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// SPDX-License-Identifier: GPL-2.0
// The DiveListNotifier emits signals when the dive-list changes (dives/trips created/deleted/moved)
// Note that vectors are passed by reference, so this will only work for signals inside the UI thread!
#ifndef DIVELISTNOTIFIER_H
#define DIVELISTNOTIFIER_H
#include "core/dive.h"
#include <QObject>
class DiveListNotifier : public QObject {
Q_OBJECT
signals:
// Note that there are no signals for trips being added / created / time-shifted,
// because these events never happen without a dive being added / created / time-shifted.
// We send one divesAdded, divesDeleted, divesChanged and divesTimeChanged signal per trip
// (non-associated dives being considered part of the null trip). This is ideal for the
// tree-view, but might be not-so-perfect for the list view, if trips intermingle or
// the deletion spans multiple trips. But most of the time only dives of a single trip
// will be affected and trips don't overlap, so these considerations are moot.
// Notes:
// - The dives are always sorted by start-time.
// - The "trip" arguments are null for top-level-dives.
void divesAdded(dive_trip *trip, bool addTrip, const QVector<dive *> &dives);
void divesDeleted(dive_trip *trip, bool deleteTrip, const QVector<dive *> &dives);
void divesChanged(dive_trip *trip, const QVector<dive *> &dives);
void divesMovedBetweenTrips(dive_trip *from, dive_trip *to, bool deleteFrom, bool createTo, const QVector<dive *> &dives);
void divesTimeChanged(dive_trip *trip, timestamp_t delta, const QVector<dive *> &dives);
// This signal is sent if the selection of dives and/or the current dive changed
void selectionChanged();
public:
// Desktop uses the QTreeView class to present the list of dives. The layout
// of this class gives us a very fundamental problem, as we can not easily
// distinguish between user-initiated changes of the selection and changes
// that are due to actions of the Command-classes. To solve this problem,
// the frontend can use this function to query whether a dive list-modifying
// command is currently executed. If this function returns true, the
// frontend is supposed to not modify the selection.
bool inCommand() const;
// The following class and function are used by divelist-modifying commands
// to signalize that are in-flight. If the returned object goes out of scope,
// the command-in-flight status is reset to its previous value. Thus, the
// function can be called recursively.
class InCommandMarker {
DiveListNotifier ¬ifier;
bool oldValue;
InCommandMarker(DiveListNotifier &);
friend DiveListNotifier;
public:
~InCommandMarker();
};
// Usage:
// void doWork()
// {
// auto marker = diveListNotifier.enterCommand();
// ... do work ...
// }
InCommandMarker enterCommand();
private:
friend InCommandMarker;
bool commandExecuting;
};
// The DiveListNotifier class has only trivial state.
// We can simply define it as a global object.
extern DiveListNotifier diveListNotifier;
// InCommandMarker is so trivial that the functions can be inlined.
// TODO: perhaps move this into own header-file.
inline DiveListNotifier::InCommandMarker::InCommandMarker(DiveListNotifier ¬ifierIn) : notifier(notifierIn),
oldValue(notifier.commandExecuting)
{
notifier.commandExecuting = true;
}
inline DiveListNotifier::InCommandMarker::~InCommandMarker()
{
notifier.commandExecuting = oldValue;
}
inline bool DiveListNotifier::inCommand() const
{
return commandExecuting;
}
inline DiveListNotifier::InCommandMarker DiveListNotifier::enterCommand()
{
return InCommandMarker(*this);
}
#endif
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