Rearrange block reservations to present consistent state in signal_reserved

diff --git a/source/libr2c2/train.cpp b/source/libr2c2/train.cpp
index 936f74aa82d6d522bb74a7d500a59eeecea0f2d2..599f2dcdf28b27d92a1401b9fe025d701c4949d1 100644 (file)
--- a/source/libr2c2/train.cpp
+++ b/source/libr2c2/train.cpp
@@ -430,10 +430,13 @@ void Train::place(Block &block, unsigned entry)
        set_active(false);
        accurate_position = false;
 
+       blocks.push_back(BlockIter(&block, entry));
        if(!block.reserve(this))
+       {
+               blocks.pop_back();
                return;
+       }
 
-       blocks.push_back(BlockIter(&block, entry));
        if(reverse)
        {
                TrackIter track = BlockIter(&block, entry).reverse().track_iter();
@@ -648,8 +651,9 @@ void Train::tick(const Time::TimeStamp &t, const Time::TimeDelta &dt)
 
                if(dist>10*layout.get_catalogue().get_scale())
                {
-                       blocks.front()->reserve(0);
+                       Block &block = *blocks.front();
                        blocks.pop_front();
+                       block.reserve(0);
                }
        }
 }
@@ -967,9 +971,11 @@ void Train::reserve_more()
                        }
                }
 
+               blocks.push_back(block);
                bool reserved = block->reserve(this);
                if(!reserved)
                {
+                       blocks.pop_back();
                        /* We've found another train.  If it wants to exit the block from the
                        same endpoint we're trying to enter from or the other way around,
                        treat it as coming towards us.  Otherwise treat it as going in the
@@ -1000,7 +1006,11 @@ void Train::reserve_more()
                                /* Ask a lesser priority train going to the same direction to free
                                the block for us */
                                if(other_train->free_block(*block))
-                                       reserved = block->reserve(this);
+                               {
+                                       blocks.push_back(block);
+                                       if(!(reserved = block->reserve(this)))
+                                               blocks.pop_back();
+                               }
                        }
                        else if(other_train!=yielding_to && (other_prio<priority || (other_prio==priority && entry_conflict)))
                        {
@@ -1036,8 +1046,6 @@ void Train::reserve_more()
                if(!contested_blocks.empty() && contested_blocks.front()==block)
                        contested_blocks.pop_front();
 
-               blocks.push_back(block);
-
                if(cur_blocks_end==blocks.end())
                        --cur_blocks_end;
                if(clear_blocks_end==blocks.end())
@@ -1337,8 +1345,8 @@ void Train::Loader::block(unsigned id)
        if(entry<0)
                entry = 0;
 
-       blk->reserve(&obj);
        obj.blocks.push_back(BlockIter(blk, entry));
+       blk->reserve(&obj);
 
        if(blk->get_sensor_id())
                obj.layout.get_driver().set_sensor(blk->get_sensor_id(), true);