Add code I forgot to push to #4422 (#4426)

src/clusterfuzz/_internal/fuzzing/corpus_manager.py

@@ -659,12 +659,11 @@ def get_proto_corpus(bucket_name,
   urls = (f'{storage.GS_PREFIX}/{bucket_name}/{url}'
           for url in storage.list_blobs(gcs_url))
 
-  if max_download_urls is not None:
-    urls = itertools.islice(urls, max_download_urls)
   # TODO(metzman): Stop limiting URLs when pruning works on oss-fuzz
   # again.
-  corpus_urls = dict(
-      storage.sign_urls_for_existing_files(urls, include_delete_urls))
+  if max_download_urls is not None:
+    urls = itertools.islice(urls, max_download_urls)
+  corpus_urls = dict(storage.sign_urls_for_existing_files(urls, include_delete_urls))
 
   upload_urls = storage.get_arbitrary_signed_upload_urls(
       gcs_url, num_uploads=max_upload_urls)

src/clusterfuzz/_internal/google_cloud_utils/storage.py

@@ -1341,9 +1341,9 @@ def delete_signed_urls(urls):
 
 
 def _sign_urls_for_existing_file(
-    corpus_element_url: str,
-    include_delete_urls: bool,
+    url_and_include_delete_urls: Tuple[str, bool],
     minutes: int = SIGNED_URL_EXPIRATION_MINUTES) -> Tuple[str, str]:
+  corpus_element_url, include_delete_urls = url_and_include_delete_urls
   download_url = get_signed_download_url(corpus_element_url, minutes)
   if include_delete_urls:
     delete_url = sign_delete_url(corpus_element_url, minutes)
@@ -1362,7 +1362,7 @@ def sign_urls_for_existing_files(urls,
   logs.info('Signing URLs for existing files.')
   args = ((url, include_delete_urls) for url in urls)
   with concurrency.make_pool(cpu_bound=True, max_pool_size=2) as pool:
-    result = pool.map(_mappable_sign_urls_for_existing_file, args)
+    result = pool.map(_sign_urls_for_existing_file, args)
   logs.info('Done signing URLs for existing files.')
   return result