Bug 1781129 - Part 2: Use BigBuffer for ShmemImage, r=edgar

The ShmemImage type was previously implemented using a Shmem, however due to
the usage patterns, `BigBuffer` is probably a better fit, and allows unifying
more code in nsContentUtils.

Differential Revision: https://phabricator.services.mozilla.com/D151853

dom/base/nsContentUtils.cpp

@@ -7942,10 +7942,10 @@ nsresult nsContentUtils::CalculateBufferSizeForImage(
   return NS_OK;
 }
 
-static already_AddRefed<DataSourceSurface> ShmemToDataSurface(
-    Shmem& aData, uint32_t aStride, const IntSize& aImageSize,
+static already_AddRefed<DataSourceSurface> BigBufferToDataSurface(
+    BigBuffer& aData, uint32_t aStride, const IntSize& aImageSize,
     SurfaceFormat aFormat) {
-  if (!aData.IsReadable() || !aImageSize.width || !aImageSize.height) {
+  if (!aData.Size() || !aImageSize.width || !aImageSize.height) {
     return nullptr;
   }
 
@@ -7956,11 +7956,11 @@ static already_AddRefed<DataSourceSurface> ShmemToDataSurface(
           aStride, aImageSize, aFormat, &maxBufLen, &imageBufLen))) {
     return nullptr;
   }
-  if (imageBufLen > aData.Size<uint8_t>()) {
+  if (imageBufLen > aData.Size()) {
     return nullptr;
   }
-  return CreateDataSourceSurfaceFromData(aImageSize, aFormat,
-                                         aData.get<uint8_t>(), aStride);
+  return CreateDataSourceSurfaceFromData(aImageSize, aFormat, aData.Data(),
+                                         aStride);
 }
 
 nsresult nsContentUtils::DeserializeDataTransferImageContainer(
@@ -8307,24 +8307,21 @@ Maybe<Shmem> nsContentUtils::GetSurfaceData(DataSourceSurface& aSurface,
                             GetSurfaceDataShmem(aAllocator));
 }
 
-Maybe<ShmemImage> nsContentUtils::SurfaceToIPCImage(
-    DataSourceSurface& aSurface, IShmemAllocator* aAllocator) {
+Maybe<IPCImage> nsContentUtils::SurfaceToIPCImage(DataSourceSurface& aSurface) {
   size_t len = 0;
   int32_t stride = 0;
-  auto mem = GetSurfaceData(aSurface, &len, &stride, aAllocator);
+  auto mem = GetSurfaceData(aSurface, &len, &stride);
   if (!mem) {
     return Nothing();
   }
-  return Some(ShmemImage{*mem, uint32_t(stride), aSurface.GetFormat(),
-                         ImageIntSize::FromUnknownSize(aSurface.GetSize())});
+  return Some(IPCImage{std::move(*mem), uint32_t(stride), aSurface.GetFormat(),
+                       ImageIntSize::FromUnknownSize(aSurface.GetSize())});
 }
 
 already_AddRefed<DataSourceSurface> nsContentUtils::IPCImageToSurface(
-    ShmemImage&& aImage, IShmemAllocator* aAllocator) {
-  auto release =
-      MakeScopeExit([&] { aAllocator->DeallocShmem(aImage.data()); });
-  return ShmemToDataSurface(aImage.data(), aImage.stride(),
-                            aImage.size().ToUnknownSize(), aImage.format());
+    IPCImage&& aImage) {
+  return BigBufferToDataSurface(aImage.data(), aImage.stride(),
+                                aImage.size().ToUnknownSize(), aImage.format());
 }
 
 Modifiers nsContentUtils::GetWidgetModifiers(int32_t aModifiers) {

dom/base/nsContentUtils.h

@@ -162,7 +162,7 @@ template <class T>
 class StaticRefPtr;
 
 namespace dom {
-class ShmemImage;
+class IPCImage;
 struct AutocompleteInfo;
 class BrowserChild;
 class BrowserParent;
@@ -2928,10 +2928,10 @@ class nsContentUtils {
       mozilla::gfx::DataSourceSurface& aSurface, size_t* aLength,
       int32_t* aStride, mozilla::ipc::IShmemAllocator* aAlloc);
 
-  static mozilla::Maybe<mozilla::dom::ShmemImage> SurfaceToIPCImage(
-      mozilla::gfx::DataSourceSurface&, mozilla::ipc::IShmemAllocator*);
+  static mozilla::Maybe<mozilla::dom::IPCImage> SurfaceToIPCImage(
+      mozilla::gfx::DataSourceSurface&);
   static already_AddRefed<mozilla::gfx::DataSourceSurface> IPCImageToSurface(
-      mozilla::dom::ShmemImage&&, mozilla::ipc::IShmemAllocator*);
+      mozilla::dom::IPCImage&&);
 
   // Helpers shared by the implementations of nsContentUtils methods and
   // nsIDOMWindowUtils methods.

dom/ipc/ContentParent.cpp

@@ -4993,10 +4993,10 @@ mozilla::ipc::IPCResult ContentParent::RecvCopyFavicon(
 }
 
 mozilla::ipc::IPCResult ContentParent::RecvFindImageText(
-    ShmemImage&& aImage, nsTArray<nsCString>&& aLanguages,
+    IPCImage&& aImage, nsTArray<nsCString>&& aLanguages,
     FindImageTextResolver&& aResolver) {
   RefPtr<DataSourceSurface> surf =
-      nsContentUtils::IPCImageToSurface(std::move(aImage), this);
+      nsContentUtils::IPCImageToSurface(std::move(aImage));
   if (!surf) {
     aResolver(TextRecognitionResultOrError("Failed to read image"_ns));
     return IPC_OK();

dom/ipc/ContentParent.h

@@ -1114,7 +1114,7 @@ class ContentParent final : public PContentParent,
   mozilla::ipc::IPCResult RecvCopyFavicon(nsIURI* aOldURI, nsIURI* aNewURI,
                                           const bool& aInPrivateBrowsing);
 
-  mozilla::ipc::IPCResult RecvFindImageText(ShmemImage&&, nsTArray<nsCString>&&,
+  mozilla::ipc::IPCResult RecvFindImageText(IPCImage&&, nsTArray<nsCString>&&,
                                             FindImageTextResolver&&);
 
   virtual void ProcessingError(Result aCode, const char* aMsgName) override;

dom/ipc/PContent.ipdl

@@ -443,8 +443,8 @@ union TextRecognitionResultOrError {
     nsCString;
 };
 
-struct ShmemImage {
-    Shmem data;
+struct IPCImage {
+    BigBuffer data;
     uint32_t stride;
     SurfaceFormat format;
     ImageIntSize size;
@@ -1243,7 +1243,7 @@ parent:
 
     async CopyFavicon(nsIURI oldURI, nsIURI newURI, bool isPrivate);
 
-    async FindImageText(ShmemImage image, nsCString[] languages)
+    async FindImageText(IPCImage image, nsCString[] languages)
         returns (TextRecognitionResultOrError result);
 
     /**

widget/TextRecognition.cpp

@@ -41,13 +41,13 @@ auto TextRecognition::FindText(gfx::DataSourceSurface& aSurface,
     -> RefPtr<NativePromise> {
   if (XRE_IsContentProcess()) {
     auto* contentChild = ContentChild::GetSingleton();
-    auto image = nsContentUtils::SurfaceToIPCImage(aSurface, contentChild);
+    auto image = nsContentUtils::SurfaceToIPCImage(aSurface);
     if (!image) {
       return NativePromise::CreateAndReject("Failed to share data surface"_ns,
                                             __func__);
     }
     auto promise = MakeRefPtr<NativePromise::Private>(__func__);
-    contentChild->SendFindImageText(*image, aLanguages)
+    contentChild->SendFindImageText(std::move(*image), aLanguages)
         ->Then(
             GetCurrentSerialEventTarget(), __func__,
             [promise](TextRecognitionResultOrError&& aResultOrError) {