Skip to content

Commit

Permalink
Simpler cli implementation (#1037)
Browse files Browse the repository at this point in the history
  • Loading branch information
@xelatihy
xelatihy committed Aug 23, 2020
1 parent 515ad9d commit 2aa3150
Show file tree
Hide file tree
Showing 2 changed files with 431 additions and 290 deletions.
293 changes: 293 additions & 0 deletions libs/yocto/yocto_commonio.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -126,3 +126,296 @@ bool make_directory(const string& dirname, string& error) {
}

} // namespace yocto

// -----------------------------------------------------------------------------
// IMPLEMENTATION OF COMMAND-LINE PARSING
// -----------------------------------------------------------------------------
namespace yocto {

// initialize a command line parser
cli_state make_cli(const string& cmd, const string& usage) {
auto cli = cli_state{};
cli.name = cmd;
cli.usage = usage;
add_option(cli, "--help/--no-help", cli.help, "Print usage.");
return cli;
}

static vector<string> split_cli_names(const string& name_) {
auto name = name_;
auto split = vector<string>{};
if (name.empty()) throw std::invalid_argument("option name cannot be empty");
if (name.find_first_of(" \t\r\n") != string::npos)
throw std::invalid_argument("option name cannot contain whitespaces");
while (name.find_first_of(",/") != string::npos) {
auto pos = name.find_first_of(",/");
if (pos > 0) split.push_back(name.substr(0, pos));
name = name.substr(pos + 1);
}
if (!name.empty()) split.push_back(name);
if (split.empty()) throw std::invalid_argument("option name cannot be empty");
for (auto& name : split)
if ((split[0][0] == '-') != (name[0] == '-'))
throw std::invalid_argument("inconsistent option names for " + name);
return split;
}

static void validate_names(const cli_state& cli) {
// check for errors
auto used = unordered_set<string>{};
for (auto& option : cli.options) {
if (option.name.empty())
throw std::invalid_argument("name cannot be empty");
auto names = split_cli_names(option.name);
if (names.empty()) throw std::invalid_argument("name cannot be empty");
for (auto& name : names) {
if (used.find(name) != used.end())
throw std::invalid_argument("option name " + name + " already in use");
used.insert(name);
if ((name[0] == '-') != (option.name[0] == '-'))
throw std::invalid_argument("inconsistent option type for " + name);
}
}
}

bool get_help(const cli_state& cli) { return cli.help; }

string get_usage(const cli_state& cli) {
auto type_name = [](const cli_option& option) -> string {
auto str = string{};
str += "<";
if (option.nargs < 0) str += "[";
if (!option.choices.empty()) str += "string";
switch (option.type) {
case cli_type::integer: str += "integer"; break;
case cli_type::uinteger: str += "uinteger"; break;
case cli_type::number: str += "number"; break;
case cli_type::string: str += "string"; break;
case cli_type::boolean: str += "boolean"; break;
}
if (option.nargs < 0) str += "]";
str += ">";
return str;
};
auto def_string = [](const cli_option& option) -> string {
if (option.req) return string{"[required]"};
auto str = string{};
str += "[";
for (auto& value : option.def) {
switch (value.type) {
case cli_type::integer:
str += option.choices.empty() ? std::to_string(value.number)
: option.choices[value.integer];
break;
case cli_type::uinteger:
str += option.choices.empty() ? std::to_string(value.number)
: option.choices[value.uinteger];
break;
case cli_type::number: str += std::to_string(value.number); break;
case cli_type::string: str += value.text; break;
case cli_type::boolean: str += value.integer ? "true" : "false"; break;
}
}
str += "]";
return str;
};
auto message = string{};
auto has_optional = false, has_positional = false;
auto usage_optional = string{}, usage_positional = string{};
for (auto& option : cli.options) {
auto line = " " + option.name + " " + type_name(option);
while (line.size() < 32) line += " ";
line += option.usage;
line += " " + def_string(option) + "\n";
if (!option.choices.empty()) {
line += " with choices: ";
auto len = 16;
for (auto& choice : option.choices) {
if (len + choice.size() + 2 > 78) {
line += "\n ";
len = 16;
}
line += choice + ", ";
len += choice.size() + 2;
}
line = line.substr(0, line.size() - 2);
line += "\n";
}
if (option.name.find("-") == 0) {
has_optional = true;
usage_optional += line;
} else {
has_positional = true;
usage_positional += line;
}
}
message += "usage: " + cli.name + (has_optional ? "" : " [options]") +
(has_positional ? "" : " <arguments>") + cli.usage + "\n\n";
if (has_optional) {
message += "options:\n" + usage_optional + "\n";
}
if (has_positional) {
message += "arguments:\n" + usage_positional + "\n";
}
return message;
}

static bool parse_value(
cli_value& value, const string& arg, const vector<string>& choices) {
if (!choices.empty()) {
if (std::find(choices.begin(), choices.end(), arg) == choices.end())
return false;
}
switch (value.type) {
case cli_type::string: {
value.text = arg;
return true;
} break;
case cli_type::boolean: {
if (arg == "true" || arg == "1") {
value.integer = 1;
return true;
} else if (arg == "false" || arg == "0") {
value.integer = 0;
return true;
} else {
return false;
}
} break;
case cli_type::integer: {
if (choices.empty()) {
auto end = (char*)nullptr;
value.integer = (int)strtol(arg.c_str(), &end, 10);
return end != nullptr;
} else {
value.integer = (int64_t)(
std::find(choices.begin(), choices.end(), arg) - choices.begin());
return true;
}
} break;
case cli_type::uinteger: {
if (choices.empty()) {
auto end = (char*)nullptr;
value.uinteger = (int)strtoul(arg.c_str(), &end, 10);
return end != nullptr;
} else {
value.uinteger = (uint64_t)(
std::find(choices.begin(), choices.end(), arg) - choices.begin());
return true;
}
} break;
case cli_type::number: {
auto end = (char*)nullptr;
value.number = strtod(arg.c_str(), &end);
return end != nullptr;
return true;
} break;
}
return false;
}

bool parse_cli(cli_state& cli, int argc, const char** argv, string& error) {
auto cli_error = [&error](const string& message) {
error = message;
return false;
};

// validate names
validate_names(cli);

// prepare args
auto args = vector<string>{argv + 1, argv + argc};
// parse options
for (auto& option : cli.options) {
if (option.name[0] != '-') continue;
option.value = option.def;
option.set = false;
auto values = vector<string>{};
for (auto& name : split_cli_names(option.name)) {
if (std::find(args.begin(), args.end(), name) == args.end()) continue;
auto pos = std::find(args.begin(), args.end(), name) - args.begin();
args.erase(args.begin() + pos);
if (option.nargs == 0) {
values = {name.find("--no-") == string::npos ? "true" : "false"};
option.set = true;
} else if (option.nargs > 0) {
if (pos + option.nargs > args.size())
return cli_error("missing value for " + name);
values = {args.begin() + pos, args.begin() + pos + option.nargs};
option.set = true;
args.erase(args.begin() + pos, args.begin() + pos + option.nargs);
} else {
throw std::invalid_argument{"unsupported number of arguments"};
}
}
if (option.set) {
option.value.clear();
for (auto& value : values) {
option.value.emplace_back();
option.value.back().type = option.type;
if (!parse_value(option.value.back(), value, option.choices))
return cli_error("bad value for " + option.name);
}
option.set_reference(option.value);
} else {
if (option.req) return cli_error("missing value for " + option.name);
}
}
// check unknown options
for (auto& arg : args) {
if (arg.find("-") == 0) return cli_error("unknown option " + arg);
}
// parse positional
for (auto& option : cli.options) {
if (option.name[0] == '-') continue;
option.value = option.def;
option.set = false;
auto values = vector<string>{};
if (args.empty()) {
if (option.req) return cli_error("missing value for " + option.name);
} else if (option.nargs < 0) {
values = args;
option.set = true;
args.clear();
} else if (option.nargs > 0) {
if (option.nargs > args.size())
return cli_error("missing value for " + option.name);
values = {args.begin(), args.begin() + option.nargs};
args.erase(args.begin(), args.begin() + option.nargs);
option.set = true;
} else {
throw std::invalid_argument{"unsupported number of arguments"};
}
if (option.set) {
option.value.clear();
for (auto& value : values) {
option.value.emplace_back();
option.value.back().type = option.type;
if (!parse_value(option.value.back(), value, option.choices))
return cli_error("bad value for " + option.name);
}
option.set_reference(option.value);
} else {
if (option.req) return cli_error("missing value for " + option.name);
}
}
// check remaining
if (!args.empty()) return cli_error("mismatched value for " + args.front());
// done
return true;
}

void parse_cli(cli_state& cli, int argc, const char** argv) {
auto error = string{};
if (!parse_cli(cli, argc, argv, error)) {
print_info("error: " + error);
print_info("");
print_info(get_usage(cli));
exit(1);
} else if (cli.help) {
print_info(get_usage(cli));
exit(0);
}
}

} // namespace yocto

0 comments on commit 2aa3150

Please sign in to comment.