crates/treehouse/src/vfs.rs

@@ -81,7 +81,7 @@ pub struct DirEntry {
     pub path: VPathBuf,
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub struct ImageSize {
     pub width: u32,
     pub height: u32,

crates/treehouse/src/vfs/content_cache.rs

@@ -11,7 +11,7 @@ use super::{walk_dir_rec, Dir, DirEntry, EditPath, ImageSize, VPath, VPathBuf};
 
 pub struct ContentCache<T> {
     inner: T,
-    cache: DashMap<VPathBuf, Vec<u8>>,
+    cache: DashMap<VPathBuf, Option<Vec<u8>>>,
 }
 
 impl<T> ContentCache<T> {
@@ -48,13 +48,10 @@ where
     }
 
     fn content(&self, path: &VPath) -> Option<Vec<u8>> {
-        self.cache.get(path).map(|x| x.clone()).or_else(|| {
-            let content = self.inner.content(path);
-            if let Some(content) = &content {
-                self.cache.insert(path.to_owned(), content.clone());
-            }
-            content
-        })
+        self.cache
+            .entry(path.to_owned())
+            .or_insert_with(|| self.inner.content(path))
+            .clone()
     }
 
     fn content_version(&self, path: &VPath) -> Option<String> {

crates/treehouse/src/vfs/content_version_cache.rs

@@ -6,7 +6,7 @@ use super::{Dir, DirEntry, EditPath, ImageSize, VPath, VPathBuf};
 
 pub struct Blake3ContentVersionCache<T> {
     inner: T,
-    cache: DashMap<VPathBuf, String>,
+    cache: DashMap<VPathBuf, Option<String>>,
 }
 
 impl<T> Blake3ContentVersionCache<T> {
@@ -31,16 +31,15 @@ where
     }
 
     fn content_version(&self, path: &VPath) -> Option<String> {
-        self.cache.get(path).map(|x| x.clone()).or_else(|| {
-            let version = self.inner.content(path).map(|content| {
+        self.cache
+            .entry(path.to_owned())
+            .or_insert_with(|| {
+                self.content(path).map(|content| {
                     let hash = blake3::hash(&content).to_hex();
                     format!("b3-{}", &hash[0..8])
-            });
-            if let Some(version) = &version {
-                self.cache.insert(path.to_owned(), version.clone());
-            }
-            version
                 })
+            })
+            .clone()
     }
 
     fn image_size(&self, path: &VPath) -> Option<ImageSize> {

crates/treehouse/src/vfs/image_size_cache.rs

@@ -10,7 +10,7 @@ use super::{Dir, DirEntry, EditPath, ImageSize, VPath, VPathBuf};
 
 pub struct ImageSizeCache<T> {
     inner: T,
-    cache: DashMap<VPathBuf, ImageSize>,
+    cache: DashMap<VPathBuf, Option<ImageSize>>,
 }
 
 impl<T> ImageSizeCache<T> {
@@ -59,17 +59,15 @@ where
     }
 
     fn image_size(&self, path: &VPath) -> Option<ImageSize> {
-        self.cache.get(path).map(|x| *x).or_else(|| {
-            let image_size = self
-                .compute_image_size(path)
+        self.cache
+            .entry(path.to_owned())
+            .or_insert_with(|| {
+                self.compute_image_size(path)
                     .inspect_err(|err| warn!("compute_image_size({path}) failed: {err:?}"))
                     .ok()
-                .flatten();
-            if let Some(image_size) = image_size {
-                self.cache.insert(path.to_owned(), image_size);
-            }
-            image_size
+                    .flatten()
             })
+            .clone()
     }
 
     fn anchor(&self, path: &VPath) -> Option<VPathBuf> {

static/js/tree.js

@@ -147,6 +147,20 @@ addSpell("b-linked", LinkedBranch);
 
 /* Fragment navigation */
 
+let rehashing = false;
+function rehash() {
+    // https://www.youtube.com/watch?v=Tv1SYqLllKI
+    if (!rehashing) {
+        rehashing = true;
+        let hash = window.location.hash;
+        if (hash.length > 0) {
+            window.location.hash = "";
+            window.location.hash = hash;
+        }
+        rehashing = false;
+    }
+}
+
 function expandDetailsRecursively(element) {
     while (element && element.tagName != "MAIN") {
         if (element.tagName == "DETAILS") {
@@ -156,6 +170,69 @@ function expandDetailsRecursively(element) {
     }
 }
 
+function navigateToPage(page) {
+    window.location.pathname = `${page}`;
+}
+
+async function navigateToBranch(fragment) {
+    if (fragment.length == 0) return;
+
+    let { navigationMap } = await import("/navmap.js");
+
+    let element = document.getElementById(fragment);
+    if (element !== null) {
+        // If the element is already loaded on the page, we're good.
+        expandDetailsRecursively(element);
+        rehash();
+
+        // NOTE(2024-03-31): Only scroll into view in the loaded case.
+        // This case happens very often with `/b`-navigated branches, and those serve the specific
+        // page that contains the provided branch.
+        // Hash-links are not used anymore so upgrading the second case is unnecessary.
+        // They were a thing before I linked to the treehouse very often so no need to update.
+        element.scrollIntoView();
+    } else {
+        // The element is not loaded, we need to load the tree that has it.
+        let parts = fragment.split(":");
+        if (parts.length >= 2) {
+            let [page, _id] = parts;
+            let fullPath = navigationMap[page];
+            if (Array.isArray(fullPath)) {
+                // TODO: This logic will probably need to be upgraded at some point to support
+                // navigation maps with roots other than index. Currently though only index is
+                // generated so that doesn't matter.
+                let [_root, ...path] = fullPath;
+                if (path !== undefined) {
+                    let isNotAtIndexHtml =
+                        window.location.pathname != "" &&
+                        window.location.pathname != "/" &&
+                        window.location.pathname != "/index.html";
+                    let lastBranch = null;
+                    for (let linked of path) {
+                        let branch = LinkedBranch.byLink.get(linked);
+
+                        if (isNotAtIndexHtml && branch === undefined) {
+                            navigateToPage("index");
+                            return;
+                        }
+
+                        await branch.loadTree("navigateToBranch");
+                        lastBranch = branch;
+                    }
+                    if (lastBranch != null) {
+                        expandDetailsRecursively(lastBranch.details);
+                    }
+                    rehash();
+                }
+            } else {
+                // In case the navigation map does not contain the given page, we can try
+                // redirecting the user to a concrete page on the site.
+                navigateToPage(page);
+            }
+        }
+    }
+}
+
 function getCurrentlyHighlightedBranch() {
     if (window.location.pathname == "/b" && window.location.search.length > 0) {
         let shortID = window.location.search.substring(1);
@@ -165,12 +242,33 @@ function getCurrentlyHighlightedBranch() {
     }
 }
 
+async function navigateToCurrentBranch() {
+    await navigateToBranch(getCurrentlyHighlightedBranch());
+}
+
+// When you click on a link, and the destination is within a <details> that is not expanded,
+// expand the <details> recursively.
+window.addEventListener("popstate", navigateToCurrentBranch);
+addEventListener("DOMContentLoaded", navigateToCurrentBranch);
+
+// When you enter the website through a link someone sent you, it would be nice if the linked branch
+// got expanded by default.
+async function expandLinkedBranch() {
+    let currentlyHighlightedBranch = getCurrentlyHighlightedBranch();
+    if (currentlyHighlightedBranch.length > 0) {
+        let linkedBranch = document.getElementById(currentlyHighlightedBranch);
+        if (linkedBranch.children.length > 0 && linkedBranch.children[0].tagName == "DETAILS") {
+            expandDetailsRecursively(linkedBranch.children[0]);
+        }
+    }
+}
+
+addEventListener("DOMContentLoaded", expandLinkedBranch);
+
 async function highlightCurrentBranch() {
     let branch = document.getElementById(getCurrentlyHighlightedBranch());
     if (branch != null) {
-        expandDetailsRecursively(branch);
         branch.classList.add("target");
-        branch.scrollIntoView();
     }
 }