toml11/toml/region.hpp
2019-06-01 19:43:35 +09:00

459 lines
15 KiB
C++

// Copyright Toru Niina 2017.
// Distributed under the MIT License.
#ifndef TOML11_REGION_HPP
#define TOML11_REGION_HPP
#include "exception.hpp"
#include <memory>
#include <vector>
#include <algorithm>
#include <initializer_list>
#include <iterator>
#include <iomanip>
#include <cassert>
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 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::string comment_before() const {return "";} // just before
virtual std::string comment_inline() const {return "";} // in the same line
virtual std::string comment() const {return "";} // concatenate
// ```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 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_);}
// 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(std::size_t n = 1) noexcept
{
this->line_number_ += std::count(this->iter_, this->iter_ + n, '\n');
this->iter_ += n;
return;
}
void retrace(std::size_t n = 1) noexcept
{
this->line_number_ -= std::count(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_ -= std::count(rollback, this->iter_, '\n');
}
else // iter < rollback [[unlikely]]
{
this->line_number_ += 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
{
return std::distance(this->line_begin(), this->iter());
}
std::size_t after() const noexcept override
{
return std::distance(this->iter(), this->line_end());
}
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)
{
if(this->begin() != other.begin() || this->end() != other.end() ||
this->last_ != other.first_)
{
throw internal_error("invalid region concatenation");
}
this->last_ = other.last_;
return *this;
}
bool is_ok() const noexcept override {return static_cast<bool>(source_);}
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
{
return std::distance(first_, last_);
}
std::size_t before() const noexcept override
{
return std::distance(this->line_begin(), this->first());
}
std::size_t after() const noexcept override
{
return std::distance(this->last(), this->line_end());
}
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::string comment_before() const override
{
auto iter = this->line_begin(); // points the first element
std::vector<std::pair<decltype(iter), decltype(iter)>> comments;
while(iter != this->begin())
{
iter = std::prev(iter);
using rev_iter = std::reverse_iterator<decltype(iter)>;
auto line_before = std::find(rev_iter(iter), rev_iter(this->begin()),
'\n').base();
// range [line_before, iter) represents the previous line
auto comment_found = std::find(line_before, iter, '#');
if(iter != comment_found && std::all_of(line_before, comment_found,
[](const char c) noexcept -> bool {
return c == ' ' || c == '\t';
}))
{
// the line before this range contains only a comment.
comments.push_back(std::make_pair(comment_found, iter));
}
else
{
break;
}
iter = line_before;
}
std::string com;
for(auto i = comments.crbegin(), e = comments.crend(); i!=e; ++i)
{
if(i != comments.crbegin()) {com += '\n';}
com += std::string(i->first, i->second);
}
return com;
}
std::string comment_inline() const override
{
if(this->contain_newline())
{
std::string com;
// check both the first and the last line.
const auto first_line_end =
std::find(this->line_begin(), this->last(), '\n');
const auto first_comment_found =
std::find(this->line_begin(), first_line_end, '#');
if(first_comment_found != first_line_end)
{
com += std::string(first_comment_found, first_line_end);
}
const auto last_comment_found =
std::find(this->last(), this->line_end(), '#');
if(last_comment_found != this->line_end())
{
if(!com.empty()){com += '\n';}
com += std::string(last_comment_found, this->line_end());
}
return com;
}
const auto comment_found =
std::find(this->line_begin(), this->line_end(), '#');
return std::string(comment_found, this->line_end());
}
std::string comment() const override
{
std::string com_bef = this->comment_before();
std::string com_inl = this->comment_inline();
if(!com_bef.empty() && !com_inl.empty())
{
com_bef += '\n';
return com_bef + com_inl;
}
else if(com_bef.empty())
{
return com_inl;
}
else
{
return com_bef;
}
}
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 = {})
{
assert(!reg_com.empty());
const auto line_num_width = 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;
retval << message << '\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 << "\n ...\n";
}
else // if filename differs, print " --> filename.toml"
{
if(iter != reg_com.begin()) {retval << '\n';}
retval << " --> " << iter->first->name() << '\n';
}
const region_base* const reg = iter->first;
const std::string& comment = iter->second;
retval << ' ' << std::setw(line_num_width) << reg->line_num();
retval << " | " << reg->line() << '\n';
retval << make_string(line_num_width + 1, ' ');
retval << " | " << make_string(reg->before(), ' ');
if(reg->size() == 1)
{
// invalid
// ^------
retval << '^';
retval << make_string(reg->after(), '-');
}
else
{
// invalid
// ~~~~~~~
const auto underline_len = std::min(reg->size(), reg->line().size());
retval << make_string(underline_len, '~');
}
retval << ' ';
retval << comment;
}
if(!helps.empty())
{
retval << '\n';
retval << make_string(line_num_width + 1, ' ');
retval << " | ";
for(const auto help : helps)
{
retval << "\nHint: ";
retval << help;
}
}
return retval.str();
}
} // detail
} // toml
#endif// TOML11_REGION_H