uhd: Create discoverable feature registry implementation

Classes which want to implement discoverable_feature can simply inherit
from this registry and get access to an ergonomic map-backed registry of
features.

7 files changed, 113 insertions, 36 deletions

diff --git a/host/include/uhd/features/CMakeLists.txt b/host/include/uhd/features/CMakeLists.txt
index efba46dc2..798844077 100644
--- a/host/include/uhd/features/CMakeLists.txt
+++ b/host/include/uhd/features/CMakeLists.txt
@@ -6,7 +6,7 @@
 
 UHD_INSTALL(FILES
     discoverable_feature.hpp
-    discoverable_feature_getter.hpp
+    discoverable_feature_getter_iface.hpp
     DESTINATION ${INCLUDE_DIR}/uhd/features
     COMPONENT headers
 )
diff --git a/host/lib/CMakeLists.txt b/host/lib/CMakeLists.txt
index c5046420a..c0b39faea 100644
--- a/host/lib/CMakeLists.txt
+++ b/host/lib/CMakeLists.txt
@@ -83,6 +83,7 @@ LIBUHD_REGISTER_COMPONENT("DPDK" ENABLE_DPDK ON "ENABLE_MPMD;DPDK_FOUND" OFF OFF
 ########################################################################
 INCLUDE_SUBDIRECTORY(include)
 INCLUDE_SUBDIRECTORY(cal)
+INCLUDE_SUBDIRECTORY(features)
 INCLUDE_SUBDIRECTORY(ic_reg_maps)
 INCLUDE_SUBDIRECTORY(types)
 INCLUDE_SUBDIRECTORY(convert)
diff --git a/host/lib/features/CMakeLists.txt b/host/lib/features/CMakeLists.txt
new file mode 100644
index 000000000..2cdd1dd56
--- /dev/null
+++ b/host/lib/features/CMakeLists.txt
@@ -0,0 +1,12 @@
+#
+# Copyright 2020 Ettus Research, a National Instruments Brand
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+
+########################################################################
+# This file included, use CMake directory variables
+########################################################################
+LIBUHD_APPEND_SOURCES(
+    ${CMAKE_CURRENT_SOURCE_DIR}/discoverable_feature_registry.cpp
+)
diff --git a/host/lib/features/discoverable_feature_registry.cpp b/host/lib/features/discoverable_feature_registry.cpp
new file mode 100644
index 000000000..5bed6a06e
--- /dev/null
+++ b/host/lib/features/discoverable_feature_registry.cpp
@@ -0,0 +1,34 @@
+//
+// Copyright 2020 Ettus Research, a National Instruments Brand
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+
+#include <uhd/exception.hpp>
+#include <uhd/features/discoverable_feature.hpp>
+#include <uhdlib/features/discoverable_feature_registry.hpp>
+#include <vector>
+
+namespace uhd { namespace features {
+
+std::vector<std::string>
+discoverable_feature_registry::enumerate_features()
+{
+    std::vector<std::string> features;
+    for (auto& entry : _features) {
+        features.push_back(entry.second->get_feature_name());
+    }
+    return features;
+}
+
+discoverable_feature::sptr discoverable_feature_registry::get_feature_ptr(
+    discoverable_feature::feature_id_t feature_id)
+{
+    auto it = _features.find(feature_id);
+    if (it == _features.end()) {
+        return discoverable_feature::sptr();
+    }
+    return it->second;
+}
+
+}} // namespace uhd::features
diff --git a/host/lib/include/uhdlib/features/discoverable_feature_registry.hpp b/host/lib/include/uhdlib/features/discoverable_feature_registry.hpp
new file mode 100644
index 000000000..f27f1a4f1
--- /dev/null
+++ b/host/lib/include/uhdlib/features/discoverable_feature_registry.hpp
@@ -0,0 +1,42 @@
+//
+// Copyright 2020 Ettus Research, a National Instruments Brand
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+
+#pragma once
+
+#include <uhd/exception.hpp>
+#include <uhd/features/discoverable_feature.hpp>
+#include <uhd/features/discoverable_feature_getter_iface.hpp>
+#include <map>
+#include <memory>
+#include <vector>
+
+namespace uhd { namespace features {
+
+/*! Map-based registry to implement discoverable_feature_getter_iface
+ */
+class discoverable_feature_registry : public virtual discoverable_feature_getter_iface
+{
+public:
+    virtual ~discoverable_feature_registry() = default;
+
+    std::vector<std::string> enumerate_features() override;
+
+    template <typename T>
+    void register_feature(std::shared_ptr<T> feature)
+    {
+        if (!_features.emplace(T::get_feature_id(), feature).second) {
+            UHD_ASSERT_THROW(false);
+        }
+    }
+
+private:
+    discoverable_feature::sptr get_feature_ptr(
+        discoverable_feature::feature_id_t feature_id) override;
+
+    std::map<discoverable_feature::feature_id_t, discoverable_feature::sptr> _features;
+};
+
+}} // namespace uhd::features
diff --git a/host/tests/CMakeLists.txt b/host/tests/CMakeLists.txt
index 47ca5b79f..6626b9c3a 100644
--- a/host/tests/CMakeLists.txt
+++ b/host/tests/CMakeLists.txt
@@ -32,7 +32,6 @@ set(test_sources
     constrained_device_args_test.cpp
     convert_test.cpp
     dict_test.cpp
-    discoverable_feature_test.cpp
     eeprom_utils_test.cpp
     error_test.cpp
     fp_compare_delta_test.cpp
@@ -339,6 +338,12 @@ UHD_ADD_NONAPI_TEST(
     ${CMAKE_SOURCE_DIR}/lib/usrp/common/pwr_cal_mgr.cpp
 )
 
+UHD_ADD_NONAPI_TEST(
+    TARGET "discoverable_feature_test.cpp"
+    EXTRA_SOURCES
+    ${CMAKE_SOURCE_DIR}/lib/features/discoverable_feature_registry.cpp
+)
+
 ########################################################################
 # demo of a loadable module
 ########################################################################
diff --git a/host/tests/discoverable_feature_test.cpp b/host/tests/discoverable_feature_test.cpp
index b75cb76f3..e35660392 100644
--- a/host/tests/discoverable_feature_test.cpp
+++ b/host/tests/discoverable_feature_test.cpp
@@ -5,6 +5,7 @@
 //
 
 #include <uhd/features/discoverable_feature_getter_iface.hpp>
+#include <uhdlib/features/discoverable_feature_registry.hpp>
 #include <boost/test/unit_test.hpp>
 #include <iostream>
 
@@ -38,43 +39,16 @@ public:
     }
 };
 
-class test_feature_getter : public discoverable_feature_getter_iface
+class test_feature_getter : public discoverable_feature_registry
 {
 public:
     test_feature_getter(bool feature0_enabled, bool feature1_enabled)
     {
         if (feature0_enabled)
-            _test_feature0.reset(new test_feature0());
+            register_feature(std::make_shared<test_feature0>());
         if (feature1_enabled)
-            _test_feature1.reset(new test_feature1);
+            register_feature(std::make_shared<test_feature1>());
     }
-
-    std::vector<std::string> enumerate_features() override
-    {
-        std::vector<std::string> features;
-        if (_test_feature0)
-            features.push_back(_test_feature0->get_feature_name());
-        if (_test_feature1)
-            features.push_back(_test_feature1->get_feature_name());
-        return features;
-    }
-
-private:
-    discoverable_feature::sptr get_feature_ptr(
-        discoverable_feature::feature_id_t feature_id) override
-    {
-        switch (feature_id) {
-            case discoverable_feature::RESERVED0:
-                return _test_feature0;
-            case discoverable_feature::RESERVED1:
-                return _test_feature1;
-            default:
-                return discoverable_feature::sptr();
-        };
-    }
-
-    discoverable_feature::sptr _test_feature0;
-    discoverable_feature::sptr _test_feature1;
 };
 
 BOOST_AUTO_TEST_CASE(test_has_feature_works)
@@ -89,10 +63,19 @@ BOOST_AUTO_TEST_CASE(test_enumerate_feature_works)
     test_feature_getter feature_getter(true, true);
     const auto features = feature_getter.enumerate_features();
 
-    // Note that ordering isn't strictly a requirement of the interface,
-    // we just leverage that here to demonstrate API usage concisely.
-    BOOST_CHECK_EQUAL(features[0], "test_feature0");
-    BOOST_CHECK_EQUAL(features[1], "test_feature1");
+    bool has_feature0 = false;
+    bool has_feature1 = false;
+    for (auto& feature : features) {
+        if (feature == "test_feature0") {
+            has_feature0 = true;
+        }
+        if (feature == "test_feature1") {
+            has_feature1 = true;
+        }
+    }
+    BOOST_CHECK_EQUAL(has_feature0, true);
+    BOOST_CHECK_EQUAL(has_feature1, true);
+    BOOST_CHECK_EQUAL(features.size(), 2);
 }
 
 BOOST_AUTO_TEST_CASE(test_get_feature_works)