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, 9 insertions, 5 deletions

diff --git a/crawl-ref/source/spl-clouds.h b/crawl-ref/source/spl-clouds.h
index b2e5a057f0..ae041cb466 100644
--- a/crawl-ref/source/spl-clouds.h
+++ b/crawl-ref/source/spl-clouds.h
@@ -1,20 +1,24 @@
 #ifndef SPL_CLOUDS_H
 #define SPL_CLOUDS_H
 
+#include "spl-cast.h"
+
 struct bolt;
 
-bool conjure_flame(int pow, const coord_def& where);
-bool stinking_cloud(int pow, bolt &beam);
+spret_type conjure_flame(int pow, const coord_def& where, bool fail);
+spret_type stinking_cloud(int pow, bolt &beam, bool fail);
 
 void big_cloud(cloud_type cl_type, const actor *agent, const coord_def& where,
                int pow, int size, int spread_rate = -1, int colour = -1,
                std::string name = "", std::string tile = "");
 
-bool cast_big_c(int pow, cloud_type cty, const actor *caster, bolt &beam);
+spret_type cast_big_c(int pow, cloud_type cty, const actor *caster, bolt &beam,
+                      bool fail);
 
-void cast_ring_of_flames(int power);
+spret_type cast_ring_of_flames(int power, bool fail);
 void manage_fire_shield(int delay);
 
+spret_type cast_corpse_rot(bool fail);
 void corpse_rot(actor* caster);
 
 int make_a_normal_cloud(coord_def where, int pow, int spread_rate,
@@ -22,7 +26,7 @@ int make_a_normal_cloud(coord_def where, int pow, int spread_rate,
                         std::string name = "", std::string tile = "");
 
 std::string get_evaporate_result_list(int potion);
-bool cast_evaporate(int pow, bolt& beem, int potion);
+spret_type cast_evaporate(int pow, bolt& beem, int potion, bool fail);
 
 int holy_flames(monster* caster, actor* defender);
 #endif