forked from lix-project/lix
4607ac7aed
If we conditionally "declare" the argument, as we did before, based upon
weather the feature is enabled, commands like
nix --experimental-features=foo ... --thing-gated-on-foo
won't work, because the experimental feature isn't enabled until *after*
we start parsing.
Instead, allow arguments to also be associated with experimental
features (just as we did for builtins and settings), and then the
command line parser will filter out the experimental ones.
Since the effects of arguments (handler functions) are performed right
away, we get the required behavior: earlier arguments can enable later
arguments enabled!
There is just one catch: we want to keep non-positional
flags...non-positional. So if
nix --experimental-features=foo ... --thing-gated-on-foo
works, then
nix --thing-gated-on-foo --experimental-features=foo ...
should also work.
This is not my favorite long-term solution, but for now this is
implemented by delaying the requirement of needed experimental features
until *after* all the arguments have been parsed.
420 lines
13 KiB
C++
420 lines
13 KiB
C++
#include "args.hh"
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#include "hash.hh"
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#include <glob.h>
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#include <nlohmann/json.hpp>
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namespace nix {
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void Args::addFlag(Flag && flag_)
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{
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auto flag = std::make_shared<Flag>(std::move(flag_));
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if (flag->handler.arity != ArityAny)
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assert(flag->handler.arity == flag->labels.size());
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assert(flag->longName != "");
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longFlags[flag->longName] = flag;
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for (auto & alias : flag->aliases)
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longFlags[alias] = flag;
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if (flag->shortName) shortFlags[flag->shortName] = flag;
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}
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void Args::removeFlag(const std::string & longName)
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{
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auto flag = longFlags.find(longName);
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assert(flag != longFlags.end());
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if (flag->second->shortName) shortFlags.erase(flag->second->shortName);
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longFlags.erase(flag);
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}
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void Completions::add(std::string completion, std::string description)
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{
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description = trim(description);
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// ellipsize overflowing content on the back of the description
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auto end_index = description.find_first_of(".\n");
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if (end_index != std::string::npos) {
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auto needs_ellipsis = end_index != description.size() - 1;
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description.resize(end_index);
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if (needs_ellipsis)
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description.append(" [...]");
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}
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insert(Completion {
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.completion = completion,
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.description = description
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});
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}
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bool Completion::operator<(const Completion & other) const
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{ return completion < other.completion || (completion == other.completion && description < other.description); }
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CompletionType completionType = ctNormal;
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std::shared_ptr<Completions> completions;
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std::string completionMarker = "___COMPLETE___";
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static std::optional<std::string> needsCompletion(std::string_view s)
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{
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if (!completions) return {};
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auto i = s.find(completionMarker);
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if (i != std::string::npos)
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return std::string(s.begin(), i);
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return {};
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}
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void Args::parseCmdline(const Strings & _cmdline)
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{
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Strings pendingArgs;
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bool dashDash = false;
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Strings cmdline(_cmdline);
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if (auto s = getEnv("NIX_GET_COMPLETIONS")) {
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size_t n = std::stoi(*s);
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assert(n > 0 && n <= cmdline.size());
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*std::next(cmdline.begin(), n - 1) += completionMarker;
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completions = std::make_shared<decltype(completions)::element_type>();
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verbosity = lvlError;
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}
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bool argsSeen = false;
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for (auto pos = cmdline.begin(); pos != cmdline.end(); ) {
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auto arg = *pos;
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/* Expand compound dash options (i.e., `-qlf' -> `-q -l -f',
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`-j3` -> `-j 3`). */
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if (!dashDash && arg.length() > 2 && arg[0] == '-' && arg[1] != '-' && isalpha(arg[1])) {
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*pos = (std::string) "-" + arg[1];
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auto next = pos; ++next;
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for (unsigned int j = 2; j < arg.length(); j++)
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if (isalpha(arg[j]))
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cmdline.insert(next, (std::string) "-" + arg[j]);
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else {
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cmdline.insert(next, std::string(arg, j));
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break;
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}
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arg = *pos;
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}
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if (!dashDash && arg == "--") {
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dashDash = true;
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++pos;
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}
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else if (!dashDash && std::string(arg, 0, 1) == "-") {
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if (!processFlag(pos, cmdline.end()))
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throw UsageError("unrecognised flag '%1%'", arg);
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}
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else {
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if (!argsSeen) {
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argsSeen = true;
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initialFlagsProcessed();
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}
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pos = rewriteArgs(cmdline, pos);
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pendingArgs.push_back(*pos++);
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if (processArgs(pendingArgs, false))
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pendingArgs.clear();
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}
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}
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processArgs(pendingArgs, true);
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if (!argsSeen)
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initialFlagsProcessed();
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/* Now that we are done parsing, make sure that any experimental
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* feature required by the flags is enabled */
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for (auto & f : flagExperimentalFeatures)
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experimentalFeatureSettings.require(f);
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}
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bool Args::processFlag(Strings::iterator & pos, Strings::iterator end)
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{
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assert(pos != end);
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auto process = [&](const std::string & name, const Flag & flag) -> bool {
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++pos;
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if (auto & f = flag.experimentalFeature)
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flagExperimentalFeatures.insert(*f);
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std::vector<std::string> args;
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bool anyCompleted = false;
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for (size_t n = 0 ; n < flag.handler.arity; ++n) {
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if (pos == end) {
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if (flag.handler.arity == ArityAny || anyCompleted) break;
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throw UsageError(
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"flag '%s' requires %d argument(s), but only %d were given",
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name, flag.handler.arity, n);
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}
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if (auto prefix = needsCompletion(*pos)) {
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anyCompleted = true;
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if (flag.completer)
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flag.completer(n, *prefix);
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}
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args.push_back(*pos++);
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}
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if (!anyCompleted)
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flag.handler.fun(std::move(args));
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return true;
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};
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if (std::string(*pos, 0, 2) == "--") {
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if (auto prefix = needsCompletion(*pos)) {
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for (auto & [name, flag] : longFlags) {
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if (!hiddenCategories.count(flag->category)
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&& hasPrefix(name, std::string(*prefix, 2)))
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{
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if (auto & f = flag->experimentalFeature)
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flagExperimentalFeatures.insert(*f);
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completions->add("--" + name, flag->description);
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}
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}
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return false;
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}
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auto i = longFlags.find(std::string(*pos, 2));
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if (i == longFlags.end()) return false;
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return process("--" + i->first, *i->second);
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}
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if (std::string(*pos, 0, 1) == "-" && pos->size() == 2) {
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auto c = (*pos)[1];
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auto i = shortFlags.find(c);
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if (i == shortFlags.end()) return false;
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return process(std::string("-") + c, *i->second);
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}
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if (auto prefix = needsCompletion(*pos)) {
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if (prefix == "-") {
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completions->add("--");
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for (auto & [flagName, flag] : shortFlags)
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if (experimentalFeatureSettings.isEnabled(flag->experimentalFeature))
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completions->add(std::string("-") + flagName, flag->description);
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}
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}
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return false;
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}
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bool Args::processArgs(const Strings & args, bool finish)
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{
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if (expectedArgs.empty()) {
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if (!args.empty())
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throw UsageError("unexpected argument '%1%'", args.front());
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return true;
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}
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auto & exp = expectedArgs.front();
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bool res = false;
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if ((exp.handler.arity == ArityAny && finish) ||
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(exp.handler.arity != ArityAny && args.size() == exp.handler.arity))
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{
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std::vector<std::string> ss;
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for (const auto &[n, s] : enumerate(args)) {
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if (auto prefix = needsCompletion(s)) {
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ss.push_back(*prefix);
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if (exp.completer)
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exp.completer(n, *prefix);
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} else
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ss.push_back(s);
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}
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exp.handler.fun(ss);
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expectedArgs.pop_front();
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res = true;
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}
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if (finish && !expectedArgs.empty() && !expectedArgs.front().optional)
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throw UsageError("more arguments are required");
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return res;
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}
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nlohmann::json Args::toJSON()
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{
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auto flags = nlohmann::json::object();
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for (auto & [name, flag] : longFlags) {
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/* Skip experimental flags when listing flags. */
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if (!experimentalFeatureSettings.isEnabled(flag->experimentalFeature)) continue;
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auto j = nlohmann::json::object();
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if (flag->aliases.count(name)) continue;
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if (flag->shortName)
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j["shortName"] = std::string(1, flag->shortName);
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if (flag->description != "")
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j["description"] = trim(flag->description);
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j["category"] = flag->category;
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if (flag->handler.arity != ArityAny)
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j["arity"] = flag->handler.arity;
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if (!flag->labels.empty())
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j["labels"] = flag->labels;
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flags[name] = std::move(j);
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}
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auto args = nlohmann::json::array();
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for (auto & arg : expectedArgs) {
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auto j = nlohmann::json::object();
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j["label"] = arg.label;
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j["optional"] = arg.optional;
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if (arg.handler.arity != ArityAny)
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j["arity"] = arg.handler.arity;
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args.push_back(std::move(j));
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}
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auto res = nlohmann::json::object();
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res["description"] = trim(description());
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res["flags"] = std::move(flags);
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res["args"] = std::move(args);
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auto s = doc();
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if (s != "") res.emplace("doc", stripIndentation(s));
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return res;
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}
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static void hashTypeCompleter(size_t index, std::string_view prefix)
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{
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for (auto & type : hashTypes)
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if (hasPrefix(type, prefix))
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completions->add(type);
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}
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Args::Flag Args::Flag::mkHashTypeFlag(std::string && longName, HashType * ht)
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{
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return Flag {
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.longName = std::move(longName),
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.description = "hash algorithm ('md5', 'sha1', 'sha256', or 'sha512')",
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.labels = {"hash-algo"},
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.handler = {[ht](std::string s) {
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*ht = parseHashType(s);
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}},
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.completer = hashTypeCompleter
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};
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}
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Args::Flag Args::Flag::mkHashTypeOptFlag(std::string && longName, std::optional<HashType> * oht)
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{
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return Flag {
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.longName = std::move(longName),
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.description = "hash algorithm ('md5', 'sha1', 'sha256', or 'sha512'). Optional as can also be gotten from SRI hash itself.",
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.labels = {"hash-algo"},
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.handler = {[oht](std::string s) {
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*oht = std::optional<HashType> { parseHashType(s) };
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}},
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.completer = hashTypeCompleter
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};
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}
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static void _completePath(std::string_view prefix, bool onlyDirs)
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{
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completionType = ctFilenames;
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glob_t globbuf;
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int flags = GLOB_NOESCAPE;
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#ifdef GLOB_ONLYDIR
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if (onlyDirs)
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flags |= GLOB_ONLYDIR;
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#endif
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// using expandTilde here instead of GLOB_TILDE(_CHECK) so that ~<Tab> expands to /home/user/
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if (glob((expandTilde(prefix) + "*").c_str(), flags, nullptr, &globbuf) == 0) {
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for (size_t i = 0; i < globbuf.gl_pathc; ++i) {
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if (onlyDirs) {
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auto st = stat(globbuf.gl_pathv[i]);
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if (!S_ISDIR(st.st_mode)) continue;
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}
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completions->add(globbuf.gl_pathv[i]);
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}
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}
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globfree(&globbuf);
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}
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void completePath(size_t, std::string_view prefix)
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{
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_completePath(prefix, false);
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}
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void completeDir(size_t, std::string_view prefix)
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{
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_completePath(prefix, true);
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}
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Strings argvToStrings(int argc, char * * argv)
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{
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Strings args;
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argc--; argv++;
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while (argc--) args.push_back(*argv++);
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return args;
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}
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MultiCommand::MultiCommand(const Commands & commands_)
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: commands(commands_)
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{
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expectArgs({
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.label = "subcommand",
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.optional = true,
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.handler = {[=,this](std::string s) {
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assert(!command);
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auto i = commands.find(s);
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if (i == commands.end()) {
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std::set<std::string> commandNames;
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for (auto & [name, _] : commands)
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commandNames.insert(name);
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auto suggestions = Suggestions::bestMatches(commandNames, s);
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throw UsageError(suggestions, "'%s' is not a recognised command", s);
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}
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command = {s, i->second()};
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command->second->parent = this;
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}},
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.completer = {[&](size_t, std::string_view prefix) {
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for (auto & [name, command] : commands)
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if (hasPrefix(name, prefix))
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completions->add(name);
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}}
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});
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categories[Command::catDefault] = "Available commands";
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}
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bool MultiCommand::processFlag(Strings::iterator & pos, Strings::iterator end)
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{
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if (Args::processFlag(pos, end)) return true;
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if (command && command->second->processFlag(pos, end)) return true;
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return false;
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}
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bool MultiCommand::processArgs(const Strings & args, bool finish)
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{
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if (command)
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return command->second->processArgs(args, finish);
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else
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return Args::processArgs(args, finish);
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}
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void MultiCommand::completionHook()
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{
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if (command)
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return command->second->completionHook();
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else
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return Args::completionHook();
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}
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nlohmann::json MultiCommand::toJSON()
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{
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auto cmds = nlohmann::json::object();
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for (auto & [name, commandFun] : commands) {
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auto command = commandFun();
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auto j = command->toJSON();
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auto cat = nlohmann::json::object();
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cat["id"] = command->category();
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cat["description"] = trim(categories[command->category()]);
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j["category"] = std::move(cat);
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cmds[name] = std::move(j);
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}
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auto res = Args::toJSON();
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res["commands"] = std::move(cmds);
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return res;
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}
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}
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