Vk: an ability to check if a particular extension revision is supported.

Qt's QVulkanWindow has that and it seems useful, especially for weird
extensions like VK_KHR_memory_model where their structure layout changes
over time.

src/Magnum/Vk/DeviceFeatures.h

@@ -1173,7 +1173,8 @@ enum class DeviceFeature: UnsignedShort {
      * chains with more than one element.
      * @see @ref DeviceFeature::VulkanMemoryModel,
      *      @ref DeviceFeature::VulkanMemoryModelDeviceScope
-     * @requires_vk12 Extension @vk_extension{KHR,vulkan_memory_model}
+     * @requires_vk12 Extension @vk_extension{KHR,vulkan_memory_model} since
+     *      revision 3
      */
     VulkanMemoryModelAvailabilityVisibilityChains,
 

src/Magnum/Vk/ExtensionProperties.cpp

@@ -113,12 +113,18 @@ Containers::ArrayView<const Containers::StringView> ExtensionProperties::names()
     return _names;
 }
 
-bool ExtensionProperties::isSupported(const Containers::StringView extension) const {
-    return std::binary_search(_names.begin(), _names.end(), extension);
+bool ExtensionProperties::isSupported(const Containers::StringView extension, const UnsignedInt revision) const {
+    /* Thanks, C++, for forcing me to have a larger bug surface instead of
+       providing a library helper to find the damn thing. */
+    auto found = std::lower_bound(_names.begin(), _names.end(), extension);
+
+    /* The view target is contents of the VkExtensionProperties structure,
+       the revision is stored nearby */
+    return found != _names.end() && *found == extension && reinterpret_cast<const VkExtensionProperties*>(found->data() - offsetof(VkExtensionProperties, extensionName))->specVersion >= revision;
 }
 
-bool ExtensionProperties::isSupported(const Extension& extension) const {
-    return isSupported(extension.string());
+bool ExtensionProperties::isSupported(const Extension& extension, const UnsignedInt revision) const {
+    return isSupported(extension.string(), revision);
 }
 
 Containers::StringView ExtensionProperties::name(const UnsignedInt id) const {
@@ -164,12 +170,12 @@ InstanceExtensionProperties::~InstanceExtensionProperties() = default;
 
 InstanceExtensionProperties& InstanceExtensionProperties::operator=(InstanceExtensionProperties&&) noexcept = default;
 
-bool InstanceExtensionProperties::isSupported(Containers::StringView extension) const {
-    return ExtensionProperties::isSupported(extension);
+bool InstanceExtensionProperties::isSupported(Containers::StringView extension, const UnsignedInt revision) const {
+    return ExtensionProperties::isSupported(extension, revision);
 }
 
-bool InstanceExtensionProperties::isSupported(const InstanceExtension& extension) const {
-    return isSupported(extension.string());
+bool InstanceExtensionProperties::isSupported(const InstanceExtension& extension, const UnsignedInt revision) const {
+    return isSupported(extension.string(), revision);
 }
 
 UnsignedInt InstanceExtensionProperties::revision(Containers::StringView extension) const {

src/Magnum/Vk/ExtensionProperties.h

@@ -99,10 +99,14 @@ class MAGNUM_VK_EXPORT ExtensionProperties {
 
         /**
          * @brief Whether given extension is supported
+         * @param extension     Extension string
+         * @param revision      Minimal required revision. If the extension is
+         *      present but in an older revision, the function returns
+         *      @cpp false @ce.
          *
-         * Accepts extensions from the @ref Extension namespace as a template
-         * parameter. Use the other overloads to query support of a runtime
-         * extension or a plain extension string.
+         * Since extension strings are easy to mistype, you're encouraged to
+         * use the other overloads such as @ref isSupported(UnsignedInt) const
+         * together with extensions from the @ref Extensions namespace.
          *
          * Search complexity is @f$ \mathcal{O}(\log n) @f$ in the total
          * extension count; in contrast extension queries on a created instance
@@ -110,15 +114,15 @@ class MAGNUM_VK_EXPORT ExtensionProperties {
          * @see @ref revision(), @ref Instance::isExtensionEnabled(),
          *      @ref Device::isExtensionEnabled()
          */
-        bool isSupported(Containers::StringView extension) const;
+        bool isSupported(Containers::StringView extension, UnsignedInt revision = 1) const;
 
         /** @overload */
-        bool isSupported(const Extension& extension) const;
+        bool isSupported(const Extension& extension, UnsignedInt revision = 1) const;
 
         /** @overload */
-        template<class E> bool isSupported() const {
-            static_assert(Implementation::IsExtension<E>::value, "expected a Vulkan deviceension");
-            return isSupported(E::string());
+        template<class E> bool isSupported(UnsignedInt revision = 1) const {
+            static_assert(Implementation::IsExtension<E>::value, "expected a Vulkan device extension");
+            return isSupported(E::string(), revision);
         }
 
         /**
@@ -219,16 +223,16 @@ class MAGNUM_VK_EXPORT InstanceExtensionProperties: public ExtensionProperties {
         /** @brief Move assignment */
         InstanceExtensionProperties& operator=(InstanceExtensionProperties&&) noexcept;
 
-        /** @copydoc ExtensionProperties::isSupported(Containers::StringView) const */
-        bool isSupported(Containers::StringView extension) const;
+        /** @copydoc ExtensionProperties::isSupported(Containers::StringView, UnsignedInt) const */
+        bool isSupported(Containers::StringView extension, UnsignedInt revision = 1) const;
 
         /** @overload */
-        bool isSupported(const InstanceExtension& extension) const;
+        bool isSupported(const InstanceExtension& extension, UnsignedInt revision = 1) const;
 
         /** @overload */
-        template<class E> bool isSupported() const {
+        template<class E> bool isSupported(UnsignedInt revision = 1) const {
             static_assert(Implementation::IsInstanceExtension<E>::value, "expected a Vulkan instance extension");
-            return isSupported(E::string());
+            return isSupported(E::string(), revision);
         }
 
         /** @copydoc ExtensionProperties::revision(UnsignedInt) const */

src/Magnum/Vk/Test/DevicePropertiesVkTest.cpp

@@ -64,6 +64,7 @@ struct DevicePropertiesVkTest: VulkanTester {
 
     void extensionConstructMove();
     void extensionIsSupported();
+    void extensionIsSupportedRevision();
     void extensionNamedRevision();
 
     void driverProperties();
@@ -118,6 +119,7 @@ DevicePropertiesVkTest::DevicePropertiesVkTest(): VulkanTester{NoCreate} {
 
               &DevicePropertiesVkTest::extensionConstructMove,
               &DevicePropertiesVkTest::extensionIsSupported,
+              &DevicePropertiesVkTest::extensionIsSupportedRevision,
               &DevicePropertiesVkTest::extensionNamedRevision,
 
               &DevicePropertiesVkTest::driverProperties,
@@ -398,6 +400,26 @@ void DevicePropertiesVkTest::extensionIsSupported() {
     CORRADE_VERIFY(properties.isSupported(Extensions::KHR::maintenance1{}));
 }
 
+void DevicePropertiesVkTest::extensionIsSupportedRevision() {
+    Containers::Array<DeviceProperties> devices = enumerateDevices(instance());
+    CORRADE_VERIFY(!devices.empty());
+
+    ExtensionProperties properties = devices[0].enumerateExtensionProperties();
+
+    /* This extension should be available almost always */
+    if(!properties.isSupported("VK_KHR_maintenance1"))
+        CORRADE_SKIP("VK_KHR_maintenance1 not supported, can't fully test");
+
+    UnsignedInt revision = properties.revision("VK_KHR_maintenance1");
+
+    CORRADE_VERIFY(properties.isSupported("VK_KHR_maintenance1", revision));
+    CORRADE_VERIFY(properties.isSupported<Extensions::KHR::maintenance1>(revision));
+    CORRADE_VERIFY(properties.isSupported(Extensions::KHR::maintenance1{}, revision));
+    CORRADE_VERIFY(!properties.isSupported("VK_KHR_maintenance1", revision + 1));
+    CORRADE_VERIFY(!properties.isSupported<Extensions::KHR::maintenance1>(revision + 1));
+    CORRADE_VERIFY(!properties.isSupported(Extensions::KHR::maintenance1{}, revision + 1));
+}
+
 void DevicePropertiesVkTest::extensionNamedRevision() {
     Containers::Array<DeviceProperties> devices = enumerateDevices(instance());
     CORRADE_VERIFY(!devices.empty());

src/Magnum/Vk/Test/ExtensionPropertiesVkTest.cpp

@@ -47,6 +47,7 @@ struct ExtensionPropertiesVkTest: TestSuite::Tester {
     void enumerateInstanceWithKhronosValidationLayer();
     void enumerateInstanceNonexistentLayer();
     void instanceExtensionIsSupported();
+    void instanceExtensionIsSupportedRevision();
 
     /* Device extensions tested in DevicePropertiesVkTest */
     void outOfRange();
@@ -60,6 +61,7 @@ ExtensionPropertiesVkTest::ExtensionPropertiesVkTest() {
               &ExtensionPropertiesVkTest::enumerateInstanceWithKhronosValidationLayer,
               &ExtensionPropertiesVkTest::enumerateInstanceNonexistentLayer,
               &ExtensionPropertiesVkTest::instanceExtensionIsSupported,
+              &ExtensionPropertiesVkTest::instanceExtensionIsSupportedRevision,
 
               &ExtensionPropertiesVkTest::outOfRange,
               &ExtensionPropertiesVkTest::namedRevision});
@@ -161,6 +163,9 @@ void ExtensionPropertiesVkTest::instanceExtensionIsSupported() {
     }
 
     CORRADE_VERIFY(!properties.isSupported("VK_this_doesnt_exist"));
+    /* Verify that we don't dereference garbage when std::lower_bound() returns
+       `last` */
+    CORRADE_VERIFY(!properties.isSupported("ZZZZZ"));
 
     /* Verify that we're not just comparing a prefix */
     const std::string extension = std::string(properties.name(0)) + "_hello";
@@ -175,6 +180,22 @@ void ExtensionPropertiesVkTest::instanceExtensionIsSupported() {
     CORRADE_VERIFY(properties.isSupported(Extensions::KHR::get_physical_device_properties2{}));
 }
 
+void ExtensionPropertiesVkTest::instanceExtensionIsSupportedRevision() {
+    InstanceExtensionProperties properties = enumerateInstanceExtensionProperties();
+    /** @todo use Extensions::KHR::surface once the extension is recognized */
+    if(!properties.isSupported("VK_KHR_get_physical_device_properties2"))
+        CORRADE_SKIP("VK_KHR_get_physical_device_properties2 not supported, can't test");
+
+    UnsignedInt revision = properties.revision("VK_KHR_get_physical_device_properties2");
+
+    CORRADE_VERIFY(properties.isSupported("VK_KHR_get_physical_device_properties2", revision));
+    CORRADE_VERIFY(properties.isSupported<Extensions::KHR::get_physical_device_properties2>(revision));
+    CORRADE_VERIFY(properties.isSupported(Extensions::KHR::get_physical_device_properties2{}, revision));
+    CORRADE_VERIFY(!properties.isSupported("VK_KHR_get_physical_device_properties2", revision + 1));
+    CORRADE_VERIFY(!properties.isSupported<Extensions::KHR::get_physical_device_properties2>(revision + 1));
+    CORRADE_VERIFY(!properties.isSupported(Extensions::KHR::get_physical_device_properties2{}, revision + 1));
+}
+
 void ExtensionPropertiesVkTest::outOfRange() {
     #ifdef CORRADE_NO_ASSERT
     CORRADE_SKIP("CORRADE_NO_ASSERT defined, can't test assertions");