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cassavacassava
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fable: Use std::string instead of std::string&& for constructors
This is the optimal form, according to an analysis by Nicolai Josuttis in a CppCon18 talk: Nicolai Josuttis “The Nightmare of Initialization in C++” https://www.youtube.com/watch?v=7DTlWPgX6zs
1 parent 1b659be commit 2084ca0

24 files changed

+64
-66
lines changed

‎fable/include/fable/schema.hpp

Lines changed: 9 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -114,8 +114,6 @@
114114

115115
#pragma once
116116

117-
#include <chrono> // for duration<>
118-
#include <map> // for map<>
119117
#include <memory> // for shared_ptr<>
120118
#include <string> // for string
121119
#include <type_traits> // for enable_if_t<>, is_arithmetic<>, is_enum<>, ...
@@ -179,25 +177,25 @@ class Schema : public schema::Interface {
179177
Schema& operator=(const Schema&) = default;
180178

181179
// Struct
182-
Schema(std::string&& desc, schema::PropertyList<> props)
180+
Schema(std::string desc, schema::PropertyList<> props)
183181
: impl_(new schema::Struct(std::move(desc), props)) {}
184182

185183
Schema(schema::PropertyList<> props) : Schema("", props) {}
186184

187-
Schema(std::string&& desc, const Schema& base, schema::PropertyList<> props)
185+
Schema(std::string desc, const Schema& base, schema::PropertyList<> props)
188186
: impl_(new schema::Struct(std::move(desc), base, props)) {}
189187

190188
Schema(const Schema& base, schema::PropertyList<> props) : Schema("", base, props) {}
191189

192190
// Variant
193191
Schema(const std::vector<Schema>& xs); // NOLINT(runtime/explicit)
194-
Schema(std::string&& desc, const std::vector<Schema>& xs);
192+
Schema(std::string desc, const std::vector<Schema>& xs);
195193

196194
Schema(schema::BoxList props); // NOLINT(runtime/explicit)
197-
Schema(std::string&& desc, schema::BoxList props);
195+
Schema(std::string desc, schema::BoxList props);
198196

199197
Schema(schema::BoxVec&& props); // NOLINT(runtime/explicit)
200-
Schema(std::string&& desc, schema::BoxVec&& props);
198+
Schema(std::string desc, schema::BoxVec&& props);
201199

202200
// Interface
203201
template <typename T, std::enable_if_t<std::is_base_of_v<schema::Interface, T>, int> = 0>
@@ -209,19 +207,19 @@ class Schema : public schema::Interface {
209207

210208
// Ignore
211209
Schema() : impl_(new schema::Ignore("")) {}
212-
explicit Schema(std::string&& desc, JsonType t = JsonType::object)
210+
explicit Schema(std::string desc, JsonType t = JsonType::object)
213211
: impl_(new schema::Ignore(std::move(desc), t)) {}
214212

215213
// Primitives
216214
template <typename T>
217-
Schema(T* ptr, std::string&& desc) : impl_(make_schema(ptr, std::move(desc)).clone()) {}
215+
Schema(T* ptr, std::string desc) : impl_(make_schema(ptr, std::move(desc)).clone()) {}
218216
template <typename T>
219-
Schema(T* ptr, const schema::Box& prototype, std::string&& desc)
217+
Schema(T* ptr, const schema::Box& prototype, std::string desc)
220218
: impl_(make_schema(ptr, prototype, std::move(desc)).clone()) {}
221219

222220
// FromJson
223221
template <typename T>
224-
Schema(T* ptr, JsonType t, std::string&& desc)
222+
Schema(T* ptr, JsonType t, std::string desc)
225223
: impl_(new schema::FromJson<T>(ptr, t, std::move(desc))) {}
226224

227225
public: // Special

‎fable/include/fable/schema/array.hpp

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -42,15 +42,15 @@ class Array : public Base<Array<T, P>> {
4242
using Type = std::vector<T>;
4343
using PrototypeSchema = std::remove_cv_t<std::remove_reference_t<P>>;
4444

45-
Array(Type* ptr, std::string&& desc);
45+
Array(Type* ptr, std::string desc);
4646
Array(Type* ptr, PrototypeSchema prototype)
4747
: Base<Array<T, P>>(JsonType::array), prototype_(std::move(prototype)), ptr_(ptr) {}
48-
Array(Type* ptr, PrototypeSchema prototype, std::string&& desc)
48+
Array(Type* ptr, PrototypeSchema prototype, std::string desc)
4949
: Base<Array<T, P>>(JsonType::array, std::move(desc)), prototype_(std::move(prototype)), ptr_(ptr) {}
5050

5151
#if 0
5252
// This is defined in: fable/schema/magic.hpp
53-
Array(Type* ptr, std::string&& desc)
53+
Array(Type* ptr, std::string desc)
5454
: Array(ptr, make_prototype<T>(), std::move(desc)) {}
5555
#endif
5656

‎fable/include/fable/schema/boolean.hpp

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -35,7 +35,7 @@ class Boolean : public Base<Boolean> {
3535
public: // Types and Constructors
3636
using Type = bool;
3737

38-
Boolean(Type* ptr, std::string&& desc);
38+
Boolean(Type* ptr, std::string desc);
3939

4040
public: // Overrides
4141
Json json_schema() const override;

‎fable/include/fable/schema/confable.hpp

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -42,14 +42,14 @@ class FromConfable : public Base<FromConfable<T>> {
4242
public: // Types and Constructors
4343
using Type = T;
4444

45-
explicit FromConfable(std::string&& desc = "") {
46-
schema_ = Type().schema();
45+
FromConfable(std::string desc = "") {
46+
schema_ = Type().schema(); // NOLINT
4747
schema_.reset_ptr();
4848
this->type_ = schema_.type();
4949
this->desc_ = std::move(desc);
5050
}
5151

52-
FromConfable(Type* ptr, std::string&& desc)
52+
FromConfable(Type* ptr, std::string desc)
5353
: Base<FromConfable<Type>>(ptr->schema().type(), std::move(desc))
5454
, schema_(ptr->schema())
5555
, ptr_(ptr) {

‎fable/include/fable/schema/const.hpp

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -39,8 +39,8 @@ class Const : public Base<Const<T, P>> {
3939
using Type = T;
4040
using PrototypeSchema = std::remove_cv_t<std::remove_reference_t<P>>;
4141

42-
Const(const Type& constant, std::string&& desc);
43-
Const(const Type& constant, PrototypeSchema prototype, std::string&& desc)
42+
Const(const Type& constant, std::string desc);
43+
Const(const Type& constant, PrototypeSchema prototype, std::string desc)
4444
: Base<Const<T, P>>(prototype.type(), std::move(desc))
4545
, prototype_(std::move(prototype))
4646
, constant_(constant) {
@@ -49,7 +49,7 @@ class Const : public Base<Const<T, P>> {
4949

5050
#if 0
5151
// This is defined in: fable/schema/magic.hpp
52-
Const(const T& constant, std::string&& desc)
52+
Const(const T& constant, std::string desc)
5353
: Const(constant, make_prototype<T>(), std::move(desc)) {}
5454
#endif
5555

‎fable/include/fable/schema/duration.hpp

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -40,15 +40,15 @@ class Duration : public Base<Duration<T, Period>> {
4040
using Type = std::chrono::duration<T, Period>;
4141

4242
template <typename X = T, std::enable_if_t<std::is_integral_v<X> && std::is_unsigned_v<X>, int> = 0>
43-
Duration(Type* ptr, std::string&& desc)
43+
Duration(Type* ptr, std::string desc)
4444
: Base<Duration<T, Period>>(JsonType::number_unsigned, std::move(desc)), ptr_(ptr) {}
4545

4646
template <typename X = T, std::enable_if_t<std::is_integral_v<X> && std::is_signed_v<X>, int> = 0>
47-
Duration(Type* ptr, std::string&& desc)
48-
: Base<Duration<T, Period>>(JsonType::number_integer, std::move(desc)), ptr_(ptr) {}
47+
Duration(Type* ptr, std::string desc)
48+
: Base<Duration<T, Period>>(JsonType::number_integer, std::move(desc)), ptr_(ptr) {}
4949

5050
template <typename X = T, std::enable_if_t<std::is_floating_point_v<X>, int> = 0>
51-
Duration(Type* ptr, std::string&& desc)
51+
Duration(Type* ptr, std::string desc)
5252
: Base<Duration<T, Period>>(JsonType::number_float, std::move(desc)), ptr_(ptr) {}
5353

5454
public: // Special

‎fable/include/fable/schema/enum.hpp

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -40,7 +40,7 @@ class Enum : public Base<Enum<T>> {
4040
public: // Types and Constructors
4141
using Type = T;
4242

43-
Enum(Type* ptr, std::string&& desc)
43+
Enum(Type* ptr, std::string desc)
4444
: Base<Enum<T>>(JsonType::string, std::move(desc))
4545
, mapping_to_(enum_serialization<T>())
4646
, mapping_from_(enum_deserialization<T>())

‎fable/include/fable/schema/factory.hpp

Lines changed: 6 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -78,14 +78,14 @@ class FactoryBase : public Base<CRTP> {
7878
*
7979
* \see add_factory()
8080
*/
81-
explicit FactoryBase(std::string&& desc = "") : Base<CRTP>(JsonType::object, std::move(desc)) {}
81+
explicit FactoryBase(std::string desc = "") : Base<CRTP>(JsonType::object, std::move(desc)) {}
8282

83-
FactoryBase(std::string&& desc, FactoryPairList fs)
83+
FactoryBase(std::string desc, FactoryPairList fs)
8484
: Base<CRTP>(JsonType::object, std::move(desc)), available_(std::move(fs)) {
8585
reset_schema();
8686
}
8787

88-
FactoryBase(std::string&& desc, FactoryMap&& fs)
88+
FactoryBase(std::string desc, FactoryMap&& fs)
8989
: Base<CRTP>(JsonType::object, std::move(desc)), available_(std::move(fs)) {
9090
reset_schema();
9191
}
@@ -381,17 +381,17 @@ class Factory : public FactoryBase<T, Factory<T>> {
381381
public: // Constructors
382382
using FactoryBase<T, Factory<T>>::FactoryBase;
383383

384-
Factory(Type* ptr, std::string&& desc) : FactoryBase<T, Factory<T>>(std::move(desc)), ptr_(ptr) {}
384+
Factory(Type* ptr, std::string desc) : FactoryBase<T, Factory<T>>(std::move(desc)), ptr_(ptr) {}
385385

386-
Factory(Type* ptr, std::string&& desc, FactoryMap&& fs)
386+
Factory(Type* ptr, std::string desc, FactoryMap&& fs)
387387
: FactoryBase<T, Factory<T>>(std::move(desc)), ptr_(ptr) {
388388
for (auto&& f : fs) {
389389
this->available_.insert(f);
390390
}
391391
this->reset_schema();
392392
}
393393

394-
Factory(Type* ptr, std::string&& desc, FactoryPairList fs)
394+
Factory(Type* ptr, std::string desc, FactoryPairList fs)
395395
: FactoryBase<T, Factory<T>>(std::move(desc)), ptr_(ptr) {
396396
for (auto&& f : fs) {
397397
this->available_.insert(f);

‎fable/include/fable/schema/ignore.hpp

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -44,7 +44,7 @@ namespace schema {
4444
class Ignore : public Base<Ignore> {
4545
public: // Constructors
4646
Ignore() : Base(JsonType::object, "ignored") {}
47-
explicit Ignore(std::string&& desc, JsonType t = JsonType::object) : Base(t, std::move(desc)) {}
47+
explicit Ignore(std::string desc, JsonType t = JsonType::object) : Base(t, std::move(desc)) {}
4848

4949
public: // Overrides
5050
Json json_schema() const override {

‎fable/include/fable/schema/interface.hpp

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -352,9 +352,9 @@ template <typename CRTP>
352352
class Base : public Interface {
353353
public:
354354
Base() = default;
355-
Base(JsonType t, std::string&& desc) : type_(t), desc_(std::move(desc)) {}
355+
Base(JsonType t, std::string desc) : type_(t), desc_(std::move(desc)) {}
356356
explicit Base(JsonType t) : type_(t) {}
357-
explicit Base(std::string&& desc) : desc_(std::move(desc)) {}
357+
explicit Base(std::string desc) : desc_(std::move(desc)) {}
358358
virtual ~Base() = default;
359359

360360
Interface* clone() const override { return new CRTP(static_cast<CRTP const&>(*this)); }
@@ -391,7 +391,7 @@ class Base : public Interface {
391391
void set_description(const std::string& s) override { desc_ = s; }
392392
void set_description(std::string&& s) { desc_ = std::move(s); }
393393
const std::string& description() const override { return desc_; }
394-
CRTP description(std::string&& desc) && {
394+
CRTP description(std::string desc) && {
395395
desc_ = std::move(desc);
396396
return std::move(*dynamic_cast<CRTP*>(this));
397397
}

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