CppGen.cpp - platform/system/tools/sysprop - Git at Google

 /*
  * Copyright (C) 2018 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #define LOG_TAG "sysprop_cpp_gen"

 #include "CppGen.h"

 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 #include <cerrno>
 #include <filesystem>
 #include <regex>
 #include <string>

 #include "CodeWriter.h"
 #include "Common.h"
 #include "sysprop.pb.h"

 using android::base::ErrnoErrorf;
 using android::base::Errorf;
 using android::base::Result;

 namespace {

 constexpr const char* kIndent = "    ";

 constexpr const char* kCppHeaderIncludes =
     R"(#include <cstdint>
 #include <optional>
 #include <string>
 #include <vector>

 )";

 constexpr const char* kCppSourceIncludes =
     R"(#include <cctype>
 #include <cerrno>
 #include <cstdio>
 #include <cstring>
 #include <limits>
 #include <utility>

 #include <strings.h>
 #include <sys/system_properties.h>

 #include <android-base/parseint.h>
 #include <log/log.h>

 )";

 constexpr const char* kCppParsersAndFormatters =
     R"(template <typename T> constexpr bool is_vector = false;

 template <typename T> constexpr bool is_vector<std::vector<T>> = true;

 template <> [[maybe_unused]] std::optional<bool> DoParse(const char* str) {
     static constexpr const char* kYes[] = {"1", "true"};
     static constexpr const char* kNo[] = {"0", "false"};

     for (const char* yes : kYes) {
         if (strcasecmp(yes, str) == 0) return std::make_optional(true);
     }

     for (const char* no : kNo) {
         if (strcasecmp(no, str) == 0) return std::make_optional(false);
     }

     return std::nullopt;
 }

 template <> [[maybe_unused]] std::optional<std::int32_t> DoParse(const char* str) {
     std::int32_t ret;
     return android::base::ParseInt(str, &ret) ? std::make_optional(ret) : std::nullopt;
 }

 template <> [[maybe_unused]] std::optional<std::int64_t> DoParse(const char* str) {
     std::int64_t ret;
     return android::base::ParseInt(str, &ret) ? std::make_optional(ret) : std::nullopt;
 }

 template <> [[maybe_unused]] std::optional<double> DoParse(const char* str) {
     int old_errno = errno;
     errno = 0;
     char* end;
     double ret = std::strtod(str, &end);
     if (errno != 0) {
         return std::nullopt;
     }
     if (str == end || *end != '\0') {
         errno = EINVAL;
         return std::nullopt;
     }
     errno = old_errno;
     return std::make_optional(ret);
 }

 template <> [[maybe_unused]] std::optional<std::string> DoParse(const char* str) {
     return *str == '\0' ? std::nullopt : std::make_optional(str);
 }

 template <typename Vec> [[maybe_unused]] Vec DoParseList(const char* str) {
     Vec ret;
     const char* p = str;
     for (;;) {
         const char* found = p;
         while (*found != '\0' && *found != ',') {
             ++found;
         }
         std::string value(p, found);
         ret.emplace_back(DoParse<typename Vec::value_type>(value.c_str()));
         if (*found == '\0') break;
         p = found + 1;
     }
     return ret;
 }

 template <typename T> inline T TryParse(const char* str) {
     if constexpr(is_vector<T>) {
         return DoParseList<T>(str);
     } else {
         return DoParse<T>(str);
     }
 }

 [[maybe_unused]] std::string FormatValue(const std::optional<std::int32_t>& value) {
     return value ? std::to_string(*value) : "";
 }

 [[maybe_unused]] std::string FormatValue(const std::optional<std::int64_t>& value) {
     return value ? std::to_string(*value) : "";
 }

 [[maybe_unused]] std::string FormatValue(const std::optional<double>& value) {
     if (!value) return "";
     char buf[1024];
     std::sprintf(buf, "%.*g", std::numeric_limits<double>::max_digits10, *value);
     return buf;
 }

 [[maybe_unused]] std::string FormatValue(const std::optional<bool>& value) {
     return value ? (*value ? "true" : "false") : "";
 }

 template <typename T>
 [[maybe_unused]] std::string FormatValue(const std::vector<T>& value) {
     if (value.empty()) return "";

     std::string ret;
     bool first = true;

     for (auto&& element : value) {
         if (!first) ret += ",";
         else first = false;
         if constexpr(std::is_same_v<T, std::optional<std::string>>) {
             if (element) ret += *element;
         } else {
             ret += FormatValue(element);
         }
     }

     return ret;
 }

 template <typename T>
 T GetProp(const char* key) {
     T ret;
     auto pi = __system_property_find(key);
     if (pi != nullptr) {
         __system_property_read_callback(pi, [](void* cookie, const char*, const char* value, std::uint32_t) {
             *static_cast<T*>(cookie) = TryParse<T>(value);
         }, &ret);
     }
     return ret;
 }

 )";

 const std::regex kRegexDot{"\\."};
 const std::regex kRegexUnderscore{"_"};

 std::string GetCppEnumName(const sysprop::Property& prop);
 std::string GetCppPropTypeName(const sysprop::Property& prop);
 std::string GetCppNamespace(const sysprop::Properties& props);

 std::string GenerateHeader(const sysprop::Properties& props,
                            sysprop::Scope scope);
 std::string GenerateSource(const sysprop::Properties& props,
                            const std::string& include_name);

 std::string GetCppEnumName(const sysprop::Property& prop) {
   return ApiNameToIdentifier(prop.api_name()) + "_values";
 }

 std::string GetCppPropTypeName(const sysprop::Property& prop) {
   switch (prop.type()) {
     case sysprop::Boolean:
       return "std::optional<bool>";
     case sysprop::Integer:
       return "std::optional<std::int32_t>";
     case sysprop::Long:
       return "std::optional<std::int64_t>";
     case sysprop::Double:
       return "std::optional<double>";
     case sysprop::String:
       return "std::optional<std::string>";
     case sysprop::Enum:
       return "std::optional<" + GetCppEnumName(prop) + ">";
     case sysprop::BooleanList:
       return "std::vector<std::optional<bool>>";
     case sysprop::IntegerList:
       return "std::vector<std::optional<std::int32_t>>";
     case sysprop::LongList:
       return "std::vector<std::optional<std::int64_t>>";
     case sysprop::DoubleList:
       return "std::vector<std::optional<double>>";
     case sysprop::StringList:
       return "std::vector<std::optional<std::string>>";
     case sysprop::EnumList:
       return "std::vector<std::optional<" + GetCppEnumName(prop) + ">>";
     default:
       __builtin_unreachable();
   }
 }

 std::string GetCppNamespace(const sysprop::Properties& props) {
   return std::regex_replace(props.module(), kRegexDot, "::");
 }

 std::string GenerateHeader(const sysprop::Properties& props,
                            sysprop::Scope scope) {
   CodeWriter writer(kIndent);

   writer.Write("%s", kGeneratedFileFooterComments);

   writer.Write("#pragma once\n\n");
   writer.Write("%s", kCppHeaderIncludes);

   std::string cpp_namespace = GetCppNamespace(props);
   writer.Write("namespace %s {\n\n", cpp_namespace.c_str());

   bool first = true;

   for (int i = 0; i < props.prop_size(); ++i) {
     const sysprop::Property& prop = props.prop(i);

     // Scope: Internal > Public
     if (prop.scope() > scope) continue;

     if (!first) {
       writer.Write("\n");
     } else {
       first = false;
     }

     std::string prop_id = ApiNameToIdentifier(prop.api_name());
     std::string prop_type = GetCppPropTypeName(prop);

     if (prop.type() == sysprop::Enum || prop.type() == sysprop::EnumList) {
       writer.Write("enum class %s {\n", GetCppEnumName(prop).c_str());
       writer.Indent();
       for (const std::string& name :
            android::base::Split(prop.enum_values(), "|")) {
         writer.Write("%s,\n", ToUpper(name).c_str());
       }
       writer.Dedent();
       writer.Write("};\n\n");
     }

     if (prop.deprecated()) writer.Write("[[deprecated]] ");
     writer.Write("%s %s();\n", prop_type.c_str(), prop_id.c_str());
     if (prop.access() != sysprop::Readonly && scope == sysprop::Internal) {
       if (prop.deprecated()) writer.Write("[[deprecated]] ");
       writer.Write("bool %s(const %s& value);\n", prop_id.c_str(),
                    prop_type.c_str());
     }
   }

   writer.Write("\n}  // namespace %s\n", cpp_namespace.c_str());

   return writer.Code();
 }

 std::string GenerateSource(const sysprop::Properties& props,
                            const std::string& include_name) {
   CodeWriter writer(kIndent);
   writer.Write("%s", kGeneratedFileFooterComments);
   writer.Write("#include <%s>\n\n", include_name.c_str());
   writer.Write("%s", kCppSourceIncludes);

   std::string cpp_namespace = GetCppNamespace(props);

   writer.Write("namespace {\n\n");
   writer.Write("using namespace %s;\n\n", cpp_namespace.c_str());
   writer.Write("template <typename T> T DoParse(const char* str);\n\n");

   for (int i = 0; i < props.prop_size(); ++i) {
     const sysprop::Property& prop = props.prop(i);
     if (prop.type() != sysprop::Enum && prop.type() != sysprop::EnumList) {
       continue;
     }

     std::string prop_id = ApiNameToIdentifier(prop.api_name());
     std::string enum_name = GetCppEnumName(prop);

     writer.Write("constexpr const std::pair<const char*, %s> %s_list[] = {\n",
                  enum_name.c_str(), prop_id.c_str());
     writer.Indent();
     for (const std::string& name :
          android::base::Split(prop.enum_values(), "|")) {
       writer.Write("{\"%s\", %s::%s},\n", name.c_str(), enum_name.c_str(),
                    ToUpper(name).c_str());
     }
     writer.Dedent();
     writer.Write("};\n\n");

     writer.Write("template <>\n");
     writer.Write("std::optional<%s> DoParse(const char* str) {\n",
                  enum_name.c_str());
     writer.Indent();
     writer.Write("for (auto [name, val] : %s_list) {\n", prop_id.c_str());
     writer.Indent();
     writer.Write("if (strcmp(str, name) == 0) {\n");
     writer.Indent();
     writer.Write("return val;\n");
     writer.Dedent();
     writer.Write("}\n");
     writer.Dedent();
     writer.Write("}\n");
     writer.Write("return std::nullopt;\n");
     writer.Dedent();
     writer.Write("}\n\n");

     if (prop.access() != sysprop::Readonly) {
       writer.Write("std::string FormatValue(std::optional<%s> value) {\n",
                    enum_name.c_str());
       writer.Indent();
       writer.Write("if (!value) return \"\";\n");
       writer.Write("for (auto [name, val] : %s_list) {\n", prop_id.c_str());
       writer.Indent();
       writer.Write("if (val == *value) {\n");
       writer.Indent();
       writer.Write("return name;\n");
       writer.Dedent();
       writer.Write("}\n");
       writer.Dedent();
       writer.Write("}\n");

       writer.Write(
           "LOG_ALWAYS_FATAL(\"Invalid value %%d for property %s\", "
           "static_cast<std::int32_t>(*value));\n",
           prop.prop_name().c_str());

       writer.Write("__builtin_unreachable();\n");
       writer.Dedent();
       writer.Write("}\n\n");
     }
   }
   writer.Write("%s", kCppParsersAndFormatters);
   writer.Write("}  // namespace\n\n");

   writer.Write("namespace %s {\n\n", cpp_namespace.c_str());

   for (int i = 0; i < props.prop_size(); ++i) {
     if (i > 0) writer.Write("\n");

     const sysprop::Property& prop = props.prop(i);
     std::string prop_id = ApiNameToIdentifier(prop.api_name());
     std::string prop_type = GetCppPropTypeName(prop);

     writer.Write("%s %s() {\n", prop_type.c_str(), prop_id.c_str());
     writer.Indent();
     writer.Write("return GetProp<%s>(\"%s\");\n", prop_type.c_str(),
                  prop.prop_name().c_str());
     writer.Dedent();
     writer.Write("}\n");

     if (prop.access() != sysprop::Readonly) {
       writer.Write("\nbool %s(const %s& value) {\n", prop_id.c_str(),
                    prop_type.c_str());
       writer.Indent();

       const char* format_expr = "FormatValue(value).c_str()";

       // Specialized formatters here
       if (prop.type() == sysprop::String) {
         format_expr = "value ? value->c_str() : \"\"";
       } else if (prop.integer_as_bool()) {
         if (prop.type() == sysprop::Boolean) {
           // optional<bool> -> optional<int>
           format_expr = "FormatValue(std::optional<int>(value)).c_str()";
         } else if (prop.type() == sysprop::BooleanList) {
           // vector<optional<bool>> -> vector<optional<int>>
           format_expr =
               "FormatValue(std::vector<std::optional<int>>("
               "value.begin(), value.end())).c_str()";
         }
       }

       writer.Write("return __system_property_set(\"%s\", %s) == 0;\n",
                    prop.prop_name().c_str(), format_expr);
       writer.Dedent();
       writer.Write("}\n");
     }
   }

   writer.Write("\n}  // namespace %s\n", cpp_namespace.c_str());

   return writer.Code();
 }

 }  // namespace

 Result<void> GenerateCppFiles(const std::string& input_file_path,
                               const std::string& header_dir,
                               const std::string& public_header_dir,
                               const std::string& source_output_dir,
                               const std::string& include_name) {
   sysprop::Properties props;

   if (auto res = ParseProps(input_file_path); res) {
     props = std::move(*res);
   } else {
     return res.error();
   }

   std::string output_basename = android::base::Basename(input_file_path);

   for (auto&& [scope, dir] : {
            std::pair(sysprop::Internal, header_dir),
            std::pair(sysprop::Public, public_header_dir),
        }) {
     std::error_code ec;
     std::filesystem::create_directories(dir, ec);
     if (ec) {
       return Errorf("Creating directory to {} failed: {}", dir, ec.message());
     }

     std::string path = dir + "/" + output_basename + ".h";
     std::string result = GenerateHeader(props, scope);

     if (!android::base::WriteStringToFile(result, path)) {
       return ErrnoErrorf("Writing generated header to {} failed", path);
     }
   }

   std::string source_path = source_output_dir + "/" + output_basename + ".cpp";
   std::string source_result = GenerateSource(props, include_name);

   if (!android::base::WriteStringToFile(source_result, source_path)) {
     return ErrnoErrorf("Writing generated source to {} failed", source_path);
   }

   return {};
 }
	/*
	* Copyright (C) 2018 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#define LOG_TAG "sysprop_cpp_gen"

	#include "CppGen.h"

	#include <android-base/file.h>
	#include <android-base/logging.h>
	#include <android-base/stringprintf.h>
	#include <android-base/strings.h>
	#include <cerrno>
	#include <filesystem>
	#include <regex>
	#include <string>

	#include "CodeWriter.h"
	#include "Common.h"
	#include "sysprop.pb.h"

	using android::base::ErrnoErrorf;
	using android::base::Errorf;
	using android::base::Result;

	namespace {

	constexpr const char* kIndent = " ";

	constexpr const char* kCppHeaderIncludes =
	R"(#include <cstdint>
	#include <optional>
	#include <string>
	#include <vector>

	)";

	constexpr const char* kCppSourceIncludes =
	R"(#include <cctype>
	#include <cerrno>
	#include <cstdio>
	#include <cstring>
	#include <limits>
	#include <utility>

	#include <strings.h>
	#include <sys/system_properties.h>

	#include <android-base/parseint.h>
	#include <log/log.h>

	)";

	constexpr const char* kCppParsersAndFormatters =
	R"(template <typename T> constexpr bool is_vector = false;

	template <typename T> constexpr bool is_vector<std::vector<T>> = true;

	template <> [[maybe_unused]] std::optional<bool> DoParse(const char* str) {
	static constexpr const char* kYes[] = {"1", "true"};
	static constexpr const char* kNo[] = {"0", "false"};

	for (const char* yes : kYes) {
	if (strcasecmp(yes, str) == 0) return std::make_optional(true);
	}

	for (const char* no : kNo) {
	if (strcasecmp(no, str) == 0) return std::make_optional(false);
	}

	return std::nullopt;
	}

	template <> [[maybe_unused]] std::optional<std::int32_t> DoParse(const char* str) {
	std::int32_t ret;
	return android::base::ParseInt(str, &ret) ? std::make_optional(ret) : std::nullopt;
	}

	template <> [[maybe_unused]] std::optional<std::int64_t> DoParse(const char* str) {
	std::int64_t ret;
	return android::base::ParseInt(str, &ret) ? std::make_optional(ret) : std::nullopt;
	}

	template <> [[maybe_unused]] std::optional<double> DoParse(const char* str) {
	int old_errno = errno;
	errno = 0;
	char* end;
	double ret = std::strtod(str, &end);
	if (errno != 0) {
	return std::nullopt;
	}
	if (str == end \|\| *end != '\0') {
	errno = EINVAL;
	return std::nullopt;
	}
	errno = old_errno;
	return std::make_optional(ret);
	}

	template <> [[maybe_unused]] std::optional<std::string> DoParse(const char* str) {
	return *str == '\0' ? std::nullopt : std::make_optional(str);
	}

	template <typename Vec> [[maybe_unused]] Vec DoParseList(const char* str) {
	Vec ret;
	const char* p = str;
	for (;;) {
	const char* found = p;
	while (found != '\0' && found != ',') {
	++found;
	}
	std::string value(p, found);
	ret.emplace_back(DoParse<typename Vec::value_type>(value.c_str()));
	if (*found == '\0') break;
	p = found + 1;
	}
	return ret;
	}

	template <typename T> inline T TryParse(const char* str) {
	if constexpr(is_vector<T>) {
	return DoParseList<T>(str);
	} else {
	return DoParse<T>(str);
	}
	}

	[[maybe_unused]] std::string FormatValue(const std::optional<std::int32_t>& value) {
	return value ? std::to_string(*value) : "";
	}

	[[maybe_unused]] std::string FormatValue(const std::optional<std::int64_t>& value) {
	return value ? std::to_string(*value) : "";
	}

	[[maybe_unused]] std::string FormatValue(const std::optional<double>& value) {
	if (!value) return "";
	char buf[1024];
	std::sprintf(buf, "%.g", std::numeric_limits<double>::max_digits10, value);
	return buf;
	}

	[[maybe_unused]] std::string FormatValue(const std::optional<bool>& value) {
	return value ? (*value ? "true" : "false") : "";
	}

	template <typename T>
	[[maybe_unused]] std::string FormatValue(const std::vector<T>& value) {
	if (value.empty()) return "";

	std::string ret;
	bool first = true;

	for (auto&& element : value) {
	if (!first) ret += ",";
	else first = false;
	if constexpr(std::is_same_v<T, std::optional<std::string>>) {
	if (element) ret += *element;
	} else {
	ret += FormatValue(element);
	}
	}

	return ret;
	}

	template <typename T>
	T GetProp(const char* key) {
	T ret;
	auto pi = __system_property_find(key);
	if (pi != nullptr) {
	__system_property_read_callback(pi, [](void* cookie, const char, const char value, std::uint32_t) {
	static_cast<T>(cookie) = TryParse<T>(value);
	}, &ret);
	}
	return ret;
	}

	)";

	const std::regex kRegexDot{"\\."};
	const std::regex kRegexUnderscore{"_"};

	std::string GetCppEnumName(const sysprop::Property& prop);
	std::string GetCppPropTypeName(const sysprop::Property& prop);
	std::string GetCppNamespace(const sysprop::Properties& props);

	std::string GenerateHeader(const sysprop::Properties& props,
	sysprop::Scope scope);
	std::string GenerateSource(const sysprop::Properties& props,
	const std::string& include_name);

	std::string GetCppEnumName(const sysprop::Property& prop) {
	return ApiNameToIdentifier(prop.api_name()) + "_values";
	}

	std::string GetCppPropTypeName(const sysprop::Property& prop) {
	switch (prop.type()) {
	case sysprop::Boolean:
	return "std::optional<bool>";
	case sysprop::Integer:
	return "std::optional<std::int32_t>";
	case sysprop::Long:
	return "std::optional<std::int64_t>";
	case sysprop::Double:
	return "std::optional<double>";
	case sysprop::String:
	return "std::optional<std::string>";
	case sysprop::Enum:
	return "std::optional<" + GetCppEnumName(prop) + ">";
	case sysprop::BooleanList:
	return "std::vector<std::optional<bool>>";
	case sysprop::IntegerList:
	return "std::vector<std::optional<std::int32_t>>";
	case sysprop::LongList:
	return "std::vector<std::optional<std::int64_t>>";
	case sysprop::DoubleList:
	return "std::vector<std::optional<double>>";
	case sysprop::StringList:
	return "std::vector<std::optional<std::string>>";
	case sysprop::EnumList:
	return "std::vector<std::optional<" + GetCppEnumName(prop) + ">>";
	default:
	__builtin_unreachable();
	}
	}

	std::string GetCppNamespace(const sysprop::Properties& props) {
	return std::regex_replace(props.module(), kRegexDot, "::");
	}

	std::string GenerateHeader(const sysprop::Properties& props,
	sysprop::Scope scope) {
	CodeWriter writer(kIndent);

	writer.Write("%s", kGeneratedFileFooterComments);

	writer.Write("#pragma once\n\n");
	writer.Write("%s", kCppHeaderIncludes);

	std::string cpp_namespace = GetCppNamespace(props);
	writer.Write("namespace %s {\n\n", cpp_namespace.c_str());

	bool first = true;

	for (int i = 0; i < props.prop_size(); ++i) {
	const sysprop::Property& prop = props.prop(i);

	// Scope: Internal > Public
	if (prop.scope() > scope) continue;

	if (!first) {
	writer.Write("\n");
	} else {
	first = false;
	}

	std::string prop_id = ApiNameToIdentifier(prop.api_name());
	std::string prop_type = GetCppPropTypeName(prop);

	if (prop.type() == sysprop::Enum \|\| prop.type() == sysprop::EnumList) {
	writer.Write("enum class %s {\n", GetCppEnumName(prop).c_str());
	writer.Indent();
	for (const std::string& name :
	android::base::Split(prop.enum_values(), "\|")) {
	writer.Write("%s,\n", ToUpper(name).c_str());
	}
	writer.Dedent();
	writer.Write("};\n\n");
	}

	if (prop.deprecated()) writer.Write("[[deprecated]] ");
	writer.Write("%s %s();\n", prop_type.c_str(), prop_id.c_str());
	if (prop.access() != sysprop::Readonly && scope == sysprop::Internal) {
	if (prop.deprecated()) writer.Write("[[deprecated]] ");
	writer.Write("bool %s(const %s& value);\n", prop_id.c_str(),
	prop_type.c_str());
	}
	}

	writer.Write("\n} // namespace %s\n", cpp_namespace.c_str());

	return writer.Code();
	}

	std::string GenerateSource(const sysprop::Properties& props,
	const std::string& include_name) {
	CodeWriter writer(kIndent);
	writer.Write("%s", kGeneratedFileFooterComments);
	writer.Write("#include <%s>\n\n", include_name.c_str());
	writer.Write("%s", kCppSourceIncludes);

	std::string cpp_namespace = GetCppNamespace(props);

	writer.Write("namespace {\n\n");
	writer.Write("using namespace %s;\n\n", cpp_namespace.c_str());
	writer.Write("template <typename T> T DoParse(const char* str);\n\n");

	for (int i = 0; i < props.prop_size(); ++i) {
	const sysprop::Property& prop = props.prop(i);
	if (prop.type() != sysprop::Enum && prop.type() != sysprop::EnumList) {
	continue;
	}

	std::string prop_id = ApiNameToIdentifier(prop.api_name());
	std::string enum_name = GetCppEnumName(prop);

	writer.Write("constexpr const std::pair<const char*, %s> %s_list[] = {\n",
	enum_name.c_str(), prop_id.c_str());
	writer.Indent();
	for (const std::string& name :
	android::base::Split(prop.enum_values(), "\|")) {
	writer.Write("{\"%s\", %s::%s},\n", name.c_str(), enum_name.c_str(),
	ToUpper(name).c_str());
	}
	writer.Dedent();
	writer.Write("};\n\n");

	writer.Write("template <>\n");
	writer.Write("std::optional<%s> DoParse(const char* str) {\n",
	enum_name.c_str());
	writer.Indent();
	writer.Write("for (auto [name, val] : %s_list) {\n", prop_id.c_str());
	writer.Indent();
	writer.Write("if (strcmp(str, name) == 0) {\n");
	writer.Indent();
	writer.Write("return val;\n");
	writer.Dedent();
	writer.Write("}\n");
	writer.Dedent();
	writer.Write("}\n");
	writer.Write("return std::nullopt;\n");
	writer.Dedent();
	writer.Write("}\n\n");

	if (prop.access() != sysprop::Readonly) {
	writer.Write("std::string FormatValue(std::optional<%s> value) {\n",
	enum_name.c_str());
	writer.Indent();
	writer.Write("if (!value) return \"\";\n");
	writer.Write("for (auto [name, val] : %s_list) {\n", prop_id.c_str());
	writer.Indent();
	writer.Write("if (val == *value) {\n");
	writer.Indent();
	writer.Write("return name;\n");
	writer.Dedent();
	writer.Write("}\n");
	writer.Dedent();
	writer.Write("}\n");

	writer.Write(
	"LOG_ALWAYS_FATAL(\"Invalid value %%d for property %s\", "
	"static_cast<std::int32_t>(*value));\n",
	prop.prop_name().c_str());

	writer.Write("__builtin_unreachable();\n");
	writer.Dedent();
	writer.Write("}\n\n");
	}
	}
	writer.Write("%s", kCppParsersAndFormatters);
	writer.Write("} // namespace\n\n");

	writer.Write("namespace %s {\n\n", cpp_namespace.c_str());

	for (int i = 0; i < props.prop_size(); ++i) {
	if (i > 0) writer.Write("\n");

	const sysprop::Property& prop = props.prop(i);
	std::string prop_id = ApiNameToIdentifier(prop.api_name());
	std::string prop_type = GetCppPropTypeName(prop);

	writer.Write("%s %s() {\n", prop_type.c_str(), prop_id.c_str());
	writer.Indent();
	writer.Write("return GetProp<%s>(\"%s\");\n", prop_type.c_str(),
	prop.prop_name().c_str());
	writer.Dedent();
	writer.Write("}\n");

	if (prop.access() != sysprop::Readonly) {
	writer.Write("\nbool %s(const %s& value) {\n", prop_id.c_str(),
	prop_type.c_str());
	writer.Indent();

	const char* format_expr = "FormatValue(value).c_str()";

	// Specialized formatters here
	if (prop.type() == sysprop::String) {
	format_expr = "value ? value->c_str() : \"\"";
	} else if (prop.integer_as_bool()) {
	if (prop.type() == sysprop::Boolean) {
	// optional<bool> -> optional<int>
	format_expr = "FormatValue(std::optional<int>(value)).c_str()";
	} else if (prop.type() == sysprop::BooleanList) {
	// vector<optional<bool>> -> vector<optional<int>>
	format_expr =
	"FormatValue(std::vector<std::optional<int>>("
	"value.begin(), value.end())).c_str()";
	}
	}

	writer.Write("return __system_property_set(\"%s\", %s) == 0;\n",
	prop.prop_name().c_str(), format_expr);
	writer.Dedent();
	writer.Write("}\n");
	}
	}

	writer.Write("\n} // namespace %s\n", cpp_namespace.c_str());

	return writer.Code();
	}

	} // namespace

	Result<void> GenerateCppFiles(const std::string& input_file_path,
	const std::string& header_dir,
	const std::string& public_header_dir,
	const std::string& source_output_dir,
	const std::string& include_name) {
	sysprop::Properties props;

	if (auto res = ParseProps(input_file_path); res) {
	props = std::move(*res);
	} else {
	return res.error();
	}

	std::string output_basename = android::base::Basename(input_file_path);

	for (auto&& [scope, dir] : {
	std::pair(sysprop::Internal, header_dir),
	std::pair(sysprop::Public, public_header_dir),
	}) {
	std::error_code ec;
	std::filesystem::create_directories(dir, ec);
	if (ec) {
	return Errorf("Creating directory to {} failed: {}", dir, ec.message());
	}

	std::string path = dir + "/" + output_basename + ".h";
	std::string result = GenerateHeader(props, scope);

	if (!android::base::WriteStringToFile(result, path)) {
	return ErrnoErrorf("Writing generated header to {} failed", path);
	}
	}

	std::string source_path = source_output_dir + "/" + output_basename + ".cpp";
	std::string source_result = GenerateSource(props, include_name);

	if (!android::base::WriteStringToFile(source_result, source_path)) {
	return ErrnoErrorf("Writing generated source to {} failed", source_path);
	}

	return {};
	}