@tablerocklaker... I wouldn't get there more than 90' before, 2h if you want to play it safe. Yet it'll probably take you much less to pass thru everything. But that's me, of course.
For info, "Europe" is not a uniform entity, within the continent, there are different organisations/treaties to which different countries adhere (or not) namely: European Union, Schengen Area, Council of Europe, EEA, Eurozone, etc. This means that not all "internal" matters, flights in this case, are treated the same. Thus, once you're in Europe, depending on the country you're flying from, the one you're flying to and the ongoing agreements you might need or might not need a VISA, to pass thru customs, to show your passport, etc. which in turn makes flying a light -or no so 'light'- affair. In this instance, a BCN-Geneva flight is within the Schengen Area, so -in principle(*)- no documentation to be shown anywhere.
In short, flying within Europe is not like flying within the US.... visitors should take that into account.
(*) Noting that these agreements provide for temporary suspension for security reasons. France, for example, did call upon this clause and did suspend the Schengen Agreement for a while after the terrorist attacks in Paris so incoming visitors were screened regardless they might have been flying from another Schengen country.