Add methods to clear data from the cluster state cache. (project-chip#34186)

This allows consumers to clear stale data when they detects
PartsList/ServerList/AttributeList changes.

Author: bzbarsky-apple

src/app/ClusterStateCache.cpp

@@ -648,6 +648,47 @@ CHIP_ERROR ClusterStateCacheT<CanEnableDataCaching>::OnUpdateDataVersionFilterLi
     return err;
 }
 
+template <bool CanEnableDataCaching>
+void ClusterStateCacheT<CanEnableDataCaching>::ClearAttributes(EndpointId endpointId)
+{
+    mCache.erase(endpointId);
+}
+
+template <bool CanEnableDataCaching>
+void ClusterStateCacheT<CanEnableDataCaching>::ClearAttributes(const ConcreteClusterPath & cluster)
+{
+    // Can't use GetEndpointState here, since that only handles const things.
+    auto endpointIter = mCache.find(cluster.mEndpointId);
+    if (endpointIter == mCache.end())
+    {
+        return;
+    }
+
+    auto & endpointState = endpointIter->second;
+    endpointState.erase(cluster.mClusterId);
+}
+
+template <bool CanEnableDataCaching>
+void ClusterStateCacheT<CanEnableDataCaching>::ClearAttribute(const ConcreteAttributePath & attribute)
+{
+    // Can't use GetClusterState here, since that only handles const things.
+    auto endpointIter = mCache.find(attribute.mEndpointId);
+    if (endpointIter == mCache.end())
+    {
+        return;
+    }
+
+    auto & endpointState = endpointIter->second;
+    auto clusterIter     = endpointState.find(attribute.mClusterId);
+    if (clusterIter == endpointState.end())
+    {
+        return;
+    }
+
+    auto & clusterState = clusterIter->second;
+    clusterState.mAttributes.erase(attribute.mAttributeId);
+}
+
 template <bool CanEnableDataCaching>
 CHIP_ERROR ClusterStateCacheT<CanEnableDataCaching>::GetLastReportDataPath(ConcreteClusterPath & aPath)
 {

src/app/ClusterStateCache.h

@@ -504,6 +504,22 @@ class ClusterStateCacheT : protected ReadClient::Callback
         }
     }
 
+    /*
+     * Clear out all the attribute data and DataVersions stored for a given endpoint.
+     */
+    void ClearAttributes(EndpointId endpoint);
+
+    /*
+     * Clear out all the attribute data and the DataVersion stored for a given cluster.
+     */
+    void ClearAttributes(const ConcreteClusterPath & cluster);
+
+    /*
+     * Clear out the data (or size, if not storing data) stored for an
+     * attribute.
+     */
+    void ClearAttribute(const ConcreteAttributePath & attribute);
+
     /*
      * Clear out the event data and status caches.
      *

src/app/tests/TestClusterStateCache.cpp

@@ -101,6 +101,11 @@ struct AttributeInstruction
         }
     }
 
+    ConcreteAttributePath GetAttributePath() const
+    {
+        return ConcreteAttributePath(mEndpointId, Clusters::UnitTesting::Id, GetAttributeId());
+    }
+
     static uint8_t sInstructionId;
 };
 
@@ -626,6 +631,94 @@ void RunAndValidateSequence(AttributeInstructionListType list)
 
         ++bufferSize;
     } while (true);
+
+    // Now check clearing behavior.  First for attributes.
+    ConcreteAttributePath firstAttr = list[0].GetAttributePath();
+
+    TLV::TLVReader reader;
+    CHIP_ERROR err = cache.Get(firstAttr, reader);
+    // Should have gotten a value or status for now.
+    EXPECT_NE(err, CHIP_ERROR_KEY_NOT_FOUND);
+
+    cache.ClearAttribute(firstAttr);
+
+    err = cache.Get(firstAttr, reader);
+    // Should have gotten no value.
+    EXPECT_EQ(err, CHIP_ERROR_KEY_NOT_FOUND);
+
+    // Now clearing for clusters.  First check that things that should be there are.
+    for (auto & listItem : list)
+    {
+        ConcreteAttributePath path = listItem.GetAttributePath();
+        if (path == firstAttr)
+        {
+            // We removed this one already.
+            continue;
+        }
+
+        err = cache.Get(path, reader);
+
+        // Should have gotten a value or status for now.
+        EXPECT_NE(err, CHIP_ERROR_KEY_NOT_FOUND);
+    }
+
+    auto firstCluster = ConcreteClusterPath(firstAttr);
+    cache.ClearAttributes(firstCluster);
+
+    for (auto & listItem : list)
+    {
+        ConcreteAttributePath path = listItem.GetAttributePath();
+
+        err = cache.Get(path, reader);
+
+        if (ConcreteClusterPath(path) == firstCluster)
+        {
+            EXPECT_EQ(err, CHIP_ERROR_KEY_NOT_FOUND);
+        }
+        else
+        {
+            // Should still have a value or status
+            EXPECT_NE(err, CHIP_ERROR_KEY_NOT_FOUND);
+        }
+    }
+
+    // Now clearing for endpoints.  First check that things that should be there are.
+    // TODO: Since all our attributes have the same cluster, this is not
+    // actually testing anything useful right now.
+    for (auto & listItem : list)
+    {
+        ConcreteAttributePath path = listItem.GetAttributePath();
+        if (ConcreteClusterPath(path) == firstCluster)
+        {
+            // We removed this one already.
+            continue;
+        }
+
+        err = cache.Get(path, reader);
+
+        // Should have gotten a value or status for now.
+        EXPECT_NE(err, CHIP_ERROR_KEY_NOT_FOUND);
+    }
+
+    auto firstEndpoint = firstAttr.mEndpointId;
+    cache.ClearAttributes(firstEndpoint);
+
+    for (auto & listItem : list)
+    {
+        ConcreteAttributePath path = listItem.GetAttributePath();
+
+        err = cache.Get(path, reader);
+
+        if (path.mEndpointId == firstEndpoint)
+        {
+            EXPECT_EQ(err, CHIP_ERROR_KEY_NOT_FOUND);
+        }
+        else
+        {
+            // Should still have a value or status
+            EXPECT_NE(err, CHIP_ERROR_KEY_NOT_FOUND);
+        }
+    }
 }
 
 /*