Bug 1873866 - RawBuffer now forbids null/size-only. r=gfx-reviewers,ahale

Differential Revision: https://phabricator.services.mozilla.com/D199939

dom/canvas/ClientWebGLContext.cpp

@@ -3453,9 +3453,7 @@ void ClientWebGLContext::BufferData(GLenum target, WebGLsizeiptr rawSize,
     EnqueueError(LOCAL_GL_OUT_OF_MEMORY, "`size` too large for platform.");
     return;
   }
-
-  const auto data = RawBuffer<>{*size};
-  Run<RPROC(BufferData)>(target, data, usage);
+  Run<RPROC(BufferData_SizeOnly)>(target, *size, usage);
 }
 
 void ClientWebGLContext::BufferData(

dom/canvas/HostWebGLContext.h

@@ -482,9 +482,12 @@ class HostWebGLContext final : public SupportsWeakPtr {
     return GetWebGL2Context()->GetBufferSubData(target, srcByteOffset, dest);
   }
 
-  void BufferData(GLenum target, const RawBuffer<>& data, GLenum usage) const {
-    const auto& beginOrNull = data.begin();
-    mContext->BufferData(target, data.size(), beginOrNull, usage);
+  void BufferData(GLenum target, const RawBuffer<>& srcData, GLenum usage) const {
+    mContext->BufferData(target, srcData.size(), srcData.begin(), usage);
+  }
+
+  void BufferData_SizeOnly(GLenum target, size_t byteSize, GLenum usage) const {
+    mContext->BufferData(target, byteSize, nullptr, usage);
   }
 
   void BufferSubData(GLenum target, uint64_t dstByteOffset,

dom/canvas/WebGLMethodDispatcher.h

@@ -102,6 +102,7 @@ DEFINE_ASYNC(HostWebGLContext::BindBuffer)
 DEFINE_ASYNC(HostWebGLContext::BindBufferRange)
 DEFINE_ASYNC(HostWebGLContext::CopyBufferSubData)
 DEFINE_ASYNC(HostWebGLContext::BufferData)
+DEFINE_ASYNC(HostWebGLContext::BufferData_SizeOnly)
 DEFINE_ASYNC(HostWebGLContext::BufferSubData)
 DEFINE_ASYNC(HostWebGLContext::BlitFramebuffer)
 DEFINE_ASYNC(HostWebGLContext::InvalidateFramebuffer)

dom/canvas/WebGLQueueParamTraits.h

@@ -122,15 +122,10 @@ struct QueueParamTraits<RawBuffer<T>> {
     const auto& elemCount = in.size();
     auto status = view.WriteParam(elemCount);
     if (!status) return status;
+
     if (!elemCount) return status;
-
-    const auto& begin = in.begin();
-    const bool hasData = static_cast<bool>(begin);
-    status = view.WriteParam(hasData);
-    if (!status) return status;
-    if (!hasData) return status;
-
     status = view.WriteFromRange(in.Data());
+
     return status;
   }
 
@@ -139,20 +134,12 @@ struct QueueParamTraits<RawBuffer<T>> {
     size_t elemCount = 0;
     auto status = view.ReadParam(&elemCount);
     if (!status) return status;
+
     if (!elemCount) {
       *out = {};
       return true;
     }
 
-    uint8_t hasData = 0;
-    status = view.ReadParam(&hasData);
-    if (!status) return status;
-    if (!hasData) {
-      auto temp = RawBuffer<T>{elemCount};
-      *out = std::move(temp);
-      return true;
-    }
-
     auto data = view.template ReadRange<T>(elemCount);
     if (!data) return false;
     *out = std::move(RawBuffer<T>{*data});

dom/canvas/WebGLTypes.h

@@ -853,33 +853,31 @@ struct VertAttribPointerCalculated final {
 
 }  // namespace webgl
 
-/**
- * Represents a block of memory that it may or may not own.  The
- * inner data type must be trivially copyable by memcpy.
- */
+// TODO: s/RawBuffer/Span/
 template <typename T = uint8_t>
 class RawBuffer final {
   const T* mBegin = nullptr;
   size_t mLen = 0;
-  UniqueBuffer mOwned;
 
  public:
   using ElementType = T;
 
-  /**
-   * If aTakeData is true, RawBuffer will delete[] the memory when destroyed.
-   */
-  explicit RawBuffer(const Range<const T>& data, UniqueBuffer&& owned = {})
-      : mBegin(data.begin().get()),
-        mLen(data.length()),
-        mOwned(std::move(owned)) {}
-
-  explicit RawBuffer(const size_t len) : mLen(len) {}
+  explicit RawBuffer(const Range<const T>& data)
+      : mBegin(data.begin().get()), mLen(data.length()) {
+    if (mLen) {
+      MOZ_ASSERT(mBegin);
+    }
+  }
 
   ~RawBuffer() = default;
 
-  Range<const T> Data() const { return {mBegin, mLen}; }
-  const auto& begin() const { return mBegin; }
+  Range<const T> Data() const { return {begin(), mLen}; }
+  const auto& begin() const {
+    if (mLen) {
+      MOZ_RELEASE_ASSERT(mBegin);
+    }
+    return mBegin;
+  }
   const auto& size() const { return mLen; }
 
   void Shrink(const size_t newLen) {