catch2/include/internal/catch_generators.hpp
2019-02-18 10:33:41 +01:00

378 lines
13 KiB
C++

/*
* Created by Phil Nash on 15/6/2018.
*
* Distributed under the Boost Software License, Version 1.0. (See accompanying
* file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
*/
#ifndef TWOBLUECUBES_CATCH_GENERATORS_HPP_INCLUDED
#define TWOBLUECUBES_CATCH_GENERATORS_HPP_INCLUDED
#include "catch_interfaces_generatortracker.h"
#include "catch_common.h"
#include "catch_enforce.h"
#include <memory>
#include <vector>
#include <cassert>
#include <utility>
#include <exception>
namespace Catch {
class GeneratorException : public std::exception {
const char* const m_msg = "";
public:
GeneratorException(const char* msg):
m_msg(msg)
{}
const char* what() const noexcept override final;
};
namespace Generators {
// !TBD move this into its own location?
namespace pf{
template<typename T, typename... Args>
std::unique_ptr<T> make_unique( Args&&... args ) {
return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
}
}
template<typename T>
struct IGenerator : GeneratorUntypedBase {
virtual ~IGenerator() = default;
// Returns the current element of the generator
//
// \Precondition The generator is either freshly constructed,
// or the last call to `next()` returned true
virtual T const& get() const = 0;
using type = T;
};
template<typename T>
class SingleValueGenerator final : public IGenerator<T> {
T m_value;
public:
SingleValueGenerator(T const& value) : m_value( value ) {}
SingleValueGenerator(T&& value) : m_value(std::move(value)) {}
T const& get() const override {
return m_value;
}
bool next() override {
return false;
}
};
template<typename T>
class FixedValuesGenerator final : public IGenerator<T> {
std::vector<T> m_values;
size_t m_idx = 0;
public:
FixedValuesGenerator( std::initializer_list<T> values ) : m_values( values ) {}
T const& get() const override {
return m_values[m_idx];
}
bool next() override {
++m_idx;
return m_idx < m_values.size();
}
};
template <typename T>
class GeneratorWrapper final {
std::unique_ptr<IGenerator<T>> m_generator;
public:
GeneratorWrapper(std::unique_ptr<IGenerator<T>> generator):
m_generator(std::move(generator))
{}
T const& get() const {
return m_generator->get();
}
bool next() {
return m_generator->next();
}
};
template <typename T>
GeneratorWrapper<T> value(T&& value) {
return GeneratorWrapper<T>(pf::make_unique<SingleValueGenerator<T>>(std::forward<T>(value)));
}
template <typename T>
GeneratorWrapper<T> values(std::initializer_list<T> values) {
return GeneratorWrapper<T>(pf::make_unique<FixedValuesGenerator<T>>(values));
}
template<typename T>
class Generators : public IGenerator<T> {
std::vector<GeneratorWrapper<T>> m_generators;
size_t m_current = 0;
void populate(GeneratorWrapper<T>&& generator) {
m_generators.emplace_back(std::move(generator));
}
void populate(T&& val) {
m_generators.emplace_back(value(std::move(val)));
}
template<typename U>
void populate(U&& val) {
populate(T(std::move(val)));
}
template<typename U, typename... Gs>
void populate(U&& valueOrGenerator, Gs... moreGenerators) {
populate(std::forward<U>(valueOrGenerator));
populate(std::forward<Gs>(moreGenerators)...);
}
public:
template <typename... Gs>
Generators(Gs... moreGenerators) {
m_generators.reserve(sizeof...(Gs));
populate(std::forward<Gs>(moreGenerators)...);
}
T const& get() const override {
return m_generators[m_current].get();
}
bool next() override {
if (m_current >= m_generators.size()) {
return false;
}
const bool current_status = m_generators[m_current].next();
if (!current_status) {
++m_current;
}
return m_current < m_generators.size();
}
};
template<typename... Ts>
GeneratorWrapper<std::tuple<Ts...>> table( std::initializer_list<std::tuple<typename std::decay<Ts>::type...>> tuples ) {
return values<std::tuple<Ts...>>( tuples );
}
// Tag type to signal that a generator sequence should convert arguments to a specific type
template <typename T>
struct as {};
template<typename T, typename... Gs>
auto makeGenerators( GeneratorWrapper<T>&& generator, Gs... moreGenerators ) -> Generators<T> {
return Generators<T>(std::move(generator), std::forward<Gs>(moreGenerators)...);
}
template<typename T>
auto makeGenerators( GeneratorWrapper<T>&& generator ) -> Generators<T> {
return Generators<T>(std::move(generator));
}
template<typename T, typename... Gs>
auto makeGenerators( T&& val, Gs... moreGenerators ) -> Generators<T> {
return makeGenerators( value( std::forward<T>( val ) ), std::forward<Gs>( moreGenerators )... );
}
template<typename T, typename U, typename... Gs>
auto makeGenerators( as<T>, U&& val, Gs... moreGenerators ) -> Generators<T> {
return makeGenerators( value( T( std::forward<U>( val ) ) ), std::forward<Gs>( moreGenerators )... );
}
template <typename T>
class TakeGenerator : public IGenerator<T> {
GeneratorWrapper<T> m_generator;
size_t m_returned = 0;
size_t m_target;
public:
TakeGenerator(size_t target, GeneratorWrapper<T>&& generator):
m_generator(std::move(generator)),
m_target(target)
{
assert(target != 0 && "Empty generators are not allowed");
}
T const& get() const override {
return m_generator.get();
}
bool next() override {
++m_returned;
if (m_returned >= m_target) {
return false;
}
const auto success = m_generator.next();
// If the underlying generator does not contain enough values
// then we cut short as well
if (!success) {
m_returned = m_target;
}
return success;
}
};
template <typename T>
GeneratorWrapper<T> take(size_t target, GeneratorWrapper<T>&& generator) {
return GeneratorWrapper<T>(pf::make_unique<TakeGenerator<T>>(target, std::move(generator)));
}
template <typename T, typename Predicate>
class FilterGenerator : public IGenerator<T> {
GeneratorWrapper<T> m_generator;
Predicate m_predicate;
public:
template <typename P = Predicate>
FilterGenerator(P&& pred, GeneratorWrapper<T>&& generator):
m_generator(std::move(generator)),
m_predicate(std::forward<P>(pred))
{
if (!m_predicate(m_generator.get())) {
// It might happen that there are no values that pass the
// filter. In that case we throw an exception.
auto has_initial_value = next();
if (!has_initial_value) {
Catch::throw_exception(GeneratorException("No valid value found in filtered generator"));
}
}
}
T const& get() const override {
return m_generator.get();
}
bool next() override {
bool success = m_generator.next();
if (!success) {
return false;
}
while (!m_predicate(m_generator.get()) && (success = m_generator.next()) == true);
return success;
}
};
template <typename T, typename Predicate>
GeneratorWrapper<T> filter(Predicate&& pred, GeneratorWrapper<T>&& generator) {
return GeneratorWrapper<T>(std::unique_ptr<IGenerator<T>>(pf::make_unique<FilterGenerator<T, Predicate>>(std::forward<Predicate>(pred), std::move(generator))));
}
template <typename T>
class RepeatGenerator : public IGenerator<T> {
GeneratorWrapper<T> m_generator;
mutable std::vector<T> m_returned;
size_t m_target_repeats;
size_t m_current_repeat = 0;
size_t m_repeat_index = 0;
public:
RepeatGenerator(size_t repeats, GeneratorWrapper<T>&& generator):
m_generator(std::move(generator)),
m_target_repeats(repeats)
{
assert(m_target_repeats > 0 && "Repeat generator must repeat at least once");
}
T const& get() const override {
if (m_current_repeat == 0) {
m_returned.push_back(m_generator.get());
return m_returned.back();
}
return m_returned[m_repeat_index];
}
bool next() override {
// There are 2 basic cases:
// 1) We are still reading the generator
// 2) We are reading our own cache
// In the first case, we need to poke the underlying generator.
// If it happily moves, we are left in that state, otherwise it is time to start reading from our cache
if (m_current_repeat == 0) {
const auto success = m_generator.next();
if (!success) {
++m_current_repeat;
}
return m_current_repeat < m_target_repeats;
}
// In the second case, we need to move indices forward and check that we haven't run up against the end
++m_repeat_index;
if (m_repeat_index == m_returned.size()) {
m_repeat_index = 0;
++m_current_repeat;
}
return m_current_repeat < m_target_repeats;
}
};
template <typename T>
GeneratorWrapper<T> repeat(size_t repeats, GeneratorWrapper<T>&& generator) {
return GeneratorWrapper<T>(pf::make_unique<RepeatGenerator<T>>(repeats, std::move(generator)));
}
template <typename T, typename U, typename Func>
class MapGenerator : public IGenerator<T> {
// TBD: provide static assert for mapping function, for friendly error message
GeneratorWrapper<U> m_generator;
Func m_function;
// To avoid returning dangling reference, we have to save the values
T m_cache;
public:
template <typename F2 = Func>
MapGenerator(F2&& function, GeneratorWrapper<U>&& generator) :
m_generator(std::move(generator)),
m_function(std::forward<F2>(function)),
m_cache(m_function(m_generator.get()))
{}
T const& get() const override {
return m_cache;
}
bool next() override {
const auto success = m_generator.next();
if (success) {
m_cache = m_function(m_generator.get());
}
return success;
}
};
template <typename T, typename U, typename Func>
GeneratorWrapper<T> map(Func&& function, GeneratorWrapper<U>&& generator) {
return GeneratorWrapper<T>(
pf::make_unique<MapGenerator<T, U, Func>>(std::forward<Func>(function), std::move(generator))
);
}
template <typename T, typename Func>
GeneratorWrapper<T> map(Func&& function, GeneratorWrapper<T>&& generator) {
return GeneratorWrapper<T>(
pf::make_unique<MapGenerator<T, T, Func>>(std::forward<Func>(function), std::move(generator))
);
}
auto acquireGeneratorTracker( SourceLineInfo const& lineInfo ) -> IGeneratorTracker&;
template<typename L>
// Note: The type after -> is weird, because VS2015 cannot parse
// the expression used in the typedef inside, when it is in
// return type. Yeah.
auto generate( SourceLineInfo const& lineInfo, L const& generatorExpression ) -> decltype(std::declval<decltype(generatorExpression())>().get()) {
using UnderlyingType = typename decltype(generatorExpression())::type;
IGeneratorTracker& tracker = acquireGeneratorTracker( lineInfo );
if (!tracker.hasGenerator()) {
tracker.setGenerator(pf::make_unique<Generators<UnderlyingType>>(generatorExpression()));
}
auto const& generator = static_cast<IGenerator<UnderlyingType> const&>( *tracker.getGenerator() );
return generator.get();
}
} // namespace Generators
} // namespace Catch
#define GENERATE( ... ) \
Catch::Generators::generate( CATCH_INTERNAL_LINEINFO, []{ using namespace Catch::Generators; return makeGenerators( __VA_ARGS__ ); } )
#endif // TWOBLUECUBES_CATCH_GENERATORS_HPP_INCLUDED