query_result_stream.h

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// BSD 3-Clause License
// Copyright (c) 2021-2025, 🍀☀🌕🌥 🌊
// See the LICENSE file in the project root for full license information.
 
#pragma once
 
#include <kcenon/pacs/core/dicom_dataset.h>
#include <kcenon/pacs/services/query_scp.h>
#include <kcenon/pacs/storage/instance_record.h>
#include <kcenon/pacs/storage/patient_record.h>
#include <kcenon/pacs/storage/series_record.h>
#include <kcenon/pacs/storage/study_record.h>
 
#include <kcenon/common/patterns/result.h>
 
#include <cstddef>
#include <memory>
#include <optional>
#include <string>
#include <variant>
#include <vector>
 
// Include database_cursor only when PACS_WITH_DATABASE_SYSTEM is defined
// IMPORTANT: Must be outside namespace to avoid polluting kcenon::pacs::services with std
#ifdef PACS_WITH_DATABASE_SYSTEM
#include "database_cursor.h"
#endif
 
namespace kcenon::pacs::storage {
class index_database;
}  // namespace kcenon::pacs::storage
 
namespace kcenon::pacs::services {
 
template <typename T>
using Result = kcenon::common::Result<T>;
 
using VoidResult = kcenon::common::VoidResult;
 
struct stream_config {
    size_t page_size = 100;
 
    bool include_total_count = false;
};
 
#ifdef PACS_WITH_DATABASE_SYSTEM
 
class query_result_stream {
public:
    ~query_result_stream() = default;
 
    // Non-copyable
    query_result_stream(const query_result_stream&) = delete;
    auto operator=(const query_result_stream&) -> query_result_stream& = delete;
 
    // Movable
    query_result_stream(query_result_stream&&) noexcept = default;
    auto operator=(query_result_stream&&) noexcept -> query_result_stream& = default;
 
    // =========================================================================
    // Factory Methods
    // =========================================================================
 
    [[nodiscard]] static auto create(storage::index_database* db, query_level level,
                                     const core::dicom_dataset& query_keys,
                                     const stream_config& config = {})
        -> Result<std::unique_ptr<query_result_stream>>;
 
    [[nodiscard]] static auto from_cursor(storage::index_database* db,
                                          const std::string& cursor_state,
                                          query_level level,
                                          const core::dicom_dataset& query_keys,
                                          const stream_config& config = {})
        -> Result<std::unique_ptr<query_result_stream>>;
 
    // =========================================================================
    // Stream Operations
    // =========================================================================
 
    [[nodiscard]] auto has_more() const noexcept -> bool;
 
    [[nodiscard]] auto next_batch() -> std::optional<std::vector<core::dicom_dataset>>;
 
    [[nodiscard]] auto total_count() const -> std::optional<size_t>;
 
    [[nodiscard]] auto position() const noexcept -> size_t;
 
    [[nodiscard]] auto level() const noexcept -> query_level;
 
    // =========================================================================
    // Cursor State
    // =========================================================================
 
    [[nodiscard]] auto cursor() const -> std::string;
 
private:
    query_result_stream(std::unique_ptr<database_cursor> cursor, query_level level,
                        const core::dicom_dataset& query_keys, stream_config config);
 
    [[nodiscard]] auto patient_to_dataset(const storage::patient_record& record) const
        -> core::dicom_dataset;
 
    [[nodiscard]] auto study_to_dataset(const storage::study_record& record) const
        -> core::dicom_dataset;
 
    [[nodiscard]] auto series_to_dataset(const storage::series_record& record) const
        -> core::dicom_dataset;
 
    [[nodiscard]] auto instance_to_dataset(const storage::instance_record& record) const
        -> core::dicom_dataset;
 
    [[nodiscard]] auto record_to_dataset(const query_record& record) const
        -> core::dicom_dataset;
 
    [[nodiscard]] static auto extract_patient_query(const core::dicom_dataset& keys)
        -> storage::patient_query;
 
    [[nodiscard]] static auto extract_study_query(const core::dicom_dataset& keys)
        -> storage::study_query;
 
    [[nodiscard]] static auto extract_series_query(const core::dicom_dataset& keys)
        -> storage::series_query;
 
    [[nodiscard]] static auto extract_instance_query(const core::dicom_dataset& keys)
        -> storage::instance_query;
 
    std::unique_ptr<database_cursor> cursor_;
 
    query_level level_;
 
    core::dicom_dataset query_keys_;
 
    stream_config config_;
 
    mutable std::optional<size_t> total_count_;
};
 
#endif  // PACS_WITH_DATABASE_SYSTEM
 
}  // namespace kcenon::pacs::services