visual continunity

frontend/static/vendors/hash-wasm/oxicloud_hash_wasm.js

@@ -0,0 +1,343 @@
+/**
+ * Incremental BLAKE3 hasher.
+ *
+ * ```js
+ * const h = new Blake3Hasher();
+ * h.update(chunkBytes);   // repeat per slice
+ * const hex = h.finalizeHex();
+ * ```
+ */
+export class Blake3Hasher {
+    __destroy_into_raw() {
+        const ptr = this.__wbg_ptr;
+        this.__wbg_ptr = 0;
+        Blake3HasherFinalization.unregister(this);
+        return ptr;
+    }
+    free() {
+        const ptr = this.__destroy_into_raw();
+        wasm.__wbg_blake3hasher_free(ptr, 0);
+    }
+    /**
+     * Bytes hashed so far — lets the worker report progress without
+     * tracking its own counter.
+     * @returns {number}
+     */
+    count() {
+        const ret = wasm.blake3hasher_count(this.__wbg_ptr);
+        return ret;
+    }
+    /**
+     * Finish and return the lowercase hex digest (64 chars). The hasher
+     * can keep receiving `update` calls afterwards (BLAKE3 finalization
+     * is non-destructive), but the frontend treats it as terminal.
+     * @returns {string}
+     */
+    finalizeHex() {
+        let deferred1_0;
+        let deferred1_1;
+        try {
+            const retptr = wasm.__wbindgen_add_to_stack_pointer(-16);
+            wasm.blake3hasher_finalizeHex(retptr, this.__wbg_ptr);
+            var r0 = getDataViewMemory0().getInt32(retptr + 4 * 0, true);
+            var r1 = getDataViewMemory0().getInt32(retptr + 4 * 1, true);
+            deferred1_0 = r0;
+            deferred1_1 = r1;
+            return getStringFromWasm0(r0, r1);
+        } finally {
+            wasm.__wbindgen_add_to_stack_pointer(16);
+            wasm.__wbindgen_export2(deferred1_0, deferred1_1, 1);
+        }
+    }
+    /**
+     * Create a fresh hasher.
+     */
+    constructor() {
+        const ret = wasm.blake3hasher_new();
+        this.__wbg_ptr = ret;
+        Blake3HasherFinalization.register(this, this.__wbg_ptr, this);
+        return this;
+    }
+    /**
+     * Feed one slice of the file.
+     * @param {Uint8Array} data
+     */
+    update(data) {
+        const ptr0 = passArray8ToWasm0(data, wasm.__wbindgen_export);
+        const len0 = WASM_VECTOR_LEN;
+        wasm.blake3hasher_update(this.__wbg_ptr, ptr0, len0);
+    }
+}
+if (Symbol.dispose) Blake3Hasher.prototype[Symbol.dispose] = Blake3Hasher.prototype.free;
+
+/**
+ * Incremental FastCDC chunker + whole-file BLAKE3, for the delta-upload
+ * worker. Feed the file in slices; every call returns the chunks that
+ * became FINAL; `finish()` flushes the tail and returns the file hash.
+ *
+ * ```js
+ * const c = new DeltaChunker();
+ * for (const slice of slices) {
+ *     for (const [h, s] of JSON.parse(c.update(bytes))) { … }
+ * }
+ * const { chunks, file_hash } = JSON.parse(c.finish());
+ * ```
+ *
+ * Correctness of the incremental split: FastCDC decides each cut by
+ * scanning at most `CDC_MAX_CHUNK` bytes from the chunk's start. When
+ * the chunker runs over the buffered prefix of a longer file, every
+ * produced chunk except the LAST ended on a content/max-size condition
+ * — its decision window was fully available, so the full-file chunker
+ * makes the same cut. Only the last chunk (cut by "end of buffer") is
+ * provisional: it stays buffered and is re-examined when more bytes
+ * arrive. By induction the emitted boundaries equal a single FastCDC
+ * pass over the whole file — the mirror test below proves it.
+ */
+export class DeltaChunker {
+    __destroy_into_raw() {
+        const ptr = this.__wbg_ptr;
+        this.__wbg_ptr = 0;
+        DeltaChunkerFinalization.unregister(this);
+        return ptr;
+    }
+    free() {
+        const ptr = this.__destroy_into_raw();
+        wasm.__wbg_deltachunker_free(ptr, 0);
+    }
+    /**
+     * Flush the provisional tail and return
+     * `{"chunks":[["<hex>",size]…],"file_hash":"<hex>","total":N}`.
+     * `chunks` holds at most one entry (the tail); an empty file has none
+     * and its `file_hash` is BLAKE3 of the empty input.
+     * @returns {string}
+     */
+    finish() {
+        let deferred1_0;
+        let deferred1_1;
+        try {
+            const retptr = wasm.__wbindgen_add_to_stack_pointer(-16);
+            wasm.deltachunker_finish(retptr, this.__wbg_ptr);
+            var r0 = getDataViewMemory0().getInt32(retptr + 4 * 0, true);
+            var r1 = getDataViewMemory0().getInt32(retptr + 4 * 1, true);
+            deferred1_0 = r0;
+            deferred1_1 = r1;
+            return getStringFromWasm0(r0, r1);
+        } finally {
+            wasm.__wbindgen_add_to_stack_pointer(16);
+            wasm.__wbindgen_export2(deferred1_0, deferred1_1, 1);
+        }
+    }
+    /**
+     * Create a chunker with the server's CDC parameters.
+     */
+    constructor() {
+        const ret = wasm.deltachunker_new();
+        this.__wbg_ptr = ret;
+        DeltaChunkerFinalization.register(this, this.__wbg_ptr, this);
+        return this;
+    }
+    /**
+     * Feed one slice. Returns a JSON array of the chunks that became
+     * final: `[["<blake3-hex>", size], …]` (possibly empty).
+     * @param {Uint8Array} data
+     * @returns {string}
+     */
+    update(data) {
+        let deferred2_0;
+        let deferred2_1;
+        try {
+            const retptr = wasm.__wbindgen_add_to_stack_pointer(-16);
+            const ptr0 = passArray8ToWasm0(data, wasm.__wbindgen_export);
+            const len0 = WASM_VECTOR_LEN;
+            wasm.deltachunker_update(retptr, this.__wbg_ptr, ptr0, len0);
+            var r0 = getDataViewMemory0().getInt32(retptr + 4 * 0, true);
+            var r1 = getDataViewMemory0().getInt32(retptr + 4 * 1, true);
+            deferred2_0 = r0;
+            deferred2_1 = r1;
+            return getStringFromWasm0(r0, r1);
+        } finally {
+            wasm.__wbindgen_add_to_stack_pointer(16);
+            wasm.__wbindgen_export2(deferred2_0, deferred2_1, 1);
+        }
+    }
+}
+if (Symbol.dispose) DeltaChunker.prototype[Symbol.dispose] = DeltaChunker.prototype.free;
+
+/**
+ * One-shot convenience for small buffers.
+ * @param {Uint8Array} data
+ * @returns {string}
+ */
+export function blake3Hex(data) {
+    let deferred2_0;
+    let deferred2_1;
+    try {
+        const retptr = wasm.__wbindgen_add_to_stack_pointer(-16);
+        const ptr0 = passArray8ToWasm0(data, wasm.__wbindgen_export);
+        const len0 = WASM_VECTOR_LEN;
+        wasm.blake3Hex(retptr, ptr0, len0);
+        var r0 = getDataViewMemory0().getInt32(retptr + 4 * 0, true);
+        var r1 = getDataViewMemory0().getInt32(retptr + 4 * 1, true);
+        deferred2_0 = r0;
+        deferred2_1 = r1;
+        return getStringFromWasm0(r0, r1);
+    } finally {
+        wasm.__wbindgen_add_to_stack_pointer(16);
+        wasm.__wbindgen_export2(deferred2_0, deferred2_1, 1);
+    }
+}
+function __wbg_get_imports() {
+    const import0 = {
+        __proto__: null,
+        __wbg___wbindgen_throw_bbadd78c1bac3a77: function(arg0, arg1) {
+            throw new Error(getStringFromWasm0(arg0, arg1));
+        },
+    };
+    return {
+        __proto__: null,
+        "./oxicloud_hash_wasm_bg.js": import0,
+    };
+}
+
+const Blake3HasherFinalization = (typeof FinalizationRegistry === 'undefined')
+    ? { register: () => {}, unregister: () => {} }
+    : new FinalizationRegistry(ptr => wasm.__wbg_blake3hasher_free(ptr, 1));
+const DeltaChunkerFinalization = (typeof FinalizationRegistry === 'undefined')
+    ? { register: () => {}, unregister: () => {} }
+    : new FinalizationRegistry(ptr => wasm.__wbg_deltachunker_free(ptr, 1));
+
+let cachedDataViewMemory0 = null;
+function getDataViewMemory0() {
+    if (cachedDataViewMemory0 === null || cachedDataViewMemory0.buffer.detached === true || (cachedDataViewMemory0.buffer.detached === undefined && cachedDataViewMemory0.buffer !== wasm.memory.buffer)) {
+        cachedDataViewMemory0 = new DataView(wasm.memory.buffer);
+    }
+    return cachedDataViewMemory0;
+}
+
+function getStringFromWasm0(ptr, len) {
+    return decodeText(ptr >>> 0, len);
+}
+
+let cachedUint8ArrayMemory0 = null;
+function getUint8ArrayMemory0() {
+    if (cachedUint8ArrayMemory0 === null || cachedUint8ArrayMemory0.byteLength === 0) {
+        cachedUint8ArrayMemory0 = new Uint8Array(wasm.memory.buffer);
+    }
+    return cachedUint8ArrayMemory0;
+}
+
+function passArray8ToWasm0(arg, malloc) {
+    const ptr = malloc(arg.length * 1, 1) >>> 0;
+    getUint8ArrayMemory0().set(arg, ptr / 1);
+    WASM_VECTOR_LEN = arg.length;
+    return ptr;
+}
+
+let cachedTextDecoder = new TextDecoder('utf-8', { ignoreBOM: true, fatal: true });
+cachedTextDecoder.decode();
+const MAX_SAFARI_DECODE_BYTES = 2146435072;
+let numBytesDecoded = 0;
+function decodeText(ptr, len) {
+    numBytesDecoded += len;
+    if (numBytesDecoded >= MAX_SAFARI_DECODE_BYTES) {
+        cachedTextDecoder = new TextDecoder('utf-8', { ignoreBOM: true, fatal: true });
+        cachedTextDecoder.decode();
+        numBytesDecoded = len;
+    }
+    return cachedTextDecoder.decode(getUint8ArrayMemory0().subarray(ptr, ptr + len));
+}
+
+let WASM_VECTOR_LEN = 0;
+
+let wasmModule, wasmInstance, wasm;
+function __wbg_finalize_init(instance, module) {
+    wasmInstance = instance;
+    wasm = instance.exports;
+    wasmModule = module;
+    cachedDataViewMemory0 = null;
+    cachedUint8ArrayMemory0 = null;
+    return wasm;
+}
+
+async function __wbg_load(module, imports) {
+    if (typeof Response === 'function' && module instanceof Response) {
+        if (typeof WebAssembly.instantiateStreaming === 'function') {
+            try {
+                return await WebAssembly.instantiateStreaming(module, imports);
+            } catch (e) {
+                const validResponse = module.ok && expectedResponseType(module.type);
+
+                if (validResponse && module.headers.get('Content-Type') !== 'application/wasm') {
+                    console.warn("`WebAssembly.instantiateStreaming` failed because your server does not serve Wasm with `application/wasm` MIME type. Falling back to `WebAssembly.instantiate` which is slower. Original error:\n", e);
+
+                } else { throw e; }
+            }
+        }
+
+        const bytes = await module.arrayBuffer();
+        return await WebAssembly.instantiate(bytes, imports);
+    } else {
+        const instance = await WebAssembly.instantiate(module, imports);
+
+        if (instance instanceof WebAssembly.Instance) {
+            return { instance, module };
+        } else {
+            return instance;
+        }
+    }
+
+    function expectedResponseType(type) {
+        switch (type) {
+            case 'basic': case 'cors': case 'default': return true;
+        }
+        return false;
+    }
+}
+
+function initSync(module) {
+    if (wasm !== undefined) return wasm;
+
+
+    if (module !== undefined) {
+        if (Object.getPrototypeOf(module) === Object.prototype) {
+            ({module} = module)
+        } else {
+            console.warn('using deprecated parameters for `initSync()`; pass a single object instead')
+        }
+    }
+
+    const imports = __wbg_get_imports();
+    if (!(module instanceof WebAssembly.Module)) {
+        module = new WebAssembly.Module(module);
+    }
+    const instance = new WebAssembly.Instance(module, imports);
+    return __wbg_finalize_init(instance, module);
+}
+
+async function __wbg_init(module_or_path) {
+    if (wasm !== undefined) return wasm;
+
+
+    if (module_or_path !== undefined) {
+        if (Object.getPrototypeOf(module_or_path) === Object.prototype) {
+            ({module_or_path} = module_or_path)
+        } else {
+            console.warn('using deprecated parameters for the initialization function; pass a single object instead')
+        }
+    }
+
+    if (module_or_path === undefined) {
+        module_or_path = new URL('oxicloud_hash_wasm_bg.wasm', import.meta.url);
+    }
+    const imports = __wbg_get_imports();
+
+    if (typeof module_or_path === 'string' || (typeof Request === 'function' && module_or_path instanceof Request) || (typeof URL === 'function' && module_or_path instanceof URL)) {
+        module_or_path = fetch(module_or_path);
+    }
+
+    const { instance, module } = await __wbg_load(await module_or_path, imports);
+
+    return __wbg_finalize_init(instance, module);
+}
+
+export { initSync, __wbg_init as default };

frontend/static/workers/deltaWorker.js

@@ -0,0 +1,330 @@
+/**
+ * OxiCloud — delta-upload worker ("upload only what changed").
+ *
+ * Runs the whole client side of the delta protocol off the main thread:
+ *
+ *   read 8 MiB slices ─► FastCDC chunk + BLAKE3 (WASM, same crate and
+ *   parameters as the server) ─► negotiate hash batches ─► upload only
+ *   the missing chunks (framed, bounded concurrency) ─► commit.
+ *
+ * The stages OVERLAP: negotiation of batch N and uploads of its missing
+ * chunks run while batch N+1 is still being hashed, so wall-clock time
+ * approaches max(hash time, upload time) instead of their sum. RAM stays
+ * flat: chunk bytes are re-sliced from the File at upload time, never
+ * hoarded.
+ *
+ * Protocol with the spawner:
+ *   in  : { file: File, folderId: string, name: string, csrfToken: string }
+ *   out : { type: 'progress', hashedBytes, reusedBytes, uploadedBytes, totalBytes }
+ *         { type: 'done', status, body }      — conclusive HTTP outcome
+ *         { type: 'fallback', reason }        — do a plain byte upload
+ */
+
+// Absolute URLs on purpose: vendors/workers are served verbatim in both
+// dev and the static build (served verbatim from /static).
+const WASM_GLUE_URL = '/vendors/hash-wasm/oxicloud_hash_wasm.js';
+
+/** File read granularity — large enough to amortize Blob→ArrayBuffer. */
+const SLICE_BYTES = 8 * 1024 * 1024;
+/** Negotiate after this many freshly hashed chunks (~64 MiB of content). */
+const NEGOTIATE_BATCH = 256;
+/** Group missing chunks into PUT bodies of at most this many bytes. */
+const UPLOAD_BATCH_BYTES = 8 * 1024 * 1024;
+/** Concurrent chunk-PUT requests. */
+const UPLOAD_CONCURRENCY = 2;
+/** Re-commit attempts when the server answers 409 still_missing. */
+const COMMIT_RETRIES = 2;
+
+/**
+ * Typed view of the dedicated-worker global scope (jsconfig targets the
+ * DOM lib, where `self` is a Window — cast to what this worker uses).
+ * @type {{ onmessage: ((event: MessageEvent) => void) | null,
+ *          postMessage: (message: unknown) => void }}
+ */
+const workerScope = /** @type {any} */ (self);
+
+/**
+ * One chunk occurrence, in file order.
+ * @typedef {{ h: string, s: number, offset: number }} WorkerChunk
+ */
+
+/** @returns {Promise<any>} the initialized WASM module */
+async function loadWasm() {
+    const mod = await import(WASM_GLUE_URL);
+    await mod.default();
+    return mod;
+}
+
+workerScope.onmessage = async (event) => {
+    const { file, folderId, name, csrfToken } = /** @type {{ file: File, folderId: string, name: string, csrfToken: string }} */ (event.data);
+
+    /** @param {string} reason */
+    const fallback = (reason) => workerScope.postMessage({ type: 'fallback', reason });
+
+    /** @type {Record<string, string>} */
+    const mutHeaders = { 'Content-Type': 'application/json' };
+    if (csrfToken) mutHeaders['X-CSRF-Token'] = csrfToken;
+
+    let wasm;
+    try {
+        wasm = await loadWasm();
+    } catch (err) {
+        fallback(`wasm unavailable: ${err instanceof Error ? err.message : String(err)}`);
+        return;
+    }
+
+    // ── Shared pipeline state ─────────────────────────────────────
+    /** @type {WorkerChunk[]} */
+    const chunks = []; // every occurrence, in file order
+    /** @type {Set<string>} */
+    const seenForNegotiate = new Set(); // distinct hashes already sent to negotiate
+    let reusedBytes = 0;
+    let uploadedBytes = 0;
+    let hashedBytes = 0;
+    let failed = /** @type {string | null} */ (null);
+
+    let lastProgress = 0;
+    const progress = (force = false) => {
+        const now = Date.now();
+        if (!force && now - lastProgress < 150) return;
+        lastProgress = now;
+        workerScope.postMessage({
+            type: 'progress',
+            hashedBytes,
+            reusedBytes,
+            uploadedBytes,
+            totalBytes: file.size
+        });
+    };
+
+    // ── Upload stage: bounded-concurrency drain of uploadByHash ──
+    /** @type {WorkerChunk[]} */
+    const uploadQueue = [];
+    /** @type {Promise<void>[]} */
+    const uploadWorkers = [];
+    let uploadsClosed = false;
+    /** @type {(() => void) | null} */
+    let wakeUploader = null;
+    const signalUploaders = () => {
+        if (wakeUploader) {
+            const w = wakeUploader;
+            wakeUploader = null;
+            w();
+        }
+    };
+
+    /** Encode a batch of chunks as [u32 BE len][bytes] frames. */
+    const encodeFrames = async (/** @type {WorkerChunk[]} */ batch) => {
+        const total = batch.reduce((n, c) => n + 4 + c.s, 0);
+        const wire = new Uint8Array(total);
+        const view = new DataView(wire.buffer);
+        let at = 0;
+        for (const c of batch) {
+            // eslint-disable-next-line no-await-in-loop -- sequential by design: constant RAM
+            const bytes = new Uint8Array(await file.slice(c.offset, c.offset + c.s).arrayBuffer());
+            view.setUint32(at, c.s, false);
+            wire.set(bytes, at + 4);
+            at += 4 + c.s;
+        }
+        return wire;
+    };
+
+    const uploadLoop = async () => {
+        while (!failed) {
+            // Take up to UPLOAD_BATCH_BYTES from the queue.
+            /** @type {WorkerChunk[]} */
+            const batch = [];
+            let bytes = 0;
+            while (uploadQueue.length > 0 && bytes < UPLOAD_BATCH_BYTES) {
+                const c = /** @type {WorkerChunk} */ (uploadQueue.shift());
+                batch.push(c);
+                bytes += c.s;
+            }
+            if (batch.length === 0) {
+                if (uploadsClosed) return;
+                // eslint-disable-next-line no-await-in-loop -- queue wait
+                await new Promise((resolve) => {
+                    wakeUploader = /** @type {() => void} */ (resolve);
+                });
+                continue;
+            }
+            try {
+                // eslint-disable-next-line no-await-in-loop -- bounded by pool size
+                const wire = await encodeFrames(batch);
+                // eslint-disable-next-line no-await-in-loop -- bounded by pool size
+                const response = await fetch('/api/files/delta/chunks', {
+                    method: 'PUT',
+                    headers: {
+                        'Content-Type': 'application/octet-stream',
+                        ...(csrfToken ? { 'X-CSRF-Token': csrfToken } : {})
+                    },
+                    body: wire
+                });
+                if (!response.ok) {
+                    failed = `chunk PUT failed (HTTP ${response.status})`;
+                    return;
+                }
+                for (const c of batch) uploadedBytes += c.s;
+                progress();
+            } catch (err) {
+                failed = `chunk PUT failed: ${err instanceof Error ? err.message : String(err)}`;
+                return;
+            }
+        }
+    };
+    for (let i = 0; i < UPLOAD_CONCURRENCY; i++) uploadWorkers.push(uploadLoop());
+
+    // ── Negotiate stage ───────────────────────────────────────────
+    /** @type {Promise<void>[]} */
+    const negotiations = [];
+    const negotiate = (/** @type {WorkerChunk[]} */ fresh) => {
+        if (fresh.length === 0 || failed) return;
+        negotiations.push(
+            (async () => {
+                try {
+                    const response = await fetch('/api/files/delta/negotiate', {
+                        method: 'POST',
+                        headers: mutHeaders,
+                        body: JSON.stringify({ chunks: fresh.map(({ h, s }) => ({ h, s })) })
+                    });
+                    if (!response.ok) {
+                        failed = failed || `negotiate failed (HTTP ${response.status})`;
+                        return;
+                    }
+                    const missing = new Set(/** @type {{missing: string[]}} */ (await response.json()).missing);
+                    for (const c of fresh) {
+                        if (missing.has(c.h)) {
+                            uploadQueue.push(c);
+                        } else {
+                            reusedBytes += c.s;
+                        }
+                    }
+                    signalUploaders();
+                    progress();
+                } catch (err) {
+                    failed = failed || `negotiate failed: ${err instanceof Error ? err.message : String(err)}`;
+                }
+            })()
+        );
+    };
+
+    // ── Chunking stage (drives the other two) ────────────────────
+    try {
+        const chunker = new wasm.DeltaChunker();
+        /** @type {WorkerChunk[]} */
+        let freshBatch = [];
+        let offset = 0;
+
+        /** @param {[string, number][]} emitted */
+        const onChunks = (emitted) => {
+            for (const [h, s] of emitted) {
+                /** @type {WorkerChunk} */
+                const chunk = { h, s, offset };
+                offset += s;
+                chunks.push(chunk);
+                if (seenForNegotiate.has(h)) {
+                    // Repeated content inside the same file: the first
+                    // occurrence decides upload vs reuse; later ones are
+                    // pure reuse for accounting.
+                    reusedBytes += s;
+                } else {
+                    seenForNegotiate.add(h);
+                    freshBatch.push(chunk);
+                    if (freshBatch.length >= NEGOTIATE_BATCH) {
+                        negotiate(freshBatch);
+                        freshBatch = [];
+                    }
+                }
+            }
+        };
+
+        for (let read = 0; read < file.size && !failed; read += SLICE_BYTES) {
+            const end = Math.min(read + SLICE_BYTES, file.size);
+            // eslint-disable-next-line no-await-in-loop -- sequential by design: constant RAM
+            const slice = new Uint8Array(await file.slice(read, end).arrayBuffer());
+            onChunks(JSON.parse(chunker.update(slice)));
+            hashedBytes = end;
+            progress();
+        }
+        const fin = JSON.parse(chunker.finish());
+        chunker.free();
+        onChunks(fin.chunks);
+        negotiate(freshBatch);
+        const fileHash = /** @type {string} */ (fin.file_hash);
+        hashedBytes = file.size;
+        progress(true);
+
+        // ── Drain: negotiations → uploads → commit ───────────────
+        await Promise.all(negotiations);
+        uploadsClosed = true;
+        signalUploaders();
+        await Promise.all(uploadWorkers);
+        if (failed) {
+            fallback(failed);
+            return;
+        }
+
+        const commitBody = {
+            file_hash: fileHash,
+            chunks: chunks.map(({ h, s }) => ({ h, s })),
+            name,
+            folder_id: folderId
+        };
+        for (let attempt = 0; ; attempt++) {
+            // eslint-disable-next-line no-await-in-loop -- retry loop
+            const response = await fetch('/api/files/delta/commit', {
+                method: 'POST',
+                headers: mutHeaders,
+                body: JSON.stringify(commitBody)
+            });
+            /** @type {any} */
+            let body = null;
+            try {
+                // eslint-disable-next-line no-await-in-loop -- retry loop
+                body = await response.json();
+            } catch (_) {}
+
+            const stillMissing = response.status === 409 && Array.isArray(body?.still_missing);
+            if (stillMissing && attempt < COMMIT_RETRIES) {
+                // GC race or a chunk we wrongly assumed claimable: upload
+                // exactly what the server names and try again.
+                const byHash = new Map(chunks.map((c) => [c.h, c]));
+                /** @type {WorkerChunk[]} */
+                const retry = [];
+                for (const h of body.still_missing) {
+                    const c = byHash.get(h);
+                    if (!c) {
+                        fallback('server requested an unknown chunk');
+                        return;
+                    }
+                    retry.push(c);
+                }
+                const wire = await encodeFrames(retry);
+                // eslint-disable-next-line no-await-in-loop -- retry loop
+                const put = await fetch('/api/files/delta/chunks', {
+                    method: 'PUT',
+                    headers: {
+                        'Content-Type': 'application/octet-stream',
+                        ...(csrfToken ? { 'X-CSRF-Token': csrfToken } : {})
+                    },
+                    body: wire
+                });
+                if (!put.ok) {
+                    fallback(`retry chunk PUT failed (HTTP ${put.status})`);
+                    return;
+                }
+                for (const c of retry) uploadedBytes += c.s;
+                progress(true);
+                continue;
+            }
+
+            // Conclusive: 201 created, or a real error (quota, name
+            // conflict, validation). The spawner maps it to the uploaders'
+            // UploadAnswer contract.
+            workerScope.postMessage({ type: 'done', status: response.status, body });
+            return;
+        }
+    } catch (err) {
+        fallback(err instanceof Error ? err.message : String(err));
+    }
+};