lazy evaluation of lluistring to improve LLUIString::format performance

reviewed by Mani

indra/llui/lluistring.cpp

@@ -39,22 +39,23 @@ LLFastTimer::DeclareTimer FTM_UI_STRING("UI String");
 
 
 LLUIString::LLUIString(const std::string& instring, const LLStringUtil::format_map_t& args)
-	: mOrig(instring),
-	  mArgs(args)
+:	mOrig(instring),
+	mArgs(args)
 {
-	format();
+	dirty();
 }
 
 void LLUIString::assign(const std::string& s)
 {
 	mOrig = s;
-	format();
+	dirty();
 }
 
 void LLUIString::setArgList(const LLStringUtil::format_map_t& args)
+
 {
 	mArgs = args;
-	format();
+	dirty();
 }
 
 void LLUIString::setArgs(const LLSD& sd)
@@ -68,40 +69,40 @@ void LLUIString::setArgs(const LLSD& sd)
 	{
 		setArg(sd_it->first, sd_it->second.asString());
 	}
-	format();
+	dirty();
 }
 
 void LLUIString::setArg(const std::string& key, const std::string& replacement)
 {
 	mArgs[key] = replacement;
-	format();
+	dirty();
 }
 
 void LLUIString::truncate(S32 maxchars)
 {
-	if (mWResult.size() > (size_t)maxchars)
+	if (getUpdatedWResult().size() > (size_t)maxchars)
 	{
-		LLWStringUtil::truncate(mWResult, maxchars);
-		mResult = wstring_to_utf8str(mWResult);
+		LLWStringUtil::truncate(getUpdatedWResult(), maxchars);
+		mResult = wstring_to_utf8str(getUpdatedWResult());
 	}
 }
 
 void LLUIString::erase(S32 charidx, S32 len)
 {
-	mWResult.erase(charidx, len);
-	mResult = wstring_to_utf8str(mWResult);
+	getUpdatedWResult().erase(charidx, len);
+	mResult = wstring_to_utf8str(getUpdatedWResult());
 }
 
 void LLUIString::insert(S32 charidx, const LLWString& wchars)
 {
-	mWResult.insert(charidx, wchars);
-	mResult = wstring_to_utf8str(mWResult);
+	getUpdatedWResult().insert(charidx, wchars);
+	mResult = wstring_to_utf8str(getUpdatedWResult());
 }
 
 void LLUIString::replace(S32 charidx, llwchar wc)
 {
-	mWResult[charidx] = wc;
-	mResult = wstring_to_utf8str(mWResult);
+	getUpdatedWResult()[charidx] = wc;
+	mResult = wstring_to_utf8str(getUpdatedWResult());
 }
 
 void LLUIString::clear()
@@ -112,8 +113,16 @@ void LLUIString::clear()
 	mWResult.clear();
 }
 
-void LLUIString::format()
+void LLUIString::dirty()
 {
+	mNeedsResult = true;
+	mNeedsWResult = true;
+}
+
+void LLUIString::updateResult() const
+{
+	mNeedsResult = false;
+
 	LLFastTimer timer(FTM_UI_STRING);
 	
 	// optimize for empty strings (don't attempt string replacement)
@@ -129,5 +138,11 @@ void LLUIString::format()
 	LLStringUtil::format_map_t combined_args = LLTrans::getDefaultArgs();
 	combined_args.insert(mArgs.begin(), mArgs.end());
 	LLStringUtil::format(mResult, combined_args);
-	mWResult = utf8str_to_wstring(mResult);
+}
+
+void LLUIString::updateWResult() const
+{
+	mNeedsWResult = false;
+
+	mWResult = utf8str_to_wstring(getUpdatedResult());
 }

indra/llui/lluistring.h

@@ -76,19 +76,19 @@ public:
 	void setArgs(const class LLSD& sd);
 	void setArg(const std::string& key, const std::string& replacement);
 
-	const std::string& getString() const { return mResult; }
-	operator std::string() const { return mResult; }
+	const std::string& getString() const { return getUpdatedResult(); }
+	operator std::string() const { return getUpdatedResult(); }
 
-	const LLWString& getWString() const { return mWResult; }
-	operator LLWString() const { return mWResult; }
+	const LLWString& getWString() const { return getUpdatedWResult(); }
+	operator LLWString() const { return getUpdatedWResult(); }
 
-	bool empty() const { return mWResult.empty(); }
-	S32 length() const { return mWResult.size(); }
+	bool empty() const { return getUpdatedResult().empty(); }
+	S32 length() const { return getUpdatedWResult().size(); }
 
 	void clear();
 	void clearArgs() { mArgs.clear(); }
 	
-	// These utuilty functions are included for text editing.
+	// These utility functions are included for text editing.
 	// They do not affect mOrig and do not perform argument substitution
 	void truncate(S32 maxchars);
 	void erase(S32 charidx, S32 len);
@@ -96,12 +96,24 @@ public:
 	void replace(S32 charidx, llwchar wc);
 	
 private:
-	void format();	
+	// something changed, requiring reformatting of strings
+	void dirty();
+
+	std::string& getUpdatedResult() const { if (mNeedsResult) { updateResult(); } return mResult; }
+	LLWString& getUpdatedWResult() const{ if (mNeedsWResult) { updateWResult(); } return mWResult; }
+
+	// do actual work of updating strings (non-inlined)
+	void updateResult() const;
+	void updateWResult() const;
 	
 	std::string mOrig;
-	std::string mResult;
-	LLWString mWResult; // for displaying
+	mutable std::string mResult;
+	mutable LLWString mWResult; // for displaying
 	LLStringUtil::format_map_t mArgs;
+
+	// controls lazy evaluation
+	mutable bool	mNeedsResult;
+	mutable bool	mNeedsWResult;
 };
 
 #endif // LL_LLUISTRING_H