fix browser opfs partial writes in ci

Storages/ManagedCode.Storage.Browser/wwwroot/browserStorage.worker.js

@@ -1,4 +1,5 @@
 const sessions = new Map();
+const maxWriteBlockBytes = 1024 * 1024;
 
 self.onmessage = async (event) => {
   const { id, command, payload } = event.data ?? {};
@@ -59,12 +60,7 @@ async function appendChunksAsync(databaseName, blobKey, chunks) {
 
   for (const chunk of Array.isArray(chunks) ? chunks : []) {
     const data = chunk.data instanceof Uint8Array ? chunk.data : new Uint8Array(chunk.data ?? []);
-    const written = session.accessHandle.write(data, { at: session.position });
-    if (written !== data.byteLength) {
-      throw new Error(`Short OPFS write for ${blobKey}: wrote ${written} of ${data.byteLength} bytes.`);
-    }
-
-    session.position += written;
+    writeAllBytes(session, blobKey, data);
   }
 }
 
@@ -156,6 +152,37 @@ function getSessionKey(databaseName, blobKey) {
   return `${databaseName}::${blobKey}`;
 }
 
+function writeAllBytes(session, blobKey, data) {
+  let offset = 0;
+
+  while (offset < data.byteLength) {
+    const bytesRemaining = data.byteLength - offset;
+    const bytesToWrite = Math.min(bytesRemaining, maxWriteBlockBytes);
+    const slice = data.subarray(offset, offset + bytesToWrite);
+    const written = normalizeBytesWritten(
+      session.accessHandle.write(slice, { at: session.position }),
+      bytesToWrite,
+      blobKey,
+      session.position);
+
+    offset += written;
+    session.position += written;
+  }
+}
+
+function normalizeBytesWritten(value, expectedBytes, blobKey, position) {
+  if (!Number.isFinite(value)) {
+    throw new Error(`Invalid OPFS write result for ${blobKey} at ${position}: ${String(value)}.`);
+  }
+
+  const written = Math.trunc(value);
+  if (written <= 0 || written > expectedBytes) {
+    throw new Error(`Invalid OPFS write result for ${blobKey} at ${position}: wrote ${written} of ${expectedBytes} bytes.`);
+  }
+
+  return written;
+}
+
 async function getDatabaseDirectoryAsync(databaseName, create) {
   const root = await navigator.storage.getDirectory();
   return await root.getDirectoryHandle(getDatabaseDirectoryName(databaseName), { create });

Tests/ManagedCode.Storage.BrowserServerHost/Components/Pages/StoragePlayground.razor

@@ -134,6 +134,13 @@
                 MimeType = "application/octet-stream"
             });
 
+            if (result.IsFailed)
+            {
+                largeOutput = $"generated:{stream.Position}";
+                status = $"large-save-failed:{result.Problem?.Detail}";
+                return;
+            }
+
             if (!stream.IsCompleted)
             {
                 largeOutput = $"generated:{stream.Position}";
@@ -145,7 +152,7 @@
             var crc = stream.CompletedCrc;
 
             largeOutput = $"expected:{length}:{crc}";
-            status = result.IsSuccess ? $"large-saved:{length}:{crc}" : $"large-save-failed:{result.Problem?.Detail}";
+            status = $"large-saved:{length}:{crc}";
             Logger.LogInformation("Completed browser storage save for {FileName} ({Bytes} bytes, crc {Crc}) in {ElapsedMilliseconds} ms.",
                 resolvedFileName,
                 length,

Tests/ManagedCode.Storage.BrowserWasmHost/Pages/StoragePlayground.razor

@@ -133,6 +133,13 @@
                 MimeType = "application/octet-stream"
             });
 
+            if (result.IsFailed)
+            {
+                largeOutput = $"generated:{stream.Position}";
+                status = $"large-save-failed:{result.Problem?.Detail}";
+                return;
+            }
+
             if (!stream.IsCompleted)
             {
                 largeOutput = $"generated:{stream.Position}";
@@ -144,7 +151,7 @@
             var crc = stream.CompletedCrc;
 
             largeOutput = $"expected:{length}:{crc}";
-            status = result.IsSuccess ? $"large-saved:{length}:{crc}" : $"large-save-failed:{result.Problem?.Detail}";
+            status = $"large-saved:{length}:{crc}";
             Logger.LogInformation("Completed browser storage save for {FileName} ({Bytes} bytes, crc {Crc}) in {ElapsedMilliseconds} ms.",
                 resolvedFileName,
                 length,