124 lines
4.0 KiB
C++
124 lines
4.0 KiB
C++
// Copyright 2015 MongoDB Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#pragma once
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#include <string>
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#include <bsoncxx/stdx/string_view.hpp>
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#include <bsoncxx/view_or_value.hpp>
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#include <bsoncxx/config/prelude.hpp>
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namespace bsoncxx {
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BSONCXX_INLINE_NAMESPACE_BEGIN
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namespace string {
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///
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/// Class representing a view-or-value variant type for strings.
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///
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/// This class adds several string-specific methods to the bsoncxx::view_or_value template:
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/// - a constructor overload for const char*
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/// - a constructor overload for std::string by l-value reference
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/// - a safe c_str() operation to return null-terminated c-style strings.
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///
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class BSONCXX_API view_or_value : public bsoncxx::view_or_value<stdx::string_view, std::string> {
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public:
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///
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/// Forward all bsoncxx::view_or_value constructors.
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///
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using bsoncxx::view_or_value<stdx::string_view, std::string>::view_or_value;
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///
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/// Default constructor, equivalent to using an empty string.
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///
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BSONCXX_INLINE view_or_value() = default;
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///
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/// Construct a string::view_or_value using a null-terminated const char *.
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/// The resulting view_or_value will keep a string_view of 'str', so it is
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/// important that the passed-in string outlive this object.
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///
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/// @param str A null-terminated string
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///
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BSONCXX_INLINE view_or_value(const char* str)
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: bsoncxx::view_or_value<stdx::string_view, std::string>(stdx::string_view(str)) {}
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///
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/// Allow construction with an l-value reference to a std::string. The resulting
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/// view_or_value will keep a string_view of 'str', so it is important that the
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/// passed-in string outlive this object.
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///
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/// Construction calls passing a std::string by r-value reference will use the
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/// constructor defined in the parent view_or_value class.
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///
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/// @param str A std::string l-value reference.
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///
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BSONCXX_INLINE view_or_value(const std::string& str)
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: bsoncxx::view_or_value<stdx::string_view, std::string>(stdx::string_view(str)) {}
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///
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/// Return a string_view_or_value that is guaranteed to hold a null-terminated
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/// string. The lifetime of the returned object must be a subset of this object's
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/// lifetime, because the new view_or_value might hold a view into this one.
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///
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/// It is recommended that this method be used before calling .data() on a
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/// view_or_value, as that method may return a non-null-terminated string.
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///
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/// @return A new view_or_value object.
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///
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view_or_value terminated() const;
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///
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/// Call data() on this view_or_value's string_view. This method is not
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/// guaranteed to return a null-terminated string unless it is used in
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/// combination with terminated().
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///
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/// @return A const char* of this string.
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///
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const char* data() const;
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};
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///
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/// @{
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///
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/// Comparison operators for comparing string::view_or_value directly with const char *.
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///
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/// @relates view_or_value
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///
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BSONCXX_INLINE bool operator==(const view_or_value& lhs, const char* rhs) {
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return lhs.view() == stdx::string_view(rhs);
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}
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BSONCXX_INLINE bool operator!=(const view_or_value& lhs, const char* rhs) {
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return !(lhs == rhs);
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}
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BSONCXX_INLINE bool operator==(const char* lhs, const view_or_value& rhs) {
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return rhs == lhs;
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}
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BSONCXX_INLINE bool operator!=(const char* lhs, const view_or_value& rhs) {
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return !(rhs == lhs);
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}
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///
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/// @}
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///
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} // namespace string
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BSONCXX_INLINE_NAMESPACE_END
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} // namespace bsoncxx
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#include <bsoncxx/config/postlude.hpp>
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