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#pragma once
/**
* @file
*
* @brief This file defines two main structs/classes used in nix error handling.
*
* ErrorInfo provides a standard payload of error information, with conversion to string
* happening in the logger rather than at the call site.
*
* BaseError is the ancestor of nix specific exceptions (and Interrupted), and contains
* an ErrorInfo.
*
* ErrorInfo structs are sent to the logger as part of an exception, or directly with the
* logError or logWarning macros.
* See libutil/tests/logging.cc for usage examples.
*/
#include "suggestions.hh"
#include "fmt.hh"
#include <cstring>
#include <list>
#include <memory>
#include <optional>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
namespace nix {
typedef enum {
lvlError = 0,
lvlWarn,
lvlNotice,
lvlInfo,
lvlTalkative,
lvlChatty,
lvlDebug,
lvlVomit
} Verbosity;
Verbosity verbosityFromIntClamped(int val);
/**
* The lines of code surrounding an error.
*/
struct LinesOfCode {
std::optional<std::string> prevLineOfCode;
std::optional<std::string> errLineOfCode;
std::optional<std::string> nextLineOfCode;
};
struct Pos;
void printCodeLines(std::ostream & out,
const std::string & prefix,
const Pos & errPos,
const LinesOfCode & loc);
struct Trace {
std::shared_ptr<Pos> pos;
HintFmt hint;
};
inline bool operator<(const Trace& lhs, const Trace& rhs);
inline bool operator> (const Trace& lhs, const Trace& rhs);
inline bool operator<=(const Trace& lhs, const Trace& rhs);
inline bool operator>=(const Trace& lhs, const Trace& rhs);
struct ErrorInfo {
Verbosity level;
HintFmt msg;
std::shared_ptr<Pos> pos;
std::list<Trace> traces;
/**
* Exit status.
*/
unsigned int status = 1;
Suggestions suggestions;
static std::optional<std::string> programName;
};
std::ostream & showErrorInfo(std::ostream & out, const ErrorInfo & einfo, bool showTrace);
/**
* BaseError should generally not be caught, as it has Interrupted as
* a subclass. Catch Error instead.
*/
class BaseError : public std::exception
{
protected:
mutable ErrorInfo err;
/**
* Cached formatted contents of `err.msg`.
*/
mutable std::optional<std::string> what_;
/**
* Format `err.msg` and set `what_` to the resulting value.
*/
const std::string & calcWhat() const;
public:
BaseError(const BaseError &) = default;
BaseError & operator=(BaseError const & rhs) = default;
template<typename... Args>
BaseError(unsigned int status, const Args & ... args)
: err { .level = lvlError, .msg = HintFmt(args...), .status = status }
{ }
template<typename... Args>
explicit BaseError(const std::string & fs, const Args & ... args)
: err { .level = lvlError, .msg = HintFmt(fs, args...) }
{ }
template<typename... Args>
BaseError(const Suggestions & sug, const Args & ... args)
: err { .level = lvlError, .msg = HintFmt(args...), .suggestions = sug }
{ }
BaseError(HintFmt hint)
: err { .level = lvlError, .msg = hint }
{ }
BaseError(ErrorInfo && e)
: err(std::move(e))
{ }
BaseError(const ErrorInfo & e)
: err(e)
{ }
const char * what() const noexcept override { return calcWhat().c_str(); }
const std::string & msg() const { return calcWhat(); }
const ErrorInfo & info() const { calcWhat(); return err; }
void withExitStatus(unsigned int status)
{
err.status = status;
}
void atPos(std::shared_ptr<Pos> pos) {
err.pos = pos;
}
void pushTrace(Trace trace)
{
err.traces.push_front(trace);
}
template<typename... Args>
void addTrace(std::shared_ptr<Pos> && e, std::string_view fs, const Args & ... args)
{
addTrace(std::move(e), HintFmt(std::string(fs), args...));
}
void addTrace(std::shared_ptr<Pos> && e, HintFmt hint);
bool hasTrace() const { return !err.traces.empty(); }
const ErrorInfo & info() { return err; };
};
#define MakeError(newClass, superClass) \
/* NOLINTNEXTLINE(bugprone-macro-parentheses) */ \
class newClass : public superClass \
{ \
public: \
using superClass::superClass; \
}
MakeError(Error, BaseError);
MakeError(UsageError, Error);
MakeError(UnimplementedError, Error);
class SysError : public Error
{
public:
int errNo;
template<typename... Args>
SysError(int errNo_, const Args & ... args)
: Error("")
{
errNo = errNo_;
auto hf = HintFmt(args...);
err.msg = HintFmt("%1%: %2%", Uncolored(hf.str()), strerror(errNo));
}
template<typename... Args>
SysError(const Args & ... args)
: SysError(errno, args ...)
{
}
};
/**
* Exception handling in destructors: print an error message, then
* ignore the exception.
*/
void ignoreException(Verbosity lvl = lvlError);
}
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