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/*
* 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.
*/
#ifndef _LIBUNWINDSTACK_SHAREDSTRING_H
#define _LIBUNWINDSTACK_SHAREDSTRING_H
#include <memory>
#include <string>
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_;
};
static inline bool operator==(const SharedString& a, SharedString& 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);
}
static inline bool operator!=(const SharedString& a, SharedString& 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
#endif // _LIBUNWINDSTACK_SHAREDSTRING_H
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