1 files changed, 76 insertions, 0 deletions
diff --git a/js/xpconnect/loader/mozJSLoaderUtils.cpp b/js/xpconnect/loader/mozJSLoaderUtils.cpp
new file mode 100644
index 0000000000..b59da16702
--- /dev/null
+++ b/js/xpconnect/loader/mozJSLoaderUtils.cpp
@@ -0,0 +1,76 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/scache/StartupCache.h"
+
+#include "jsapi.h"
+#include "jsfriendapi.h"
+#include "js/CompileOptions.h"
+#include "js/Transcoding.h"
+#include "js/experimental/JSStencil.h"
+
+#include "mozilla/BasePrincipal.h"
+#include "mozilla/Span.h"
+
+using namespace JS;
+using namespace mozilla::scache;
+using mozilla::UniquePtr;
+
+static nsresult HandleTranscodeResult(JSContext* cx,
+                                      JS::TranscodeResult result) {
+  if (result == JS::TranscodeResult::Ok) {
+    return NS_OK;
+  }
+
+  if (result == JS::TranscodeResult::Throw) {
+    JS_ClearPendingException(cx);
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  MOZ_ASSERT(IsTranscodeFailureResult(result));
+  return NS_ERROR_FAILURE;
+}
+
+nsresult ReadCachedStencil(StartupCache* cache, nsACString& cachePath,
+                           JSContext* cx,
+                           const JS::ReadOnlyDecodeOptions& options,
+                           JS::Stencil** stencilOut) {
+  MOZ_ASSERT(options.borrowBuffer);
+  MOZ_ASSERT(!options.usePinnedBytecode);
+
+  const char* buf;
+  uint32_t len;
+  nsresult rv =
+      cache->GetBuffer(PromiseFlatCString(cachePath).get(), &buf, &len);
+  if (NS_FAILED(rv)) {
+    return rv;  // don't warn since NOT_AVAILABLE is an ok error
+  }
+
+  JS::TranscodeRange range(AsBytes(mozilla::Span(buf, len)));
+  JS::TranscodeResult code = JS::DecodeStencil(cx, options, range, stencilOut);
+  return HandleTranscodeResult(cx, code);
+}
+
+nsresult WriteCachedStencil(StartupCache* cache, nsACString& cachePath,
+                            JSContext* cx, JS::Stencil* stencil) {
+  JS::TranscodeBuffer buffer;
+  JS::TranscodeResult code = JS::EncodeStencil(cx, stencil, buffer);
+  if (code != JS::TranscodeResult::Ok) {
+    return HandleTranscodeResult(cx, code);
+  }
+
+  size_t size = buffer.length();
+  if (size > UINT32_MAX) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Move the vector buffer into a unique pointer buffer.
+  mozilla::UniqueFreePtr<char[]> buf(
+      reinterpret_cast<char*>(buffer.extractOrCopyRawBuffer()));
+  nsresult rv = cache->PutBuffer(PromiseFlatCString(cachePath).get(),
+                                 std::move(buf), size);
+  return rv;
+}