trie: implement clone() method (#852)

* Add Clone() for StringMap

* Fix for std::string addition

* trie: broken return key.

* clonetrie: correct handle leakage.

Co-authored-by: Kyle Sanderson <kyle.leet@gmail.com>

core/logic/smn_adt_trie.cpp

@@ -636,6 +636,56 @@ static cell_t GetTrieSnapshotKey(IPluginContext *pContext, const cell_t *params)
 	return written;
 }
 
+static cell_t CloneTrie(IPluginContext *pContext, const cell_t *params)
+{
+	HandleError err;
+	HandleSecurity sec = HandleSecurity(pContext->GetIdentity(), g_pCoreIdent);
+
+	CellTrie *pOldTrie;
+	if ((err = handlesys->ReadHandle(params[1], htCellTrie, &sec, (void **)&pOldTrie))
+		!= HandleError_None)
+	{
+		return pContext->ThrowNativeError("Invalid Handle %x (error %d)", params[1], err);
+	}
+
+	CellTrie *pNewTrie = new CellTrie;
+	Handle_t hndl = handlesys->CreateHandle(htCellTrie, pNewTrie, pContext->GetIdentity(), g_pCoreIdent, NULL);
+	if (!hndl)
+	{
+		delete pNewTrie;
+		return hndl;
+	}
+
+	for (StringHashMap<Entry>::iterator it = pOldTrie->map.iter(); !it.empty(); it.next())
+	{
+		const char *key = it->key.c_str();
+		StringHashMap<Entry>::Insert insert = pNewTrie->map.findForAdd(key);
+		if (pNewTrie->map.add(insert, key))
+		{
+			StringHashMap<Entry>::Result result = pOldTrie->map.find(key);
+			if (result->value.isCell())
+			{
+				insert->value.setCell(result->value.cell());
+			}
+			else if (result->value.isString())
+			{
+				insert->value.setString(result->value.c_str());
+			}
+			else if (result->value.isArray())
+			{
+				insert->value.setArray(result->value.array(), result->value.arrayLength());
+			}
+			else
+			{
+				handlesys->FreeHandle(hndl, NULL);
+				return pContext->ThrowNativeError("Unhandled data type encountered, file a bug and reference pr #852");
+			}
+		}
+	}
+
+	return hndl;
+}
+
 REGISTER_NATIVES(trieNatives)
 {
 	{"ClearTrie",				ClearTrie},
@@ -666,6 +716,7 @@ REGISTER_NATIVES(trieNatives)
 	{"StringMap.SetValue",		SetTrieValue},
 	{"StringMap.Size.get",		GetTrieSize},
 	{"StringMap.Snapshot",		CreateTrieSnapshot},
+	{"StringMap.Clone",			CloneTrie},
 
 	{"StringMapSnapshot.Length.get",	TrieSnapshotLength},
 	{"StringMapSnapshot.KeyBufferSize", TrieSnapshotKeyBufferSize},

plugins/include/adt_trie.inc

@@ -52,6 +52,14 @@ methodmap StringMap < Handle
 	// The StringMap must be freed via delete or CloseHandle().
 	public native StringMap();
 
+	// Clones a string map, returning a new handle with the same size and data.
+	// This should NOT be confused with CloneHandle. This is a completely new
+	// handle with the same data but no relation to the original. It should be
+	// closed when no longer needed with delete or CloseHandle().
+	//
+	// @return              New handle to the cloned string map
+	public native StringMap Clone();
+
 	// Sets a value in a hash map, either inserting a new entry or replacing an old one.
 	//
 	// @param key        Key string.

public/sm_trie_tpl.h

@@ -48,7 +48,7 @@ enum NodeType
  * @brief DEPRECATED. This class scales extremely poorly; insertion scales
  * quadratic (O(n^2)) with respect to the number of elements in the table.
  * Only use this class if you have less than 200 elements or so. Otherwise,
- * use StringHashMap in sm_hashtable.h which scales linearly and has comparable
+ * use StringHashMap in sm_stringhashmap.h which scales linearly and has comparable
  * retrievable performance.
  *
  * See bug 5878 for more detail.