library/cpp/yson_pull/read_ops.cpp


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#include "read_ops.h" 
 
using namespace NYsonPull; 
using namespace NYsonPull::NReadOps; 
 
namespace { 
    bool TrySkipValueUntil(EEventType end, TReader& reader) {
        const auto& event = reader.NextEvent(); 
        if (event.Type() == end) { 
            return false;
        }
        SkipCurrentValue(event, reader);
        return true;
    }
 
    bool TrySkipKeyValueUntil(EEventType end, TReader& reader) {
        const auto& event = reader.NextEvent(); 
        if (event.Type() == end) { 
            return false;
        }
        Expect(event, EEventType::Key); 
        SkipValue(reader);
        return true;
    }
} 
 
void NYsonPull::NReadOps::SkipCurrentValue(const TEvent& event, TReader& reader) { 
    switch (event.Type()) { 
        case EEventType::BeginList: 
            while (TrySkipValueUntil(EEventType::EndList, reader)) { 
            }
            return;
 
        case EEventType::BeginMap: 
            while (TrySkipKeyValueUntil(EEventType::EndMap, reader)) { 
            }
            return;
 
        case EEventType::BeginAttributes: 
            while (TrySkipKeyValueUntil(EEventType::EndAttributes, reader)) { 
            }
            // attributes after attributes are disallowed in TReader
            SkipValue(reader);
            return;
 
        case EEventType::Scalar: 
            return;
 
        default:
            throw yexception() << "Unexpected event: " << event;
    }
} 
 
void NYsonPull::NReadOps::SkipValue(TReader& reader) { 
    const auto& event = reader.NextEvent(); 
    SkipCurrentValue(event, reader);
} 
 
void NYsonPull::NReadOps::SkipControlRecords(TReader& reader) { 
    const auto* event = &reader.LastEvent(); 
    while (event->Type() == EEventType::BeginAttributes) { 
        SkipCurrentValue(*event, reader); 
        event = &reader.NextEvent(); 
    } 
    Expect(*event, EEventType::BeginMap); 
}