TerrariumTileFetcher.h

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/****************************************************************************
 *
 * (c) 2009-2024 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
 *
 * QGroundControl is licensed according to the terms in the file
 * COPYING.md in the root of the source code directory.
 *
 ****************************************************************************/
 
#pragma once
 
#include <QtCore/QElapsedTimer>
#include <QtCore/QHash>
#include <QtCore/QRectF>
#include <QtCore/QSet>
 
#include "ElevationTilePyramid.h"
#include "HeightSource.h"
 
class HeightField;
class QImage;
class QNetworkAccessManager;
class QNetworkReply;
 
class TerrariumTileFetcher : public HeightSource
{
    Q_OBJECT
 
public:
    explicit TerrariumTileFetcher(QObject* parent = nullptr, QNetworkAccessManager* networkManager = nullptr);
 
    static constexpr int kMaxTileZoom = 15;
 
    static constexpr int kAnchorZoom = 10;
 
    static constexpr int kMaxGridSize = 256;
 
    int requestPatchHeights(const TileMath::TileKey& key, int gridSize) final;
    void cancelRequest(int requestId) final;
 
    bool requestTile(const TileMath::TileKey& key) override;
 
    int pendingCount() const { return _pending.count(); }
 
    TileMath::TileKey lastFetchKey() const { return _lastFetchKey; }
 
private:
    struct PendingRequest
    {
        TileMath::TileKey fetchKey;  
        QRectF subWindow;            
        int gridSize = 0;
    };
 
    struct HeldTile
    {
        ElevationTilePyramid::Grid grid;
        QSet<TileMath::TileKey> anchors;  
    };
 
    void _insertIntoField(const TileMath::TileKey& fetchKey, ElevationTilePyramid::Grid grid);
    int _releaseHeld(const TileMath::TileKey& anchor);
    void _failAsync(int requestId);
    bool _fetchInFlight(const TileMath::TileKey& fetchKey) const;
    bool _startFetch(const TileMath::TileKey& fetchKey);
    void _fetchFromNetwork(const TileMath::TileKey& fetchKey);
    void _deliverAll(const TileMath::TileKey& fetchKey, const QImage& image);
    void _failAll(const TileMath::TileKey& fetchKey, const QString& reason);
    void _deliver(int requestId, const QImage& image);
    void _finishFailed(int requestId);
    bool _shouldWarnFailure();
 
    static constexpr int kFailureWarnIntervalMs = 10000;  
 
    QNetworkAccessManager* _networkManager = nullptr;
    const int _mapId;
    QHash<int, PendingRequest> _pending;
    QHash<TileMath::TileKey, QList<int>> _waiters;            
    QSet<TileMath::TileKey> _fieldRequests;                   
    QHash<TileMath::TileKey, HeldTile> _held;                 
    QHash<TileMath::TileKey, QNetworkReply*> _activeReplies;  
    TileMath::TileKey _lastFetchKey;
    QElapsedTimer _failureWarnTimer;                          
};