divelog: turn owning-pointers into unique_ptr<>s

Since everything is C++ now, we can use unique_ptr<>s. This makes
the code significantly shorter, because we can now use the default
move constructor and assignment operators.

This has a semantic change when std::move()-ing the divelog:
now not the contents of the tables are moved, but the pointers.
That is, the moved-from object now has no more tables and
must not be used anymore. This made it necessary to replace
std::move()s by std::swap()s. In that regard, the old code was
in principle broken: it used moved-from objects, which may work
but usually doesn't.

This commit adds a myriad of .get() function calls where the code
expects a C-style pointer. The plan is to remove virtually all of
them, when we move free-standing functions into the class it acts
on. Or, replace C-style pointers by references where we don't support
NULL.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/datatrak.cpp

@@ -700,7 +700,7 @@ int datatrak_import(std::string &mem, std::string &wl_mem, struct divelog *log)
 	runner = mem.data();
 	JUMP(runner, 12);
 
-	// Secuential parsing. Abort if received NULL from dt_dive_parser.
+	// Sequential parsing. Abort if received NULL from dt_dive_parser.
 	while ((i < numdives) && (runner < maxbuf)) {
 		struct dive *ptdive = alloc_dive();
 
@@ -713,12 +713,12 @@ int datatrak_import(std::string &mem, std::string &wl_mem, struct divelog *log)
 			rc = 1;
 			goto out;
 		} else {
-			record_dive_to_table(ptdive, log->dives);
+			record_dive_to_table(ptdive, log->dives.get());
 		}
 		i++;
 	}
 out:
-	sort_dive_table(log->dives);
+	sort_dive_table(log->dives.get());
 	return rc;
 bail:
 	return 1;