krz/orgo

Lightning fast org-mode static site generator.

clone: git clone https://gitbay.org/krz/orgo.git

v0.19.1: src/site.rs · raw

   1//! Site build: walk a source directory, PARSE every `.org` file, INDEX their targets,
   2//! then RESOLVE + RENDER + TEMPLATE each page into a linked static site, copying
   3//! non-`.org` assets through unchanged (spec §2.1 DISCOVER…EMIT).
   4//!
   5//! v0.3 wires in the incremental layer (spec §4, [`crate::incremental`]): a persisted
   6//! cache manifest lets a rebuild re-render only the pages whose composed `render_key`
   7//! changed, plus the pages that *link into* a changed file's targets (the dependency
   8//! graph, spec §4.3). Unchanged pages keep their existing on-disk output untouched.
   9//! `--no-cache` forces a full rebuild; the cache is never a correctness dependency, so a
  10//! full rebuild and an incremental rebuild produce byte-identical output.
  11
  12use std::collections::{HashMap, HashSet};
  13use std::fs;
  14
  15use anyhow::{Context, Result};
  16use camino::{Utf8Path, Utf8PathBuf};
  17use rayon::prelude::*;
  18use walkdir::WalkDir;
  19
  20use crate::incremental::{
  21    self, combine, config_hash, render_key, resolved_links_hash, site_structure_hash,
  22    site_structure_hash_ordered, template_hash, DepGraph, Hash, Manifest, PageRecord,
  23    CACHE_FORMAT_VERSION,
  24};
  25use crate::index::{document_targets, SymbolTable, TargetId};
  26use crate::model::{ContentHash, Diagnostic, Document};
  27use crate::parser::parse;
  28use crate::render::{self, render_with, Html, RenderOptions, SyntectHighlighter};
  29use crate::resolve::resolve;
  30use crate::config::{self, Config, NavMode, SortKey, SortOrder};
  31use crate::template::{
  32    GroupContext, NavItem, PageContext, Paginator, PaginatorPage, RenderContext, SiteContext,
  33    Templater,
  34};
  35use crate::util::{
  36    document_text, first_paragraph, is_draft, iso_date, iso_time, option_enabled,
  37    output_path, output_url,
  38    relative_root, slugify, table_of_contents,
  39};
  40
  41/// Reading speed for [`PageContext::reading_time`]. 200 wpm is the conventional figure
  42/// for prose on screen.
  43const WORDS_PER_MINUTE: usize = 200;
  44
  45/// A fully built page: source and output paths (relative to their roots) and its
  46/// final templated HTML.
  47#[derive(Debug, Clone)]
  48pub struct BuiltPage {
  49    pub source: Utf8PathBuf,
  50    pub output: Utf8PathBuf,
  51    pub title: String,
  52    pub html: String,
  53}
  54
  55/// Unresolved internal links found during a build: `(page, target)` (spec §4.3.4).
  56pub type BrokenLinks = Vec<(Utf8PathBuf, TargetId)>;
  57
  58/// Options controlling a site build.
  59#[derive(Debug, Clone, Default)]
  60pub struct BuildOptions {
  61    /// Bypass the incremental cache and re-render every page (spec §4.5).
  62    pub no_cache: bool,
  63    /// Treat broken internal links as a build error rather than a warning (spec §4.3.4).
  64    pub strict: bool,
  65    /// Explicit config file, overriding `orgo.toml` in the source directory.
  66    pub config_path: Option<Utf8PathBuf>,
  67    /// Include pages marked `#+DRAFT:`, overriding `build.drafts` when set.
  68    pub drafts: bool,
  69}
  70
  71/// Summary of a site build.
  72#[derive(Debug, Default)]
  73pub struct SiteReport {
  74    /// Every output page (rendered this build or reused from cache).
  75    pub pages: Vec<Utf8PathBuf>,
  76    /// Pages actually re-rendered and written this build (the invalidation set).
  77    pub rendered: Vec<Utf8PathBuf>,
  78    /// Pages whose existing on-disk output was reused unchanged (spec §4.1 skip rule).
  79    pub skipped: Vec<Utf8PathBuf>,
  80    pub assets: Vec<Utf8PathBuf>,
  81    /// Unresolved internal links: `(page, target)`. Warnings, not failures (spec §4.3.4).
  82    pub broken: Vec<(Utf8PathBuf, TargetId)>,
  83    /// Parse diagnostics: `(source file, diagnostic)`, in file then line order.
  84    pub diagnostics: Vec<(Utf8PathBuf, Diagnostic)>,
  85}
  86
  87impl SiteReport {
  88    /// Every diagnostic and broken link, formatted one per line as
  89    /// `file:line: message` — the form an editor can jump to.
  90    pub fn warnings(&self) -> Vec<String> {
  91        let mut out: Vec<String> = self
  92            .diagnostics
  93            .iter()
  94            .map(|(path, d)| format!("{path}:{}: {}", d.line, d.message))
  95            .collect();
  96        out.extend(
  97            self.broken
  98                .iter()
  99                .map(|(page, target)| format!("{page}: unresolved link {target}")),
 100        );
 101        out
 102    }
 103}
 104
 105/// Everything a build needs about one page *before* the decision to render it: its
 106/// hashes, its resolved element tree, and the dependency edges it participates in.
 107struct PagePrep {
 108    source: Utf8PathBuf,
 109    output: Utf8PathBuf,
 110    title: String,
 111    content_hash: ContentHash,
 112    resolved: crate::resolve::ResolvedDoc,
 113    used: HashSet<TargetId>,
 114    defines: HashSet<TargetId>,
 115    broken: Vec<TargetId>,
 116    diagnostics: Vec<Diagnostic>,
 117    nav: Vec<NavItem>,
 118    context: PageContext,
 119    /// The layout this page renders through: `#+TEMPLATE:`, a `[[pages]]` rule, or
 120    /// `base.html` (see [`config::page_template`]).
 121    template: String,
 122}
 123
 124/// A generated page, resolved against the pages it lists.
 125struct Listing {
 126    output: Utf8PathBuf,
 127    template: String,
 128    title: String,
 129    /// The pages it lists, already sorted. Empty for a group index, which lists groups.
 130    entries: Vec<PageContext>,
 131    /// The group this page is for, when it belongs to a grouped collection.
 132    group: Option<GroupContext>,
 133    /// Every group of the owning collection. The content of a group index, and context
 134    /// for a group page.
 135    groups: Vec<GroupContext>,
 136    /// Set when this is one page of a paginated listing.
 137    paginator: Option<Paginator>,
 138    /// Render each entry's body into `entry.content` (see
 139    /// [`Collection::include_content`](crate::config::Collection::include_content)).
 140    include_content: bool,
 141    /// Content hash of each entry's source, in `entries` order. Not shown to templates —
 142    /// it is how a content-carrying listing notices that a body it embeds has changed,
 143    /// without rendering every body to find out.
 144    entry_hashes: Vec<ContentHash>,
 145}
 146
 147/// Split one listing's entries across numbered pages, appending each as its own
 148/// [`Listing`].
 149///
 150/// Page 1 keeps `output`, so a section's canonical URL never moves as its page count
 151/// changes — only pages 2..N are named by `paginate_output`. An empty listing still
 152/// emits page 1, because a section that exists but has nothing in it should be a page
 153/// saying so rather than a 404.
 154#[allow(clippy::too_many_arguments)]
 155fn push_paginated(
 156    listings: &mut Vec<Listing>,
 157    collection: &config::Collection,
 158    output: Utf8PathBuf,
 159    title: String,
 160    entries: Vec<PageContext>,
 161    entry_hashes: Vec<ContentHash>,
 162    group: Option<GroupContext>,
 163    groups: Vec<GroupContext>,
 164) {
 165    let per_page = collection.paginate;
 166    if per_page == 0 {
 167        listings.push(Listing {
 168            output,
 169            template: collection.template.clone(),
 170            title,
 171            entries,
 172            group,
 173            groups,
 174            paginator: None,
 175            include_content: collection.include_content,
 176            entry_hashes: entry_hashes.clone(),
 177        });
 178        return;
 179    }
 180
 181    let total_entries = entries.len();
 182    let total = entries.len().div_ceil(per_page).max(1);
 183    let slug = group.as_ref().map(|g| g.slug.clone()).unwrap_or_default();
 184    let page_output = |n: usize| -> Utf8PathBuf {
 185        if n == 1 {
 186            return output.clone();
 187        }
 188        Utf8PathBuf::from(
 189            collection
 190                .paginate_output
 191                .as_str()
 192                .replace(config::GROUP_PLACEHOLDER, &slug)
 193                .replace(config::PAGE_PLACEHOLDER, &n.to_string()),
 194        )
 195    };
 196    let outputs: Vec<Utf8PathBuf> = (1..=total).map(page_output).collect();
 197
 198    for (idx, chunk) in entries.chunks(per_page).chain(
 199        // `chunks` yields nothing for an empty slice; page 1 still has to exist.
 200        std::iter::once(&[][..]).take(usize::from(total_entries == 0)),
 201    ) .enumerate()
 202    {
 203        let current = idx + 1;
 204        let here = &outputs[idx];
 205        let url_to = |n: usize| output_url(here, &outputs[n - 1], None);
 206        listings.push(Listing {
 207            output: here.clone(),
 208            template: collection.template.clone(),
 209            include_content: collection.include_content,
 210            entry_hashes: entry_hashes.clone(),
 211            title: title.clone(),
 212            entries: chunk.to_vec(),
 213            group: group.clone(),
 214            groups: groups.clone(),
 215            paginator: Some(Paginator {
 216                current,
 217                total,
 218                per_page,
 219                total_entries,
 220                prev_url: (current > 1).then(|| url_to(current - 1)),
 221                next_url: (current < total).then(|| url_to(current + 1)),
 222                first_url: url_to(1),
 223                last_url: url_to(total),
 224                pages: (1..=total)
 225                    .map(|n| PaginatorPage {
 226                        number: n,
 227                        url: url_to(n),
 228                        current: n == current,
 229                    })
 230                    .collect(),
 231            }),
 232        });
 233    }
 234}
 235
 236/// Build the listing pages a config asks for, each with its entries sorted.
 237fn build_listings(config: &Config, preps: &[PagePrep]) -> Result<Vec<Listing>> {
 238    let mut listings = Vec::new();
 239    let hashes: HashMap<&str, ContentHash> = preps
 240        .iter()
 241        .map(|p| (p.source.as_str(), p.content_hash))
 242        .collect();
 243    let hashes_of = |entries: &[PageContext]| -> Vec<ContentHash> {
 244        entries
 245            .iter()
 246            .filter_map(|e| hashes.get(e.source.as_str()).copied())
 247            .collect()
 248    };
 249    for collection in &config.collections {
 250        let mut entries: Vec<PageContext> = preps
 251            .iter()
 252            .filter(|p| {
 253                collection.source.as_str().is_empty() || p.source.starts_with(&collection.source)
 254            })
 255            .map(|p| p.context.clone())
 256            .collect();
 257
 258        // Sort ascending first, then reverse for `desc`, so the two orders are exact
 259        // mirrors of one another rather than two separately-written comparisons.
 260        match collection.sort {
 261            SortKey::Title => entries.sort_by(|a, b| a.title.cmp(&b.title)),
 262            SortKey::Path => entries.sort_by(|a, b| a.url.cmp(&b.url)),
 263            // Undated pages sort last in the final order regardless of direction: a
 264            // draft with no date should not lead an archive.
 265            SortKey::Date => entries.sort_by(|a, b| {
 266                // Date *and* time: org records when a note was written, and two notes
 267                // from the same day have an order that the day alone cannot express.
 268                let key = |p: &PageContext| {
 269                    p.date_iso.as_ref().map(|d| {
 270                        let time = p
 271                            .date
 272                            .as_deref()
 273                            .and_then(iso_time)
 274                            .unwrap_or_else(|| "00:00:00".to_string());
 275                        format!("{d}T{time}")
 276                    })
 277                };
 278                match (key(a), key(b)) {
 279                    (Some(x), Some(y)) => x.cmp(&y).then_with(|| a.url.cmp(&b.url)),
 280                    (Some(_), None) => std::cmp::Ordering::Greater,
 281                    (None, Some(_)) => std::cmp::Ordering::Less,
 282                    (None, None) => a.url.cmp(&b.url),
 283                }
 284            }),
 285        }
 286        if collection.order == SortOrder::Desc {
 287            entries.reverse();
 288        }
 289
 290        if collection.group_by.is_empty() {
 291            let entry_hashes = hashes_of(&entries);
 292            push_paginated(
 293                &mut listings,
 294                collection,
 295                collection.output.clone(),
 296                collection.title.clone(),
 297                entries,
 298                entry_hashes,
 299                None,
 300                Vec::new(),
 301            );
 302            continue;
 303        }
 304
 305        // Grouped: one page per distinct term. `entries` is already sorted, and grouping
 306        // preserves that order within each group.
 307        let mut terms: Vec<String> = Vec::new();
 308        let mut members: HashMap<String, Vec<PageContext>> = HashMap::new();
 309        for entry in &entries {
 310            for term in group_terms(entry, &collection.group_by) {
 311                if !members.contains_key(&term) {
 312                    terms.push(term.clone());
 313                }
 314                members.entry(term).or_default().push(entry.clone());
 315            }
 316        }
 317        // Terms are discovered in page order, which is arbitrary from a reader's point of
 318        // view; sort so a tag index reads alphabetically and hashes deterministically.
 319        terms.sort();
 320
 321        let mut groups: Vec<GroupContext> = Vec::new();
 322        let mut slugs: HashMap<String, String> = HashMap::new();
 323        for term in &terms {
 324            let slug = slugify(term);
 325            if slug.is_empty() {
 326                anyhow::bail!(
 327                    "the {} value {term:?} has no URL-safe form; it cannot name a page",
 328                    collection.group_by
 329                );
 330            }
 331            // `C++` and `C  ++` both slugify to `c`, and one would silently overwrite the
 332            // other's page.
 333            if let Some(other) = slugs.insert(slug.clone(), term.clone()) {
 334                anyhow::bail!(
 335                    "the {} values {other:?} and {term:?} both become {slug:?} in a URL; \
 336                     rename one so their pages do not collide",
 337                    collection.group_by
 338                );
 339            }
 340            groups.push(GroupContext {
 341                name: term.clone(),
 342                slug: slug.clone(),
 343                url: if collection.output.as_str().is_empty() {
 344                    String::new()
 345                } else {
 346                    collection
 347                        .output
 348                        .as_str()
 349                        .replace(config::GROUP_PLACEHOLDER, &slug)
 350                }
 351                .to_string(),
 352                count: members.get(term).map(Vec::len).unwrap_or(0),
 353            });
 354        }
 355
 356        if !collection.output.as_str().is_empty() {
 357            for group in &groups {
 358                let members_of = members.get(&group.name).cloned().unwrap_or_default();
 359                let entry_hashes = hashes_of(&members_of);
 360                push_paginated(
 361                    &mut listings,
 362                    collection,
 363                    Utf8PathBuf::from(&group.url),
 364                    collection
 365                        .title
 366                        .replace(config::GROUP_PLACEHOLDER, &group.name),
 367                    members_of,
 368                    entry_hashes,
 369                    Some(group.clone()),
 370                    // Deliberately not the whole group list. A page that can see every
 371                    // group depends on every group, so one new post would re-render every
 372                    // tag page — cost that scales with tag count, to support a tag cloud
 373                    // nobody has asked for. A tag page depends on its own posts, and the
 374                    // group index is where the group list belongs.
 375                    Vec::new(),
 376                );
 377            }
 378        }
 379        if !collection.index_output.as_str().is_empty() {
 380            listings.push(Listing {
 381                output: collection.index_output.clone(),
 382                template: collection.index_template.clone(),
 383                title: collection.index_title.clone(),
 384                entries: Vec::new(),
 385                group: None,
 386                groups: groups.clone(),
 387                paginator: None,
 388                // A group index lists groups, not pages; there are no bodies to carry.
 389                include_content: false,
 390                entry_hashes: Vec::new(),
 391            });
 392        }
 393    }
 394
 395    // A generated page writing over a real page would silently replace it. Group pages
 396    // make this easy to hit by accident, since their paths come from content.
 397    for listing in &listings {
 398        if let Some(clash) = preps.iter().find(|p| p.output == listing.output) {
 399            anyhow::bail!(
 400                "collection output {} collides with the page built from {}",
 401                listing.output,
 402                clash.source
 403            );
 404        }
 405    }
 406    let mut claimed: HashMap<&Utf8PathBuf, ()> = HashMap::new();
 407    for listing in &listings {
 408        if claimed.insert(&listing.output, ()).is_some() {
 409            anyhow::bail!("two generated pages both write to {}", listing.output);
 410        }
 411    }
 412    Ok(listings)
 413}
 414
 415/// The `(output, title)` a collection contributes to the nav. A grouped collection
 416/// offers its index; an ungrouped one offers its single page.
 417fn nav_target(collection: &config::Collection) -> (Utf8PathBuf, String) {
 418    if !collection.group_by.is_empty() {
 419        return (
 420            collection.index_output.clone(),
 421            collection.index_title.clone(),
 422        );
 423    }
 424    (collection.output.clone(), collection.title.clone())
 425}
 426
 427/// The group terms a page belongs to. `tags` is multi-valued — a page appears under
 428/// every tag it carries — while any other key names a single-valued `#+KEYWORD:`.
 429fn group_terms(page: &PageContext, group_by: &str) -> Vec<String> {
 430    if group_by.eq_ignore_ascii_case("tags") {
 431        return page.tags.clone();
 432    }
 433    page.keywords
 434        .get(&group_by.to_lowercase())
 435        .map(|v| v.trim())
 436        .filter(|v| !v.is_empty())
 437        .map(|v| vec![v.to_string()])
 438        .unwrap_or_default()
 439}
 440
 441/// Everything a listing template can see about its entries, hashed. This is the listing
 442/// page's whole dependency: if none of these change, its output cannot have changed.
 443///
 444/// Entries are hashed through their *serialization* rather than a hand-picked set of
 445/// fields. Picking fields means the hash drifts from what a template can read the moment
 446/// one is added — which it had: the excerpt was missing, so rewriting a post's first
 447/// paragraph left the old excerpt on the index until something else invalidated it.
 448fn listing_entries_hash(listing: &Listing) -> Hash {
 449    let mut fields: Vec<(String, String)> = listing
 450        .entries
 451        .iter()
 452        .map(|e| {
 453            (
 454                e.url.clone(),
 455                serde_json::to_string(e).unwrap_or_else(|_| e.title.clone()),
 456            )
 457        })
 458        // A group index has no entries at all — its content *is* the group list, so the
 459        // groups have to be in the hash or a tag index would never notice a new tag.
 460        .chain(
 461            listing
 462                .groups
 463                .iter()
 464                .map(|g| (g.url.clone(), format!("{}\u{0}{}", g.name, g.count))),
 465        )
 466        .chain(listing.paginator.iter().map(|p| {
 467            (
 468                format!("{}/{}", p.current, p.total),
 469                format!("{:?}|{:?}", p.prev_url, p.next_url),
 470            )
 471        }))
 472        .chain([(listing.title.clone(), listing.template.clone())])
 473        .collect();
 474
 475    // A listing that embeds its entries' bodies depends on those bodies. The source hash
 476    // stands in for the rendered HTML, so noticing a change does not cost a render of
 477    // every page listed.
 478    if listing.include_content {
 479        fields.extend(
 480            listing
 481                .entry_hashes
 482                .iter()
 483                .map(|h| ("content".to_string(), format!("{h:?}"))),
 484        );
 485    }
 486
 487    // Entry *order* is meaningful in a listing, so this hashes the sorted-by-us sequence
 488    // rather than a set: a re-ordering is a real change to the page.
 489    site_structure_hash_ordered(&fields)
 490}
 491
 492/// A listing's entries with their rendered bodies attached, for a template that asked
 493/// for them — a full-content feed being the case that needs it.
 494///
 495/// An entry whose source is not among the prepared pages keeps `content: none` rather
 496/// than failing: the listing is still a valid page, and a feed item without a body is a
 497/// better outcome than no feed.
 498fn entries_with_content(
 499    entries: &[PageContext],
 500    preps: &[PagePrep],
 501    highlighter: &SyntectHighlighter,
 502    config: &Config,
 503) -> Vec<PageContext> {
 504    let by_source: HashMap<&str, &PagePrep> =
 505        preps.iter().map(|p| (p.source.as_str(), p)).collect();
 506    let opts = render_options(config);
 507    entries
 508        .par_iter()
 509        .map(|entry| {
 510            let mut entry = entry.clone();
 511            if let Some(prep) = by_source.get(entry.source.as_str()) {
 512                let Html(html) = render_with(&prep.resolved, highlighter, &opts);
 513                entry.content = Some(html);
 514            }
 515            entry
 516        })
 517        .collect()
 518}
 519
 520/// The nav a listing page shows: whatever the site's nav is, relativized to this
 521/// listing's own location.
 522fn listing_nav(preps: &[PagePrep], output: &Utf8Path) -> Vec<NavItem> {
 523    let Some(first) = preps.first() else {
 524        return Vec::new();
 525    };
 526    first
 527        .nav
 528        .iter()
 529        .map(|item| {
 530            // Nav URLs on `preps[0]` are relative to that page; re-resolve them against
 531            // the site root, then against this listing's depth.
 532            let absolute = resolve_relative(&first.output, &item.url);
 533            NavItem {
 534                title: item.title.clone(),
 535                url: output_url(output, &absolute, None),
 536            }
 537        })
 538        .collect()
 539}
 540
 541/// Turn a URL relative to `from` back into a site-root-relative path.
 542fn resolve_relative(from: &Utf8Path, url: &str) -> Utf8PathBuf {
 543    if url == "#" {
 544        return from.to_owned();
 545    }
 546    let base = from.parent().unwrap_or_else(|| Utf8Path::new(""));
 547    let mut stack: Vec<&str> = base.components().map(|c| c.as_str()).collect();
 548    for part in url.split('/') {
 549        match part {
 550            "." | "" => {}
 551            ".." => {
 552                stack.pop();
 553            }
 554            other => stack.push(other),
 555        }
 556    }
 557    Utf8PathBuf::from(stack.join("/"))
 558}
 559
 560/// The `PageContext` a listing page presents for *itself*.
 561fn listing_context(listing: &Listing) -> PageContext {
 562    PageContext {
 563        title: listing.title.clone(),
 564        url: listing.output.to_string(),
 565        source: String::new(),
 566        date: None,
 567        date_iso: None,
 568        year: None,
 569        tags: Vec::new(),
 570        excerpt: String::new(),
 571        content: None,
 572        word_count: 0,
 573        reading_time: 0,
 574        keywords: Default::default(),
 575        toc: Vec::new(),
 576    }
 577}
 578
 579/// Which pages the configured [`NavMode`] selects, in nav order.
 580fn nav_selection<'a>(config: &Config, candidates: &'a [NavCandidate]) -> Vec<&'a NavCandidate> {
 581    match config.nav.mode {
 582        NavMode::None => Vec::new(),
 583        NavMode::All => candidates.iter().collect(),
 584        // Generated pages are a section's landing page, which is what a nav entry should
 585        // point at whatever depth the section lives at.
 586        NavMode::TopLevel => candidates
 587            .iter()
 588            .filter(|c| c.generated || is_top_level(&c.output))
 589            .collect(),
 590        // Configured order wins over discovery order — a hand-written nav is a designed
 591        // sequence, not an alphabetical one.
 592        NavMode::Explicit => {
 593            let mut chosen: Vec<&NavCandidate> = config
 594                .nav
 595                .pages
 596                .iter()
 597                .filter_map(|want| candidates.iter().find(|c| c.matches(want)))
 598                .collect();
 599            // A collection that asked for the nav but was not listed is appended rather
 600            // than dropped, so `nav = true` never silently does nothing. Listing it puts
 601            // it exactly where you said instead.
 602            for candidate in candidates.iter().filter(|c| c.generated) {
 603                if !chosen.iter().any(|c| c.output == candidate.output) {
 604                    chosen.push(candidate);
 605                }
 606            }
 607            chosen
 608        }
 609    }
 610}
 611
 612/// A page the navigation could contain: one written as `.org`, or one generated by a
 613/// collection.
 614struct NavCandidate {
 615    /// The source path of an authored page. Empty for a generated one, which has none.
 616    source: Utf8PathBuf,
 617    output: Utf8PathBuf,
 618    title: String,
 619    /// Generated pages are appended when an explicit nav does not name them.
 620    generated: bool,
 621}
 622
 623impl NavCandidate {
 624    /// Does `name` in `nav.pages` refer to this entry?
 625    ///
 626    /// Authored pages are named by their source — `about.org` — because that is the file
 627    /// you wrote and its output path may be moved by `#+SLUG:`. Generated pages have no
 628    /// source, so they are named by their output — `blog/index.html`. Either spelling is
 629    /// accepted for either, so a config that names an output path still works.
 630    fn matches(&self, name: &Utf8Path) -> bool {
 631        (!self.source.as_str().is_empty() && self.source == name) || self.output == name
 632    }
 633}
 634
 635/// Every page the navigation could contain, authored pages first.
 636fn nav_candidates(
 637    config: &Config,
 638    pages: &[(Utf8PathBuf, Utf8PathBuf, String)],
 639) -> Vec<NavCandidate> {
 640    let mut candidates: Vec<NavCandidate> = pages
 641        .iter()
 642        .map(|(source, output, title)| NavCandidate {
 643            source: source.clone(),
 644            output: output.clone(),
 645            title: title.clone(),
 646            generated: false,
 647        })
 648        .collect();
 649    for collection in config.collections.iter().filter(|c| c.nav) {
 650        let (output, title) = nav_target(collection);
 651        candidates.push(NavCandidate {
 652            source: Utf8PathBuf::new(),
 653            output,
 654            title,
 655            generated: true,
 656        });
 657    }
 658    candidates
 659}
 660
 661/// DISCOVER + PARSE + INDEX + RESOLVE the whole site, returning per-page prep and the
 662/// global symbol table. RENDER/TEMPLATE is deferred to the caller so the incremental
 663/// build can render only the pages it must. PARSE/INDEX/RESOLVE are cheap and pure, so
 664/// they run for every file each build; the incremental win is on RENDER + EMIT (spec §4.4).
 665fn prepare_pages(
 666    src: &Utf8Path,
 667    config: &Config,
 668    out: Option<&Utf8Path>,
 669) -> Result<(Vec<PagePrep>, SymbolTable)> {
 670    let (org_rel, _assets) = discover(src, config, out)?;
 671
 672    // PARSE every file (relative paths keep snapshots and links machine-independent).
 673    // PARSE is a pure function of one file's bytes (spec §2.1), which is exactly the
 674    // property that makes it safe to run in parallel. `par_iter().collect()` preserves
 675    // input order, so the document list — and everything downstream of it — is identical
 676    // to the sequential build regardless of how the work was scheduled.
 677    let docs: Vec<Document> = org_rel
 678        .par_iter()
 679        .map(|rel| {
 680            let abs = src.join(rel);
 681            let source = fs::read_to_string(&abs).with_context(|| format!("reading {abs}"))?;
 682            parse(rel.as_path(), &source).with_context(|| format!("parsing {rel}"))
 683        })
 684        .collect::<Result<Vec<_>>>()?;
 685
 686    // Drop drafts before anything else sees them. Removing them here rather than at emit
 687    // time means they are absent from listings, the nav and the symbol table too — so a
 688    // link *to* a draft is reported as broken, which is exactly what it would be on the
 689    // published site.
 690    let docs: Vec<Document> = docs
 691        .into_iter()
 692        .filter(|d| config.build.drafts || !is_draft(&d.keywords))
 693        .collect();
 694
 695    // INDEX: collect every link target across the corpus.
 696    let mut symbols = SymbolTable::new();
 697    for doc in &docs {
 698        symbols.index_document(doc);
 699    }
 700
 701    // `(source, output, title)` for every page. Titles come from #+TITLE (falling back to
 702    // the file stem) and URLs from each page's output path, which `#+SLUG:` can rename.
 703    let all_pages: Vec<(Utf8PathBuf, Utf8PathBuf, String)> = docs
 704        .iter()
 705        .map(|d| {
 706            (
 707                d.source_path.clone(),
 708                output_path(&d.source_path, &d.keywords),
 709                page_title(d),
 710            )
 711        })
 712        .collect();
 713
 714    // Two sources emitting one page would silently drop a page — and with slugs, a
 715    // collision is a typo away and invisible in the source filenames.
 716    let mut claimed: std::collections::HashMap<&Utf8PathBuf, &Utf8PathBuf> =
 717        std::collections::HashMap::new();
 718    for (source, out, _) in &all_pages {
 719        if let Some(other) = claimed.insert(out, source) {
 720            anyhow::bail!(
 721                "output collision: {other} and {source} both build to {out} \
 722                 (check their #+SLUG:)"
 723            );
 724        }
 725    }
 726
 727    // Authored pages and the landing pages collections generate, in one list so an
 728    // explicit nav can order them together.
 729    let candidates = nav_candidates(config, &all_pages);
 730
 731    // An explicit nav naming something that does not exist is a typo, and a silently
 732    // shorter nav is a poor way to learn about it.
 733    if config.nav.mode == NavMode::Explicit {
 734        for want in &config.nav.pages {
 735            if !candidates.iter().any(|c| c.matches(want)) {
 736                anyhow::bail!(
 737                    "nav.pages lists {want}, which is neither a page in {src} nor a \
 738                     collection with `nav = true`"
 739                );
 740            }
 741        }
 742    }
 743    let entries: Vec<(Utf8PathBuf, String)> = nav_selection(config, &candidates)
 744        .into_iter()
 745        .map(|c| (c.output.clone(), c.title.clone()))
 746        .collect();
 747
 748    // RESOLVE reads the shared symbol table and writes only into its own page's output,
 749    // so it parallelizes for free once INDEX has finished building the table.
 750    let pages: Vec<PagePrep> = docs
 751        .par_iter()
 752        .map(|doc| {
 753        let out = resolve(doc, &symbols);
 754        let used: HashSet<TargetId> = out.used_targets.iter().cloned().collect();
 755        let broken: Vec<TargetId> = out.broken.iter().map(|b| b.target.clone()).collect();
 756        let defines: HashSet<TargetId> = document_targets(doc).into_iter().collect();
 757
 758        let output = output_path(&doc.source_path, &doc.keywords);
 759
 760        // Nav links are relative to *this* page (spec URL scheme, §8 Q3).
 761        let nav: Vec<NavItem> = entries
 762            .iter()
 763            .map(|(path, title)| NavItem {
 764                title: title.clone(),
 765                url: output_url(&output, path, None),
 766            })
 767            .collect();
 768
 769            PagePrep {
 770                context: page_context(doc, &output, config),
 771                template: config::page_template(config, &doc.source_path, &doc.keywords),
 772                source: doc.source_path.clone(),
 773                output,
 774                title: page_title(doc),
 775                content_hash: doc.content_hash,
 776                resolved: out.resolved,
 777                used,
 778                defines,
 779                broken,
 780                diagnostics: doc.diagnostics.clone(),
 781                nav,
 782            }
 783        })
 784        .collect();
 785
 786    Ok((pages, symbols))
 787}
 788
 789/// Fail before rendering if any page names a template that does not exist.
 790///
 791/// minijinja would report the missing name on its own, but only once a page reaches it
 792/// — and a typo in `#+TEMPLATE:` or a `[[pages]]` rule is worth naming together with the
 793/// page that carries it and the templates that do exist.
 794fn check_page_templates(templater: &Templater, preps: &[PagePrep]) -> Result<()> {
 795    for p in preps {
 796        if !templater.has(&p.template) {
 797            let mut available = templater.names();
 798            available.sort_unstable();
 799            anyhow::bail!(
 800                "{} renders through {}, which is not in the templates directory. \
 801                 Available: {}",
 802                p.source,
 803                p.template,
 804                available.join(", ")
 805            );
 806        }
 807    }
 808    Ok(())
 809}
 810
 811/// Parse + index + resolve + render + template a whole site *in memory*, without
 812/// touching the output directory. Shared by the tests (full render, every page).
 813pub fn render_site(src: &Utf8Path) -> Result<(Vec<BuiltPage>, BrokenLinks)> {
 814    let config = Config::load(src)?;
 815    config.validate()?;
 816    let (preps, _symbols) = prepare_pages(src, &config, None)?;
 817    let highlighter = SyntectHighlighter::new();
 818    let templater = Templater::load(Some(&src.join(&config.templates.dir)), &config.site.base_url)?;
 819    check_page_templates(&templater, &preps)?;
 820    let site = site_context(&config);
 821    let listing = page_listing(&config, &preps);
 822
 823    let mut pages = Vec::new();
 824    let mut broken = Vec::new();
 825    for p in &preps {
 826        for t in &p.broken {
 827            broken.push((p.source.clone(), t.clone()));
 828        }
 829        let html = render_page(&templater, &highlighter, &site, listing.as_deref(), &config, p)?;
 830        pages.push(BuiltPage {
 831            source: p.source.clone(),
 832            output: p.output.clone(),
 833            title: p.title.clone(),
 834            html,
 835        });
 836    }
 837    Ok((pages, broken))
 838}
 839
 840/// The site's render options. A document's own `#+OPTIONS:` switches are applied by the
 841/// renderer, so every caller gets them.
 842fn render_options(config: &Config) -> RenderOptions {
 843    RenderOptions {
 844        heading_offset: config.html.heading_offset,
 845        section_numbers: config.html.section_numbers,
 846        special_strings: config.html.special_strings,
 847        sub_superscript: config.html.sub_superscript,
 848        entities: config.html.entities,
 849    }
 850}
 851
 852fn site_context(config: &Config) -> SiteContext {
 853    SiteContext {
 854        title: config.site.title.clone(),
 855        base_url: config.site.base_url.clone(),
 856        description: config.site.description.clone(),
 857        language: config.site.language.clone(),
 858    }
 859}
 860
 861/// The `pages` list templates see, when configured to see one (see
 862/// [`crate::config::Templates::expose_page_list`]).
 863fn page_listing(config: &Config, preps: &[PagePrep]) -> Option<Vec<PageContext>> {
 864    config
 865        .templates
 866        .expose_page_list
 867        .then(|| preps.iter().map(|p| p.context.clone()).collect())
 868}
 869
 870/// RENDER + TEMPLATE one prepared page into its final HTML string.
 871#[allow(clippy::too_many_arguments)]
 872fn render_page(
 873    templater: &Templater,
 874    highlighter: &SyntectHighlighter,
 875    site: &SiteContext,
 876    pages: Option<&[PageContext]>,
 877    config: &Config,
 878    p: &PagePrep,
 879) -> Result<String> {
 880    let opts = render_options(config);
 881    let Html(fragment) = render_with(&p.resolved, highlighter, &opts);
 882    // Relative to the *output* path, since `#+SLUG:` can move a page between depths.
 883    let root = relative_root(&p.output);
 884    let stylesheet = format!("{root}{SYNTAX_STYLESHEET}");
 885    let mut ctx = RenderContext::new(site, &p.context, &p.nav, &stylesheet, &root);
 886    ctx.body = &fragment;
 887    ctx.pages = pages;
 888    templater
 889        .render(&p.template, &ctx)
 890        .with_context(|| format!("templating {} through {}", p.source, p.template))
 891}
 892
 893/// Site-root-relative name of the generated syntax stylesheet. Every page links to it.
 894pub const SYNTAX_STYLESHEET: &str = "syntax.css";
 895
 896/// Full site build with the incremental layer (spec §4). Renders only the pages whose
 897/// `render_key` changed or that link into a changed file's targets; reuses the on-disk
 898/// output of everything else; persists an updated cache manifest.
 899pub fn build_site(src: &Utf8Path, out: &Utf8Path, opts: &BuildOptions) -> Result<SiteReport> {
 900    let mut cfg = match &opts.config_path {
 901        Some(path) => Config::load_file(path)?,
 902        None => Config::load(src)?,
 903    };
 904    cfg.validate()?;
 905    // The flag turns drafts on; it never turns off a config that asked for them.
 906    cfg.build.drafts |= opts.drafts;
 907
 908    // Create the output directory up front so it can be recognised and excluded when it
 909    // lives inside the source tree.
 910    fs::create_dir_all(out).with_context(|| format!("creating {out}"))?;
 911    let (_org_rel, source_assets) = discover(src, &cfg, Some(out))?;
 912    let assets = collect_assets(src, &cfg, Some(out), &source_assets)?;
 913    let (preps, symbols) = prepare_pages(src, &cfg, Some(out))?;
 914
 915    let templater = Templater::load(Some(&src.join(&cfg.templates.dir)), &cfg.site.base_url)?;
 916    check_page_templates(&templater, &preps)?;
 917    let syntax_css = render::syntax_css(&cfg.highlight.theme).ok_or_else(|| {
 918        anyhow::anyhow!(
 919            "unknown highlight.theme {:?}. Available: {}",
 920            cfg.highlight.theme,
 921            render::available_themes().join(", ")
 922        )
 923    })?;
 924
 925    // The global hash classes (spec §4.1): a change in any invalidates the site. The
 926    // config hash is combined with a site-structure hash covering the global chrome each
 927    // page carries, so a change to that chrome re-renders the pages showing it.
 928    //
 929    // Which pages belong in that hash depends on what a template can *see*. Normally it
 930    // is the nav only — a nested page cannot change another page's nav, so adding a blog
 931    // post should render one page, not the site. But `expose_page_list` hands every
 932    // template every page's metadata, and then any page's output really can depend on
 933    // any other page, so the hash has to widen to match. Keyed on output paths, since a
 934    // `#+SLUG:` change moves a page's URL without moving its source.
 935    let all_pages: Vec<(Utf8PathBuf, Utf8PathBuf, String)> = preps
 936        .iter()
 937        .map(|p| (p.source.clone(), p.output.clone(), p.title.clone()))
 938        .collect();
 939    let structure_hash = if cfg.templates.expose_page_list {
 940        let entries: Vec<(String, String)> = all_pages
 941            .iter()
 942            .map(|(_, out, title)| (out.to_string(), title.clone()))
 943            .collect();
 944        site_structure_hash(&entries)
 945    } else {
 946        // The same selection the nav itself is built from, so the two can never drift.
 947        // Hashed in order, because the nav's order is itself part of every page.
 948        let entries: Vec<(String, String)> = nav_selection(&cfg, &nav_candidates(&cfg, &all_pages))
 949            .into_iter()
 950            .map(|c| (c.output.to_string(), c.title.clone()))
 951            .collect();
 952        site_structure_hash_ordered(&entries)
 953    };
 954    let cfg_hash = combine(config_hash(&cfg), structure_hash);
 955    // Per template rather than per site: a page's render key covers the layout it uses
 956    // and that layout's own includes, so editing `feed.xml` re-renders the feed.
 957    let tmpl_hash_for = |name: &str| template_hash(&templater.sources_for(name));
 958
 959    // Compose each page's render key and record its dependency edges.
 960    let mut new_graph = DepGraph::default();
 961    let mut new_records: Vec<(Utf8PathBuf, PageRecord, Hash)> = Vec::new();
 962    let listings = build_listings(&cfg, &preps)?;
 963    for p in &preps {
 964        let rlh = resolved_links_hash(&p.source, &p.used, &symbols);
 965        let key = render_key(p.content_hash, rlh, cfg_hash, tmpl_hash_for(&p.template));
 966        new_graph.defines.insert(p.source.clone(), p.defines.clone());
 967        new_graph.uses.insert(p.source.clone(), p.used.clone());
 968        new_records.push((
 969            p.source.clone(),
 970            PageRecord {
 971                content_hash: p.content_hash,
 972                render_key: key,
 973                output_path: p.output.clone(),
 974            },
 975            key,
 976        ));
 977    }
 978
 979    // Load the prior manifest (unless bypassed). Absent/corrupt/version-mismatch ⇒ None
 980    // ⇒ full rebuild (spec §4.5).
 981    let prior = if opts.no_cache {
 982        None
 983    } else {
 984        incremental::load_manifest(out)
 985    };
 986
 987    let rebuild: HashSet<Utf8PathBuf> = compute_rebuild_set(
 988        &preps,
 989        &new_records,
 990        &new_graph,
 991        cfg_hash,
 992        out,
 993        prior.as_ref(),
 994    );
 995
 996    // Delete outputs for pages that existed last build but are gone now (spec §4.3 step 1:
 997    // removed files). Their targets are already in the merged graph, so their linkers were
 998    // invalidated above.
 999    if let Some(prior) = &prior {
1000        // Keyed by source path for real pages and by output path for generated listings,
1001        // which is also how each records itself in the manifest. Listings have to be in
1002        // this set or the cleanup would delete the file it just decided to keep — and a
1003        // removed collection genuinely should have its output deleted.
1004        let mut current: HashSet<&Utf8PathBuf> = preps.iter().map(|p| &p.source).collect();
1005        current.extend(listings.iter().map(|l| &l.output));
1006        for (key, rec) in &prior.pages {
1007            if !current.contains(key) {
1008                let dest = out.join(&rec.output_path);
1009                let _ = fs::remove_file(&dest);
1010            }
1011        }
1012    }
1013
1014    let highlighter = SyntectHighlighter::with_syntaxes(Some(&src.join(&cfg.highlight.syntaxes_dir)));
1015    let site = site_context(&cfg);
1016    let listing = page_listing(&cfg, &preps);
1017    let mut report = SiteReport::default();
1018
1019    // RENDER + TEMPLATE + EMIT, in parallel. This is where a build's time actually goes
1020    // (syntect highlighting and templating dominate), and each page writes only its own
1021    // file, so the pages are independent.
1022    //
1023    // The parallel pass returns whether each page was written; the report is assembled
1024    // sequentially afterwards from `preps` order. Pushing to the report from inside the
1025    // parallel pass would make `rendered`/`skipped` ordering depend on thread scheduling,
1026    // which would be a non-deterministic build report over a deterministic build.
1027    let written: Vec<bool> = preps
1028        .par_iter()
1029        .map(|p| {
1030            if !rebuild.contains(&p.source) {
1031                // Skip: the on-disk output is already correct (spec §4.1). Leave it alone.
1032                return Ok(false);
1033            }
1034            let dest = out.join(&p.output);
1035            if let Some(parent) = dest.parent() {
1036                fs::create_dir_all(parent).with_context(|| format!("creating {parent}"))?;
1037            }
1038            let html = render_page(&templater, &highlighter, &site, listing.as_deref(), &cfg, p)?;
1039            fs::write(&dest, &html).with_context(|| format!("writing {dest}"))?;
1040            Ok(true)
1041        })
1042        .collect::<Result<Vec<_>>>()?;
1043
1044    for (p, was_written) in preps.iter().zip(&written) {
1045        for t in &p.broken {
1046            report.broken.push((p.source.clone(), t.clone()));
1047        }
1048        for d in &p.diagnostics {
1049            report.diagnostics.push((p.source.clone(), d.clone()));
1050        }
1051        report.pages.push(p.output.clone());
1052        if *was_written {
1053            report.rendered.push(p.output.clone());
1054        } else {
1055            report.skipped.push(p.output.clone());
1056        }
1057    }
1058
1059    // Generated listing pages (spec §2.1 EMIT). A listing has no source file, so it is
1060    // cached on the one thing it actually depends on: the entries it lists. Adding a post
1061    // therefore re-renders that section's index and nothing else — the same precision the
1062    // rest of the build gets from content hashing.
1063    for listing in &listings {
1064        let key = combine(
1065            listing_entries_hash(listing),
1066            combine(cfg_hash, tmpl_hash_for(&listing.template)),
1067        );
1068        let dest = out.join(&listing.output);
1069        let cached = prior
1070            .as_ref()
1071            .and_then(|m| m.pages.get(&listing.output))
1072            .map(|rec| rec.render_key == key)
1073            .unwrap_or(false);
1074
1075        report.pages.push(listing.output.clone());
1076        if cached && dest.exists() {
1077            report.skipped.push(listing.output.clone());
1078        } else {
1079            if let Some(parent) = dest.parent() {
1080                fs::create_dir_all(parent).with_context(|| format!("creating {parent}"))?;
1081            }
1082            let root = relative_root(&listing.output);
1083            let stylesheet = format!("{root}{SYNTAX_STYLESHEET}");
1084            let nav = listing_nav(&preps, &listing.output);
1085            let page_ctx = listing_context(listing);
1086            // Bodies are rendered here rather than when the listing was built, so a
1087            // cached feed costs nothing. This is the only place a page is rendered twice.
1088            let with_content = listing
1089                .include_content
1090                .then(|| entries_with_content(&listing.entries, &preps, &highlighter, &cfg));
1091            let mut ctx = RenderContext::new(&site, &page_ctx, &nav, &stylesheet, &root);
1092            ctx.pages = Some(with_content.as_deref().unwrap_or(&listing.entries));
1093            ctx.group = listing.group.as_ref();
1094            ctx.groups = &listing.groups;
1095            ctx.paginator = listing.paginator.as_ref();
1096            let html = templater
1097                .render(&listing.template, &ctx)
1098                .with_context(|| {
1099                    format!(
1100                        "rendering collection {} with template {} (available: {})",
1101                        listing.output,
1102                        listing.template,
1103                        templater.names().join(", ")
1104                    )
1105                })?;
1106            fs::write(&dest, &html).with_context(|| format!("writing {dest}"))?;
1107            report.rendered.push(listing.output.clone());
1108        }
1109
1110        new_records.push((
1111            listing.output.clone(),
1112            PageRecord {
1113                content_hash: key,
1114                render_key: key,
1115                output_path: listing.output.clone(),
1116            },
1117            key,
1118        ));
1119    }
1120
1121    // The syntax stylesheet the highlighter's CSS classes refer to. Written every build
1122    // (it is a few KB and depends only on the theme, which lives in the config hash).
1123    fs::write(out.join(SYNTAX_STYLESHEET), &syntax_css)
1124        .with_context(|| format!("writing {SYNTAX_STYLESHEET} under {out}"))?;
1125
1126    // Assets are a dumb copy in v0.3 (spec §8 Q11): copy every run. Cheap, and keeps the
1127    // full-vs-incremental byte equivalence trivially true for non-`.org` files.
1128    for asset in &assets {
1129        let dest = out.join(&asset.rel);
1130        if let Some(parent) = dest.parent() {
1131            fs::create_dir_all(parent).with_context(|| format!("creating {parent}"))?;
1132        }
1133        fs::copy(&asset.from, &dest)
1134            .with_context(|| format!("copying {} -> {dest}", asset.from))?;
1135        report.assets.push(asset.rel.clone());
1136    }
1137
1138    // Persist the manifest for the next build.
1139    let manifest = Manifest {
1140        format_version: CACHE_FORMAT_VERSION,
1141        config_hash: Some(cfg_hash),
1142        pages: new_records
1143            .into_iter()
1144            .map(|(src_path, rec, _)| (src_path, rec))
1145            .collect(),
1146        graph: new_graph,
1147    };
1148    incremental::save_manifest(out, &manifest)
1149        .with_context(|| format!("writing cache manifest under {out}"))?;
1150
1151    let warnings = report.warnings();
1152    if opts.strict && !warnings.is_empty() {
1153        for w in &warnings {
1154            eprintln!("error: {w}");
1155        }
1156        anyhow::bail!(
1157            "{} problem(s) under --strict ({} parse diagnostic(s), {} unresolved link(s))",
1158            warnings.len(),
1159            report.diagnostics.len(),
1160            report.broken.len()
1161        );
1162    }
1163    for w in &warnings {
1164        eprintln!("warning: {w}");
1165    }
1166
1167    Ok(report)
1168}
1169
1170/// The set of source files to (re)render this build (spec §4.3 invalidation algorithm),
1171/// as the union of:
1172/// - **no prior cache** (absent/corrupt/version-mismatch/`--no-cache`) ⇒ every page;
1173/// - a **global** config- or template-hash change ⇒ every page (spec §4.1);
1174/// - **content-changed** files ∪ pages that link into a changed file's targets, via the
1175///   dependency graph merged with the prior build's `defines` (spec §4.3, so a removed
1176///   target still invalidates its linkers);
1177/// - any page whose composed **render_key** differs from the cached one (catches URL
1178///   changes on linked targets precisely);
1179/// - any page whose **output file is missing** on disk.
1180fn compute_rebuild_set(
1181    preps: &[PagePrep],
1182    new_records: &[(Utf8PathBuf, PageRecord, Hash)],
1183    new_graph: &DepGraph,
1184    cfg_hash: Hash,
1185    out: &Utf8Path,
1186    prior: Option<&Manifest>,
1187) -> HashSet<Utf8PathBuf> {
1188    let all: HashSet<Utf8PathBuf> = preps.iter().map(|p| p.source.clone()).collect();
1189
1190    let Some(prior) = prior else {
1191        return all; // No usable cache ⇒ full rebuild.
1192    };
1193
1194    // A config change invalidates every page. Template changes do not come through here:
1195    // each page's render key carries the hash of the templates *it* uses, so the key
1196    // comparison below invalidates exactly the pages whose layout moved.
1197    if prior.config_hash != Some(cfg_hash) {
1198        return all;
1199    }
1200
1201    // Content-changed = hash differs from the cached record, or the file is new.
1202    let mut changed: HashSet<Utf8PathBuf> = HashSet::new();
1203    for p in preps {
1204        match prior.pages.get(&p.source) {
1205            Some(rec) if rec.content_hash == p.content_hash => {}
1206            _ => {
1207                changed.insert(p.source.clone());
1208            }
1209        }
1210    }
1211
1212    // Graph expansion: changed files ∪ pages that link into a changed file's targets.
1213    // Merge prior `defines` so a target a changed file removed still pulls its linkers.
1214    let merged = prior.graph.merged_defines_with(new_graph);
1215    let mut rebuild = incremental::invalidation_set(&changed, &merged);
1216
1217    // Precise render_key delta (catches a linked target's URL change; also a belt for the
1218    // graph). A page whose render_key matches the cache and whose output exists is correct.
1219    for (src_path, _rec, key) in new_records {
1220        let unchanged = prior
1221            .pages
1222            .get(src_path)
1223            .map(|old| old.render_key == *key)
1224            .unwrap_or(false);
1225        if !unchanged {
1226            rebuild.insert(src_path.clone());
1227        }
1228    }
1229
1230    // Any page whose output file is missing must be re-emitted regardless.
1231    for p in preps {
1232        if !out.join(&p.output).exists() {
1233            rebuild.insert(p.source.clone());
1234        }
1235    }
1236
1237    rebuild
1238}
1239
1240/// Walk `src`, returning `.org` source paths and non-`.org` asset paths, both relative
1241/// to `src` and sorted for deterministic output. The cache manifest is not an asset.
1242fn discover(
1243    src: &Utf8Path,
1244    config: &Config,
1245    out: Option<&Utf8Path>,
1246) -> Result<(Vec<Utf8PathBuf>, Vec<Utf8PathBuf>)> {
1247    let skip_dirs = excluded_dirs(src, config, out);
1248    let mut org = Vec::new();
1249    let mut assets = Vec::new();
1250
1251    let walker = WalkDir::new(src).sort_by_file_name().into_iter();
1252    for entry in walker.filter_entry(|e| {
1253        let Some(path) = Utf8Path::from_path(e.path()) else {
1254            return false;
1255        };
1256        let rel = path.strip_prefix(src).unwrap_or(path);
1257        // The source root itself always passes; `filter_entry` prunes whole subtrees.
1258        rel.as_str().is_empty() || !is_excluded(rel, &skip_dirs)
1259    }) {
1260        let entry = entry.with_context(|| format!("walking {src}"))?;
1261        if !entry.file_type().is_file() {
1262            continue;
1263        }
1264        let abs = Utf8PathBuf::from_path_buf(entry.into_path())
1265            .map_err(|p| anyhow::anyhow!("non-UTF-8 path: {}", p.display()))?;
1266        let rel = abs
1267            .strip_prefix(src)
1268            .map(|p| p.to_owned())
1269            .unwrap_or_else(|_| abs.clone());
1270        if rel == config::CONFIG_FILE {
1271            continue;
1272        }
1273        if rel.extension() == Some("org") {
1274            org.push(rel);
1275        } else {
1276            assets.push(rel);
1277        }
1278    }
1279    org.sort();
1280    assets.sort();
1281    Ok((org, assets))
1282}
1283
1284/// One file to copy through to the output: where it is, and where it goes.
1285#[derive(Debug, Clone, PartialEq)]
1286pub struct Asset {
1287    /// Path to read from.
1288    pub from: Utf8PathBuf,
1289    /// Path to write, relative to the output root.
1290    pub rel: Utf8PathBuf,
1291}
1292
1293/// Every file to copy: the source directory's non-`.org` files, then each extra asset
1294/// root's contents, flattened onto the site root.
1295///
1296/// Two files claiming one output path is an error rather than a race — whichever won
1297/// would depend on directory order, and a site whose favicon changes when a file is
1298/// renamed elsewhere is worse than a build that stops.
1299fn collect_assets(
1300    src: &Utf8Path,
1301    config: &Config,
1302    out: Option<&Utf8Path>,
1303    from_source: &[Utf8PathBuf],
1304) -> Result<Vec<Asset>> {
1305    let mut assets: Vec<Asset> = from_source
1306        .iter()
1307        .map(|rel| Asset {
1308            from: src.join(rel),
1309            rel: rel.clone(),
1310        })
1311        .collect();
1312
1313    for root in &config.build.assets {
1314        let base = src.join(root);
1315        if !base.is_dir() {
1316            anyhow::bail!(
1317                "build.assets lists {root}, which is not a directory (looked in {base})"
1318            );
1319        }
1320        let base_canon = std::fs::canonicalize(&base)
1321            .ok()
1322            .and_then(|p| Utf8PathBuf::from_path_buf(p).ok())
1323            .unwrap_or_else(|| base.clone());
1324        // An asset root that contains the output directory would copy the site into
1325        // itself, one build at a time.
1326        let out_canon = out
1327            .and_then(|out| std::fs::canonicalize(out).ok())
1328            .and_then(|p| Utf8PathBuf::from_path_buf(p).ok());
1329        if out_canon.is_some_and(|o| o.starts_with(&base_canon)) {
1330            anyhow::bail!(
1331                "build.assets lists {root}, which contains the output directory {}",
1332                out.unwrap_or(Utf8Path::new("(none)"))
1333            );
1334        }
1335        for entry in WalkDir::new(&base).sort_by_file_name() {
1336            let entry = entry.with_context(|| format!("walking {base}"))?;
1337            if !entry.file_type().is_file() {
1338                continue;
1339            }
1340            let abs = Utf8PathBuf::from_path_buf(entry.into_path())
1341                .map_err(|p| anyhow::anyhow!("non-UTF-8 path: {}", p.display()))?;
1342            let rel = abs
1343                .strip_prefix(&base)
1344                .map(|p| p.to_owned())
1345                .unwrap_or_else(|_| abs.clone());
1346            if rel.components().any(|c| c.as_str().starts_with('.')) {
1347                continue;
1348            }
1349            assets.push(Asset { from: abs, rel });
1350        }
1351    }
1352
1353    let mut seen: HashMap<&Utf8Path, &Utf8Path> = HashMap::new();
1354    for asset in &assets {
1355        if let Some(first) = seen.insert(&asset.rel, &asset.from) {
1356            anyhow::bail!(
1357                "two files both publish to {}: {first} and {}",
1358                asset.rel,
1359                asset.from
1360            );
1361        }
1362    }
1363    assets.sort_by(|a, b| a.rel.cmp(&b.rel));
1364    Ok(assets)
1365}
1366
1367/// Source-relative directories that DISCOVER must not descend into: the template
1368/// directory (build input, not content) and the output directory when it lives inside
1369/// the source.
1370///
1371/// The output case is not a corner case — `orgo build . -o _site` is the obvious
1372/// thing to type, and without this the build copies its own output back into itself,
1373/// growing `_site/_site/_site/…` on every run.
1374fn excluded_dirs(src: &Utf8Path, config: &Config, out: Option<&Utf8Path>) -> Vec<Utf8PathBuf> {
1375    let mut dirs = vec![config.templates.dir.clone()];
1376    if let Some(out) = out {
1377        // Compare canonicalized paths so `.`, `./x` and an absolute path all agree.
1378        // The output may not exist yet, in which case it cannot contain anything and
1379        // the textual fallback is enough.
1380        let canon = |p: &Utf8Path| -> Option<Utf8PathBuf> {
1381            std::fs::canonicalize(p)
1382                .ok()
1383                .and_then(|p| Utf8PathBuf::from_path_buf(p).ok())
1384        };
1385        match (canon(src), canon(out)) {
1386            (Some(src_abs), Some(out_abs)) => {
1387                if let Ok(rel) = out_abs.strip_prefix(&src_abs) {
1388                    if !rel.as_str().is_empty() {
1389                        dirs.push(rel.to_owned());
1390                    }
1391                }
1392            }
1393            _ => {
1394                if let Ok(rel) = out.strip_prefix(src) {
1395                    if !rel.as_str().is_empty() {
1396                        dirs.push(rel.to_owned());
1397                    }
1398                }
1399            }
1400        }
1401    }
1402    dirs
1403}
1404
1405/// Is this source-relative path excluded from discovery?
1406///
1407/// Dot-entries are skipped wholesale. That is the conventional rule for site generators,
1408/// and the reason is safety rather than tidiness: a source directory is very often a git
1409/// repository, and publishing `.git` — or `.env` — is a way to leak a project's entire
1410/// history alongside its homepage.
1411fn is_excluded(rel: &Utf8Path, skip_dirs: &[Utf8PathBuf]) -> bool {
1412    if rel
1413        .components()
1414        .any(|c| c.as_str().starts_with('.') && c.as_str() != "." && c.as_str() != "..")
1415    {
1416        return true;
1417    }
1418    skip_dirs
1419        .iter()
1420        .any(|dir| !dir.as_str().is_empty() && rel.starts_with(dir))
1421}
1422
1423/// Does this output path sit at the site root?
1424///
1425/// The nav is the site's global chrome, and listing *every* page in it makes an `n`-page
1426/// site emit `n²` nav links — 1,790 pages produced 284 MB of output, most of it nav. A
1427/// nav is a map of the site's top level, not an index of its contents, so it is built
1428/// from root-level pages only. Section pages reach their siblings through that section's
1429/// own landing page.
1430fn is_top_level(output: &Utf8Path) -> bool {
1431    output.parent().is_none_or(|p| p.as_str().is_empty())
1432}
1433
1434/// Everything a template can know about one page. Every `#+KEYWORD:` is passed through
1435/// under its lowercased name, so a template can use metadata this crate has never heard
1436/// of without the crate needing a release to support it.
1437fn page_context(doc: &Document, output: &Utf8Path, config: &Config) -> PageContext {
1438    let words = document_text(&doc.root).split_whitespace().count();
1439    let keyword = |name: &str| {
1440        doc.keywords
1441            .entries
1442            .iter()
1443            .find(|(k, _)| k.eq_ignore_ascii_case(name))
1444            .map(|(_, v)| v.clone())
1445    };
1446    PageContext {
1447        title: page_title(doc),
1448        url: output.to_string(),
1449        source: doc.source_path.to_string(),
1450        date_iso: keyword("DATE").as_deref().and_then(iso_date),
1451        year: keyword("DATE")
1452            .as_deref()
1453            .and_then(iso_date)
1454            .map(|d| d[..4].to_string()),
1455        date: keyword("DATE"),
1456        excerpt: keyword("DESCRIPTION")
1457            .filter(|d| !d.trim().is_empty())
1458            .or_else(|| first_paragraph(&doc.root))
1459            .unwrap_or_default(),
1460        content: None,
1461        word_count: words,
1462        reading_time: words.div_ceil(WORDS_PER_MINUTE).max(usize::from(words > 0)),
1463        toc: if option_enabled(&doc.keywords, "toc", config.html.toc) {
1464            table_of_contents(&doc.root)
1465        } else {
1466            Vec::new()
1467        },
1468        tags: keyword("FILETAGS")
1469            .unwrap_or_default()
1470            .split(':')
1471            .filter(|t| !t.trim().is_empty())
1472            .map(|t| t.trim().to_string())
1473            .collect(),
1474        keywords: doc
1475            .keywords
1476            .entries
1477            .iter()
1478            .map(|(k, v)| (k.to_lowercase(), v.clone()))
1479            .collect(),
1480    }
1481}
1482
1483fn page_title(doc: &Document) -> String {
1484    doc.keywords
1485        .entries
1486        .iter()
1487        .find(|(k, _)| k.eq_ignore_ascii_case("TITLE"))
1488        .map(|(_, v)| v.clone())
1489        .unwrap_or_else(|| {
1490            doc.source_path
1491                .file_stem()
1492                .unwrap_or("untitled")
1493                .to_string()
1494        })
1495}