tskv_parser_read.hpp File Reference

Detailed Description

Read all keys-values for 1 TSKV record.

Definition in file tskv_parser_read.hpp.

Go to the source code of this file.

#include <utility>
#include <userver/compiler/thread_local.hpp>
#include <userver/utils/encoding/tskv_parser.hpp>

Namespaces
namespace	utils
	Utilities.

Functions
template<typename TagConsumer>
TskvParser::RecordStatus	utils::encoding::TskvReadRecord (TskvParser &parser, TagConsumer consumer)
	Read all keys-values for 1 TSKV record.

Function Documentation

TskvReadRecord()

template<typename TagConsumer>

TskvParser::RecordStatus utils::encoding::TskvReadRecord	(	TskvParser &	parser,
		TagConsumer	consumer )

Read all keys-values for 1 TSKV record.

Parameters

parser	parser that should have already found the start of the TSKV record using TskvParser::SkipToRecordBegin
consumer	a lambda with the signature (const std::string&, const std::string&) -> bool; the strings are temporaries, references to them should not be stored; can return false to skip the record and return immediately

Usage example:

struct Record {
    std::vector<std::pair<std::string, std::string>> tags;
};
struct Junk {
    std::string data;
};
struct Incomplete {
    std::string data;
};
using SingleParsedRecord = std::variant<Record, Junk, Incomplete>;
using ParsedRecords = std::vector<SingleParsedRecord>;
 
ParsedRecords ParseTskv(std::string_view in) {
    ParsedRecords result;
    utils::encoding::TskvParser parser{in};
 
    const auto account_incomplete = [&](const char* incomplete_begin) {
        const std::string_view remaining(incomplete_begin, in.data() + in.size() - incomplete_begin);
        if (!remaining.empty()) {
            result.push_back(Incomplete{std::string(remaining)});
        }
    };
 
    while (true) {
        const char* const junk_begin = parser.GetStreamPosition();
        const char* const record_begin = parser.SkipToRecordBegin();
 
        if (!record_begin) {
            // Note: production code should stop and wait for more data here.
            account_incomplete(junk_begin);
            break;
        }
 
        // Note: accounting for junk in-between records is supported, but is
        // typically not important in production.
        if (record_begin != junk_begin) {
            result.push_back(Junk{std::string(junk_begin, record_begin)});
        }
 
        std::vector<std::pair<std::string, std::string>> tags;
 
        const auto status =
            utils::encoding::TskvReadRecord(parser, [&](const std::string& key, const std::string& value) {
                tags.emplace_back(key, value);
                return true;
            });
 
        if (status == utils::encoding::TskvParser::RecordStatus::kIncomplete) {
            // Note: production code should stop and wait for more data here.
            account_incomplete(record_begin);
            break;
        }
 
        result.push_back(Record{std::move(tags)});
    }
 
    return result;
}

Definition at line 38 of file tskv_parser_read.hpp.