78 lines
2.7 KiB
C++
78 lines
2.7 KiB
C++
/*
|
|
* Copyright (C) 2021 The Android Open Source Project
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <memory>
|
|
#include <string>
|
|
#include <type_traits>
|
|
|
|
namespace unwindstack {
|
|
|
|
// Ref-counted read-only string. Used to avoid string allocations/copies.
|
|
// It is intended to be transparent std::string replacement in most cases.
|
|
class SharedString {
|
|
public:
|
|
SharedString() : data_() {}
|
|
SharedString(std::string&& s) : data_(std::make_shared<const std::string>(std::move(s))) {}
|
|
SharedString(const std::string& s) : SharedString(std::string(s)) {}
|
|
SharedString(const char* s) : SharedString(std::string(s)) {}
|
|
|
|
void clear() { data_.reset(); }
|
|
bool is_null() const { return data_.get() == nullptr; }
|
|
bool empty() const { return is_null() ? true : data_->empty(); }
|
|
const char* c_str() const { return is_null() ? "" : data_->c_str(); }
|
|
|
|
operator const std::string&() const {
|
|
[[clang::no_destroy]] static const std::string empty;
|
|
return data_ ? *data_.get() : empty;
|
|
}
|
|
|
|
operator std::string_view() const { return static_cast<const std::string&>(*this); }
|
|
|
|
private:
|
|
std::shared_ptr<const std::string> data_;
|
|
};
|
|
|
|
template <typename T, typename = std::enable_if_t<std::is_same_v<T, SharedString>>>
|
|
static inline bool operator==(const T& a, const T& b) {
|
|
return static_cast<std::string_view>(a) == static_cast<std::string_view>(b);
|
|
}
|
|
static inline bool operator==(const SharedString& a, std::string_view b) {
|
|
return static_cast<std::string_view>(a) == b;
|
|
}
|
|
static inline bool operator==(std::string_view a, const SharedString& b) {
|
|
return a == static_cast<std::string_view>(b);
|
|
}
|
|
template <typename T, typename = std::enable_if_t<std::is_same_v<T, SharedString>>>
|
|
static inline bool operator!=(const T& a, const T& b) {
|
|
return !(a == b);
|
|
}
|
|
static inline bool operator!=(const SharedString& a, std::string_view b) {
|
|
return !(a == b);
|
|
}
|
|
static inline bool operator!=(std::string_view a, const SharedString& b) {
|
|
return !(a == b);
|
|
}
|
|
static inline std::string operator+(const SharedString& a, const char* b) {
|
|
return static_cast<const std::string&>(a) + b;
|
|
}
|
|
static inline std::string operator+(const char* a, const SharedString& b) {
|
|
return a + static_cast<const std::string&>(b);
|
|
}
|
|
|
|
} // namespace unwindstack
|