an installed riki
 given file site/page.mdwn from fenced-code
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -120,7 +120,7 @@ must have an img element.
 given an installed riki
 given file site/page.mdwn from image-link
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -137,7 +137,7 @@ in HTML output._
 given an installed riki
 given file site/page.mdwn from emph
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -154,7 +154,7 @@ strong element in HTML output._
 given an installed riki
 given file site/page.mdwn from strong
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -171,7 +171,7 @@ element in HTML output._
 given an installed riki
 given file site/page.mdwn from strike
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -190,7 +190,7 @@ supported._
 given an installed riki
 given file site/page.mdwn from headings
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -212,7 +212,7 @@ element in HTML output._
 given an installed riki
 given file site/page.mdwn from backticks
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -231,7 +231,7 @@ output._
 given an installed riki
 given file site/page.mdwn from table
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -252,7 +252,7 @@ HTML output._
 given an installed riki
 given file site/page.mdwn from rule
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -273,7 +273,7 @@ in HTML output._
 given an installed riki
 given file site/page.mdwn from ul
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -294,7 +294,7 @@ the same as the Markdown.***
 given an installed riki
 given file site/page.mdwn from ol
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 <!--
@@ -313,7 +313,7 @@ in HTML output._
 given an installed riki
 given file site/page.mdwn from tasklist
 when I run riki build --plain-body site output
-then AST of site/page.mdwn matches that of output/page.html
+then AST of site/page.mdwn matches that of output/page/index.html
 ~~~
 
 
@@ -347,7 +347,7 @@ then stderr contains "definition list"
 
 given file site/page.mdwn from dl-3
 when I run riki build --plain-body site output
-then file output/page.html contains ": bar"
+then file output/page/index.html contains ": bar"
 ~~~
 
 ~~~{#dl-1 .file}
@@ -381,10 +381,10 @@ given file site/dir/sibling.mdwn from empty
 given file site/dir/foo/child.mdwn from empty
 given file site/dir/foo/child/grandchild.mdwn from empty
 when I run riki build --plain-body site output
-then file output/dir/foo.html contains "href="../absolute""
-then file output/dir/foo.html contains "href="sibling""
-then file output/dir/foo.html contains "href="foo/child""
-then file output/dir/foo.html contains "href="foo/child/grandchild""
+then file output/dir/foo/index.html contains "href="../absolute""
+then file output/dir/foo/index.html contains "href="sibling""
+then file output/dir/foo/index.html contains "href="foo/child""
+then file output/dir/foo/index.html contains "href="foo/child/grandchild""
 ~~~
 
 Note the uppercase link to the `child` page in the test page below.
@@ -558,7 +558,7 @@ given an installed riki
 given file site/a.mdwn from use_shortcut
 given file site/b.mdwn from define_shortcut
 when I run riki build site output
-then file output/a.html contains "<a href="https://example.com/foo/123">foo!123</a>"
+then file output/a/index.html contains "<a href="https://example.com/foo/123">foo!123</a>"
 ~~~
 
 ~~~{#use_shortcut .file .markdown}
@@ -635,8 +635,8 @@ given an installed riki
 given file site/foo/page.mdwn from image
 given file site/bar/image.jpg from para
 when I run riki build --plain-body site output
-then AST of site/foo/page.mdwn matches that of output/foo/page.html
-then files site/bar//image.jpg and output/bar/image.jpg match
+then AST of site/foo/page.mdwn matches that of output/foo/page/index.html
+then files site/bar/image.jpg and output/bar/image.jpg match
 ~~~
 
 ## Output directory tree
diff --git a/src/name.rs b/src/name.rs
index 4cb5f16..3cb0157 100644
--- a/src/name.rs
+++ b/src/name.rs
@@ -1,5 +1,7 @@
 use crate::util::{join_subpath, make_path_absolute, make_path_relative_to};
+use log::trace;
 use std::cmp::Ordering;
+use std::ffi::OsStr;
 use std::fmt;
 use std::path::{Path, PathBuf};
 
@@ -14,9 +16,16 @@ pub struct Name {
 
 impl Name {
     fn new(is_wikitext: bool, src: PathBuf, dest: PathBuf, page: PathBuf) -> Self {
+        trace!(
+            "Name::new: is_wikitext={} src={} dest={} page={}",
+            is_wikitext,
+            src.display(),
+            dest.display(),
+            page.display()
+        );
         let page_name = page
             .file_name()
-            .unwrap_or_else(|| panic!("get filename from {}", page.display()))
+            .unwrap_or_else(|| OsStr::new("/"))
             .to_string_lossy()
             .to_string();
         Self {
@@ -94,25 +103,41 @@ impl NameBuilder {
         &self.destdir
     }
 
-    fn name(&self, path: &Path, ext: Option<&str>) -> Name {
+    pub fn page(&self, path: &Path) -> Name {
         assert!(path.starts_with(&self.srcdir));
         let src = path.into();
         let relative = make_path_relative_to(&self.srcdir, path);
-        let dest = join_subpath(&self.destdir, &relative);
-        let page = make_path_absolute(&relative);
-        if let Some(ext) = ext {
-            Name::new(true, src, dest.with_extension(ext), page.with_extension(""))
+
+        let (dest, page) = if path.ends_with("index.mdwn") {
+            let dest = join_subpath(&self.destdir, &relative.with_extension("html"));
+            let dirname = relative
+                .parent()
+                .unwrap_or_else(|| panic!("expected parent directory for {}", relative.display()));
+            let page = make_path_absolute(dirname);
+            (dest, page)
         } else {
-            Name::new(false, src, dest, page)
-        }
-    }
+            let dirname = relative
+                .parent()
+                .unwrap_or_else(|| panic!("expected a parent for {}", relative.display()));
+            let basename = relative
+                .file_stem()
+                .unwrap_or_else(|| panic!("expected stem for {}", relative.display()));
+            let page_relative = dirname.join(basename);
+            let dest = join_subpath(&self.destdir, &page_relative.join("index.html"));
+            let page = make_path_absolute(&page_relative);
+            (dest, page)
+        };
 
-    pub fn page(&self, path: &Path) -> Name {
-        self.name(path, Some("html"))
+        Name::new(true, src, dest, page)
     }
 
     pub fn file(&self, path: &Path) -> Name {
-        self.name(path, None)
+        assert!(path.starts_with(&self.srcdir));
+        let src = path.into();
+        let relative = make_path_relative_to(&self.srcdir, path);
+        let page = make_path_absolute(&relative);
+        let dest = join_subpath(&self.destdir, &relative);
+        Name::new(false, src, dest, page)
     }
 }
 
@@ -164,12 +189,24 @@ mod test {
     fn builds_page_name() {
         let name = builder().page(Path::new("/src/foo/bar.mdwn"));
         assert_eq!(name.source_path(), Path::new("/src/foo/bar.mdwn"));
-        assert_eq!(name.destination_path(), Path::new("/dest/foo/bar.html"));
+        assert_eq!(
+            name.destination_path(),
+            Path::new("/dest/foo/bar/index.html")
+        );
         assert_eq!(name.page_path(), Path::new("/foo/bar"));
         assert_eq!(name.page_name(), "bar");
     }
 
     #[test]
+    fn builds_page_name_for_index_mdwn() {
+        let name = builder().page(Path::new("/src/foo/index.mdwn"));
+        assert_eq!(name.source_path(), Path::new("/src/foo/index.mdwn"));
+        assert_eq!(name.destination_path(), Path::new("/dest/foo/index.html"));
+        assert_eq!(name.page_path(), Path::new("/foo"));
+        assert_eq!(name.page_name(), "foo");
+    }
+
+    #[test]
     fn builds_file_name() {
         let name = builder().file(Path::new("/src/foo/bar.jpg"));
         assert_eq!(name.source_path(), Path::new("/src/foo/bar.jpg"));