dawn_wire: Implement requestAdapter and requestDevice

This implements requestAdapter and requestDevice by
forwarding commands the the server and relaying back
replies. After an adapter or device is created,
limits/properties/features are queried and also sent
back to the client.

Bug: dawn:689
Change-Id: Ie0c2984b8ebb661efb0c284a14ae8b74ae4af2ea
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/71522
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Loko Kung <lokokung@google.com>
Commit-Queue: Austin Eng <enga@chromium.org>

src/dawn_wire/server/ServerAdapter.cpp

@@ -0,0 +1,112 @@
+// Copyright 2021 The Dawn Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "dawn_wire/server/Server.h"
+
+#include "dawn_wire/SupportedFeatures.h"
+
+namespace dawn_wire { namespace server {
+
+    bool Server::DoAdapterRequestDevice(ObjectId adapterId,
+                                        uint64_t requestSerial,
+                                        ObjectHandle deviceHandle,
+                                        const WGPUDeviceDescriptor* descriptor) {
+        auto* adapter = AdapterObjects().Get(adapterId);
+        if (adapter == nullptr) {
+            return false;
+        }
+
+        auto* resultData = DeviceObjects().Allocate(deviceHandle.id, AllocationState::Reserved);
+        if (resultData == nullptr) {
+            return false;
+        }
+
+        resultData->generation = deviceHandle.generation;
+
+        auto userdata = MakeUserdata<RequestDeviceUserdata>();
+        userdata->adapter = ObjectHandle{adapterId, adapter->generation};
+        userdata->requestSerial = requestSerial;
+        userdata->deviceObjectId = deviceHandle.id;
+
+        mProcs.adapterRequestDevice(
+            adapter->handle, descriptor,
+            ForwardToServer<decltype(
+                &Server::OnRequestDeviceCallback)>::Func<&Server::OnRequestDeviceCallback>(),
+            userdata.release());
+        return true;
+    }
+
+    void Server::OnRequestDeviceCallback(WGPURequestDeviceStatus status,
+                                         WGPUDevice device,
+                                         const char* message,
+                                         RequestDeviceUserdata* data) {
+        auto* deviceObject = DeviceObjects().Get(data->deviceObjectId, AllocationState::Reserved);
+        // Should be impossible to fail. ObjectIds can't be freed by a destroy command until
+        // they move from Reserved to Allocated, or if they are destroyed here.
+        ASSERT(deviceObject != nullptr);
+
+        ReturnAdapterRequestDeviceCallbackCmd cmd = {};
+        cmd.adapter = data->adapter;
+        cmd.requestSerial = data->requestSerial;
+        cmd.status = status;
+        cmd.message = message;
+
+        if (status != WGPURequestDeviceStatus_Success) {
+            // Free the ObjectId which will make it unusable.
+            DeviceObjects().Free(data->deviceObjectId);
+            ASSERT(device == nullptr);
+            SerializeCommand(cmd);
+            return;
+        }
+
+        std::vector<WGPUFeatureName> features;
+
+        uint32_t featuresCount = mProcs.deviceEnumerateFeatures(device, nullptr);
+        features.resize(featuresCount);
+        mProcs.deviceEnumerateFeatures(device, features.data());
+
+        // The client should only be able to request supported features, so all enumerated
+        // features that were enabled must also be supported by the wire.
+        // Note: We fail the callback here, instead of immediately upon receiving
+        // the request to preserve callback ordering.
+        for (WGPUFeatureName f : features) {
+            if (!IsFeatureSupported(f)) {
+                // Release the device.
+                mProcs.deviceRelease(device);
+                // Free the ObjectId which will make it unusable.
+                DeviceObjects().Free(data->deviceObjectId);
+
+                cmd.status = WGPURequestDeviceStatus_Error;
+                cmd.message = "Requested feature not supported.";
+                SerializeCommand(cmd);
+                return;
+            }
+        }
+
+        cmd.featuresCount = features.size();
+        cmd.features = features.data();
+
+        WGPUSupportedLimits limits = {};
+        mProcs.deviceGetLimits(device, &limits);
+        cmd.limits = &limits;
+
+        // Assign the handle and allocated status if the device is created successfully.
+        deviceObject->state = AllocationState::Allocated;
+        deviceObject->handle = device;
+        SetForwardingDeviceCallbacks(deviceObject);
+
+        SerializeCommand(cmd);
+    }
+
+}}  // namespace dawn_wire::server