Add a server cluster interface registry for use by codegen.

src/app/server-cluster/ServerClusterInterface.h

@@ -43,7 +43,12 @@ class ServerClusterInterface
     virtual ~ServerClusterInterface() = default;
 
     ///////////////////////////////////// Cluster Metadata Support //////////////////////////////////////////////////
-    [[nodiscard]] virtual ClusterId GetClusterId() const = 0;
+
+    /// The path to this cluster instance.
+    ///
+    /// This path (endpointid,clusterid) is expected to remain constant once the server
+    /// cluster interface is in use.
+    [[nodiscard]] virtual ConcreteClusterPath GetPath() const = 0;
 
     /// Gets the data version for this cluster instance.
     ///

src/app/server-cluster/tests/TestDefaultServerCluster.cpp

@@ -18,6 +18,7 @@
 
 #include <access/Privilege.h>
 #include <app-common/zap-generated/ids/Attributes.h>
+#include <app/ConcreteClusterPath.h>
 #include <app/data-model-provider/MetadataList.h>
 #include <app/data-model-provider/MetadataTypes.h>
 #include <app/data-model-provider/OperationTypes.h>
@@ -44,9 +45,9 @@ namespace {
 class FakeDefaultServerCluster : public DefaultServerCluster
 {
 public:
-    FakeDefaultServerCluster(ClusterId id) : mClusterId(id) {}
+    FakeDefaultServerCluster(ConcreteClusterPath path) : mPath(path) {}
 
-    ClusterId GetClusterId() const override { return mClusterId; }
+    [[nodiscard]] ConcreteClusterPath GetPath() const override { return mPath; }
 
     DataModel::ActionReturnStatus ReadAttribute(const DataModel::ReadAttributeRequest & request,
                                                 AttributeValueEncoder & encoder) override
@@ -64,14 +65,14 @@ class FakeDefaultServerCluster : public DefaultServerCluster
     void TestIncreaseDataVersion() { IncreaseDataVersion(); }
 
 private:
-    ClusterId mClusterId;
+    ConcreteClusterPath mPath;
 };
 
 } // namespace
 
 TEST(TestDefaultServerCluster, TestDataVersion)
 {
-    FakeDefaultServerCluster cluster(1);
+    FakeDefaultServerCluster cluster({ 1, 2 });
 
     DataVersion v1 = cluster.GetDataVersion();
     cluster.TestIncreaseDataVersion();
@@ -80,13 +81,22 @@ TEST(TestDefaultServerCluster, TestDataVersion)
 
 TEST(TestDefaultServerCluster, TestFlagsDefault)
 {
-    FakeDefaultServerCluster cluster(1);
+    FakeDefaultServerCluster cluster({ 1, 2 });
     ASSERT_EQ(cluster.GetClusterFlags().Raw(), 0u);
 }
 
+TEST(TestDefaultServerCluster, ListWriteNotification)
+{
+    FakeDefaultServerCluster cluster({ 1, 2 });
+
+    // this does not test anything really, except we get 100% coverage and we see that we do not crash
+    cluster.ListAttributeWriteNotification({ 1, 2, 3 }, DataModel::ListWriteOperation::kListWriteBegin);
+    cluster.ListAttributeWriteNotification({ 1, 2, 3 }, DataModel::ListWriteOperation::kListWriteFailure);
+}
+
 TEST(TestDefaultServerCluster, AttributesDefault)
 {
-    FakeDefaultServerCluster cluster(1);
+    FakeDefaultServerCluster cluster({ 1, 2 });
 
     DataModel::ListBuilder<AttributeEntry> attributes;
 
@@ -114,7 +124,7 @@ TEST(TestDefaultServerCluster, AttributesDefault)
 
 TEST(TestDefaultServerCluster, CommandsDefault)
 {
-    FakeDefaultServerCluster cluster(1);
+    FakeDefaultServerCluster cluster({ 1, 2 });
 
     DataModel::ListBuilder<AcceptedCommandEntry> acceptedCommands;
     ASSERT_EQ(cluster.AcceptedCommands({ 1, 1 }, acceptedCommands), CHIP_NO_ERROR);
@@ -127,7 +137,7 @@ TEST(TestDefaultServerCluster, CommandsDefault)
 
 TEST(TestDefaultServerCluster, WriteAttributeDefault)
 {
-    FakeDefaultServerCluster cluster(1);
+    FakeDefaultServerCluster cluster({ 1, 2 });
 
     WriteOperation test(0 /* endpoint */, 1 /* cluster */, 1234 /* attribute */);
     test.SetSubjectDescriptor(kAdminSubjectDescriptor);
@@ -140,7 +150,7 @@ TEST(TestDefaultServerCluster, WriteAttributeDefault)
 
 TEST(TestDefaultServerCluster, InvokeDefault)
 {
-    FakeDefaultServerCluster cluster(1);
+    FakeDefaultServerCluster cluster({ 1, 2 });
 
     TLV::TLVReader tlvReader;
     InvokeRequest request;

src/data-model-providers/codegen/BUILD.gn

@@ -45,3 +45,17 @@ source_set("instance-header") {
   # generally being unit tests or data_model.gni/data_model.cmake files)
   sources = [ "Instance.h" ]
 }
+
+source_set("registry") {
+  sources = [
+    "ServerClusterInterfaceRegistry.cpp",
+    "ServerClusterInterfaceRegistry.h",
+  ]
+
+  public_deps = [
+    "${chip_root}/src/app:paths",
+    "${chip_root}/src/app/server-cluster",
+    "${chip_root}/src/lib/core:types",
+    "${chip_root}/src/lib/support",
+  ]
+}

src/data-model-providers/codegen/ServerClusterInterfaceRegistry.cpp

@@ -0,0 +1,162 @@
+/*
+ *    Copyright (c) 2025 Project CHIP Authors
+ *    All rights reserved.
+ *
+ *    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 <data-model-providers/codegen/ServerClusterInterfaceRegistry.h>
+
+#include <app/ConcreteClusterPath.h>
+#include <app/server-cluster/ServerClusterInterface.h>
+#include <lib/core/CHIPError.h>
+#include <lib/core/DataModelTypes.h>
+#include <lib/support/CHIPMem.h>
+#include <lib/support/CodeUtils.h>
+
+namespace chip {
+namespace app {
+
+ServerClusterInterfaceRegistry::~ServerClusterInterfaceRegistry()
+{
+    while (mRegistrations != nullptr)
+    {
+        ServerClusterRegistration * next = mRegistrations->next;
+        mRegistrations->next             = nullptr;
+        mRegistrations                   = next;
+    }
+}
+
+CHIP_ERROR ServerClusterInterfaceRegistry::Register(ServerClusterRegistration & entry)
+{
+    // we have no strong way to check if entry is already registered somewhere else, so we use "next" as some
+    // form of double-check
+    VerifyOrReturnError(entry.next == nullptr, CHIP_ERROR_INVALID_ARGUMENT);
+    VerifyOrReturnError(entry.serverClusterInterface != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
+
+    ConcreteClusterPath path = entry.serverClusterInterface->GetPath();
+
+    VerifyOrReturnError(path.HasValidIds(), CHIP_ERROR_INVALID_ARGUMENT);
+
+    // Double-checking for duplicates makes the checks O(n^2) on the total number of registered
+    // items. We preserve this however we may want to make this optional at some point in time.
+    VerifyOrReturnError(Get(path) == nullptr, CHIP_ERROR_DUPLICATE_KEY_ID);
+
+    entry.next     = mRegistrations;
+    mRegistrations = &entry;
+
+    return CHIP_NO_ERROR;
+}
+
+ServerClusterInterface * ServerClusterInterfaceRegistry::Unregister(const ConcreteClusterPath & path)
+{
+    ServerClusterRegistration * prev    = nullptr;
+    ServerClusterRegistration * current = mRegistrations;
+
+    while (current != nullptr)
+    {
+        if (current->serverClusterInterface->GetPath() == path)
+        {
+            // take the item out of the current list and return it.
+            ServerClusterRegistration * next = current->next;
+
+            if (prev == nullptr)
+            {
+                mRegistrations = next;
+            }
+            else
+            {
+                prev->next = next;
+            }
+
+            if (mCachedInterface == current->serverClusterInterface)
+            {
+                mCachedInterface = nullptr;
+            }
+
+            current->next = nullptr; // Make sure current does not look like part of a list.
+            return current->serverClusterInterface;
+        }
+
+        prev    = current;
+        current = current->next;
+    }
+
+    // Not found.
+    return nullptr;
+}
+
+ServerClusterInterfaceRegistry::ClustersList ServerClusterInterfaceRegistry::ClustersOnEndpoint(EndpointId endpointId)
+{
+    return { mRegistrations, endpointId };
+}
+
+void ServerClusterInterfaceRegistry::UnregisterAllFromEndpoint(EndpointId endpointId)
+{
+    ServerClusterRegistration * prev    = nullptr;
+    ServerClusterRegistration * current = mRegistrations;
+    while (current != nullptr)
+    {
+        if (current->serverClusterInterface->GetPath().mEndpointId == endpointId)
+        {
+            if (mCachedInterface == current->serverClusterInterface)
+            {
+                mCachedInterface = nullptr;
+            }
+            if (prev == nullptr)
+            {
+                mRegistrations = current->next;
+            }
+            else
+            {
+                prev->next = current->next;
+            }
+            ServerClusterRegistration * actual_next = current->next;
+            current->next                           = nullptr; // Make sure current does not look like part of a list.
+            current                                 = actual_next;
+        }
+        else
+        {
+            prev    = current;
+            current = current->next;
+        }
+    }
+}
+
+ServerClusterInterface * ServerClusterInterfaceRegistry::Get(const ConcreteClusterPath & path)
+{
+    // Check the cache to speed things up
+    if ((mCachedInterface != nullptr) && (mCachedInterface->GetPath() == path))
+    {
+        return mCachedInterface;
+    }
+
+    // The cluster searched for is not cached, do a linear search for it
+    ServerClusterRegistration * current = mRegistrations;
+
+    while (current != nullptr)
+    {
+        if (current->serverClusterInterface->GetPath() == path)
+        {
+            mCachedInterface = current->serverClusterInterface;
+            return mCachedInterface;
+        }
+
+        current = current->next;
+    }
+
+    // not found
+    return nullptr;
+}
+
+} // namespace app
+} // namespace chip