Merge pull request #1486 from StrajnarFilip/claude/fix-1059-fig-embedded-copies

M6: .fig embedded images are copied once per blob, not once per hash (#1059)

ROADMAP.md

@@ -2,7 +2,7 @@
 
 **Stage: alpha** · next: beta, ~26 points and ~162–292 h away (one Opus 5.5 agent; ~33–67 h wall-clock with 5 agents)
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-28 · **Change:** minor (page ruler guides survive save and reopen (#1476); colour picker LCH and OKLCH models; non-ASCII layer names transliterate in code export (#1235); branches in live sessions and branch history entries, gap 17; plugin widgets take text input and a property menu (plugin API 4); boards: templates and tables; boards: a shared timer and voting sessions; boards: the dot grid, connector ends dragged to re-attach, curved connectors; Installed weights of an embedded font family (#1246); `.sketch` import, best effort (Sketch 48 and newer); CJK line breaking: JIS X 4051's line-start and line-end sets completed with the halfwidth small kana, the halfwidth and spacing (semi-)voiced sound marks, the iteration marks 〱–〵 and the halfwidth parentheses, with behaviour cases for each; Adobe Fonts found on macOS (#298); egui 0.37 hidden-capture deadline contract; Dev Mode measurements kept on the canvas and a read-only layers panel; boards: a board area row and progress entry; community fixes in #507, #510, #529 and #530: auto-save, a text box by dragging, batch step references, removing someone from a live session, Russian and Turkish catalogs reviewed, Czech and Indonesian drafts, the Japanese draft completed, zoom previews, the web clipboard, Alt-drag snapping and Cmd+D repeat, recovery copies, crash and rollback fixes, colour emoji, `.fig` import fixes; earlier changes are in the revision history below) · **Target:** Figma Design (desktop app 126.10.7)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-28 · **Change:** minor (.fig embedded images are copied once per blob, not once per hash (#1059); page ruler guides survive save and reopen (#1476); colour picker LCH and OKLCH models; non-ASCII layer names transliterate in code export (#1235); branches in live sessions and branch history entries, gap 17; plugin widgets take text input and a property menu (plugin API 4); boards: templates and tables; boards: a shared timer and voting sessions; boards: the dot grid, connector ends dragged to re-attach, curved connectors; Installed weights of an embedded font family (#1246); `.sketch` import, best effort (Sketch 48 and newer); CJK line breaking: JIS X 4051's line-start and line-end sets completed with the halfwidth small kana, the halfwidth and spacing (semi-)voiced sound marks, the iteration marks 〱–〵 and the halfwidth parentheses, with behaviour cases for each; Adobe Fonts found on macOS (#298); egui 0.37 hidden-capture deadline contract; Dev Mode measurements kept on the canvas and a read-only layers panel; boards: a board area row and progress entry; community fixes in #507, #510, #529 and #530: auto-save, a text box by dragging, batch step references, removing someone from a live session, Russian and Turkish catalogs reviewed, Czech and Indonesian drafts, the Japanese draft completed, zoom previews, the web clipboard, Alt-drag snapping and Cmd+D repeat, recovery copies, crash and rollback fixes, colour emoji, `.fig` import fixes; earlier changes are in the revision history below) · **Target:** Figma Design (desktop app 126.10.7)
 
 FigCraft is a clean-room, open-source, pure-Rust reimplementation of the Figma design workflow,
 native on macOS, Windows, Linux and FreeBSD and in the browser, fully drivable by agents through
@@ -132,6 +132,7 @@ Ranked; detail and milestones in [`docs/roadmap.md`](docs/roadmap.md).
 
 ## Progress log
 
+- **2026-10-28** · M6, #1059: `.fig` import copies each image carried inside the message once per blob, shared by every hash that names it, instead of once per hash: a file pointing many hashes at one large blob no longer multiplies it in memory (100 hashes on a 250 MB blob were 25 GB). Regression test. Numbers unchanged.
 - **2026-10-28** · M1, #1476: page ruler guides survive save and reopen. A page kept its guides in the page kind while the layer's own `guides` field (frame guides, #70) took that key when a file was read, so a reopened page's guides vanished, and saving it wrote `guides` twice, which then refused to open. Every layer now keeps its guides in the one field, and a page with two `guides` lists opens with both. Regressions in the doc and format crates. Numbers unchanged.
 - **2026-10-26** · Non-ASCII layer names transliterate in code export (M6, #1235): `class_name` runs the name through `deunicode` before its ASCII filter, so 로그인 화면 → `rogeuin-hwamyeon`, кнопка → `knopka`, über → `uber` in the HTML/CSS/React/Leptos class names, component roots and `data-*` variant attributes (SwiftUI/Compose type names unchanged); a name left with nothing (symbols only) takes the node's kind (`.text`, `.frame`) instead of `layer-`, and the 40-character cut lands on a word boundary. New dependency: deunicode (pure Rust tables, zero deps, BSD-3-Clause, the `slug` crate's base). `html_codegen_tests`. Numbers unchanged.
 - **2026-10-25** · egui 0.37 capture lifecycle: screenshots with hidden or unknown visibility queue, request a hidden paint, and expire after 60 seconds if no capture arrives (headless-tested contract). Logic-only edits, saves and inspection continue while hidden. Native visible GUI and forced hidden-window paint, browser and Wayland behavior remain unqualified; parity percentages are unchanged.
@@ -349,6 +350,7 @@ Ranked; detail and milestones in [`docs/roadmap.md`](docs/roadmap.md).
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-28 | minor | M6, #1059: `.fig` import copies embedded image blobs once per blob, not once per hash naming them. Numbers unchanged. |
 | 2026-10-28 | minor | M1, #1476: page ruler guides survive save and reopen; files written with a page's `guides` key twice open again with both lists. Numbers unchanged. |
 | 2026-10-26 | minor | Non-ASCII layer names transliterate in code export (M6, #1235): `class_name` transliterates through the new `deunicode` dependency (pure Rust tables, zero deps, BSD-3-Clause), so Korean, Cyrillic, Latin-diacritic and CJK names become readable ASCII classes (`rogeuin-hwamyeon`, `knopka`, `uber`, `an-niu`) in HTML/CSS/React/Leptos output, component roots and `data-*` variant attributes; symbols-only names take the node's kind (`.text`) instead of `layer-`, and the 40-character cut lands on a word boundary. `html_codegen_tests` updated and extended. Numbers unchanged |
 | 2026-10-25 | minor | egui 0.37 capture lifecycle: screenshots with hidden or unknown visibility queue, request a hidden paint, and expire after 60 seconds if no capture arrives (headless-tested contract). Logic-only edits, saves and inspection continue while hidden. Native visible GUI and forced hidden-window paint, browser and Wayland behavior remain unqualified; parity percentages are unchanged. |

crates/format/src/fig.rs

@@ -47,6 +47,7 @@ mod text_style_tests;
 
 use std::collections::BTreeMap;
 use std::io::Read;
+use std::sync::Arc;
 
 use figcraft_doc::Document;
 
@@ -109,9 +110,9 @@ pub fn import(bytes: &[u8], name: &str) -> Result<(Document, Vec<String>), Forma
     let file_name = archive.file_name.as_deref().filter(|n| !n.trim().is_empty()).unwrap_or(name);
     let (json, mut warnings, networks) = map::to_rest(&msg, file_name, max_nodes);
     // The message goes before the layers are built, so the images it carries are copied out first.
-    let embedded: BTreeMap<String, Vec<u8>> = embedded_images(&msg).into_iter().map(|(hash, bytes)| (hash, bytes.to_vec())).collect();
+    let embedded = embedded_copies(&msg);
     drop(msg);
-    let images = |r: &str| archive.image(r).or_else(|| embedded.get(r).cloned());
+    let images = |r: &str| archive.image(r).or_else(|| embedded.get(r).map(|b| b.to_vec()));
     let (doc, more) = crate::rest::import_with_networks(&json, &images, networks, max_nodes)?;
     // Both stages stop at the same cap and say so in the same words: one note (#981).
     for w in more.into_iter().filter_map(map::adapt_warning) {
@@ -151,17 +152,17 @@ fn corrupt(msg: impl Into<String>) -> FormatError {
 /// Image bytes that travel inside the message, by image hash (lowercase hex): a paint's
 /// `image.dataBlob` indexes the message's `blobs`. Copies written by plugins and other tools embed
 /// their images this way, and a bare canvas (what the clipboard carries) has no `images/`. The
-/// walk is iterative (no recursion on nested data) and skips blobs larger than [`MAX_IMAGE`]. The
-/// bytes stay borrowed from the message.
-fn embedded_images<'m>(msg: &'m Kv) -> BTreeMap<String, &'m [u8]> {
+/// walk is iterative (no recursion on nested data) and skips blobs larger than [`MAX_IMAGE`].
+/// Returns the index of each hash's blob.
+fn embedded_images(msg: &Kv) -> BTreeMap<String, usize> {
     let blobs = msg.get("blobs").map(Kv::list).unwrap_or_default();
     let mut found = BTreeMap::new();
     let mut pending = vec![msg];
     while let Some(value) = pending.pop() {
         match value {
             Kv::Object(fields) => {
-                if let Some((hash, bytes)) = value.get("image").and_then(|image| embedded_image(image, blobs)) {
-                    found.entry(hash).or_insert(bytes);
+                if let Some((hash, index)) = value.get("image").and_then(|image| embedded_image(image, blobs)) {
+                    found.entry(hash).or_insert(index);
                 }
                 pending.extend(fields.iter().filter(|(name, _)| *name != "blobs").map(|(_, field)| field));
             }
@@ -172,15 +173,35 @@ fn embedded_images<'m>(msg: &'m Kv) -> BTreeMap<String, &'m [u8]> {
     found
 }
 
-/// The hash and bytes of an `Image` value whose `dataBlob` points at a usable blob.
-fn embedded_image<'k>(image: &Kv, blobs: &'k [Kv]) -> Option<(String, &'k [u8])> {
+/// The images that travel inside the message ([`embedded_images`]), copied out of it once per
+/// blob: every hash naming the same blob shares its copy. A file can point any number of hashes
+/// at one large blob, and a copy for each would multiply it (#1059).
+fn embedded_copies(msg: &Kv) -> BTreeMap<String, Arc<[u8]>> {
+    let blobs = msg.get("blobs").map(Kv::list).unwrap_or_default();
+    let mut copies: BTreeMap<usize, Arc<[u8]>> = BTreeMap::new();
+    let mut out = BTreeMap::new();
+    for (hash, index) in embedded_images(msg) {
+        let Some(bytes) = blob(blobs, index) else { continue };
+        out.insert(hash, Arc::clone(copies.entry(index).or_insert_with(|| Arc::from(bytes))));
+    }
+    out
+}
+
+/// The hash and blob index of an `Image` value whose `dataBlob` points at a usable blob.
+fn embedded_image(image: &Kv, blobs: &[Kv]) -> Option<(String, usize)> {
     let hash = image.get("hash").and_then(Kv::bytes).filter(|h| !h.is_empty() && h.len() <= 64)?;
     let Some(Kv::Uint(index)) = image.get("dataBlob") else { return None };
-    let bytes = blobs.get(usize::try_from(*index).ok()?)?.get("bytes").and_then(Kv::bytes)?;
+    let index = usize::try_from(*index).ok()?;
+    let bytes = blob(blobs, index)?;
     if bytes.is_empty() || bytes.len() as u64 > MAX_IMAGE {
         return None;
     }
-    Some((hash.iter().map(|b| format!("{b:02x}")).collect(), bytes))
+    Some((hash.iter().map(|b| format!("{b:02x}")).collect(), index))
+}
+
+/// The bytes of blob `index`.
+fn blob<'k>(blobs: &'k [Kv], index: usize) -> Option<&'k [u8]> {
+    blobs.get(index)?.get("bytes").and_then(Kv::bytes)
 }
 
 /// The parts of a `.fig` archive the import reads.

crates/format/src/fig/tests.rs

@@ -777,6 +777,23 @@ fn a_data_blob_past_the_blobs_stays_a_placeholder() {
     assert!(warnings.iter().any(|w| w.contains("isn't in the file")), "{warnings:?}");
 }
 
+/// A file can point any number of image hashes at one large blob; each used to get its own copy
+/// of it (#1059).
+#[test]
+fn hashes_naming_one_blob_share_one_copy_of_it() {
+    let image = |hash: u8, blob: u64| o(vec![("image", o(vec![("hash", Kv::Bytes(vec![hash; 20])), ("dataBlob", u(blob))]))]);
+    let msg = o(vec![
+        ("blobs", Kv::Array(vec![o(vec![("bytes", Kv::Bytes(png()))]), o(vec![("bytes", Kv::Bytes(vec![7; 16]))])])),
+        ("nodeChanges", Kv::Array((1..=50).map(|h| image(h, 0)).chain([image(99, 1), image(98, 2)]).collect())),
+    ]);
+    let copies = embedded_copies(&msg);
+    assert_eq!(copies.len(), 51, "the hash naming no blob is left out");
+    let first = &copies[&"01".repeat(20)];
+    assert_eq!(**first, *png());
+    assert_eq!(copies.values().filter(|c| Arc::ptr_eq(c, first)).count(), 50);
+    assert_eq!(*copies[&"63".repeat(20)], [7; 16]);
+}
+
 #[test]
 fn other_files_are_not_fig() {
     assert!(try_import(b"{\"document\": {}}", "x").is_none());