1 files changed, 303 insertions, 0 deletions
diff --git a/thirdparty/openxr/src/loader/loader_instance.cpp b/thirdparty/openxr/src/loader/loader_instance.cpp
new file mode 100644
index 0000000000..b24c8de53b
--- /dev/null
+++ b/thirdparty/openxr/src/loader/loader_instance.cpp
@@ -0,0 +1,303 @@
+// Copyright (c) 2017-2022, The Khronos Group Inc.
+// Copyright (c) 2017-2019 Valve Corporation
+// Copyright (c) 2017-2019 LunarG, Inc.
+//
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+//
+// Initial Author: Mark Young <marky@lunarg.com>
+//
+
+#if defined(_MSC_VER) && !defined(_CRT_SECURE_NO_WARNINGS)
+#define _CRT_SECURE_NO_WARNINGS
+#endif  // defined(_MSC_VER) && !defined(_CRT_SECURE_NO_WARNINGS)
+
+#include "loader_instance.hpp"
+
+#include "api_layer_interface.hpp"
+#include "hex_and_handles.h"
+#include "loader_interfaces.h"
+#include "loader_logger.hpp"
+#include "runtime_interface.hpp"
+#include "xr_generated_dispatch_table.h"
+#include "xr_generated_loader.hpp"
+
+#include <openxr/openxr.h>
+
+#include <cstring>
+#include <memory>
+#include <sstream>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace {
+std::unique_ptr<LoaderInstance>& GetSetCurrentLoaderInstance() {
+    static std::unique_ptr<LoaderInstance> current_loader_instance;
+    return current_loader_instance;
+}
+}  // namespace
+
+namespace ActiveLoaderInstance {
+XrResult Set(std::unique_ptr<LoaderInstance> loader_instance, const char* log_function_name) {
+    if (GetSetCurrentLoaderInstance() != nullptr) {
+        LoaderLogger::LogErrorMessage(log_function_name, "Active XrInstance handle already exists");
+        return XR_ERROR_LIMIT_REACHED;
+    }
+
+    GetSetCurrentLoaderInstance() = std::move(loader_instance);
+    return XR_SUCCESS;
+}
+
+XrResult Get(LoaderInstance** loader_instance, const char* log_function_name) {
+    *loader_instance = GetSetCurrentLoaderInstance().get();
+    if (*loader_instance == nullptr) {
+        LoaderLogger::LogErrorMessage(log_function_name, "No active XrInstance handle.");
+        return XR_ERROR_HANDLE_INVALID;
+    }
+
+    return XR_SUCCESS;
+}
+
+bool IsAvailable() { return GetSetCurrentLoaderInstance() != nullptr; }
+
+void Remove() { GetSetCurrentLoaderInstance().release(); }
+}  // namespace ActiveLoaderInstance
+
+// Extensions that are supported by the loader, but may not be supported
+// the the runtime.
+const std::array<XrExtensionProperties, 1>& LoaderInstance::LoaderSpecificExtensions() {
+    static const std::array<XrExtensionProperties, 1> extensions = {XrExtensionProperties{
+        XR_TYPE_EXTENSION_PROPERTIES, nullptr, XR_EXT_DEBUG_UTILS_EXTENSION_NAME, XR_EXT_debug_utils_SPEC_VERSION}};
+    return extensions;
+}
+
+namespace {
+class InstanceCreateInfoManager {
+   public:
+    explicit InstanceCreateInfoManager(const XrInstanceCreateInfo* info) : original_create_info(info), modified_create_info(*info) {
+        Reset();
+    }
+
+    // Reset the "modified" state to match the original state.
+    void Reset() {
+        enabled_extensions_cstr.clear();
+        enabled_extensions_cstr.reserve(original_create_info->enabledExtensionCount);
+
+        for (uint32_t i = 0; i < original_create_info->enabledExtensionCount; ++i) {
+            enabled_extensions_cstr.push_back(original_create_info->enabledExtensionNames[i]);
+        }
+        Update();
+    }
+
+    // Remove extensions named in the parameter and return a pointer to the current state.
+    const XrInstanceCreateInfo* FilterOutExtensions(const std::vector<const char*>& extensions_to_skip) {
+        if (enabled_extensions_cstr.empty()) {
+            return Get();
+        }
+        if (extensions_to_skip.empty()) {
+            return Get();
+        }
+        for (auto& ext : extensions_to_skip) {
+            FilterOutExtension(ext);
+        }
+        return Update();
+    }
+    // Remove the extension named in the parameter and return a pointer to the current state.
+    const XrInstanceCreateInfo* FilterOutExtension(const char* extension_to_skip) {
+        if (enabled_extensions_cstr.empty()) {
+            return &modified_create_info;
+        }
+        auto b = enabled_extensions_cstr.begin();
+        auto e = enabled_extensions_cstr.end();
+        auto it = std::find_if(b, e, [&](const char* extension) { return strcmp(extension_to_skip, extension) == 0; });
+        if (it != e) {
+            // Just that one element goes away
+            enabled_extensions_cstr.erase(it);
+        }
+        return Update();
+    }
+
+    // Get the current modified XrInstanceCreateInfo
+    const XrInstanceCreateInfo* Get() const { return &modified_create_info; }
+
+   private:
+    const XrInstanceCreateInfo* Update() {
+        modified_create_info.enabledExtensionCount = static_cast<uint32_t>(enabled_extensions_cstr.size());
+        modified_create_info.enabledExtensionNames = enabled_extensions_cstr.empty() ? nullptr : enabled_extensions_cstr.data();
+        return &modified_create_info;
+    }
+    const XrInstanceCreateInfo* original_create_info;
+
+    XrInstanceCreateInfo modified_create_info;
+    std::vector<const char*> enabled_extensions_cstr;
+};
+}  // namespace
+
+// Factory method
+XrResult LoaderInstance::CreateInstance(PFN_xrGetInstanceProcAddr get_instance_proc_addr_term,
+                                        PFN_xrCreateInstance create_instance_term,
+                                        PFN_xrCreateApiLayerInstance create_api_layer_instance_term,
+                                        std::vector<std::unique_ptr<ApiLayerInterface>> api_layer_interfaces,
+                                        const XrInstanceCreateInfo* info, std::unique_ptr<LoaderInstance>* loader_instance) {
+    LoaderLogger::LogVerboseMessage("xrCreateInstance", "Entering LoaderInstance::CreateInstance");
+
+    // Check the list of enabled extensions to make sure something supports them, and, if we do,
+    // add it to the list of enabled extensions
+    XrResult last_error = XR_SUCCESS;
+    for (uint32_t ext = 0; ext < info->enabledExtensionCount; ++ext) {
+        bool found = false;
+        // First check the runtime
+        if (RuntimeInterface::GetRuntime().SupportsExtension(info->enabledExtensionNames[ext])) {
+            found = true;
+        }
+        // Next check the loader
+        if (!found) {
+            for (auto& loader_extension : LoaderInstance::LoaderSpecificExtensions()) {
+                if (strcmp(loader_extension.extensionName, info->enabledExtensionNames[ext]) == 0) {
+                    found = true;
+                    break;
+                }
+            }
+        }
+        // Finally, check the enabled layers
+        if (!found) {
+            for (auto& layer_interface : api_layer_interfaces) {
+                if (layer_interface->SupportsExtension(info->enabledExtensionNames[ext])) {
+                    found = true;
+                    break;
+                }
+            }
+        }
+        if (!found) {
+            std::string msg = "LoaderInstance::CreateInstance, no support found for requested extension: ";
+            msg += info->enabledExtensionNames[ext];
+            LoaderLogger::LogErrorMessage("xrCreateInstance", msg);
+            last_error = XR_ERROR_EXTENSION_NOT_PRESENT;
+            break;
+        }
+    }
+
+    // Topmost means "closest to the application"
+    PFN_xrGetInstanceProcAddr topmost_gipa = get_instance_proc_addr_term;
+    XrInstance instance{XR_NULL_HANDLE};
+
+    if (XR_SUCCEEDED(last_error)) {
+        // Remove the loader-supported-extensions (debug utils), if it's in the list of enabled extensions but not supported by
+        // the runtime.
+        InstanceCreateInfoManager create_info_manager{info};
+        const XrInstanceCreateInfo* modified_create_info = info;
+        if (info->enabledExtensionCount > 0) {
+            std::vector<const char*> extensions_to_skip;
+            for (const auto& ext : LoaderInstance::LoaderSpecificExtensions()) {
+                if (!RuntimeInterface::GetRuntime().SupportsExtension(ext.extensionName)) {
+                    extensions_to_skip.emplace_back(ext.extensionName);
+                }
+            }
+            modified_create_info = create_info_manager.FilterOutExtensions(extensions_to_skip);
+        }
+
+        // Only start the xrCreateApiLayerInstance stack if we have layers.
+        if (!api_layer_interfaces.empty()) {
+            // Initialize an array of ApiLayerNextInfo structs
+            std::unique_ptr<XrApiLayerNextInfo[]> next_info_list(new XrApiLayerNextInfo[api_layer_interfaces.size()]);
+            auto ni_index = static_cast<uint32_t>(api_layer_interfaces.size() - 1);
+            for (uint32_t i = 0; i <= ni_index; i++) {
+                next_info_list[i].structType = XR_LOADER_INTERFACE_STRUCT_API_LAYER_NEXT_INFO;
+                next_info_list[i].structVersion = XR_API_LAYER_NEXT_INFO_STRUCT_VERSION;
+                next_info_list[i].structSize = sizeof(XrApiLayerNextInfo);
+            }
+
+            // Go through all layers, and override the instance pointers with the layer version.  However,
+            // go backwards through the layer list so we replace in reverse order so the layers can call their next function
+            // appropriately.
+            PFN_xrCreateApiLayerInstance topmost_cali_fp = create_api_layer_instance_term;
+            XrApiLayerNextInfo* topmost_nextinfo = nullptr;
+            for (auto layer_interface = api_layer_interfaces.rbegin(); layer_interface != api_layer_interfaces.rend();
+                 ++layer_interface) {
+                // Collect current layer's function pointers
+                PFN_xrGetInstanceProcAddr cur_gipa_fp = (*layer_interface)->GetInstanceProcAddrFuncPointer();
+                PFN_xrCreateApiLayerInstance cur_cali_fp = (*layer_interface)->GetCreateApiLayerInstanceFuncPointer();
+
+                // Fill in layer info and link previous (lower) layer fxn pointers
+                strncpy(next_info_list[ni_index].layerName, (*layer_interface)->LayerName().c_str(),
+                        XR_MAX_API_LAYER_NAME_SIZE - 1);
+                next_info_list[ni_index].layerName[XR_MAX_API_LAYER_NAME_SIZE - 1] = '\0';
+                next_info_list[ni_index].next = topmost_nextinfo;
+                next_info_list[ni_index].nextGetInstanceProcAddr = topmost_gipa;
+                next_info_list[ni_index].nextCreateApiLayerInstance = topmost_cali_fp;
+
+                // Update saved pointers for next iteration
+                topmost_nextinfo = &next_info_list[ni_index];
+                topmost_gipa = cur_gipa_fp;
+                topmost_cali_fp = cur_cali_fp;
+                ni_index--;
+            }
+
+            // Populate the ApiLayerCreateInfo struct and pass to topmost CreateApiLayerInstance()
+            XrApiLayerCreateInfo api_layer_ci = {};
+            api_layer_ci.structType = XR_LOADER_INTERFACE_STRUCT_API_LAYER_CREATE_INFO;
+            api_layer_ci.structVersion = XR_API_LAYER_CREATE_INFO_STRUCT_VERSION;
+            api_layer_ci.structSize = sizeof(XrApiLayerCreateInfo);
+            api_layer_ci.loaderInstance = nullptr;  // Not used.
+            api_layer_ci.settings_file_location[0] = '\0';
+            api_layer_ci.nextInfo = next_info_list.get();
+            //! @todo do we filter our create info extension list here?
+            //! Think that actually each layer might need to filter...
+            last_error = topmost_cali_fp(modified_create_info, &api_layer_ci, &instance);
+
+        } else {
+            // The loader's terminator is the topmost CreateInstance if there are no layers.
+            last_error = create_instance_term(modified_create_info, &instance);
+        }
+
+        if (XR_FAILED(last_error)) {
+            LoaderLogger::LogErrorMessage("xrCreateInstance", "LoaderInstance::CreateInstance chained CreateInstance call failed");
+        }
+    }
+
+    if (XR_SUCCEEDED(last_error)) {
+        loader_instance->reset(new LoaderInstance(instance, info, topmost_gipa, std::move(api_layer_interfaces)));
+
+        std::ostringstream oss;
+        oss << "LoaderInstance::CreateInstance succeeded with ";
+        oss << (*loader_instance)->LayerInterfaces().size();
+        oss << " layers enabled and runtime interface - created instance = ";
+        oss << HandleToHexString((*loader_instance)->GetInstanceHandle());
+        LoaderLogger::LogInfoMessage("xrCreateInstance", oss.str());
+    }
+
+    return last_error;
+}
+
+XrResult LoaderInstance::GetInstanceProcAddr(const char* name, PFN_xrVoidFunction* function) {
+    return _topmost_gipa(_runtime_instance, name, function);
+}
+
+LoaderInstance::LoaderInstance(XrInstance instance, const XrInstanceCreateInfo* create_info, PFN_xrGetInstanceProcAddr topmost_gipa,
+                               std::vector<std::unique_ptr<ApiLayerInterface>> api_layer_interfaces)
+    : _runtime_instance(instance),
+      _topmost_gipa(topmost_gipa),
+      _api_layer_interfaces(std::move(api_layer_interfaces)),
+      _dispatch_table(new XrGeneratedDispatchTable{}) {
+    for (uint32_t ext = 0; ext < create_info->enabledExtensionCount; ++ext) {
+        _enabled_extensions.push_back(create_info->enabledExtensionNames[ext]);
+    }
+
+    GeneratedXrPopulateDispatchTable(_dispatch_table.get(), instance, topmost_gipa);
+}
+
+LoaderInstance::~LoaderInstance() {
+    std::ostringstream oss;
+    oss << "Destroying LoaderInstance = ";
+    oss << PointerToHexString(this);
+    LoaderLogger::LogInfoMessage("xrDestroyInstance", oss.str());
+}
+
+bool LoaderInstance::ExtensionIsEnabled(const std::string& extension) {
+    for (std::string& cur_enabled : _enabled_extensions) {
+        if (cur_enabled == extension) {
+            return true;
+        }
+    }
+    return false;
+}