kapi: introduce device interfaces

1 files changed, 199 insertions, 0 deletions

diff --git a/kernel/kapi/devices/interface_registry.tests.cpp b/kernel/kapi/devices/interface_registry.tests.cpp
new file mode 100644
index 00000000..ffd9f0d6
--- /dev/null
+++ b/kernel/kapi/devices/interface_registry.tests.cpp
@@ -0,0 +1,199 @@
+#include <kapi/devices.hpp>
+
+#include <kstd/memory.hpp>
+
+#include <catch2/catch_test_macros.hpp>
+
+namespace
+{
+  struct probe_device
+  {
+    constexpr auto static id = kapi::devices::interface{"probe"};
+
+    virtual ~probe_device() = default;
+
+    [[nodiscard]] auto virtual get_value() const noexcept -> int = 0;
+  };
+
+  struct const_device
+  {
+    constexpr auto static id = kapi::devices::interface{"flip"};
+
+    virtual ~const_device() = default;
+
+    [[nodiscard]] auto get_constant() const noexcept -> int
+    {
+      return 0;
+    }
+  };
+
+  struct test_device final : kapi::devices::device, probe_device
+  {
+    explicit test_device(int value, const_device & const_device)
+        : device{0, 0, "probeable"}
+        , m_value{value}
+        , m_const_device{&const_device}
+    {}
+
+    auto init() -> bool override
+    {
+      return true;
+    }
+
+    [[nodiscard]] constexpr auto get_value() const noexcept -> int override
+    {
+      return m_value;
+    }
+
+    auto query_interface(kapi::devices::interface interface) -> void * override
+    {
+      if (interface == probe_device::id)
+      {
+        return static_cast<probe_device *>(this);
+      }
+      if (interface == const_device::id)
+      {
+        return m_const_device;
+      }
+
+      return kapi::devices::device::query_interface(interface);
+    }
+
+  private:
+    int m_value;
+    const_device * m_const_device;
+  };
+
+}  // namespace
+
+SCENARIO("Publishing and finding a device", "[kapi][devices][interface_registry]")
+{
+  GIVEN("An empty registry, a device, and an interface the device implements by inheritance")
+  {
+    auto registry = kapi::devices::interface_registry{};
+    auto free_standing_interface = const_device{};
+    auto device = kstd::make_shared<test_device>(128, free_standing_interface);
+
+    THEN("Publishing an interface without a name fails")
+    {
+      REQUIRE_FALSE(registry.publish<probe_device>(device, ""));
+    }
+
+    WHEN("publishing the interface for the device")
+    {
+      CHECK(device->is_a<probe_device>());
+      CHECK(device->is_a<const_device>());
+      auto published = registry.publish(device, "probe0", device->as<probe_device>());
+
+      THEN("publishing is successful")
+      {
+        REQUIRE(published);
+      }
+
+      THEN("publishing the same device and interface with a different name fails")
+      {
+        REQUIRE_FALSE(registry.publish(device, "probe1", device->as<probe_device>()));
+      }
+
+      THEN("publishing a second interface for the same device succeeds")
+      {
+        REQUIRE(registry.publish<const_device>(device, "probe0"));
+      }
+
+      THEN("publishing a free standing second interface for the same device succeeds")
+      {
+        REQUIRE(registry.publish(device, "probe0", &free_standing_interface));
+      }
+
+      AND_WHEN("getting all devices implementing that interface")
+      {
+        auto probeable_devices = registry.all(probe_device::id);
+
+        THEN("there is exactly one such device")
+        {
+          REQUIRE(probeable_devices.size() == 1);
+        }
+
+        THEN("the name of the device is 'probe0'")
+        {
+          REQUIRE(probeable_devices[0].name() == "probe0");
+        }
+
+        THEN("the returned device pointer is lockable")
+        {
+          REQUIRE(probeable_devices[0].device().lock());
+        }
+
+        THEN("the returned implementation equals the result of device::as")
+        {
+          REQUIRE(probeable_devices[0].implementation() == device->as<probe_device>());
+        }
+
+        THEN("the interface provided function can be invoked")
+        {
+          auto implementation = probeable_devices[0].as<probe_device>();
+          REQUIRE(implementation->get_value() == device->get_value());
+        }
+      }
+
+      THEN("find finds the published capability by name")
+      {
+        REQUIRE(registry.find<probe_device>("probe0"));
+      }
+
+      THEN("find for an unpublished capability does not find a device")
+      {
+        REQUIRE_FALSE(registry.find<const_device>("probe0"));
+      }
+
+      THEN("find for an unpublished device does not find a device")
+      {
+        REQUIRE_FALSE(registry.find<probe_device>("probe1"));
+      }
+
+      THEN("withdrawing an interface for a device removes it from the registry")
+      {
+        registry.unpublish(*device, probe_device::id);
+        REQUIRE_FALSE(registry.find<probe_device>("probe0"));
+      }
+    }
+
+    WHEN("the device is destroyed without withdrawing it")
+    {
+      CHECK(registry.publish(device, "probe0", device->as<probe_device>()));
+      device.reset();
+
+      THEN("querying all does no longer report it")
+      {
+        REQUIRE(registry.all(probe_device::id).empty());
+      }
+
+      THEN("find() no longer finds it")
+      {
+        REQUIRE_FALSE(registry.find<probe_device>("probe0"));
+      }
+    }
+  }
+
+  GIVEN("no device has ever been published")
+  {
+    auto registry = kapi::devices::interface_registry{};
+
+    THEN("all() returns an empty vector")
+    {
+      REQUIRE(registry.all(probe_device::id).empty());
+    }
+  }
+
+  GIVEN("a null device")
+  {
+    auto registry = kapi::devices::interface_registry{};
+    auto device = kstd::shared_ptr<kapi::devices::device>{};
+    auto interface = const_device{};
+
+    THEN("publishing the interface for the device fails")
+    {
+      REQUIRE_FALSE(registry.publish(device, "probe0", &interface));
+    }
+  }
+}