1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ART_CMDLINE_CMDLINE_TYPE_PARSER_H_ 18 #define ART_CMDLINE_CMDLINE_TYPE_PARSER_H_ 19 20 #include "cmdline_parse_result.h" 21 22 namespace art { 23 24 // Base class for user-defined CmdlineType<T> specializations. 25 // 26 // Not strictly necessary, but if the specializations fail to Define all of these functions 27 // the compilation will fail. 28 template <typename T> 29 struct CmdlineTypeParser { 30 // Return value of parsing attempts. Represents a Success(T value) or an Error(int code) 31 using Result = CmdlineParseResult<T>; 32 33 // Parse a single value for an argument definition out of the wildcard component. 34 // 35 // e.g. if the argument definition was "foo:_", and the user-provided input was "foo:bar", 36 // then args is "bar". ParseCmdlineTypeParser37 Result Parse(const std::string& args ATTRIBUTE_UNUSED) { 38 assert(false); 39 return Result::Failure("Missing type specialization and/or value map"); 40 } 41 42 // Parse a value and append it into the existing value so far, for argument 43 // definitions which are marked with AppendValues(). 44 // 45 // The value is parsed out of the wildcard component as in Parse. 46 // 47 // If the initial value does not exist yet, a default value is created by 48 // value-initializing with 'T()'. ParseAndAppendCmdlineTypeParser49 Result ParseAndAppend(const std::string& args ATTRIBUTE_UNUSED, 50 T& existing_value ATTRIBUTE_UNUSED) { 51 assert(false); 52 return Result::Failure("Missing type specialization and/or value map"); 53 } 54 55 // Runtime type name of T, so that we can print more useful error messages. NameCmdlineTypeParser56 static const char* Name() { assert(false); return "UnspecializedType"; } 57 58 // Whether or not your type can parse argument definitions defined without a "_" 59 // e.g. -Xenable-profiler just mutates the existing profiler struct in-place 60 // so it doesn't need to do any parsing other than token recognition. 61 // 62 // If this is false, then either the argument definition has a _, from which the parsing 63 // happens, or the tokens get mapped to a value list/map from which a 1:1 matching occurs. 64 // 65 // This should almost *always* be false! 66 static constexpr bool kCanParseBlankless = false; 67 68 protected: 69 // Don't accidentally initialize instances of this directly; they will assert at runtime. 70 CmdlineTypeParser() = default; 71 }; 72 73 74 } // namespace art 75 76 #endif // ART_CMDLINE_CMDLINE_TYPE_PARSER_H_ 77