Add a unique id to every dive

This id is just held in memory. It's not supposed to be used for anything
but having a unique handle that represents a dive. Whenever you need to
remember a dive across an operation that might change the dive_table, this
is what you should hold on to, not a dive number, a dive pointer, or
anything like that.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

3 files changed, 43 insertions, 1 deletions

diff --git a/dive.c b/dive.c
index 540f40eb5..a902bca68 100644
--- a/dive.c
+++ b/dive.c
@@ -892,6 +892,7 @@ struct dive *fixup_dive(struct dive *dive)
 		weightsystem_t *ws = dive->weightsystem + i;
 		add_weightsystem_description(ws);
 	}
+	dive->id = getUniqID(dive);
 
 	return dive;
 }
diff --git a/dive.h b/dive.h
index a0c22935f..649a7e5e6 100644
--- a/dive.h
+++ b/dive.h
@@ -412,9 +412,10 @@ struct dive {
 	pressure_t surface_pressure;
 	duration_t duration;
 	int salinity; // kg per 10000 l
-	struct tag_entry *tag_list;
 
+	struct tag_entry *tag_list;
 	struct divecomputer dc;
+	int id; // unique ID for this dive
 };
 
 static inline int dive_has_gps_location(struct dive *dive)
@@ -611,6 +612,21 @@ static inline struct dive *get_dive_by_diveid(uint32_t diveid, uint32_t deviceid
 	}
 	return NULL;
 }
+// this is very different from get_dive_by_diveid() (which is only used
+// by the UEMIS downloader) -- this uses the unique diveID to allow us
+// to hold an identifier for a dive across operations that might change
+// the dive_table
+static inline struct dive *getDiveById(int id)
+{
+	int i;
+	struct dive *dive = NULL;
+
+	for_each_dive(i, dive) {
+		if (dive->id == id)
+			break;
+	}
+	return dive;
+}
 extern struct dive *find_dive_including(timestamp_t when);
 extern bool dive_within_time_range(struct dive *dive, timestamp_t when, timestamp_t offset);
 struct dive *find_dive_n_near(timestamp_t when, int n, timestamp_t offset);
@@ -654,6 +670,7 @@ extern void finish_sample(struct divecomputer *dc);
 
 extern void sort_table(struct dive_table *table);
 extern struct dive *fixup_dive(struct dive *dive);
+extern int getUniqID(struct dive *d);
 extern unsigned int dc_airtemp(struct divecomputer *dc);
 extern unsigned int dc_watertemp(struct divecomputer *dc);
 extern struct dive *merge_dives(struct dive *a, struct dive *b, int offset, bool prefer_downloaded);
diff --git a/qthelper.cpp b/qthelper.cpp
index 7eb1e48f4..9d503cb6a 100644
--- a/qthelper.cpp
+++ b/qthelper.cpp
@@ -217,3 +217,27 @@ QList< int > getDivesInTrip ( dive_trip_t* trip )
 	}
 	return ret;
 }
+
+// we need this to be uniq, but also make sure
+// it doesn't change during the life time of a Subsurface session
+// oh, and it has no meaning whatsoever - that's why we have the
+// silly initial number and increment by 3 :-)
+int getUniqID(struct dive *d)
+{
+	static QSet<int> ids;
+	static int maxId = 83529;
+
+	int id = d->id;
+	if (id) {
+		if (!ids.contains(id)) {
+			qDebug() << "WTF - only I am allowed to create IDs";
+			ids.insert(id);
+		}
+		return id;
+	}
+	maxId += 3;
+	id = maxId;
+	Q_ASSERT(!ids.contains(id));
+	ids.insert(id);
+	return id;
+}