2 files changed, 52 insertions, 7 deletions

diff --git a/core/divefilter.cpp b/core/divefilter.cpp
index 5bb05b947..7f47e45ac 100644
--- a/core/divefilter.cpp
+++ b/core/divefilter.cpp
@@ -8,10 +8,12 @@ DiveFilter::DiveFilter()
 {
 }
 
-bool DiveFilter::showDive(const struct dive *d) const
+ShownChange DiveFilter::update(const QVector<dive *> &) const
+{
+}
+
+ShownChange DiveFilter::updateAll() const
 {
-	// TODO: Do something useful
-	return true;
 }
 
 #else // SUBSURFACE_MOBILE
@@ -24,6 +26,37 @@ bool DiveFilter::showDive(const struct dive *d) const
 #include "core/divesite.h"
 #include "qt-models/filtermodels.h"
 
+void DiveFilter::updateDiveStatus(dive *d, ShownChange &change) const
+{
+	bool newStatus = showDive(d);
+	if (filter_dive(d, newStatus)) {
+		if (newStatus)
+			change.newShown.push_back(d);
+		else
+			change.newHidden.push_back(d);
+	}
+}
+
+ShownChange DiveFilter::update(const QVector<dive *> &dives) const
+{
+	dive *old_current = current_dive;
+	ShownChange res;
+	for (dive *d: dives)
+		updateDiveStatus(d, res);
+	res.currentChanged = old_current != current_dive;
+	return res;
+}
+
+ShownChange DiveFilter::updateAll() const
+{
+	dive *old_current = current_dive;
+	ShownChange res;
+	for (int i = 0; i < dive_table.nr; ++i)
+		updateDiveStatus(get_dive(i), res);
+	res.currentChanged = old_current != current_dive;
+	return res;
+}
+
 namespace {
 	// Pointer to function that takes two strings and returns whether
 	// the first matches the second according to a criterion (substring, starts-with, exact).
diff --git a/core/divefilter.h b/core/divefilter.h
index 2ad3c4b9b..aa166d022 100644
--- a/core/divefilter.h
+++ b/core/divefilter.h
@@ -3,6 +3,16 @@
 #ifndef DIVE_FILTER_H
 #define DIVE_FILTER_H
 
+#include <QVector>
+struct dive;
+
+// Structure describing changes of shown status upon applying the filter
+struct ShownChange {
+	QVector<dive *> newShown;
+	QVector<dive *> newHidden;
+	bool currentChanged;
+};
+
 // The dive filter for mobile is currently much simpler than for desktop.
 // Therefore, for now we have two completely separate implementations.
 // This should be unified in the future.
@@ -12,7 +22,8 @@ class DiveFilter {
 public:
 	static DiveFilter *instance();
 
-	bool showDive(const struct dive *d) const;
+	ShownChange update(const QVector<dive *> &dives) const; // Update filter status of given dives and return dives whose status changed
+	ShownChange updateAll() const; // Update filter status of all dives and return dives whose status changed
 private:
 	DiveFilter();
 };
@@ -21,9 +32,7 @@ private:
 
 #include <QDateTime>
 #include <QStringList>
-#include <QVector>
 
-struct dive;
 struct dive_trip;
 struct dive_site;
 
@@ -82,15 +91,18 @@ class DiveFilter {
 public:
 	static DiveFilter *instance();
 
-	bool showDive(const struct dive *d) const;
 	bool diveSiteMode() const; // returns true if we're filtering on dive site
 	const QVector<dive_site *> &filteredDiveSites() const;
 	void startFilterDiveSites(QVector<dive_site *> ds);
 	void setFilterDiveSite(QVector<dive_site *> ds);
 	void stopFilterDiveSites();
 	void setFilter(const FilterData &data);
+	ShownChange update(const QVector<dive *> &dives) const; // Update filter status of given dives and return dives whose status changed
+	ShownChange updateAll() const; // Update filter status of all dives and return dives whose status changed
 private:
 	DiveFilter();
+	void updateDiveStatus(dive *d, ShownChange &change) const;
+	bool showDive(const struct dive *d) const; // Should that dive be shown?
 
 	QVector<dive_site *> dive_sites;
 	FilterData filterData;