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Fix race condition that happens when we're pushing sync blocks faster than get_synopsis calls are getting through to the main thread

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This commit is contained in:
Eric Frias 2015-09-11 17:33:20 -04:00
parent e9e3b0d679
commit 76a36a67ac
1 changed files with 23 additions and 0 deletions
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23
libraries/app/application.cpp
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@ -595,6 +595,21 @@ namespace detail {
assert(reference_point_block_num > 0);
high_block_num = reference_point_block_num;
non_fork_high_block_num = high_block_num;
if (reference_point_block_num < low_block_num)
{
// we're on the same fork (at least as far as reference_point) but we've passed
// reference point and could no longer undo that far if we diverged after that
// block. This should probably only happen due to a race condition where
// the network thread calls this function, and then immediately pushes a bunch of blocks,
// then the main thread finally processes this function.
// with the current framework, there's not much we can do to tell the network
// thread what our current head block is, so we'll just pretend that
// our head is actually the reference point.
// this *may* enable us to fetch blocks that we're unable to push, but that should
// be a rare case (and correctly handled)
low_block_num = reference_point_block_num;
}
}
else
{
@ -659,7 +674,15 @@ namespace detail {
if (low_block_num <= non_fork_high_block_num)
synopsis.push_back(_chain_db->get_block_id_for_num(low_block_num));
else
{
// for debugging
int index = low_block_num - non_fork_high_block_num - 1;
if (index < 0 || index > fork_history.size())
{
int i = 0;
}
synopsis.push_back(fork_history[low_block_num - non_fork_high_block_num - 1]);
}
low_block_num += (true_high_block_num - low_block_num + 2) / 2;
}
while (low_block_num <= high_block_num);