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move constrains to meta namespace, remove cache
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remove cache in narrowing_cursor
add tests using environment as a range
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@rehdi93
rehdi93 committed Sep 12, 2020
1 parent 6d2eecc commit 428d625
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Showing 3 changed files with 55 additions and 59 deletions.
91 changes: 36 additions & 55 deletions include/red/sessions/session.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,22 @@

namespace red::session {

namespace meta
{
template <class T>
using is_strview = std::enable_if_t<
std::conjunction_v<
std::is_convertible<const T&, std::string_view>,
std::negation<std::is_convertible<const T&, const char*>>
>
, bool>;

template <class T>
using is_strview_convertible = std::enable_if_t<
std::is_convertible_v<const T&, std::string_view>
, bool>;
}

// system layer (impl detail)
namespace sys {
#ifdef WIN32
Expand Down Expand Up @@ -79,53 +95,31 @@ namespace detail {

struct narrowing_cursor : env_cursor
{
narrowing_cursor() = default;
narrowing_cursor(sys::env_t e) : env_cursor(e)
{
elem = *e;
current = sys::narrow(elem);
}

using value_type = std::string;

value_type& read() const
{
using env_cursor::env_cursor;

auto read() const {
auto cur = env_cursor::read();
if (cur != elem) {
current = sys::narrow(cur);
elem = cur;
}

return current;
return sys::narrow(cur);
}

private:
mutable sys::envchar* elem = nullptr; // last read elem.
mutable std::string current; // last read data
};

class environ_view : public ranges::view_facade<environ_view>
{
friend ranges::range_access;
using cursor = narrowing_cursor;
auto begin_cursor() const { return cursor(sys::envp()); }
};

using environ_iterator = ranges::iterator_t<environ_view>;

using native_iterator = ranges::basic_iterator<env_cursor>;
using narrowing_iterator = ranges::basic_iterator<narrowing_cursor>;

inline auto get_key_view(const environ_base& rng)
inline auto get_key_view()
{
using namespace ranges;
auto rng = subrange(narrowing_iterator(sys::envp()), default_sentinel);
return views::transform(rng, [](std::string const& line){
auto const eq = line.find('=');
return line.substr(0, eq);
});
}

inline auto get_value_view(const environ_base& rng)
inline auto get_value_view()
{
using namespace ranges;
auto rng = subrange(narrowing_iterator(sys::envp()), default_sentinel);
return views::transform(rng, [](std::string const& line){
auto const eq = line.find('=');
return line.substr(eq+1);
Expand All @@ -136,7 +130,6 @@ namespace detail {

class environment
{
detail::environ_base m_rng;
public:
class variable
{
Expand All @@ -159,54 +152,42 @@ namespace detail {
// the separator char. used in the PATH variable
static const char path_separator;

using iterator = ranges::common_iterator<ranges::iterator_t<detail::environ_view>, ranges::default_sentinel_t>;
using iterator = ranges::common_iterator<detail::narrowing_iterator, ranges::default_sentinel_t>;
using value_type = variable;
using size_type = std::size_t;
using value_range = decltype(detail::get_value_view({}));
using key_range = decltype(detail::get_key_view({}));

template <class T>
using Is_Strview = std::enable_if_t<
std::conjunction_v<
std::is_convertible<const T&, std::string_view>,
std::negation<std::is_convertible<const T&, const char*>>
>
>;
template <class T>
using Is_Strview_Convertible = std::enable_if_t<std::is_convertible_v<const T&, std::string_view>>;

using value_range = decltype(detail::get_value_view());
using key_range = decltype(detail::get_key_view());

environment() noexcept;

template <class T, class = Is_Strview<T>>
template <class T, meta::is_strview<T> = true>
variable operator [] (T const& k) const { return variable(k); }

variable operator [] (std::string_view k) const { return variable(k); }
variable operator [] (std::string const& k) const { return variable(k); }
variable operator [] (char const* k) const { return variable(k); }

template <class K, class = Is_Strview_Convertible<K>>
template <class K, meta::is_strview_convertible<K> = true>
iterator find(K const& key) const noexcept { return do_find(key); }

bool contains(std::string_view key) const;

iterator begin() const noexcept { return m_rng.begin(); }
iterator end() const noexcept { return m_rng.end(); }
iterator begin() const noexcept { return detail::narrowing_iterator(sys::envp()); }
iterator end() const noexcept { return ranges::default_sentinel; }
iterator cbegin() const noexcept { return begin(); }
iterator cend() const noexcept { return end(); }

size_type size() const noexcept;
[[nodiscard]] bool empty() const noexcept { return size() == 0; }

template <class K, class = Is_Strview_Convertible<K>>
template <class K, meta::is_strview_convertible<K> = true>
void erase(K const& key) { do_erase(key); }


value_range values() const noexcept {
return get_value_view(m_rng);
return detail::get_value_view();
}
key_range keys() const noexcept {
return get_key_view(m_rng);
return detail::get_key_view();
}

private:
Expand Down
3 changes: 2 additions & 1 deletion src/session.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -337,7 +337,8 @@ namespace red::session

auto environment::size() const noexcept -> size_type
{
return ranges::distance(m_rng);
//return ranges::distance(*this); //BUG: SIGSEGV - Stack overflow on "remove env. variables"
return ranges::distance(begin(), end());
}

environment::environment() noexcept
Expand Down
20 changes: 17 additions & 3 deletions test/test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@
#include <range/v3/view.hpp>
#include <range/v3/action.hpp>
#include <range/v3/range/conversion.hpp>
#include <range/v3/algorithm.hpp>

#include "red/sessions/session.hpp"

Expand Down Expand Up @@ -64,9 +65,6 @@ TEST_CASE("get environment variables", "[environment]")
test_vars_guard _;
environment env;

auto const env_size = env.size();
CAPTURE(env_size);

SECTION("operator[]")
{
for(auto[key, value] : TEST_VARS)
Expand Down Expand Up @@ -188,6 +186,22 @@ TEST_CASE("environment::variable", "[environment]")

}

TEST_CASE("use environment like a range","[environment][range]")
{
test_vars_guard _g_;

environment environment;
auto dist = ranges::distance(environment);
REQUIRE(dist == environment.size());

auto const envline = string(TEST_VARS[0].first) + "="s + string(TEST_VARS[0].second);
auto range_it = ranges::find(environment, envline);
auto env_it = environment.find(TEST_VARS[0].first);

REQUIRE(range_it == env_it);
REQUIRE(ranges::distance(environment.begin(), range_it) == ranges::distance(environment.begin(), env_it));
}

TEST_CASE("join_paths")
{
auto elems = sv_array<5> {
Expand Down

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