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https://github.com/matrix-construct/construct
synced 2024-06-11 06:28:55 +02:00
ircd::rfc1459: Output grammar [part 2: protocol-safe format strings].
This commit is contained in:
Jason Volk
parent
1e2ce3617d
commit
1837f55d11
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@ -188,6 +188,45 @@ std::ostream &operator<<(std::ostream &, const cmd &);
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std::ostream &operator<<(std::ostream &, const parv &);
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std::ostream &operator<<(std::ostream &, const line &); // unterminated
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namespace fmt
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{
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IRCD_EXCEPTION(rfc1459::error, error);
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IRCD_EXCEPTION(error, fmtstr_invalid);
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IRCD_EXCEPTION(error, fmtstr_mismatch);
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struct spec;
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// internal API
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using ptrs = std::vector<const void *>;
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using types = std::vector<std::type_index>;
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using arg = std::tuple<const void *const &, const std::type_index &>;
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using handler = std::function<bool (char *&, const size_t &, const spec &, const arg &)>;
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ssize_t _snprintf(char *const &, const size_t &, const char *const &, const ptrs &, const types &);
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// public API
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template<class... Args> ssize_t snprintf(char *const &buf, const size_t &max, const char *const &fmt, Args&&... args);
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}
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template<class... Args>
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ssize_t
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fmt::snprintf(char *const &buf,
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const size_t &max,
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const char *const &fmt,
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Args&&... args)
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{
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static const std::vector<std::type_index> types
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{
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typeid(Args)...
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};
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const std::vector<const void *> ptrs
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{
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std::addressof(args)...
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};
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return _snprintf(buf, max, fmt, ptrs, types);
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}
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inline bool
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less::operator()(const std::string *const &a,
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268
ircd/rfc1459.cc
268
ircd/rfc1459.cc
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@ -340,6 +340,274 @@ rfc1459::gen::grammar<it, top>::grammar(karma::rule<it, top> &top_rule)
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{
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}
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namespace ircd {
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namespace rfc1459 {
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namespace fmt {
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const char SPECIFIER
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{
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'%'
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};
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struct spec
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{
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char sign;
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int width;
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std::string name;
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spec(): sign('+'), width(0)
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{
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name.reserve(14);
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}
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};
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template<class generator> bool generate_string(char *&out, const generator &, const arg &);
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bool handle_nick(char *&out, const size_t &max, const spec &, const arg &);
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bool handle_user(char *&out, const size_t &max, const spec &, const arg &);
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bool handle_host(char *&out, const size_t &max, const spec &, const arg &);
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void handle_specifier(char *&out, const size_t &max, const spec &, const arg &);
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bool is_specifier(const std::string &name);
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std::map<std::string, handler> handlers
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{
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{ "nick", handle_nick },
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{ "user", handle_user },
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{ "host", handle_host },
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};
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} // namespace fmt
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} // namespace rfc1459
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} // namespace ircd
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BOOST_FUSION_ADAPT_STRUCT
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(
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ircd::rfc1459::fmt::spec,
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( char, sign )
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( int, width )
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( std::string, name )
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)
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bool
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rfc1459::fmt::is_specifier(const std::string &name)
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{
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return handlers.count(name);
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}
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void
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rfc1459::fmt::handle_specifier(char *&out,
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const size_t &max,
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const spec &spec,
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const arg &val)
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try
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{
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const auto &type(get<1>(val));
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const auto &handler(handlers.at(spec.name));
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if(!handler(out, max, spec, val))
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throw fmtstr_mismatch("Invalid type `%s' for format specifier '%c%s'",
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type.name(),
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SPECIFIER,
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spec.name.c_str());
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}
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catch(const std::out_of_range &e)
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{
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throw fmtstr_invalid("Unhandled specifier `%s' in format string",
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spec.name.c_str());
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}
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bool
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rfc1459::fmt::handle_host(char *&out,
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const size_t &max,
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const spec &spec,
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const arg &val)
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{
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using karma::eps;
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using karma::maxwidth;
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struct generator
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:gen::grammar<char *, std::string()>
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{
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generator(): grammar{grammar::user} {}
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}
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static const generator;
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const auto gen(maxwidth(max)[generator] | eps);
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return generate_string(out, gen, val);
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}
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bool
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rfc1459::fmt::handle_nick(char *&out,
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const size_t &max,
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const spec &spec,
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const arg &val)
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{
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using karma::eps;
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using karma::maxwidth;
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struct generator
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:gen::grammar<char *, std::string()>
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{
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generator(): grammar{grammar::nick} {}
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}
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static const generator;
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const auto gen(maxwidth(max)[generator] | eps);
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return generate_string(out, gen, val);
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}
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bool
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rfc1459::fmt::handle_user(char *&out,
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const size_t &max,
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const spec &spec,
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const arg &val)
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{
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using karma::eps;
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using karma::maxwidth;
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struct generator
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:gen::grammar<char *, std::string()>
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{
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generator(): grammar{grammar::user} {}
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}
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static const generator;
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const auto gen(maxwidth(max)[generator] | eps);
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return generate_string(out, gen, val);
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}
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template<class generator>
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bool
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rfc1459::fmt::generate_string(char *&out,
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const generator &gen,
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const arg &val)
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{
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const auto &ptr(get<0>(val));
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const auto &type(get<1>(val));
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if(type == typeid(std::string))
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{
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const auto &str(*reinterpret_cast<const std::string *>(ptr));
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karma::generate(out, gen, str);
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return true;
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}
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else if(type == typeid(const char *))
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{
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const auto &str(reinterpret_cast<const char *>(ptr));
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karma::generate(out, gen, str);
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return true;
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}
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else return false;
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}
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namespace ircd {
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namespace rfc1459 {
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namespace fmt {
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using qi::lit;
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using qi::char_;
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using qi::int_;
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using qi::eps;
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using qi::repeat;
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using qi::omit;
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template<class it,
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class top>
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struct grammar
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:qi::grammar<it, top>
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{
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qi::rule<it> specsym;
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qi::rule<it, std::string()> name;
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qi::rule<it, fmt::spec> spec;
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grammar(qi::rule<it, top> &top_rule);
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};
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struct parse_specifier
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:fmt::grammar<const char *, fmt::spec>
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{
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parse_specifier(): grammar{grammar::spec} {}
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}
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static const parse_specifier;
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} // namespace fmt
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} // namespace rfc1459
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} // namespace ircd
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template<class it,
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class top>
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rfc1459::fmt::grammar<it, top>::grammar(qi::rule<it, top> &top_rule)
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:grammar<it, top>::base_type
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{
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top_rule
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}
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,specsym
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{
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lit(SPECIFIER)
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}
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,name
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{
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repeat(1,14)[char_("A-Za-z")]
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}
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{
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spec %= specsym >> -char_("+-") >> -int_ >> name[([]
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(auto &str, auto &ctx, auto &valid)
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{
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valid = is_specifier(str);
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})];
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}
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ssize_t
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rfc1459::fmt::_snprintf(char *const &buf,
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const size_t &max,
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const char *const &fmt,
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const std::vector<const void *> &p,
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const std::vector<std::type_index> &t)
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try
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{
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if(unlikely(!max))
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return 0;
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char *out(buf); // Always points at next place to write
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const char *stop(fmt); // Saves the 'last' place to copy a literal from
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const char *start(strchr(fmt, SPECIFIER)); // The running position of the format string parse
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const char *const end(fmt + strlen(fmt)); // The end of the format string
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// Copies string data between format specifiers.
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const auto copy_literal([&stop, &buf, &out, &max]
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(const char *const &end)
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{
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const size_t rem(max - std::distance(buf, out) - 1);
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const size_t len(std::distance(stop, end));
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const size_t &cpsz(std::min(len, rem));
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memcpy(out, stop, cpsz);
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out += cpsz;
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});
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size_t index(0); // The current position for vectors p and t (specifier count)
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for(; start && start != end; stop = start++, start = strchr(start, SPECIFIER))
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{
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// Copy literal data from where the last parse stopped up to the found specifier
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copy_literal(start);
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// Parse the specifier with the grammar
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fmt::spec spec;
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if(!qi::parse(start, end, fmt::parse_specifier, spec))
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continue;
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// Throws if the format string has more specifiers than arguments.
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const auto rem(max - std::distance(buf, out) - 1);
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handle_specifier(out, rem, spec, { p.at(index), t.at(index) });
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index++;
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}
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// If the end of the string is not a format specifier itself, it needs to be copied
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if(!start)
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copy_literal(end);
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*out = '\0';
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return std::distance(buf, out);
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}
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catch(const std::out_of_range &e)
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{
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throw fmtstr_invalid("Format string requires more than %zu arguments.", p.size());
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}
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//NOTE: unterminated
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//TODO: Fix carriage
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std::ostream &
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