Remove adjlist-based path implementation

brood/src/commands.rs

@@ -3,6 +3,5 @@ pub mod list_links;
 pub mod list_pages;
 pub mod longest_shortest_path;
 pub mod path;
-pub mod path2;
 pub mod philosophy_game;
 pub mod reexport;

brood/src/commands/path.rs

@@ -1,158 +1,76 @@
-use std::collections::BinaryHeap;
+use std::{
-use std::fs::File;
+    fs::File,
-use std::io::{self, BufReader};
+    io::{self, BufReader},
-use std::path::Path;
+    path::Path,
+};
 
-use crate::data::adjacency_list::AdjacencyList;
+use crate::{
-use crate::data::info::{LinkInfo, PageInfo};
+    algo::Dijkstra,
-use crate::data::store;
+    data::{info::PageInfo, store},
-use crate::util;
+    graph::{Graph, NodeIdx},
+    util,
+};
 
-struct DijkstraPageInfo {
+pub fn find_index_of_title(pages: &[PageInfo], title: &str) -> NodeIdx {
-    cost: u32,
+    let title = util::normalize_link(title);
-    prev: u32,
+    pages
-    redirect: bool,
+        .iter()
+        .enumerate()
+        .find(|(_, p)| util::normalize_link(&p.title) == title)
+        .map(|(i, _)| NodeIdx::new(i))
+        .expect("invalid title")
 }
 
-impl DijkstraPageInfo {
+pub fn resolve_redirects(pages: &[PageInfo], graph: &Graph, mut page: NodeIdx) -> NodeIdx {
-    fn from_page_info(info: PageInfo) -> Self {
+    loop {
-        Self {
+        if pages[page.usize()].redirect {
-            cost: u32::MAX,
+            if let Some(next) = graph.edges_for(page).first() {
-            prev: u32::MAX,
+                page = *next;
-            redirect: info.redirect,
+                continue;
-        }
-    }
-}
-
-struct DijkstraLinkInfo {
-    cost: u32,
-}
-
-impl DijkstraLinkInfo {
-    fn from_link_info(info: LinkInfo) -> Self {
-        Self {
-            cost: 1,
-            // cost: 1000 + info.start,
-            // cost: 10000 + info.start,
-            // cost: 1000 + info.start / 10,
-        }
-    }
-}
-
-#[derive(Clone, Copy, PartialEq, Eq)]
-struct Entry {
-    cost: u32,
-    page_idx: u32,
-}
-
-impl Entry {
-    pub fn new(cost: u32, page_idx: u32) -> Self {
-        Self { cost, page_idx }
-    }
-}
-
-// Manual implementation so the queue is a min-heap instead of a max-heap.
-impl Ord for Entry {
-    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        other
-            .cost
-            .cmp(&self.cost)
-            .then_with(|| self.page_idx.cmp(&other.page_idx))
-    }
-}
-
-impl PartialOrd for Entry {
-    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
-/// Closely matches the dijkstra example in [std::collections::binary_heap].
-fn dijkstra(data: AdjacencyList<PageInfo, LinkInfo>, from: u32, to: u32) -> Option<Vec<u32>> {
-    println!("> Prepare state");
-    let mut data = data
-        .change_page_data(DijkstraPageInfo::from_page_info)
-        .change_link_data(DijkstraLinkInfo::from_link_info);
-    let mut queue = BinaryHeap::new();
-    data.page_mut(from).data.cost = 0;
-    queue.push(Entry::new(0, from));
-
-    println!("> Run dijkstra");
-    while let Some(Entry { cost, page_idx }) = queue.pop() {
-        if page_idx == to {
-            // We've found the shortest path to our target
-            break;
-        }
-
-        let page = data.page(page_idx);
-        if cost > page.data.cost {
-            // This queue entry is outdated
-            continue;
-        }
-
-        let redirect = page.data.redirect;
-        for link_idx in data.link_range(page_idx) {
-            let link = data.link(link_idx);
-
-            let next = Entry {
-                cost: cost + if redirect { 0 } else { link.data.cost },
-                page_idx: link.to,
-            };
-
-            let target_page = data.page_mut(link.to);
-            if next.cost < target_page.data.cost {
-                target_page.data.cost = next.cost;
-                target_page.data.prev = page_idx;
-                queue.push(next);
             }
         }
-    }
 
-    println!("> Collect results");
+        return page;
-    let mut steps = vec![];
-    let mut at = to;
-    loop {
-        steps.push(at);
-        at = data.page(at).data.prev;
-        if at == u32::MAX {
-            break;
-        };
-    }
-    steps.reverse();
-    if steps.first() == Some(&from) {
-        Some(steps)
-    } else {
-        None
     }
 }
 
-pub fn path(datafile: &Path, from: &str, to: &str) -> io::Result<()> {
+pub fn path(datafile: &Path, start: &str, goal: &str) -> io::Result<()> {
     println!(">> Import");
     let mut databuf = BufReader::new(File::open(datafile)?);
-    let data = store::read_adjacency_list(&mut databuf)?;
+    let (pages, _links, graph) = store::read_graph(&mut databuf)?;
-    let pages = data.pages.clone();
 
     println!(">> Locate from and to");
-    let from_idx = util::resolve_redirects(&data, util::find_index_of_title(&pages, from));
+    let start = resolve_redirects(&pages, &graph, find_index_of_title(&pages, start));
-    let to_idx = util::resolve_redirects(&data, util::find_index_of_title(&pages, to));
+    let goal = resolve_redirects(&pages, &graph, find_index_of_title(&pages, goal));
-    println!("From: {:?}", data.page(from_idx).data.title);
+    println!("Start: {:?}", pages[start.usize()].title);
-    println!("To:   {:?}", data.page(to_idx).data.title);
+    println!("Goal:  {:?}", pages[goal.usize()].title);
 
     println!(">> Find path");
-    let path = dijkstra(data, from_idx, to_idx);
+    println!("> Preparing dijkstra");
+    let mut dijkstra = Dijkstra::new(&graph);
+    println!("> Running dijkstra");
+    dijkstra.run(
+        start,
+        |node| node == goal,
+        |source, _edge, _target| !pages[source.usize()].redirect as u32,
+    );
 
-    if let Some(path) = path {
+    if dijkstra.cost(goal) == u32::MAX {
-        println!("Path found:");
-        for page_idx in path {
-            let page = &pages[page_idx as usize];
-            if page.data.redirect {
-                println!(" v {:?}", page.data.title);
-            } else {
-                println!(" - {:?}", page.data.title);
-            }
-        }
-    } else {
         println!("No path found");
+        return Ok(());
+    }
+
+    println!("> Collecting path");
+    let path = dijkstra.path(goal);
+    let cost = dijkstra.cost(goal);
+    println!("Path found (cost {cost}, length {}):", path.len());
+    for page in path {
+        let info = &pages[page.usize()];
+        if info.redirect {
+            println!(" v {:?}", info.title);
+        } else {
+            println!(" - {:?}", info.title);
+        }
     }
 
     Ok(())

brood/src/commands/path2.rs

@@ -1,77 +0,0 @@
-use std::{
-    fs::File,
-    io::{self, BufReader},
-    path::Path,
-};
-
-use crate::{
-    algo::Dijkstra,
-    data::{info::PageInfo, store},
-    graph::{Graph, NodeIdx},
-    util,
-};
-
-pub fn find_index_of_title(pages: &[PageInfo], title: &str) -> NodeIdx {
-    let title = util::normalize_link(title);
-    pages
-        .iter()
-        .enumerate()
-        .find(|(_, p)| util::normalize_link(&p.title) == title)
-        .map(|(i, _)| NodeIdx::new(i))
-        .expect("invalid title")
-}
-
-pub fn resolve_redirects(pages: &[PageInfo], graph: &Graph, mut page: NodeIdx) -> NodeIdx {
-    loop {
-        if pages[page.usize()].redirect {
-            if let Some(next) = graph.edges_for(page).first() {
-                page = *next;
-                continue;
-            }
-        }
-
-        return page;
-    }
-}
-
-pub fn path(datafile: &Path, start: &str, goal: &str) -> io::Result<()> {
-    println!(">> Import");
-    let mut databuf = BufReader::new(File::open(datafile)?);
-    let (pages, _links, graph) = store::read_graph(&mut databuf)?;
-
-    println!(">> Locate from and to");
-    let start = resolve_redirects(&pages, &graph, find_index_of_title(&pages, start));
-    let goal = resolve_redirects(&pages, &graph, find_index_of_title(&pages, goal));
-    println!("Start: {:?}", pages[start.usize()].title);
-    println!("Goal:  {:?}", pages[goal.usize()].title);
-
-    println!(">> Find path");
-    println!("> Preparing dijkstra");
-    let mut dijkstra = Dijkstra::new(&graph);
-    println!("> Running dijkstra");
-    dijkstra.run(
-        start,
-        |node| node == goal,
-        |source, _edge, _target| !pages[source.usize()].redirect as u32,
-    );
-
-    if dijkstra.cost(goal) == u32::MAX {
-        println!("No path found");
-        return Ok(());
-    }
-
-    println!("> Collecting path");
-    let path = dijkstra.path(goal);
-    let cost = dijkstra.cost(goal);
-    println!("Path found (cost {cost}, length {}):", path.len());
-    for page in path {
-        let info = &pages[page.usize()];
-        if info.redirect {
-            println!(" v {:?}", info.title);
-        } else {
-            println!(" - {:?}", info.title);
-        }
-    }
-
-    Ok(())
-}

brood/src/main.rs

@@ -40,14 +40,6 @@ enum Command {
         #[arg(short, long)]
         flip: bool,
     },
-    /// Find a path from one article to another.
-    Path2 {
-        from: String,
-        to: String,
-        /// Flip start and end article.
-        #[arg(short, long)]
-        flip: bool,
-    },
     /// Find the longest shortest path starting at an article.
     LongestShortestPath {
         from: String,
@@ -90,13 +82,6 @@ fn main() -> io::Result<()> {
                 commands::path::path(&args.datafile, &from, &to)
             }
         }
-        Command::Path2 { from, to, flip } => {
-            if flip {
-                commands::path2::path(&args.datafile, &to, &from)
-            } else {
-                commands::path2::path(&args.datafile, &from, &to)
-            }
-        }
         Command::LongestShortestPath { from } => {
             commands::longest_shortest_path::run(&args.datafile, &from)
         }