1 files changed, 27 insertions, 2 deletions
diff --git a/indra/llui/llkeywords.h b/indra/llui/llkeywords.h
index 53377869ca..e5b66dfa56 100644
--- a/indra/llui/llkeywords.h
+++ b/indra/llui/llkeywords.h
@@ -92,8 +92,33 @@ public:
 					const std::string& key,
 					const LLColor3& color,
 					const std::string& tool_tip = LLStringUtil::null);
-
-	typedef std::map<LLWString, LLKeywordToken*> word_token_map_t;
+	
+	// This class is here as a performance optimization.
+	// The word token map used to be defined as std::map<LLWString, LLKeywordToken*>.
+	// This worked, but caused a performance bottleneck due to memory allocation and string copies
+	//  because it's not possible to search such a map without creating an LLWString.
+	// Using this class as the map index instead allows us to search using segments of an existing
+	//  text run without copying them first, which greatly reduces overhead in LLKeywords::findSegments().
+	class WStringMapIndex
+	{
+	public:
+		// copy constructor
+		WStringMapIndex(const WStringMapIndex& other);
+		// constructor from a string (copies the string's data into the new object)
+		WStringMapIndex(const LLWString& str);
+		// constructor from pointer and length
+		// NOTE: does NOT copy data, caller must ensure that the lifetime of the pointer exceeds that of the new object!
+		WStringMapIndex(const llwchar *start, size_t length);
+		~WStringMapIndex();
+		bool operator<(const WStringMapIndex &other) const;
+	private:
+		void copyData(const llwchar *start, size_t length);
+		const llwchar *mData;
+		size_t mLength;
+		bool mOwner;
+	};
+
+	typedef std::map<WStringMapIndex, LLKeywordToken*> word_token_map_t;
 	typedef word_token_map_t::const_iterator keyword_iterator_t;
 	keyword_iterator_t begin() const { return mWordTokenMap.begin(); }
 	keyword_iterator_t end() const { return mWordTokenMap.end(); }