lix/src/libutil/error.cc
2020-07-01 10:37:31 -06:00

383 lines
10 KiB
C++

#include "error.hh"
#include <iostream>
#include <optional>
#include "serialise.hh"
#include <sstream>
namespace nix {
const std::string nativeSystem = SYSTEM;
BaseError & BaseError::addTrace(std::optional<ErrPos> e, hintformat hint)
{
err.traces.push_front(Trace { .pos = e, .hint = hint});
return *this;
}
// c++ std::exception descendants must have a 'const char* what()' function.
// This stringifies the error and caches it for use by what(), or similarly by msg().
const string& BaseError::calcWhat() const
{
if (what_.has_value())
return *what_;
else {
err.name = sname();
std::ostringstream oss;
showErrorInfo(oss, err, false);
what_ = oss.str();
return *what_;
}
}
std::optional<string> ErrorInfo::programName = std::nullopt;
std::ostream& operator<<(std::ostream &os, const hintformat &hf)
{
return os << hf.str();
}
string showErrPos(const ErrPos &errPos)
{
if (errPos.line > 0) {
if (errPos.column > 0) {
return fmt("(%1%:%2%)", errPos.line, errPos.column);
} else {
return fmt("(%1%)", errPos.line);
}
}
else {
return "";
}
}
std::optional<LinesOfCode> getCodeLines(const ErrPos &errPos)
{
if (errPos.line <= 0)
return std::nullopt;
if (errPos.origin == foFile) {
LinesOfCode loc;
try {
AutoCloseFD fd = open(errPos.file.c_str(), O_RDONLY | O_CLOEXEC);
if (!fd) {
logError(SysError("opening file '%1%'", errPos.file).info());
return std::nullopt;
}
else
{
// count the newlines.
int count = 0;
string line;
int pl = errPos.line - 1;
do
{
line = readLine(fd.get());
++count;
if (count < pl)
{
;
}
else if (count == pl) {
loc.prevLineOfCode = line;
} else if (count == pl + 1) {
loc.errLineOfCode = line;
} else if (count == pl + 2) {
loc.nextLineOfCode = line;
break;
}
} while (true);
return loc;
}
}
catch (EndOfFile &eof) {
// TODO: return maybe partial loc?
return std::nullopt;
}
catch (std::exception &e) {
printError("error reading nix file: %s\n%s", errPos.file, e.what());
return std::nullopt;
}
} else {
std::istringstream iss(errPos.file);
// count the newlines.
int count = 0;
string line;
int pl = errPos.line - 1;
LinesOfCode loc;
do
{
std::getline(iss, line);
++count;
if (count < pl)
{
;
}
else if (count == pl) {
loc.prevLineOfCode = line;
} else if (count == pl + 1) {
loc.errLineOfCode = line;
} else if (count == pl + 2) {
loc.nextLineOfCode = line;
break;
}
if (!iss.good())
break;
} while (true);
return loc;
}
}
// print lines of code to the ostream, indicating the error column.
void printCodeLines(std::ostream &out,
const string &prefix,
const ErrPos &errPos,
const LinesOfCode &loc)
{
// previous line of code.
if (loc.prevLineOfCode.has_value()) {
out << std::endl
<< fmt("%1% %|2$5d|| %3%",
prefix,
(errPos.line - 1),
*loc.prevLineOfCode);
}
if (loc.errLineOfCode.has_value()) {
// line of code containing the error.
out << std::endl
<< fmt("%1% %|2$5d|| %3%",
prefix,
(errPos.line),
*loc.errLineOfCode);
// error arrows for the column range.
if (errPos.column > 0) {
int start = errPos.column;
std::string spaces;
for (int i = 0; i < start; ++i) {
spaces.append(" ");
}
std::string arrows("^");
out << std::endl
<< fmt("%1% |%2%" ANSI_RED "%3%" ANSI_NORMAL,
prefix,
spaces,
arrows);
}
}
// next line of code.
if (loc.nextLineOfCode.has_value()) {
out << std::endl
<< fmt("%1% %|2$5d|| %3%",
prefix,
(errPos.line + 1),
*loc.nextLineOfCode);
}
}
void printAtPos(const string &prefix, const ErrPos &pos, std::ostream &out)
{
if (pos)
{
switch (pos.origin) {
case foFile: {
out << prefix << ANSI_BLUE << "at: " << ANSI_YELLOW << showErrPos(pos) <<
ANSI_BLUE << " in file: " << ANSI_NORMAL << pos.file;
break;
}
case foString: {
out << prefix << ANSI_BLUE << "at: " << ANSI_YELLOW << showErrPos(pos) <<
ANSI_BLUE << " from string" << ANSI_NORMAL;
break;
}
case foStdin: {
out << prefix << ANSI_BLUE << "at: " << ANSI_YELLOW << showErrPos(pos) <<
ANSI_BLUE << " from stdin" << ANSI_NORMAL;
break;
}
default:
throw Error("invalid FileOrigin in errPos");
}
}
}
std::ostream& showErrorInfo(std::ostream &out, const ErrorInfo &einfo, bool showTrace)
{
auto errwidth = std::max<size_t>(getWindowSize().second, 20);
string prefix = "";
string levelString;
switch (einfo.level) {
case Verbosity::lvlError: {
levelString = ANSI_RED;
levelString += "error:";
levelString += ANSI_NORMAL;
break;
}
case Verbosity::lvlWarn: {
levelString = ANSI_YELLOW;
levelString += "warning:";
levelString += ANSI_NORMAL;
break;
}
case Verbosity::lvlInfo: {
levelString = ANSI_GREEN;
levelString += "info:";
levelString += ANSI_NORMAL;
break;
}
case Verbosity::lvlTalkative: {
levelString = ANSI_GREEN;
levelString += "talk:";
levelString += ANSI_NORMAL;
break;
}
case Verbosity::lvlChatty: {
levelString = ANSI_GREEN;
levelString += "chat:";
levelString += ANSI_NORMAL;
break;
}
case Verbosity::lvlVomit: {
levelString = ANSI_GREEN;
levelString += "vomit:";
levelString += ANSI_NORMAL;
break;
}
case Verbosity::lvlDebug: {
levelString = ANSI_YELLOW;
levelString += "debug:";
levelString += ANSI_NORMAL;
break;
}
default: {
levelString = fmt("invalid error level: %1%", einfo.level);
break;
}
}
auto ndl = prefix.length()
+ filterANSIEscapes(levelString, true).length()
+ 7
+ einfo.name.length()
+ einfo.programName.value_or("").length();
auto dashwidth = std::max<int>(errwidth - ndl, 3);
std::string dashes(dashwidth, '-');
// divider.
if (einfo.name != "")
out << fmt("%1%%2%" ANSI_BLUE " --- %3% %4% %5%" ANSI_NORMAL,
prefix,
levelString,
einfo.name,
dashes,
einfo.programName.value_or(""));
else
out << fmt("%1%%2%" ANSI_BLUE " -----%3% %4%" ANSI_NORMAL,
prefix,
levelString,
dashes,
einfo.programName.value_or(""));
bool nl = false; // intersperse newline between sections.
if (einfo.errPos.has_value() && (*einfo.errPos)) {
out << prefix << std::endl;
printAtPos(prefix, *einfo.errPos, out);
nl = true;
}
// description
if (einfo.description != "") {
if (nl)
out << std::endl << prefix;
out << std::endl << prefix << einfo.description;
nl = true;
}
if (einfo.errPos.has_value()) {
auto loc = getCodeLines(*einfo.errPos);
// lines of code.
if (loc.has_value()) {
if (nl)
out << std::endl << prefix;
printCodeLines(out, prefix, *einfo.errPos, *loc);
nl = true;
}
}
// hint
if (einfo.hint.has_value()) {
if (nl)
out << std::endl << prefix;
out << std::endl << prefix << *einfo.hint;
nl = true;
}
// traces
if (showTrace && !einfo.traces.empty())
{
const string tracetitle(" show-trace ");
int fill = errwidth - tracetitle.length();
int lw = 0;
int rw = 0;
const int min_dashes = 3;
if (fill > min_dashes * 2) {
if (fill % 2 != 0) {
lw = fill / 2;
rw = lw + 1;
}
else
{
lw = rw = fill / 2;
}
}
else
lw = rw = min_dashes;
if (nl)
out << std::endl << prefix;
out << ANSI_BLUE << std::string(lw, '-') << tracetitle << std::string(rw, '-') << ANSI_NORMAL;
for (auto iter = einfo.traces.rbegin(); iter != einfo.traces.rend(); ++iter)
{
try {
out << std::endl << prefix;
out << ANSI_BLUE << "trace: " << ANSI_NORMAL << iter->hint.str();
nl = true;
auto pos = *iter->pos;
if (pos) {
out << std::endl << prefix;
printAtPos(prefix, pos, out);
auto loc = getCodeLines(pos);
if (loc.has_value())
{
out << std::endl << prefix;
printCodeLines(out, prefix, pos, *loc);
out << std::endl << prefix;
}
}
} catch(const std::bad_optional_access& e) {
out << iter->hint.str() << std::endl;
}
}
}
return out;
}
}