Clean up the redundant user labels when the list becomes smaller than previous list for a given endpoint (#21336)

* Clean up unused UserLabel after it is not in use

* Conduct user label cleanup in the user label cluster

Author: yufengwangca

examples/providers/DeviceInfoProviderImpl.cpp

@@ -149,6 +149,13 @@ CHIP_ERROR DeviceInfoProviderImpl::SetUserLabelAt(EndpointId endpoint, size_t in
                                      static_cast<uint16_t>(writer.GetLengthWritten()));
 }
 
+CHIP_ERROR DeviceInfoProviderImpl::DeleteUserLabelAt(EndpointId endpoint, size_t index)
+{
+    DefaultStorageKeyAllocator keyAlloc;
+
+    return mStorage->SyncDeleteKeyValue(keyAlloc.UserLabelIndexKey(endpoint, index));
+}
+
 DeviceInfoProvider::UserLabelIterator * DeviceInfoProviderImpl::IterateUserLabel(EndpointId endpoint)
 {
     return chip::Platform::New<UserLabelIteratorImpl>(*this, endpoint);

examples/providers/DeviceInfoProviderImpl.h

@@ -97,6 +97,7 @@ class DeviceInfoProviderImpl : public DeviceInfoProvider
     CHIP_ERROR SetUserLabelLength(EndpointId endpoint, size_t val) override;
     CHIP_ERROR GetUserLabelLength(EndpointId endpoint, size_t & val) override;
     CHIP_ERROR SetUserLabelAt(EndpointId endpoint, size_t index, const UserLabelType & userLabel) override;
+    CHIP_ERROR DeleteUserLabelAt(EndpointId endpoint, size_t index) override;
 
 private:
     static constexpr size_t UserLabelTLVMaxSize() { return TLV::EstimateStructOverhead(kMaxLabelNameLength, kMaxLabelValueLength); }

src/app/clusters/user-label-server/user-label-server.cpp

@@ -25,7 +25,9 @@
 #include <app-common/zap-generated/ids/Attributes.h>
 #include <app-common/zap-generated/ids/Clusters.h>
 #include <app/AttributeAccessInterface.h>
+#include <app/server/Server.h>
 #include <app/util/attribute-storage.h>
+#include <credentials/FabricTable.h>
 #include <lib/support/CodeUtils.h>
 #include <lib/support/logging/CHIPLogging.h>
 #include <platform/DeviceInfoProvider.h>
@@ -184,7 +186,39 @@ CHIP_ERROR UserLabelAttrAccess::Write(const ConcreteDataAttributePath & aPath, A
 
 } // anonymous namespace
 
+class UserLabelFabricTableDelegate : public chip::FabricTable::Delegate
+{
+public:
+    // Gets called when a fabric is deleted
+    void OnFabricRemoved(const FabricTable & fabricTable, FabricIndex fabricIndex) override
+    {
+        // If the FabricIndex matches the last remaining entry in the Fabrics list, then the device SHALL delete all Matter
+        // related data on the node which was created since it was commissioned.
+        if (Server::GetInstance().GetFabricTable().FabricCount() == 0)
+        {
+            ChipLogProgress(Zcl, "UserLabel: Last Fabric index 0x%x was removed", static_cast<unsigned>(fabricIndex));
+
+            // Delete all user label data on the node which was added since it was commissioned.
+            DeviceLayer::DeviceInfoProvider * provider = DeviceLayer::GetDeviceInfoProvider();
+            if (provider)
+            {
+                for (auto endpoint : EnabledEndpointsWithServerCluster(UserLabel::Id))
+                {
+                    // If UserLabel cluster is implemented on this endpoint
+                    if (CHIP_NO_ERROR != provider->ClearUserLabelList(endpoint))
+                    {
+                        ChipLogError(Zcl, "UserLabel::Failed to clear UserLabelList for endpoint:%d", endpoint);
+                    }
+                }
+            }
+        }
+    }
+};
+
+UserLabelFabricTableDelegate gUserLabelFabricDelegate;
+
 void MatterUserLabelPluginServerInitCallback(void)
 {
     registerAttributeAccessOverride(&gAttrAccess);
+    Server::GetInstance().GetFabricTable().AddFabricDelegate(&gUserLabelFabricDelegate);
 }

src/app/tests/suites/TestUserLabelCluster.yaml

@@ -28,6 +28,30 @@ tests:
               - name: "nodeId"
                 value: nodeId
 
+    - label: "Commit User Label List"
+      command: "writeAttribute"
+      attribute: "label list"
+      arguments:
+          value:
+              [
+                  { label: "room", value: "bedroom 1" },
+                  { label: "orientation", value: "South" },
+                  { label: "floor", value: "2" },
+                  { label: "direction", value: "down" },
+              ]
+
+    - label: "Verify committed User Label List"
+      command: "readAttribute"
+      attribute: "label list"
+      response:
+          value:
+              [
+                  { label: "room", value: "bedroom 1" },
+                  { label: "orientation", value: "South" },
+                  { label: "floor", value: "2" },
+                  { label: "direction", value: "down" },
+              ]
+
     - label: "Clear User Label List"
       command: "writeAttribute"
       attribute: "label list"
@@ -64,7 +88,7 @@ tests:
               - name: "nodeId"
                 value: nodeId
 
-    - label: "Verify"
+    - label: "Verify User Label List after reboot"
       command: "readAttribute"
       attribute: "label list"
       response:

src/include/platform/DeviceInfoProvider.h

@@ -90,6 +90,7 @@ class DeviceInfoProvider
     void SetStorageDelegate(PersistentStorageDelegate * storage);
 
     CHIP_ERROR SetUserLabelList(EndpointId endpoint, const AttributeList<UserLabelType, kMaxUserLabelListLength> & labelList);
+    CHIP_ERROR ClearUserLabelList(EndpointId endpoint);
     CHIP_ERROR AppendUserLabel(EndpointId endpoint, const UserLabelType & label);
 
     // Iterators
@@ -133,6 +134,16 @@ class DeviceInfoProvider
      */
     virtual CHIP_ERROR SetUserLabelAt(EndpointId endpoint, size_t index, const UserLabelType & userLabel) = 0;
 
+    /**
+     * @brief Delete the UserLabel at the specified index of the UserLabelList on a given endpoint
+     *
+     * @param endpoint - id to UserLabelList on which to delete the UserLabel.
+     * @param index - index within the UserLabelList for which to remove the UserLabel.
+     * @return CHIP_NO_ERROR on success, CHIP_ERROR_INVALID_KEY_ID if index exceed the range (Total length - 1),
+     *         or other CHIP_ERROR values from implementation on other errors.
+     */
+    virtual CHIP_ERROR DeleteUserLabelAt(EndpointId endpoint, size_t index) = 0;
+
     /**
      * @brief Set the total length of the UserLabelList on a given endpoint
      *

src/platform/DeviceInfoProvider.cpp

@@ -38,15 +38,43 @@ DeviceInfoProvider * gDeviceInfoProvider = nullptr;
 CHIP_ERROR DeviceInfoProvider::SetUserLabelList(EndpointId endpoint,
                                                 const AttributeList<UserLabelType, kMaxUserLabelListLength> & labelList)
 {
-    size_t index = 0;
+    size_t index          = 0;
+    size_t previousLength = 0;
+    size_t currentLength  = labelList.size();
 
-    ReturnErrorOnFailure(SetUserLabelLength(endpoint, labelList.size()));
+    CHIP_ERROR err = GetUserLabelLength(endpoint, previousLength);
+    VerifyOrReturnError(err == CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND || err == CHIP_NO_ERROR, err);
+
+    ReturnErrorOnFailure(SetUserLabelLength(endpoint, currentLength));
 
     for (const UserLabelType & label : labelList)
     {
         ReturnErrorOnFailure(SetUserLabelAt(endpoint, index++, label));
     }
 
+    // If the list becomes smaller than previous list for a given endpoint, all "over-size" keys
+    // (keys for [current_length..previous_length-1]) should be deleted, to recover space.
+    for (size_t i = currentLength; i < previousLength; i++)
+    {
+        ReturnErrorOnFailure(DeleteUserLabelAt(endpoint, i));
+    }
+
+    return CHIP_NO_ERROR;
+}
+
+CHIP_ERROR DeviceInfoProvider::ClearUserLabelList(EndpointId endpoint)
+{
+    size_t length;
+
+    CHIP_ERROR err = GetUserLabelLength(endpoint, length);
+    VerifyOrReturnError(err != CHIP_ERROR_PERSISTED_STORAGE_VALUE_NOT_FOUND, CHIP_NO_ERROR);
+    ReturnErrorOnFailure(err);
+
+    for (size_t i = 0; i < length; i++)
+    {
+        ReturnErrorOnFailure(DeleteUserLabelAt(endpoint, i));
+    }
+
     return CHIP_NO_ERROR;
 }