lix/src/libutil/args.cc

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#include "args.hh"
#include "hash.hh"
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#include <glob.h>
#include <nlohmann/json.hpp>
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;
for (auto & alias : flag->aliases)
longFlags[alias] = flag;
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if (flag->shortName) shortFlags[flag->shortName] = flag;
}
void Args::removeFlag(const std::string & longName)
{
auto flag = longFlags.find(longName);
assert(flag != longFlags.end());
if (flag->second->shortName) shortFlags.erase(flag->second->shortName);
longFlags.erase(flag);
}
void Completions::add(std::string completion, std::string description)
{
assert(description.find('\n') == std::string::npos);
insert(Completion {
.completion = completion,
.description = description
});
}
bool Completion::operator<(const Completion & other) const
{ return completion < other.completion || (completion == other.completion && description < other.description); }
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bool pathCompletions = false;
std::shared_ptr<Completions> completions;
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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>();
verbosity = lvlError;
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}
bool argsSeen = false;
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("unrecognised flag '%1%'", arg);
}
else {
if (!argsSeen) {
argsSeen = true;
initialFlagsProcessed();
}
pos = rewriteArgs(cmdline, pos);
pendingArgs.push_back(*pos++);
if (processArgs(pendingArgs, false))
pendingArgs.clear();
}
}
processArgs(pendingArgs, true);
if (!argsSeen)
initialFlagsProcessed();
}
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;
bool anyCompleted = 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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throw UsageError("flag '%s' requires %d argument(s)", name, flag.handler.arity);
}
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if (flag.completer)
if (auto prefix = needsCompletion(*pos)) {
anyCompleted = true;
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flag.completer(n, *prefix);
}
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args.push_back(*pos++);
}
if (!anyCompleted)
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->add("--" + name, flag->description);
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}
}
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->add("--");
for (auto & [flagName, flag] : shortFlags)
completions->add(std::string("-") + flagName, flag->description);
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}
}
return false;
}
bool Args::processArgs(const Strings & args, bool finish)
{
if (expectedArgs.empty()) {
if (!args.empty())
throw UsageError("unexpected argument '%1%'", args.front());
return true;
}
auto & exp = expectedArgs.front();
bool res = false;
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if ((exp.handler.arity == ArityAny && finish) ||
(exp.handler.arity != ArityAny && args.size() == exp.handler.arity))
{
std::vector<std::string> ss;
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for (const auto &[n, s] : enumerate(args)) {
ss.push_back(s);
if (exp.completer)
if (auto prefix = needsCompletion(s))
exp.completer(n, *prefix);
}
exp.handler.fun(ss);
expectedArgs.pop_front();
res = true;
}
if (finish && !expectedArgs.empty() && !expectedArgs.front().optional)
throw UsageError("more arguments are required");
return res;
}
nlohmann::json Args::toJSON()
{
auto flags = nlohmann::json::object();
for (auto & [name, flag] : longFlags) {
auto j = nlohmann::json::object();
if (flag->aliases.count(name)) continue;
if (flag->shortName)
j["shortName"] = std::string(1, flag->shortName);
if (flag->description != "")
j["description"] = flag->description;
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j["category"] = flag->category;
if (flag->handler.arity != ArityAny)
j["arity"] = flag->handler.arity;
if (!flag->labels.empty())
j["labels"] = flag->labels;
flags[name] = std::move(j);
}
auto args = nlohmann::json::array();
for (auto & arg : expectedArgs) {
auto j = nlohmann::json::object();
j["label"] = arg.label;
j["optional"] = arg.optional;
if (arg.handler.arity != ArityAny)
j["arity"] = arg.handler.arity;
args.push_back(std::move(j));
}
auto res = nlohmann::json::object();
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res["description"] = description();
res["flags"] = std::move(flags);
res["args"] = std::move(args);
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auto s = doc();
if (s != "") res.emplace("doc", stripIndentation(s));
return res;
}
static void hashTypeCompleter(size_t index, std::string_view prefix)
{
for (auto & type : hashTypes)
if (hasPrefix(type, prefix))
completions->add(type);
}
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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) {
*ht = parseHashType(s);
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}},
.completer = hashTypeCompleter
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};
}
Args::Flag Args::Flag::mkHashTypeOptFlag(std::string && longName, std::optional<HashType> * oht)
{
return Flag {
.longName = std::move(longName),
.description = "hash algorithm ('md5', 'sha1', 'sha256', or 'sha512'). Optional as can also be gotten from SRI hash itself.",
.labels = {"hash-algo"},
.handler = {[oht](std::string s) {
*oht = std::optional<HashType> { parseHashType(s) };
}},
.completer = hashTypeCompleter
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};
}
static void _completePath(std::string_view prefix, bool onlyDirs)
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{
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pathCompletions = true;
glob_t globbuf;
int flags = GLOB_NOESCAPE | GLOB_TILDE;
#ifdef GLOB_ONLYDIR
if (onlyDirs)
flags |= GLOB_ONLYDIR;
#endif
if (glob((std::string(prefix) + "*").c_str(), flags, nullptr, &globbuf) == 0) {
for (size_t i = 0; i < globbuf.gl_pathc; ++i) {
if (onlyDirs) {
auto st = lstat(globbuf.gl_pathv[i]);
if (!S_ISDIR(st.st_mode)) continue;
}
completions->add(globbuf.gl_pathv[i]);
}
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globfree(&globbuf);
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}
}
void completePath(size_t, std::string_view prefix)
{
_completePath(prefix, false);
}
void completeDir(size_t, std::string_view prefix)
{
_completePath(prefix, true);
}
Strings argvToStrings(int argc, char * * argv)
{
Strings args;
argc--; argv++;
while (argc--) args.push_back(*argv++);
return args;
}
MultiCommand::MultiCommand(const Commands & commands_)
: commands(commands_)
{
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expectArgs({
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.label = "subcommand",
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.optional = true,
.handler = {[=](std::string s) {
assert(!command);
if (auto prefix = needsCompletion(s)) {
for (auto & [name, command] : commands)
if (hasPrefix(name, *prefix))
completions->add(name);
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}
auto i = commands.find(s);
if (i == commands.end())
throw UsageError("'%s' is not a recognised command", s);
command = {s, i->second()};
}}
});
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categories[Command::catDefault] = "Available commands";
}
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);
}
nlohmann::json MultiCommand::toJSON()
{
auto cmds = nlohmann::json::object();
for (auto & [name, commandFun] : commands) {
auto command = commandFun();
auto j = command->toJSON();
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auto cat = nlohmann::json::object();
cat["id"] = command->category();
cat["description"] = categories[command->category()];
j["category"] = std::move(cat);
cmds[name] = std::move(j);
}
auto res = Args::toJSON();
res["commands"] = std::move(cmds);
return res;
}
}