lix/src/libutil/args.cc

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#include "args.hh"
#include "hash.hh"
namespace nix {
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void Args::addFlag(Flag && flag_)
{
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auto flag = std::make_shared<Flag>(std::move(flag_));
if (flag->handler.arity != ArityAny)
assert(flag->handler.arity == flag->labels.size());
assert(flag->longName != "");
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longFlags[flag->longName] = flag;
if (flag->shortName) shortFlags[flag->shortName] = flag;
}
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std::shared_ptr<std::set<std::string>> completions;
std::string completionMarker = "___COMPLETE___";
std::optional<std::string> needsCompletion(std::string_view s)
{
if (!completions) return {};
auto i = s.find(completionMarker);
if (i != std::string::npos)
return std::string(s.begin(), i);
return {};
}
void Args::parseCmdline(const Strings & _cmdline)
{
Strings pendingArgs;
bool dashDash = false;
Strings cmdline(_cmdline);
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if (auto s = getEnv("NIX_GET_COMPLETIONS")) {
size_t n = std::stoi(*s);
assert(n > 0 && n <= cmdline.size());
*std::next(cmdline.begin(), n - 1) += completionMarker;
completions = std::make_shared<decltype(completions)::element_type>();
}
for (auto pos = cmdline.begin(); pos != cmdline.end(); ) {
auto arg = *pos;
/* Expand compound dash options (i.e., `-qlf' -> `-q -l -f',
`-j3` -> `-j 3`). */
if (!dashDash && arg.length() > 2 && arg[0] == '-' && arg[1] != '-' && isalpha(arg[1])) {
*pos = (string) "-" + arg[1];
auto next = pos; ++next;
for (unsigned int j = 2; j < arg.length(); j++)
if (isalpha(arg[j]))
cmdline.insert(next, (string) "-" + arg[j]);
else {
cmdline.insert(next, string(arg, j));
break;
}
arg = *pos;
}
if (!dashDash && arg == "--") {
dashDash = true;
++pos;
}
else if (!dashDash && std::string(arg, 0, 1) == "-") {
if (!processFlag(pos, cmdline.end()))
throw UsageError(format("unrecognised flag '%1%'") % arg);
}
else {
pendingArgs.push_back(*pos++);
if (processArgs(pendingArgs, false))
pendingArgs.clear();
}
}
processArgs(pendingArgs, true);
}
void Args::printHelp(const string & programName, std::ostream & out)
{
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std::cout << fmt(ANSI_BOLD "Usage:" ANSI_NORMAL " %s " ANSI_ITALIC "FLAGS..." ANSI_NORMAL, programName);
for (auto & exp : expectedArgs) {
std::cout << renderLabels({exp.label});
// FIXME: handle arity > 1
if (exp.arity == 0) std::cout << "...";
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if (exp.optional) std::cout << "?";
}
std::cout << "\n";
auto s = description();
if (s != "")
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std::cout << "\n" ANSI_BOLD "Summary:" ANSI_NORMAL " " << s << ".\n";
if (longFlags.size()) {
std::cout << "\n";
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std::cout << ANSI_BOLD "Flags:" ANSI_NORMAL "\n";
printFlags(out);
}
}
void Args::printFlags(std::ostream & out)
{
Table2 table;
for (auto & flag : longFlags) {
if (hiddenCategories.count(flag.second->category)) continue;
table.push_back(std::make_pair(
(flag.second->shortName ? std::string("-") + flag.second->shortName + ", " : " ")
+ "--" + flag.first + renderLabels(flag.second->labels),
flag.second->description));
}
printTable(out, table);
}
bool Args::processFlag(Strings::iterator & pos, Strings::iterator end)
{
assert(pos != end);
auto process = [&](const std::string & name, const Flag & flag) -> bool {
++pos;
std::vector<std::string> args;
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bool anyNeedsCompletion = false;
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for (size_t n = 0 ; n < flag.handler.arity; ++n) {
if (pos == end) {
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if (flag.handler.arity == ArityAny) break;
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if (anyNeedsCompletion)
args.push_back("");
else
throw UsageError("flag '%s' requires %d argument(s)", name, flag.handler.arity);
} else {
if (needsCompletion(*pos))
anyNeedsCompletion = true;
args.push_back(*pos++);
}
}
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flag.handler.fun(std::move(args));
return true;
};
if (string(*pos, 0, 2) == "--") {
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if (auto prefix = needsCompletion(*pos)) {
for (auto & [name, flag] : longFlags) {
if (!hiddenCategories.count(flag->category)
&& hasPrefix(name, std::string(*prefix, 2)))
completions->insert("--" + name);
}
}
auto i = longFlags.find(string(*pos, 2));
if (i == longFlags.end()) return false;
return process("--" + i->first, *i->second);
}
if (string(*pos, 0, 1) == "-" && pos->size() == 2) {
auto c = (*pos)[1];
auto i = shortFlags.find(c);
if (i == shortFlags.end()) return false;
return process(std::string("-") + c, *i->second);
}
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if (auto prefix = needsCompletion(*pos)) {
if (prefix == "-") {
completions->insert("--");
for (auto & [flag, _] : shortFlags)
completions->insert(std::string("-") + flag);
}
}
return false;
}
bool Args::processArgs(const Strings & args, bool finish)
{
if (expectedArgs.empty()) {
if (!args.empty())
throw UsageError(format("unexpected argument '%1%'") % args.front());
return true;
}
auto & exp = expectedArgs.front();
bool res = false;
if ((exp.arity == 0 && finish) ||
(exp.arity > 0 && args.size() == exp.arity))
{
std::vector<std::string> ss;
for (auto & s : args) ss.push_back(s);
exp.handler(std::move(ss));
expectedArgs.pop_front();
res = true;
}
if (finish && !expectedArgs.empty() && !expectedArgs.front().optional)
throw UsageError("more arguments are required");
return res;
}
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Args::Flag Args::Flag::mkHashTypeFlag(std::string && longName, HashType * ht)
{
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return Flag {
.longName = std::move(longName),
.description = "hash algorithm ('md5', 'sha1', 'sha256', or 'sha512')",
.labels = {"hash-algo"},
.handler = {[ht](std::string s) {
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if (auto prefix = needsCompletion(s))
for (auto & type : hashTypes)
if (hasPrefix(type, *prefix))
completions->insert(type);
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*ht = parseHashType(s);
if (*ht == htUnknown)
throw UsageError("unknown hash type '%1%'", s);
}}
};
}
Strings argvToStrings(int argc, char * * argv)
{
Strings args;
argc--; argv++;
while (argc--) args.push_back(*argv++);
return args;
}
std::string renderLabels(const Strings & labels)
{
std::string res;
for (auto label : labels) {
for (auto & c : label) c = std::toupper(c);
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res += " " ANSI_ITALIC + label + ANSI_NORMAL;
}
return res;
}
void printTable(std::ostream & out, const Table2 & table)
{
size_t max = 0;
for (auto & row : table)
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max = std::max(max, filterANSIEscapes(row.first, true).size());
for (auto & row : table) {
out << " " << row.first
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<< std::string(max - filterANSIEscapes(row.first, true).size() + 2, ' ')
<< row.second << "\n";
}
}
void Command::printHelp(const string & programName, std::ostream & out)
{
Args::printHelp(programName, out);
auto exs = examples();
if (!exs.empty()) {
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out << "\n" ANSI_BOLD "Examples:" ANSI_NORMAL "\n";
for (auto & ex : exs)
out << "\n"
<< " " << ex.description << "\n" // FIXME: wrap
<< " $ " << ex.command << "\n";
}
}
MultiCommand::MultiCommand(const Commands & commands)
: commands(commands)
{
expectedArgs.push_back(ExpectedArg{"command", 1, true, [=](std::vector<std::string> ss) {
assert(!command);
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if (auto prefix = needsCompletion(ss[0])) {
for (auto & [name, command] : commands)
if (hasPrefix(name, *prefix))
completions->insert(name);
}
auto i = commands.find(ss[0]);
if (i == commands.end())
throw UsageError("'%s' is not a recognised command", ss[0]);
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command = {ss[0], i->second()};
}});
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categories[Command::catDefault] = "Available commands";
}
void MultiCommand::printHelp(const string & programName, std::ostream & out)
{
if (command) {
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command->second->printHelp(programName + " " + command->first, out);
return;
}
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out << fmt(ANSI_BOLD "Usage:" ANSI_NORMAL " %s " ANSI_ITALIC "COMMAND FLAGS... ARGS..." ANSI_NORMAL "\n", programName);
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out << "\n" ANSI_BOLD "Common flags:" ANSI_NORMAL "\n";
printFlags(out);
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std::map<Command::Category, std::map<std::string, ref<Command>>> commandsByCategory;
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for (auto & [name, commandFun] : commands) {
auto command = commandFun();
commandsByCategory[command->category()].insert_or_assign(name, command);
}
for (auto & [category, commands] : commandsByCategory) {
out << fmt("\n" ANSI_BOLD "%s:" ANSI_NORMAL "\n", categories[category]);
Table2 table;
for (auto & [name, command] : commands) {
auto descr = command->description();
if (!descr.empty())
table.push_back(std::make_pair(name, descr));
}
printTable(out, table);
}
}
bool MultiCommand::processFlag(Strings::iterator & pos, Strings::iterator end)
{
if (Args::processFlag(pos, end)) return true;
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if (command && command->second->processFlag(pos, end)) return true;
return false;
}
bool MultiCommand::processArgs(const Strings & args, bool finish)
{
if (command)
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return command->second->processArgs(args, finish);
else
return Args::processArgs(args, finish);
}
}