Don't miscast when the spell can still be aborted (#4281).

This is a significant refactoring. All the spells now return a spret_type and
take a boolean which tells if the spell has actually failed.
Also some code clean up in _do_cast(). All spells have their own function now.

Also fix the following bugs:
* Properly abort fire storm if forced casting on a wall with '!'.
  Also put a message for forced out of range casting (like cloud spells).
* Casting summon elemental on an invisible monster aborted with no cost.
* if a summoning spell aborts because create_monster fails, you don't lose a
  turn. You still get a chance of miscast in this rare case.
* s2s, tukima and branding spells abort properly instead of consuming turn and
MP when player is not wielding appropriate object.
* s2s abort message when wielding a non-snakable.

1 files changed, 7 insertions, 3 deletions

diff --git a/crawl-ref/source/spl-monench.cc b/crawl-ref/source/spl-monench.cc
index ac8d78dd29..63c4dfb802 100644
--- a/crawl-ref/source/spl-monench.cc
+++ b/crawl-ref/source/spl-monench.cc
@@ -46,9 +46,11 @@ static int _sleep_monsters(coord_def where, int pow, int, actor *)
     return (1);
 }
 
-void cast_mass_sleep(int pow)
+spret_type cast_mass_sleep(int pow, bool fail)
 {
+    fail_check();
     apply_area_visible(_sleep_monsters, pow, true);
+    return SPRET_SUCCESS;
 }
 
 bool backlight_monsters(coord_def where, int pow, int garbage)
@@ -116,8 +118,10 @@ bool do_slow_monster(monster* mon, const actor* agent)
     return (false);
 }
 
-bool project_noise()
+// XXX: Not sure why you can't exit map and cancel the spell.
+spret_type project_noise(bool fail)
 {
+    fail_check();
     bool success = false;
 
     coord_def pos(1, 0);
@@ -155,5 +159,5 @@ bool project_noise()
         }
     }
 
-    return (success);
+    return SPRET_SUCCESS;
 }