From 528a4c1e20c2b9b8ecf451af72c77ae36e4f95b5 Mon Sep 17 00:00:00 2001
From: Lars Wirzenius <liw@liw.fi>
Date: Wed, 25 Jan 2023 19:22:44 +0200
Subject: feat: keep track of which pages a page links to

Via wiki links or the meta link directive.

Sponsored-by: author
---
 src/bin/riki.rs       | 32 ++++++++++++++++++++++++++++++++
 src/directive/meta.rs |  7 +++++++
 src/page.rs           | 17 ++++++++++++++++-
 src/site.rs           |  8 +++++++-
 src/wikitext.rs       |  1 +
 5 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/src/bin/riki.rs b/src/bin/riki.rs
index c1f9e4b..bff1a72 100644
--- a/src/bin/riki.rs
+++ b/src/bin/riki.rs
@@ -52,6 +52,7 @@ fn real_main() -> Result<(), RikiError> {
             Command::Timestamps(cmd) => cmd.run()?,
             Command::ParseDate(cmd) => cmd.run()?,
             Command::PageSpec(cmd) => cmd.run()?,
+            Command::Links(cmd) => cmd.run()?,
         }
     }
 
@@ -77,6 +78,7 @@ enum Command {
     Timestamps(Timestamps),
     ParseDate(ParseDate),
     PageSpec(PageSpec),
+    Links(Links),
 }
 
 /// Build the site.
@@ -247,3 +249,33 @@ impl PageSpec {
         Ok(())
     }
 }
+
+/// List links in the pages listed on the command line.
+#[derive(Parser)]
+struct Links {
+    /// Directory where source files are.
+    srcdir: PathBuf,
+
+    /// Path to pages whose links are to be listed.
+    pages: Vec<PathBuf>,
+}
+
+impl Links {
+    fn run(&self) -> Result<(), RikiError> {
+        let srcdir = canonicalize(&self.srcdir)?;
+        let mut site = Site::new(&srcdir, &PathBuf::from("/tmp"));
+        site.scan()?;
+        site.process()?;
+
+        for path in self.pages.iter() {
+            if let Some(page) = site.page(path) {
+                println!("page: {:?}", page.meta().path().display());
+                for path in page.meta().links_to() {
+                    println!("  {}", path.display());
+                }
+            }
+        }
+
+        Ok(())
+    }
+}
diff --git a/src/directive/meta.rs b/src/directive/meta.rs
index 974a955..5e07eed 100644
--- a/src/directive/meta.rs
+++ b/src/directive/meta.rs
@@ -4,10 +4,13 @@ use crate::site::Site;
 use crate::time::parse_timestamp;
 use crate::wikitext::ParsedDirective;
 
+use std::path::PathBuf;
+
 #[derive(Default, Debug, Eq, PartialEq)]
 pub struct Meta {
     title: Option<String>,
     date: Option<String>,
+    link: PathBuf,
 }
 
 impl DirectiveImplementation for Meta {
@@ -24,6 +27,9 @@ impl DirectiveImplementation for Meta {
         if let Some(date) = args.get("date") {
             meta.set_date(date);
         }
+        if let Some(link) = args.get("link") {
+            meta.link = PathBuf::from(link);
+        }
         meta
     }
 
@@ -34,6 +40,7 @@ impl DirectiveImplementation for Meta {
         if let Some(mtime) = &self.date {
             meta.set_mtime(parse_timestamp(mtime)?);
         }
+        meta.add_link(&self.link);
         Ok(Processed::Markdown("".into()))
     }
 }
diff --git a/src/page.rs b/src/page.rs
index d84721c..453c29b 100644
--- a/src/page.rs
+++ b/src/page.rs
@@ -30,6 +30,7 @@ pub enum PageError {
     Parser(#[from] crate::parser::ParserError),
 }
 
+#[derive(Debug)]
 pub struct Page {
     meta: PageMeta,
     unprocessed: UnprocessedPage,
@@ -193,6 +194,7 @@ pub struct PageMeta {
     name: Name,
     title: Option<String>,
     mtime: SystemTime,
+    links_to: Vec<PathBuf>,
 }
 
 impl PageMeta {
@@ -203,7 +205,12 @@ impl PageMeta {
             title,
             mtime,
         );
-        Self { name, title, mtime }
+        Self {
+            name,
+            title,
+            mtime,
+            links_to: vec![],
+        }
     }
 
     pub fn destination_filename(&self) -> PathBuf {
@@ -234,6 +241,14 @@ impl PageMeta {
     pub fn set_mtime(&mut self, mtime: SystemTime) {
         self.mtime = mtime;
     }
+
+    pub fn add_link(&mut self, path: &Path) {
+        self.links_to.push(path.into());
+    }
+
+    pub fn links_to(&self) -> &[PathBuf] {
+        &self.links_to
+    }
 }
 
 #[derive(Debug, Default)]
diff --git a/src/site.rs b/src/site.rs
index 4d2ce29..cfd5017 100644
--- a/src/site.rs
+++ b/src/site.rs
@@ -93,7 +93,7 @@ impl Site {
         info!("add wikitext page {}", page.meta().path().display());
         self.pages_that_will_exist.insert(&page);
 
-        debug!("parsing wikitext page {}", page.meta().path().display());
+        trace!("parsing wikitext page {}", page.meta().path().display());
         let mut parser = WikitextParser::new(page.wikitext(), &self.patterns);
         let page = UnprocessedPage::new(page.meta().clone(), &mut parser)?;
         page.prepare(self)?;
@@ -151,6 +151,12 @@ impl Site {
         self.pages_that_will_exist.get_path(path).is_some()
     }
 
+    pub fn page(&self, path: &Path) -> Option<&MarkdownPage> {
+        self.markdown_pages
+            .iter()
+            .find(|&page| page.meta().path() == path)
+    }
+
     fn all_files(&self) -> Result<Vec<Name>, SiteError> {
         let whatchanged = git_whatchanged(self.name_builder.srcdir())?;
 
diff --git a/src/wikitext.rs b/src/wikitext.rs
index 4d8578a..57dff88 100644
--- a/src/wikitext.rs
+++ b/src/wikitext.rs
@@ -48,6 +48,7 @@ impl Snippet {
             Snippet::WikiLink(w) => {
                 let resolved = site.resolve(meta.path(), Path::new(w.target()))?;
                 trace!("resolved {} to {}", w.target(), resolved.display());
+                meta.add_link(&resolved);
                 let link = format!("[{}]({})", w.link_text(), resolved.display());
                 Processed::Markdown(link)
             }
-- 
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