[address-resolver] simplify EntryInfo and Iterator (#8055)

src/core/api/thread_ftd_api.cpp

@@ -260,10 +260,8 @@ otError otThreadGetRouterInfo(otInstance *aInstance, uint16_t aRouterId, otRoute
 
 otError otThreadGetNextCacheEntry(otInstance *aInstance, otCacheEntryInfo *aEntryInfo, otCacheEntryIterator *aIterator)
 {
-    AssertPointerIsNotNull(aIterator);
-    AssertPointerIsNotNull(aEntryInfo);
-
-    return AsCoreType(aInstance).Get<AddressResolver>().GetNextCacheEntry(*aEntryInfo, *aIterator);
+    return AsCoreType(aInstance).Get<AddressResolver>().GetNextCacheEntry(AsCoreType(aEntryInfo),
+                                                                          AsCoreType(aIterator));
 }
 
 #if OPENTHREAD_CONFIG_MLE_STEERING_DATA_SET_OOB_ENABLE

src/core/thread/address_resolver.cpp

@@ -96,11 +96,8 @@ void AddressResolver::Clear(void)
 Error AddressResolver::GetNextCacheEntry(EntryInfo &aInfo, Iterator &aIterator) const
 {
     Error                 error = kErrorNone;
-    const CacheEntryList *list;
-    const CacheEntry *    entry;
-
-    list  = reinterpret_cast<const CacheEntryList *>(aIterator.mData[kIteratorListIndex]);
-    entry = reinterpret_cast<const CacheEntry *>(aIterator.mData[kIteratorEntryIndex]);
+    const CacheEntryList *list  = aIterator.GetList();
+    const CacheEntry *    entry = aIterator.GetEntry();
 
     while (entry == nullptr)
     {
@@ -130,16 +127,16 @@ Error AddressResolver::GetNextCacheEntry(EntryInfo &aInfo, Iterator &aIterator)
 
     // Update the iterator then populate the `aInfo`.
 
-    aIterator.mData[kIteratorEntryIndex] = entry->GetNext();
-    aIterator.mData[kIteratorListIndex]  = list;
+    aIterator.SetEntry(entry->GetNext());
+    aIterator.SetList(list);
 
-    memset(&aInfo, 0, sizeof(aInfo));
+    aInfo.Clear();
     aInfo.mTarget = entry->GetTarget();
     aInfo.mRloc16 = entry->GetRloc16();
 
     if (list == &mCachedList)
     {
-        aInfo.mState          = OT_CACHE_ENTRY_STATE_CACHED;
+        aInfo.mState          = MapEnum(EntryInfo::kStateCached);
         aInfo.mCanEvict       = true;
         aInfo.mValidLastTrans = entry->IsLastTransactionTimeValid();
 
@@ -154,15 +151,15 @@ Error AddressResolver::GetNextCacheEntry(EntryInfo &aInfo, Iterator &aIterator)
 
     if (list == &mSnoopedList)
     {
-        aInfo.mState = OT_CACHE_ENTRY_STATE_SNOOPED;
+        aInfo.mState = MapEnum(EntryInfo::kStateSnooped);
     }
     else if (list == &mQueryList)
     {
-        aInfo.mState = OT_CACHE_ENTRY_STATE_QUERY;
+        aInfo.mState = MapEnum(EntryInfo::kStateQuery);
     }
     else
     {
-        aInfo.mState = OT_CACHE_ENTRY_STATE_RETRY_QUERY;
+        aInfo.mState = MapEnum(EntryInfo::kStateRetryQuery);
     }
 
     aInfo.mCanEvict   = entry->CanEvict();

src/core/thread/address_resolver.hpp

@@ -37,6 +37,7 @@
 #include "openthread-core-config.h"
 
 #include "coap/coap.hpp"
+#include "common/as_core_type.hpp"
 #include "common/linked_list.hpp"
 #include "common/locator.hpp"
 #include "common/non_copyable.hpp"
@@ -66,18 +67,42 @@ class AddressResolver : public InstanceLocator, private NonCopyable
 {
     friend class TimeTicker;
 
+    class CacheEntry;
+    class CacheEntryList;
+
 public:
     /**
      * This type represents an iterator used for iterating through the EID cache table entries.
      *
      */
-    typedef otCacheEntryIterator Iterator;
+    class Iterator : public otCacheEntryIterator, public Clearable<Iterator>
+    {
+        friend class AddressResolver;
+
+        static constexpr uint8_t kListIndex  = 0;
+        static constexpr uint8_t kEntryIndex = 1;
+
+        const CacheEntry *    GetEntry(void) const { return static_cast<const CacheEntry *>(mData[kEntryIndex]); }
+        void                  SetEntry(const CacheEntry *aEntry) { mData[kEntryIndex] = aEntry; }
+        const CacheEntryList *GetList(void) const { return static_cast<const CacheEntryList *>(mData[kListIndex]); }
+        void                  SetList(const CacheEntryList *aList) { mData[kListIndex] = aList; }
+    };
 
     /**
      * This type represents an EID cache entry.
      *
      */
-    typedef otCacheEntryInfo EntryInfo;
+    class EntryInfo : public otCacheEntryInfo, public Clearable<EntryInfo>
+    {
+    public:
+        enum State : uint8_t ///< Entry state.
+        {
+            kStateCached     = OT_CACHE_ENTRY_STATE_CACHED,      ///< Cached and in-use.
+            kStateSnooped    = OT_CACHE_ENTRY_STATE_SNOOPED,     ///< Created by snoop optimization.
+            kStateQuery      = OT_CACHE_ENTRY_STATE_QUERY,       ///< Ongoing query for the EID.
+            kStateRetryQuery = OT_CACHE_ENTRY_STATE_RETRY_QUERY, ///< In retry wait mode.
+        };
+    };
 
     /**
      * This constructor initializes the object.
@@ -215,9 +240,6 @@ private:
     static constexpr uint16_t kAddressQueryMaxRetryDelay     = OPENTHREAD_CONFIG_TMF_ADDRESS_QUERY_MAX_RETRY_DELAY;
     static constexpr uint16_t kSnoopBlockEvictionTimeout     = OPENTHREAD_CONFIG_TMF_SNOOP_CACHE_ENTRY_TIMEOUT;
 
-    static constexpr uint8_t kIteratorListIndex  = 0;
-    static constexpr uint8_t kIteratorEntryIndex = 1;
-
     class CacheEntry : public InstanceLocatorInit
     {
     public:
@@ -281,7 +303,10 @@ private:
     };
 
     typedef Pool<CacheEntry, kCacheEntries> CacheEntryPool;
-    typedef LinkedList<CacheEntry>          CacheEntryList;
+
+    class CacheEntryList : public LinkedList<CacheEntry>
+    {
+    };
 
     enum EntryChange : uint8_t
     {
@@ -367,6 +392,10 @@ private:
  * @}
  */
 
+DefineCoreType(otCacheEntryIterator, AddressResolver::Iterator);
+DefineCoreType(otCacheEntryInfo, AddressResolver::EntryInfo);
+DefineMapEnum(otCacheEntryState, AddressResolver::EntryInfo::State);
+
 } // namespace ot
 
 #endif // ADDRESS_RESOLVER_HPP_