diff options
Diffstat (limited to 'third_party/nix/src/libutil/args.hh')
-rw-r--r-- | third_party/nix/src/libutil/args.hh | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/third_party/nix/src/libutil/args.hh b/third_party/nix/src/libutil/args.hh new file mode 100644 index 000000000000..2c352a04368c --- /dev/null +++ b/third_party/nix/src/libutil/args.hh @@ -0,0 +1,219 @@ +#pragma once + +#include <iostream> +#include <map> +#include <memory> + +#include <absl/strings/numbers.h> + +#include "util.hh" + +namespace nix { + +MakeError(UsageError, Error) + + enum HashType : char; + +class Args { + public: + /* Parse the command line, throwing a UsageError if something goes + wrong. */ + void parseCmdline(const Strings& cmdline); + + virtual void printHelp(const std::string& programName, std::ostream& out); + + virtual std::string description() { return ""; } + + protected: + static const size_t ArityAny = std::numeric_limits<size_t>::max(); + + /* Flags. */ + struct Flag { + typedef std::shared_ptr<Flag> ptr; + std::string longName; + char shortName = 0; + std::string description; + Strings labels; + size_t arity = 0; + std::function<void(std::vector<std::string>)> handler; + std::string category; + }; + + std::map<std::string, Flag::ptr> longFlags; + std::map<char, Flag::ptr> shortFlags; + + virtual bool processFlag(Strings::iterator& pos, Strings::iterator end); + + virtual void printFlags(std::ostream& out); + + /* Positional arguments. */ + struct ExpectedArg { + std::string label; + size_t arity; // 0 = any + bool optional; + std::function<void(std::vector<std::string>)> handler; + }; + + std::list<ExpectedArg> expectedArgs; + + virtual bool processArgs(const Strings& args, bool finish); + + std::set<std::string> hiddenCategories; + + public: + class FlagMaker { + Args& args; + Flag::ptr flag; + friend class Args; + FlagMaker(Args& args) : args(args), flag(std::make_shared<Flag>()){}; + + public: + ~FlagMaker(); + FlagMaker& longName(const std::string& s) { + flag->longName = s; + return *this; + }; + FlagMaker& shortName(char s) { + flag->shortName = s; + return *this; + }; + FlagMaker& description(const std::string& s) { + flag->description = s; + return *this; + }; + FlagMaker& label(const std::string& l) { + flag->arity = 1; + flag->labels = {l}; + return *this; + }; + FlagMaker& labels(const Strings& ls) { + flag->arity = ls.size(); + flag->labels = ls; + return *this; + }; + FlagMaker& arity(size_t arity) { + flag->arity = arity; + return *this; + }; + FlagMaker& handler(std::function<void(std::vector<std::string>)> handler) { + flag->handler = handler; + return *this; + }; + FlagMaker& handler(std::function<void()> handler) { + flag->handler = [handler](std::vector<std::string>) { handler(); }; + return *this; + }; + FlagMaker& handler(std::function<void(std::string)> handler) { + flag->arity = 1; + flag->handler = [handler](std::vector<std::string> ss) { + handler(std::move(ss[0])); + }; + return *this; + }; + FlagMaker& category(const std::string& s) { + flag->category = s; + return *this; + }; + + template <class T> + FlagMaker& dest(T* dest) { + flag->arity = 1; + flag->handler = [=](std::vector<std::string> ss) { *dest = ss[0]; }; + return *this; + } + + template <class T> + FlagMaker& set(T* dest, const T& val) { + flag->arity = 0; + flag->handler = [=](std::vector<std::string> ss) { *dest = val; }; + return *this; + } + + FlagMaker& mkHashTypeFlag(HashType* ht); + }; + + FlagMaker mkFlag(); + + /* Helper functions for constructing flags / positional + arguments. */ + + void mkFlag1(char shortName, const std::string& longName, + const std::string& label, const std::string& description, + std::function<void(std::string)> fun) { + mkFlag() + .shortName(shortName) + .longName(longName) + .labels({label}) + .description(description) + .arity(1) + .handler([=](std::vector<std::string> ss) { fun(ss[0]); }); + } + + void mkFlag(char shortName, const std::string& name, + const std::string& description, bool* dest) { + mkFlag(shortName, name, description, dest, true); + } + + template <class T> + void mkFlag(char shortName, const std::string& longName, + const std::string& description, T* dest, const T& value) { + mkFlag() + .shortName(shortName) + .longName(longName) + .description(description) + .handler([=](std::vector<std::string> ss) { *dest = value; }); + } + + template <class I> + void mkIntFlag(char shortName, const std::string& longName, + const std::string& description, I* dest) { + mkFlag<I>(shortName, longName, description, [=](I n) { *dest = n; }); + } + + template <class I> + void mkFlag(char shortName, const std::string& longName, + const std::string& description, std::function<void(I)> fun) { + mkFlag() + .shortName(shortName) + .longName(longName) + .labels({"N"}) + .description(description) + .arity(1) + .handler([=](std::vector<std::string> ss) { + I n; + if (!absl::SimpleAtoi(ss[0], &n)) + throw UsageError("flag '--%s' requires a integer argument", + longName); + fun(n); + }); + } + + /* Expect a string argument. */ + void expectArg(const std::string& label, std::string* dest, + bool optional = false) { + expectedArgs.push_back( + ExpectedArg{label, 1, optional, + [=](std::vector<std::string> ss) { *dest = ss[0]; }}); + } + + /* Expect 0 or more arguments. */ + void expectArgs(const std::string& label, std::vector<std::string>* dest) { + expectedArgs.push_back(ExpectedArg{ + label, 0, false, + [=](std::vector<std::string> ss) { *dest = std::move(ss); }}); + } + + friend class MultiCommand; +}; + +Strings argvToStrings(int argc, char** argv); + +/* Helper function for rendering argument labels. */ +std::string renderLabels(const Strings& labels); + +/* Helper function for printing 2-column tables. */ +typedef std::vector<std::pair<std::string, std::string>> Table2; + +void printTable(std::ostream& out, const Table2& table); + +} // namespace nix |