Fix incorrectly escaped arguments for CreateProcess

fixes #10245

doc/20-library-reference.md

@@ -21,6 +21,7 @@ get_time()                      | Returns the current UNIX timestamp.
 parse_performance_data(pd)      | Parses a performance data string and returns an array describing the values.
 dirname(path)                   | Returns the directory portion of the specified path.
 basename(path)                  | Returns the filename portion of the specified path.
+escape\_create\_process\_arg(text)| (Windows only) Escapes a string for use as an argument for CreateProcess().
 exit(integer)                   | Terminates the application.
 
 ## <a id="object-accessor-functions"></a> Object Accessor Functions

lib/base/process.cpp

@@ -133,7 +133,7 @@ Process::Arguments Process::PrepareCommand(const Value& command)
 			if (args != "")
 				args += " ";
 
-			args += Utility::EscapeShellArg(argument);
+			args += Utility::EscapeCreateProcessArg(argument);
 #else /* _WIN32 */
 			args.push_back(argument);
 #endif /* _WIN32 */

lib/base/scriptutils.cpp

@@ -58,6 +58,7 @@ REGISTER_SCRIPTFUNCTION(get_time, &Utility::GetTime);
 REGISTER_SCRIPTFUNCTION(basename, &Utility::BaseName);
 REGISTER_SCRIPTFUNCTION(dirname, &Utility::DirName);
 REGISTER_SCRIPTFUNCTION(msi_get_component_path, &ScriptUtils::MsiGetComponentPathShim);
+REGISTER_SCRIPTFUNCTION(escape_create_process_arg, &Utility::EscapeCreateProcessArg);
 
 String ScriptUtils::CastString(const Value& value)
 {

lib/base/string.hpp

@@ -204,6 +204,11 @@ public:
 
 	void Trim(void);
 
+	inline void Append(int count, char ch)
+	{
+		m_Data.append(count, ch);
+	}
+
 	inline bool Contains(const String& str) const
 	{
 		return (m_Data.find(str) != std::string::npos);

lib/base/utility.cpp

@@ -1016,6 +1016,40 @@ String Utility::EscapeShellArg(const String& s)
 	return result;
 }
 
+#ifdef _WIN32
+String Utility::EscapeCreateProcessArg(const String& arg)
+{
+	if (arg.FindFirstOf(" \t\n\v\"") == String::NPos)
+		return arg;
+
+	String result = "\"";
+
+	for (String::ConstIterator it = arg.Begin(); ; it++) {
+		int numBackslashes = 0;
+
+		while (it != arg.End() && *it == '\\') {
+			it++;
+			numBackslashes++;
+		}
+
+		if (it == arg.End()) {
+			result.Append(numBackslashes * 2, '\\');
+			break;
+		} else if (*it == '"') {
+			result.Append(numBackslashes * 2, '\\');
+			result.Append(1, *it);
+		} else {
+			result.Append(numBackslashes, '\\');
+			result.Append(1, *it);
+		}
+	}
+
+	result += "\"";
+
+	return result;
+}
+#endif /* _WIN32 */
+
 #ifdef _WIN32
 static void WindowsSetThreadName(const char *name)
 {

lib/base/utility.hpp

@@ -108,6 +108,7 @@ public:
 
 	static String EscapeShellCmd(const String& s);
 	static String EscapeShellArg(const String& s);
+	static String EscapeCreateProcessArg(const String& arg);
 
 	static String EscapeString(const String& s, const String& chars);
 	static String UnescapeString(const String& s);