toml11/toml/region.hpp
2020-02-11 06:13:55 -06:00

526 lines
19 KiB
C++

// Copyright Toru Niina 2017.
// Distributed under the MIT License.
#ifndef TOML11_REGION_HPP
#define TOML11_REGION_HPP
#include <memory>
#include <vector>
#include <algorithm>
#include <initializer_list>
#include <iterator>
#include <iomanip>
#include <cassert>
#include "color.hpp"
namespace toml
{
namespace detail
{
// helper function to avoid std::string(0, 'c') or std::string(iter, iter)
template<typename Iterator>
std::string make_string(Iterator first, Iterator last)
{
if(first == last) {return "";}
return std::string(first, last);
}
inline std::string make_string(std::size_t len, char c)
{
if(len == 0) {return "";}
return std::string(len, c);
}
// region_base is a base class of location and region that are defined below.
// it will be used to generate better error messages.
struct region_base
{
region_base() = default;
virtual ~region_base() = default;
region_base(const region_base&) = default;
region_base(region_base&& ) = default;
region_base& operator=(const region_base&) = default;
region_base& operator=(region_base&& ) = default;
virtual bool is_ok() const noexcept {return false;}
virtual char front() const noexcept {return '\0';}
virtual std::string str() const {return std::string("unknown region");}
virtual std::string name() const {return std::string("unknown file");}
virtual std::string line() const {return std::string("unknown line");}
virtual std::string line_num() const {return std::string("?");}
// length of the region
virtual std::size_t size() const noexcept {return 0;}
// number of characters in the line before the region
virtual std::size_t before() const noexcept {return 0;}
// number of characters in the line after the region
virtual std::size_t after() const noexcept {return 0;}
virtual std::vector<std::string> comments()const {return {};}
// ```toml
// # comment_before
// key = "value" # comment_inline
// ```
};
// location represents a position in a container, which contains a file content.
// it can be considered as a region that contains only one character.
//
// it contains pointer to the file content and iterator that points the current
// location.
template<typename Container>
struct location final : public region_base
{
using const_iterator = typename Container::const_iterator;
using difference_type = typename const_iterator::difference_type;
using source_ptr = std::shared_ptr<const Container>;
static_assert(std::is_same<char, typename Container::value_type>::value,"");
static_assert(std::is_same<std::random_access_iterator_tag,
typename std::iterator_traits<const_iterator>::iterator_category>::value,
"container should be randomly accessible");
location(std::string name, Container cont)
: source_(std::make_shared<Container>(std::move(cont))), line_number_(1),
source_name_(std::move(name)), iter_(source_->cbegin())
{}
location(const location&) = default;
location(location&&) = default;
location& operator=(const location&) = default;
location& operator=(location&&) = default;
~location() = default;
bool is_ok() const noexcept override {return static_cast<bool>(source_);}
char front() const noexcept override {return *iter_;}
// this const prohibits codes like `++(loc.iter())`.
const const_iterator iter() const noexcept {return iter_;}
const_iterator begin() const noexcept {return source_->cbegin();}
const_iterator end() const noexcept {return source_->cend();}
// XXX `location::line_num()` used to be implemented using `std::count` to
// count a number of '\n'. But with a long toml file (typically, 10k lines),
// it becomes intolerably slow because each time it generates error messages,
// it counts '\n' from thousands of characters. To workaround it, I decided
// to introduce `location::line_number_` member variable and synchronize it
// to the location changes the point to look. So an overload of `iter()`
// which returns mutable reference is removed and `advance()`, `retrace()`
// and `reset()` is added.
void advance(difference_type n = 1) noexcept
{
this->line_number_ += static_cast<std::size_t>(
std::count(this->iter_, std::next(this->iter_, n), '\n'));
this->iter_ += n;
return;
}
void retrace(difference_type n = 1) noexcept
{
this->line_number_ -= static_cast<std::size_t>(
std::count(std::prev(this->iter_, n), this->iter_, '\n'));
this->iter_ -= n;
return;
}
void reset(const_iterator rollback) noexcept
{
// since c++11, std::distance works in both ways for random-access
// iterators and returns a negative value if `first > last`.
if(0 <= std::distance(rollback, this->iter_)) // rollback < iter
{
this->line_number_ -= static_cast<std::size_t>(
std::count(rollback, this->iter_, '\n'));
}
else // iter < rollback [[unlikely]]
{
this->line_number_ += static_cast<std::size_t>(
std::count(this->iter_, rollback, '\n'));
}
this->iter_ = rollback;
return;
}
std::string str() const override {return make_string(1, *this->iter());}
std::string name() const override {return source_name_;}
std::string line_num() const override
{
return std::to_string(this->line_number_);
}
std::string line() const override
{
return make_string(this->line_begin(), this->line_end());
}
const_iterator line_begin() const noexcept
{
using reverse_iterator = std::reverse_iterator<const_iterator>;
return std::find(reverse_iterator(this->iter()),
reverse_iterator(this->begin()), '\n').base();
}
const_iterator line_end() const noexcept
{
return std::find(this->iter(), this->end(), '\n');
}
// location is always points a character. so the size is 1.
std::size_t size() const noexcept override
{
return 1u;
}
std::size_t before() const noexcept override
{
const auto sz = std::distance(this->line_begin(), this->iter());
assert(sz >= 0);
return static_cast<std::size_t>(sz);
}
std::size_t after() const noexcept override
{
const auto sz = std::distance(this->iter(), this->line_end());
assert(sz >= 0);
return static_cast<std::size_t>(sz);
}
source_ptr const& source() const& noexcept {return source_;}
source_ptr&& source() && noexcept {return std::move(source_);}
private:
source_ptr source_;
std::size_t line_number_;
std::string source_name_;
const_iterator iter_;
};
// region represents a range in a container, which contains a file content.
//
// it contains pointer to the file content and iterator that points the first
// and last location.
template<typename Container>
struct region final : public region_base
{
using const_iterator = typename Container::const_iterator;
using source_ptr = std::shared_ptr<const Container>;
static_assert(std::is_same<char, typename Container::value_type>::value,"");
static_assert(std::is_same<std::random_access_iterator_tag,
typename std::iterator_traits<const_iterator>::iterator_category>::value,
"container should be randomly accessible");
// delete default constructor. source_ never be null.
region() = delete;
region(const location<Container>& loc)
: source_(loc.source()), source_name_(loc.name()),
first_(loc.iter()), last_(loc.iter())
{}
region(location<Container>&& loc)
: source_(loc.source()), source_name_(loc.name()),
first_(loc.iter()), last_(loc.iter())
{}
region(const location<Container>& loc, const_iterator f, const_iterator l)
: source_(loc.source()), source_name_(loc.name()), first_(f), last_(l)
{}
region(location<Container>&& loc, const_iterator f, const_iterator l)
: source_(loc.source()), source_name_(loc.name()), first_(f), last_(l)
{}
region(const region&) = default;
region(region&&) = default;
region& operator=(const region&) = default;
region& operator=(region&&) = default;
~region() = default;
region& operator+=(const region& other)
{
// different regions cannot be concatenated
assert(this->begin() == other.begin() && this->end() == other.end() &&
this->last_ == other.first_);
this->last_ = other.last_;
return *this;
}
bool is_ok() const noexcept override {return static_cast<bool>(source_);}
char front() const noexcept override {return *first_;}
std::string str() const override {return make_string(first_, last_);}
std::string line() const override
{
if(this->contain_newline())
{
return make_string(this->line_begin(),
std::find(this->line_begin(), this->last(), '\n'));
}
return make_string(this->line_begin(), this->line_end());
}
std::string line_num() const override
{
return std::to_string(1 + std::count(this->begin(), this->first(), '\n'));
}
std::size_t size() const noexcept override
{
const auto sz = std::distance(first_, last_);
assert(sz >= 0);
return static_cast<std::size_t>(sz);
}
std::size_t before() const noexcept override
{
const auto sz = std::distance(this->line_begin(), this->first());
assert(sz >= 0);
return static_cast<std::size_t>(sz);
}
std::size_t after() const noexcept override
{
const auto sz = std::distance(this->last(), this->line_end());
assert(sz >= 0);
return static_cast<std::size_t>(sz);
}
bool contain_newline() const noexcept
{
return std::find(this->first(), this->last(), '\n') != this->last();
}
const_iterator line_begin() const noexcept
{
using reverse_iterator = std::reverse_iterator<const_iterator>;
return std::find(reverse_iterator(this->first()),
reverse_iterator(this->begin()), '\n').base();
}
const_iterator line_end() const noexcept
{
return std::find(this->last(), this->end(), '\n');
}
const_iterator begin() const noexcept {return source_->cbegin();}
const_iterator end() const noexcept {return source_->cend();}
const_iterator first() const noexcept {return first_;}
const_iterator last() const noexcept {return last_;}
source_ptr const& source() const& noexcept {return source_;}
source_ptr&& source() && noexcept {return std::move(source_);}
std::string name() const override {return source_name_;}
std::vector<std::string> comments() const override
{
// assuming the current region (`*this`) points a value.
// ```toml
// a = "value"
// ^^^^^^^- this region
// ```
using rev_iter = std::reverse_iterator<const_iterator>;
std::vector<std::string> com{};
{
// find comments just before the current region.
// ```toml
// # this should be collected.
// # this also.
// a = value # not this.
// ```
// # this is a comment for `a`, not array elements.
// a = [1, 2, 3, 4, 5]
if(this->first() == std::find_if(this->line_begin(), this->first(),
[](const char c) noexcept -> bool {return c == '[' || c == '{';}))
{
auto iter = this->line_begin(); // points the first character
while(iter != this->begin())
{
iter = std::prev(iter);
// range [line_start, iter) represents the previous line
const auto line_start = std::find(
rev_iter(iter), rev_iter(this->begin()), '\n').base();
const auto comment_found = std::find(line_start, iter, '#');
if(comment_found == iter)
{
break; // comment not found.
}
// exclude the following case.
// > a = "foo" # comment // <-- this is not a comment for b but a.
// > b = "current value"
if(std::all_of(line_start, comment_found,
[](const char c) noexcept -> bool {
return c == ' ' || c == '\t';
}))
{
// unwrap the first '#' by std::next.
auto str = make_string(std::next(comment_found), iter);
if(str.back() == '\r') {str.pop_back();}
com.push_back(std::move(str));
}
else
{
break;
}
iter = line_start;
}
}
}
if(com.size() > 1)
{
std::reverse(com.begin(), com.end());
}
{
// find comments just after the current region.
// ```toml
// # not this.
// a = value # this one.
// a = [ # not this (technically difficult)
//
// ] # and this.
// ```
// The reason why it's difficult is that it requires parsing in the
// following case.
// ```toml
// a = [ 10 # this comment is for `10`. not for `a` but `a[0]`.
// # ...
// ] # this is apparently a comment for a.
//
// b = [
// 3.14 ] # there is no way to add a comment to `3.14` currently.
//
// c = [
// 3.14 # do this if you need a comment here.
// ]
// ```
const auto comment_found =
std::find(this->last(), this->line_end(), '#');
if(comment_found != this->line_end()) // '#' found
{
// table = {key = "value"} # what is this for?
// the above comment is not for "value", but {key="value"}.
if(comment_found == std::find_if(this->last(), comment_found,
[](const char c) noexcept -> bool {
return !(c == ' ' || c == '\t' || c == ',');
}))
{
// unwrap the first '#' by std::next.
auto str = make_string(std::next(comment_found), this->line_end());
if(str.back() == '\r') {str.pop_back();}
com.push_back(std::move(str));
}
}
}
return com;
}
private:
source_ptr source_;
std::string source_name_;
const_iterator first_, last_;
};
// to show a better error message.
inline std::string format_underline(const std::string& message,
const std::vector<std::pair<region_base const*, std::string>>& reg_com,
const std::vector<std::string>& helps = {},
const bool colorize = TOML11_ERROR_MESSAGE_COLORIZED)
{
assert(!reg_com.empty());
const auto line_num_width = static_cast<int>(std::max_element(
reg_com.begin(), reg_com.end(),
[](std::pair<region_base const*, std::string> const& lhs,
std::pair<region_base const*, std::string> const& rhs)
{
return lhs.first->line_num().size() < rhs.first->line_num().size();
}
)->first->line_num().size());
std::ostringstream retval;
if(colorize)
{
retval << color::colorize; // turn on ANSI color
}
// XXX
// Here, before `colorize` support, it does not output `[error]` prefix
// automatically. So some user may output it manually and this change may
// duplicate the prefix. To avoid it, check the first 7 characters and
// if it is "[error]", it removes that part from the message shown.
if(message.size() > 7 && message.substr(0, 7) == "[error]")
{
retval << color::bold << color::red << "[error]" << color::reset
<< color::bold << message.substr(7) << color::reset << '\n';
}
else
{
retval << color::bold << color::red << "[error] " << color::reset
<< color::bold << message << color::reset << '\n';
}
for(auto iter = reg_com.begin(); iter != reg_com.end(); ++iter)
{
// if the filenames are the same, print "..."
if(iter != reg_com.begin() &&
std::prev(iter)->first->name() == iter->first->name())
{
retval << color::bold << color::blue << "\n ...\n" << color::reset;
}
else // if filename differs, print " --> filename.toml"
{
if(iter != reg_com.begin()) {retval << '\n';}
retval << color::bold << color::blue << " --> " << color::reset
<< iter->first->name() << '\n';
// add one almost-empty line for readability
retval << make_string(static_cast<std::size_t>(line_num_width + 1), ' ')
<< color::bold << color::blue << " | " << color::reset << '\n';
}
const region_base* const reg = iter->first;
const std::string& comment = iter->second;
retval << ' ' << color::bold << color::blue << std::setw(line_num_width)
<< std::right << reg->line_num() << " | " << color::reset
<< reg->line() << '\n';
retval << make_string(static_cast<std::size_t>(line_num_width + 1), ' ')
<< color::bold << color::blue << " | " << color::reset
<< make_string(reg->before(), ' ');
if(reg->size() == 1)
{
// invalid
// ^------
retval << color::bold << color::red
<< '^' << make_string(reg->after(), '-') << color::reset;
}
else
{
// invalid
// ~~~~~~~
const auto underline_len = std::min(reg->size(), reg->line().size());
retval << color::bold << color::red
<< make_string(underline_len, '~') << color::reset;
}
retval << ' ';
retval << comment;
}
if(!helps.empty())
{
retval << '\n';
retval << make_string(static_cast<std::size_t>(line_num_width + 1), ' ');
retval << color::bold << color::blue << " | " << color::reset;
for(const auto& help : helps)
{
retval << color::bold << "\nHint: " << color::reset;
retval << help;
}
}
return retval.str();
}
} // detail
} // toml
#endif// TOML11_REGION_H