encapsulate item::contents into a new class

src/activity_handlers.cpp

@@ -1026,7 +1026,6 @@ void activity_handlers::butcher_finish( player_activity *act, player *p )
     }
 
     item &corpse_item = *target;
-    std::list<item> contents = corpse_item.contents;
     const mtype *corpse = corpse_item.get_mtype();
     const field_type_id type_blood = corpse->bloodType();
     const field_type_id type_gib = corpse->gibType();
@@ -1113,16 +1112,17 @@ void activity_handlers::butcher_finish( player_activity *act, player *p )
     // therefore operations on this activities targets and values may be invalidated.
     // reveal hidden items / hidden content
     if( action != F_DRESS && action != SKIN ) {
-        for( auto &content : contents ) {
+        corpse_item.visit_items( [&]( item * content ) {
             if( ( roll_butchery() + 10 ) * 5 > rng( 0, 100 ) ) {
                 //~ %1$s - item name, %2$s - monster name
-                p->add_msg_if_player( m_good, _( "You discover a %1$s in the %2$s!" ), content.tname(),
+                p->add_msg_if_player( m_good, _( "You discover a %1$s in the %2$s!" ), content->tname(),
                                       corpse->nname() );
-                g->m.add_item_or_charges( p->pos(), content );
-            } else if( content.is_bionic() ) {
+                g->m.add_item_or_charges( p->pos(), *content );
+            } else if( content->is_bionic() ) {
                 g->m.spawn_item( p->pos(), "burnt_out_bionic", 1, 0, calendar::turn );
             }
-        }
+            return VisitResponse::NEXT;
+        } );
     }
 
     //end messages and effects
@@ -2656,7 +2656,7 @@ void activity_handlers::gunmod_add_finish( player_activity *act, player *p )
     if( rng( 0, 100 ) <= roll ) {
         add_msg( m_good, _( "You successfully attached the %1$s to your %2$s." ), mod.tname(),
                  gun.tname() );
-        gun.contents.push_back( p->i_rem( &mod ) );
+        gun.put_in( p->i_rem( &mod ) );
 
     } else if( rng( 0, 100 ) <= risk ) {
         if( gun.inc_damage() ) {
@@ -2691,7 +2691,7 @@ void activity_handlers::toolmod_add_finish( player_activity *act, player *p )
     p->add_msg_if_player( m_good, _( "You successfully attached the %1$s to your %2$s." ),
                           mod.tname(), tool.tname() );
     mod.item_tags.insert( "IRREMOVABLE" );
-    tool.contents.push_back( mod );
+    tool.put_in( mod );
     act->targets[1].remove_item();
 }
 
@@ -3966,15 +3966,18 @@ void activity_handlers::unload_mag_finish( player_activity *act, player *p )
     int qty = 0;
     item &it = *act->targets[ 0 ];
 
-    // remove the ammo leads in the belt
-    it.contents.erase( std::remove_if( it.contents.begin(),
-    it.contents.end(), [&]( item & e ) {
-        if( !p->add_or_drop_with_msg( e, true ) ) {
-            return false;
+    std::vector<item *> remove_contained;
+    it.visit_items( [&]( item * contained ) {
+        if( p->add_or_drop_with_msg( *contained, true ) ) {
+            qty += contained->charges;
+            remove_contained.push_back( contained );
         }
-        qty += e.charges;
-        return true;
-    } ), it.contents.end() );
+        return VisitResponse::NEXT;
+    } );
+    // remove the ammo leads in the belt
+    for( item *remove : remove_contained ) {
+        it.remove_item( *remove );
+    }
 
     // remove the belt linkage
     if( it.is_ammo_belt() ) {
@@ -4584,6 +4587,6 @@ void activity_handlers::mind_splicer_finish( player_activity *act, player *p )
     item &data_card = *act->targets[0];
     p->add_msg_if_player( m_info, _( "…you finally find the memory banks." ) );
     p->add_msg_if_player( m_info, _( "The kit makes a copy of the data inside the bionic." ) );
-    data_card.contents.clear();
+    data_card.contents.clear_items();
     data_card.put_in( item( "mind_scan_robofac" ) );
 }

src/advanced_inv.cpp

@@ -1632,7 +1632,7 @@ bool advanced_inventory::move_content( item &src_container, item &dest_container
 
     uistate.adv_inv_container_content_type = dest_container.contents.front().typeId();
     if( src_contents.charges <= 0 ) {
-        src_container.contents.clear();
+        src_container.contents.clear_items();
     }
 
     return true;

src/avatar_action.cpp

@@ -923,7 +923,7 @@ void avatar_action::eat( avatar &you, item_location loc )
 
     } else if( you.consume_item( *it ) ) {
         if( it->is_food_container() || !you.can_consume_as_is( *it ) ) {
-            it->contents.erase( it->contents.begin() );
+            it->remove_item( it->contents.front() );
             add_msg( _( "You leave the empty %s." ), it->tname() );
         } else {
             loc.remove_item();

src/ballistics.cpp

@@ -38,7 +38,7 @@
 static void drop_or_embed_projectile( const dealt_projectile_attack &attack )
 {
     const auto &proj = attack.proj;
-    const auto &drop_item = proj.get_drop();
+    const item &drop_item = proj.get_drop();
     const auto &effects = proj.proj_effects;
     if( drop_item.is_null() ) {
         return;
@@ -52,9 +52,11 @@ static void drop_or_embed_projectile( const dealt_projectile_attack &attack )
             add_msg( _( "The %s shatters!" ), drop_item.tname() );
         }
 
-        for( const item &i : drop_item.contents ) {
-            g->m.add_item_or_charges( pt, i );
-        }
+        drop_item.visit_items( [&pt]( const item * it ) {
+            g->m.add_item_or_charges( pt, *it );
+            return VisitResponse::NEXT;
+        } );
+
         // TODO: Non-glass breaking
         // TODO: Wine glass breaking vs. entire sheet of glass breaking
         sounds::sound( pt, 16, sounds::sound_t::combat, _( "glass breaking!" ), false, "bullet_hit",
@@ -68,9 +70,8 @@ static void drop_or_embed_projectile( const dealt_projectile_attack &attack )
             add_msg( _( "The %s bursts!" ), drop_item.tname() );
         }
 
-        for( const item &i : drop_item.contents ) {
-            g->m.add_item_or_charges( pt, i );
-        }
+        // copies the drop item to spill the contents
+        item( drop_item ).spill_contents( pt );
 
         // TODO: Sound
         return;

src/character.cpp

@@ -1660,11 +1660,9 @@ item Character::i_rem( const item *it )
     return tmp.front();
 }
 
-void Character::i_rem_keep_contents( const int pos )
+void Character::i_rem_keep_contents( const int idx )
 {
-    for( auto &content : i_rem( pos ).contents ) {
-        i_add_or_drop( content );
-    }
+    i_rem( idx ).spill_contents( pos() );
 }
 
 bool Character::i_add_or_drop( item &it, int qty )
@@ -7365,7 +7363,9 @@ void Character::absorb_hit( body_part bp, damage_instance &dam )
                 destroyed_armor_msg( *this, pre_damage_name );
                 armor_destroyed = true;
                 armor.on_takeoff( *this );
-                worn_remains.insert( worn_remains.end(), armor.contents.begin(), armor.contents.end() );
+                for( const item *it : armor.contents.all_items_top() ) {
+                    worn_remains.push_back( *it );
+                }
                 // decltype is the type name of the iterator, note that reverse_iterator::base returns the
                 // iterator to the next element, not the one the revers_iterator points to.
                 // http://stackoverflow.com/questions/1830158/how-to-call-erase-with-a-reverse-iterator

src/character.h

@@ -1126,7 +1126,7 @@ class Character : public Creature, public visitable<Character>
          * @return A copy of the removed item.
          */
         item i_rem( const item *it );
-        void i_rem_keep_contents( int pos );
+        void i_rem_keep_contents( int idx );
         /** Sets invlet and adds to inventory if possible, drops otherwise, returns true if either succeeded.
          *  An optional qty can be provided (and will perform better than separate calls). */
         bool i_add_or_drop( item &it, int qty = 1 );

src/computer_session.cpp

@@ -690,7 +690,7 @@ void computer_session::action_download_software()
         g->u.moves -= 30;
         item software( miss->get_item_id(), 0 );
         software.mission_id = comp.mission_id;
-        usb->contents.clear();
+        usb->contents.clear_items();
         usb->put_in( software );
         print_line( _( "Software downloaded." ) );
     } else {
@@ -728,7 +728,7 @@ void computer_session::action_blood_anal()
                     if( query_bool( _( "Download data?" ) ) ) {
                         if( item *const usb = pick_usb() ) {
                             item software( "software_blood_data", 0 );
-                            usb->contents.clear();
+                            usb->contents.clear_items();
                             usb->put_in( software );
                             print_line( _( "Software downloaded." ) );
                         } else {

src/consumption.cpp

@@ -277,7 +277,7 @@ std::pair<nutrients, nutrients> Character::compute_nutrient_range(
         nutrients this_max;
 
         item result_it = rec->create_result();
-        if( result_it.contents.size() == 1 ) {
+        if( result_it.contents.num_item_stacks() == 1 ) {
             const item alt_result = result_it.contents.front();
             if( alt_result.typeId() == comest_it.typeId() ) {
                 result_it = alt_result;

src/crafting.cpp

@@ -1540,11 +1540,11 @@ static void empty_buckets( player &p )
         return it.is_bucket_nonempty() && &it != &p.weapon;
     }, INT_MAX );
     for( auto &it : buckets ) {
-        for( const item &in : it.contents ) {
-            drop_or_handle( in, p );
+        for( const item *in : it.contents.all_items_top() ) {
+            drop_or_handle( *in, p );
         }
 
-        it.contents.clear();
+        it.contents.clear_items();
         drop_or_handle( it, p );
     }
 }
@@ -2302,14 +2302,13 @@ void drop_or_handle( const item &newit, player &p )
 
 void remove_ammo( item &dis_item, player &p )
 {
-    for( auto iter = dis_item.contents.begin(); iter != dis_item.contents.end(); ) {
-        if( iter->is_irremovable() ) {
-            iter++;
-            continue;
+    dis_item.remove_items_with( [&p]( const item & it ) {
+        if( it.is_irremovable() ) {
+            return false;
         }
-        drop_or_handle( *iter, p );
-        iter = dis_item.contents.erase( iter );
-    }
+        drop_or_handle( it, p );
+        return true;
+    } );
 
     if( dis_item.has_flag( flag_NO_UNLOAD ) ) {
         return;

src/dump.cpp

@@ -67,7 +67,7 @@ bool game::dump_stats( const std::string &what, dump_mode mode,
     test_items[ "G2" ] = item( "hk_mp5" ).ammo_set( "9mm" );
     test_items[ "G3" ] = item( "ar15" ).ammo_set( "223" );
     test_items[ "G4" ] = item( "remington_700" ).ammo_set( "270" );
-    test_items[ "G4" ].emplace_back( "rifle_scope" );
+    test_items[ "G4" ].put_in( item( "rifle_scope" ) );
 
     if( what == "AMMO" ) {
         header = {
@@ -212,14 +212,14 @@ bool game::dump_stats( const std::string &what, dump_mode mode,
             if( e->gun ) {
                 item gun( e );
                 if( !gun.magazine_integral() ) {
-                    gun.emplace_back( gun.magazine_default() );
+                    gun.put_in( item( gun.magazine_default() ) );
                 }
                 gun.ammo_set( gun.ammo_default( false ), gun.ammo_capacity() );
 
                 dump( test_npcs[ "S1" ], gun );
 
                 if( gun.type->gun->barrel_length > 0_ml ) {
-                    gun.emplace_back( "barrel_small" );
+                    gun.put_in( item( "barrel_small" ) );
                     dump( test_npcs[ "S1" ], gun );
                 }
             }

src/faction_camp.cpp

@@ -3700,7 +3700,7 @@ bool basecamp::distribute_food()
         for( item &i : initial_items ) {
             if( i.is_container() && i.get_contained().is_food() ) {
                 auto comest = i.get_contained();
-                i.contents.clear();
+                i.contents.clear_items();
                 //NPCs are lazy bastards who leave empties all around the camp fire
                 tripoint litter_spread = p_litter;
                 litter_spread.x += rng( -3, 3 );

src/gamemode_defense.cpp

@@ -1084,7 +1084,7 @@ void defense_game::caravan()
             // Guns bought from the caravan should always come with an empty
             // magazine.
             if( tmp.is_gun() && !tmp.magazine_integral() ) {
-                tmp.emplace_back( tmp.magazine_default() );
+                tmp.put_in( item( tmp.magazine_default() ) );
             }
 
             for( int j = 0; j < item_count[0][i]; j++ ) {

src/handle_action.cpp

@@ -712,9 +712,7 @@ static void smash()
             if( u.weapon.made_of( material_id( "glass" ) ) &&
                 rng( 0, vol + 3 ) < vol ) {
                 add_msg( m_bad, _( "Your %s shatters!" ), u.weapon.tname() );
-                for( auto &elem : u.weapon.contents ) {
-                    m.add_item_or_charges( u.pos(), elem );
-                }
+                u.weapon.spill_contents( u.pos() );
                 sounds::sound( u.pos(), 24, sounds::sound_t::combat, "CRACK!", true, "smash", "glass" );
                 u.deal_damage( nullptr, bp_hand_r, damage_instance( DT_CUT, rng( 0, vol ) ) );
                 if( vol > 20 ) {

src/handle_liquid.cpp

@@ -121,7 +121,7 @@ bool handle_liquid_from_ground( map_stack::iterator on_ground,
     return true;
 }
 
-bool handle_liquid_from_container( std::list<item>::iterator in_container,
+bool handle_liquid_from_container( item *in_container,
                                    item &container, int radius )
 {
     // TODO: not all code paths on handle_liquid consume move points, fix that.
@@ -131,16 +131,23 @@ bool handle_liquid_from_container( std::list<item>::iterator in_container,
         container.on_contents_changed();
     }
 
-    if( in_container->charges > 0 ) {
-        return false;
-    }
-    container.contents.erase( in_container );
-    return true;
+    return in_container->charges <= 0;
 }
 
 bool handle_liquid_from_container( item &container, int radius )
 {
-    return handle_liquid_from_container( container.contents.begin(), container, radius );
+    std::vector<item *> remove;
+    bool handled = false;
+    for( item *contained : container.contents.all_items_top() ) {
+        if( handle_liquid_from_container( contained, container, radius ) ) {
+            remove.push_back( contained );
+            handled = true;
+        }
+    }
+    for( item *contained : remove ) {
+        container.remove_item( *contained );
+    }
+    return handled;
 }
 
 static bool get_liquid_target( item &liquid, item *const source, const int radius,

src/handle_liquid.h

@@ -82,7 +82,7 @@ bool handle_liquid_from_ground( map_stack::iterator on_ground, const tripoint &p
  * The iterator is invalidated in that case. Otherwise the item remains but may have
  * fewer charges.
  */
-bool handle_liquid_from_container( std::list<item>::iterator in_container, item &container,
+bool handle_liquid_from_container( item *in_container, item &container,
                                    int radius = 0 );
 /**
  * Shortcut to the above: handles the first item in the container.