refactor: asynchronous blob backing store (#10969)

Co-authored-by: Luca Casonato <hello@lcas.dev>

5 files changed, 23 insertions, 2 deletions

diff --git a/cli/tests/blob_gc_finalization.js b/cli/tests/blob_gc_finalization.js
new file mode 100644
index 000000000..34c878513
--- /dev/null
+++ b/cli/tests/blob_gc_finalization.js
@@ -0,0 +1,11 @@
+// This test creates 1024 blobs of 128 MB each. This will only work if the blobs
+// and their backing data is GCed as expected.
+for (let i = 0; i < 1024; i++) {
+  // Create a 128MB byte array, and then a blob from it.
+  const buf = new Uint8Array(128 * 1024 * 1024);
+  new Blob([buf]);
+  // It is very important that there is a yield here, otherwise the finalizer
+  // for the blob is not called and the memory is not freed.
+  await new Promise((resolve) => setTimeout(resolve, 0));
+}
+console.log("GCed all blobs");
diff --git a/cli/tests/blob_gc_finalization.js.out b/cli/tests/blob_gc_finalization.js.out
new file mode 100644
index 000000000..dcc4500f8
--- /dev/null
+++ b/cli/tests/blob_gc_finalization.js.out
@@ -0,0 +1 @@
+GCed all blobs
diff --git a/cli/tests/integration/run_tests.rs b/cli/tests/integration/run_tests.rs
index 025ee07e1..374cd473b 100644
--- a/cli/tests/integration/run_tests.rs
+++ b/cli/tests/integration/run_tests.rs
@@ -366,6 +366,12 @@ itest!(js_import_detect {
   exit_code: 0,
 });
 
+itest!(blob_gc_finalization {
+  args: "run blob_gc_finalization.js",
+  output: "blob_gc_finalization.js.out",
+  exit_code: 0,
+});
+
 itest!(lock_write_requires_lock {
   args: "run --lock-write some_file.ts",
   output: "lock_write_requires_lock.out",
diff --git a/cli/tests/unit/fetch_test.ts b/cli/tests/unit/fetch_test.ts
index a84e18367..24a820dba 100644
--- a/cli/tests/unit/fetch_test.ts
+++ b/cli/tests/unit/fetch_test.ts
@@ -821,7 +821,9 @@ unitTest(function responseRedirect(): void {
 unitTest(async function responseWithoutBody(): Promise<void> {
   const response = new Response();
   assertEquals(await response.arrayBuffer(), new ArrayBuffer(0));
-  assertEquals(await response.blob(), new Blob([]));
+  const blob = await response.blob();
+  assertEquals(blob.size, 0);
+  assertEquals(await blob.arrayBuffer(), new ArrayBuffer(0));
   assertEquals(await response.text(), "");
   await assertThrowsAsync(async () => {
     await response.json();
diff --git a/cli/tests/unit/response_test.ts b/cli/tests/unit/response_test.ts
index 9993eb925..7e444fd83 100644
--- a/cli/tests/unit/response_test.ts
+++ b/cli/tests/unit/response_test.ts
@@ -34,7 +34,8 @@ unitTest(async function responseBlob() {
   assert(blobPromise instanceof Promise);
   const blob = await blobPromise;
   assert(blob instanceof Blob);
-  assertEquals(blob, new Blob([new Uint8Array([1, 2, 3])]));
+  assertEquals(blob.size, 3);
+  assertEquals(await blob.arrayBuffer(), new Uint8Array([1, 2, 3]).buffer);
 });
 
 // TODO(lucacasonato): re-enable test once #10002 is fixed.