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#pragma once
#include <boost/format.hpp>
#include <list>
#include <map>
#include <memory>
#include <set>
#include <string>
#include "libutil/ref.hh"
/* Before 4.7, gcc's std::exception uses empty throw() specifiers for
* its (virtual) destructor and what() in c++11 mode, in violation of spec
*/
#ifdef __GNUC__
#if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 7)
#define EXCEPTION_NEEDS_THROW_SPEC
#endif
#endif
namespace nix {
/* Inherit some names from other namespaces for convenience. */
using boost::format;
/* A variadic template that does nothing. Useful to call a function
for all variadic arguments but ignoring the result. */
struct nop {
template <typename... T>
nop(T...) {}
};
struct FormatOrString {
std::string s;
FormatOrString(const std::string& s) : s(s){};
FormatOrString(const format& f) : s(f.str()){};
FormatOrString(const char* s) : s(s){};
};
/* A helper for formatting strings. ‘fmt(format, a_0, ..., a_n)’ is
equivalent to ‘boost::format(format) % a_0 % ... %
... a_n’. However, ‘fmt(s)’ is equivalent to ‘s’ (so no %-expansion
takes place). */
inline std::string fmt(const std::string& s) { return s; }
inline std::string fmt(std::string_view s) { return std::string(s); }
inline std::string fmt(const char* s) { return s; }
inline std::string fmt(const FormatOrString& fs) { return fs.s; }
template <typename... Args>
inline std::string fmt(const std::string& fs, Args... args) {
boost::format f(fs);
f.exceptions(boost::io::all_error_bits ^ boost::io::too_many_args_bit);
nop{boost::io::detail::feed(f, args)...};
return f.str();
}
/* BaseError should generally not be caught, as it has Interrupted as
a subclass. Catch Error instead. */
class BaseError : public std::exception {
protected:
std::string prefix_; // used for location traces etc.
std::string err;
public:
unsigned int status = 1; // exit status
template <typename... Args>
BaseError(unsigned int status, Args... args)
: err(fmt(args...)), status(status) {}
template <typename... Args>
BaseError(Args... args) : err(fmt(args...)) {}
#ifdef EXCEPTION_NEEDS_THROW_SPEC
~BaseError() noexcept {};
const char* what() const noexcept { return err.c_str(); }
#else
const char* what() const noexcept { return err.c_str(); }
#endif
const std::string& msg() const { return err; }
const std::string& prefix() const { return prefix_; }
BaseError& addPrefix(const FormatOrString& fs);
};
#define MakeError(newClass, superClass) \
class newClass : public superClass { \
public: \
using superClass::superClass; \
};
MakeError(Error, BaseError)
class SysError : public Error {
public:
int errNo;
template <typename... Args>
SysError(Args... args) : Error(addErrno(fmt(args...))) {}
private:
std::string addErrno(const std::string& s);
};
typedef std::list<std::string> Strings;
typedef std::set<std::string> StringSet;
typedef std::map<std::string, std::string> StringMap;
/* Paths are just strings. */
typedef std::string Path;
typedef std::list<Path> Paths;
typedef std::set<Path> PathSet;
} // namespace nix
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