88 lines
2.3 KiB
C++
88 lines
2.3 KiB
C++
/** Handling of SQL arrays.
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*
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* DO NOT INCLUDE THIS FILE DIRECTLY; include drogon/orm/Field.h instead.
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*
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* Copyright (c) 2018, Jeroen T. Vermeulen.
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*
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* See COPYING for copyright license. If you did not receive a file called
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* COPYING with this source code, please notify the distributor of this mistake,
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* or contact the author.
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*/
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// Taken from libpqxx and modified
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/**
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*
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* @file ArrayParser.h
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* @author An Tao
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*
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* Copyright 2018, An Tao. All rights reserved.
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* https://github.com/an-tao/drogon
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* Use of this source code is governed by a MIT license
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* that can be found in the License file.
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*
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* Drogon
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*
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*/
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#pragma once
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#include <drogon/exports.h>
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#include <stdexcept>
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#include <string>
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#include <utility>
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namespace drogon
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{
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namespace orm
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{
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/// Low-level array parser.
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/** Use this to read an array field retrieved from the database.
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*
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* Use this only if your client encoding is UTF-8, ASCII, or a single-byte
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* encoding which is a superset of ASCII.
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*
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* The input is a C-style string containing the textual representation of an
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* array, as returned by the database. The parser reads this representation
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* on the fly. The string must remain in memory until parsing is done.
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*
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* Parse the array by making calls to @c get_next until it returns a
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* @c juncture of "done". The @c juncture tells you what the parser found in
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* that step: did the array "nest" to a deeper level, or "un-nest" back up?
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*/
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class DROGON_EXPORT ArrayParser
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{
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public:
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/// What's the latest thing found in the array?
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enum juncture
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{
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/// Starting a new row.
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row_start,
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/// Ending the current row.
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row_end,
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/// Found a NULL value.
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null_value,
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/// Found a string value.
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string_value,
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/// Parsing has completed.
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done,
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};
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/// Constructor. You don't need this; use @c field::as_array instead.
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explicit ArrayParser(const char input[]);
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/// Parse the next step in the array.
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/** Returns what it found. If the juncture is @c string_value, the string
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* will contain the value. Otherwise, it will be empty.
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*
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* Call this until the @c juncture it returns is @c done.
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*/
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std::pair<juncture, std::string> getNext();
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private:
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/// Current parsing position in the input.
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const char *pos_;
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};
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} // namespace orm
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} // namespace drogon
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