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Lock when accessing parser to prevent antlr bugs

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Reviewers: buda, mferencevic

Reviewed By: buda, mferencevic

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D625
This commit is contained in:
Mislav Bradac 2017-08-03 13:28:50 +02:00
parent 71ded22b65
commit d750970381
1 changed files with 20 additions and 4 deletions
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24
src/query/interpreter.hpp
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@ -47,8 +47,12 @@ class Interpreter {
}
// stripped query -> AST
frontend::opencypher::Parser parser(query);
auto low_level_tree = parser.tree();
auto parser = [&] {
// Be careful about unlocking since parser can throw.
std::unique_lock<SpinLock>(antlr_lock_);
return std::make_unique<frontend::opencypher::Parser>(query);
}();
auto low_level_tree = parser->tree();
// AST -> high level tree
frontend::CypherMainVisitor visitor(ctx);
@ -63,8 +67,13 @@ class Interpreter {
auto it = ast_cache_accessor.find(stripped.hash());
if (it == ast_cache_accessor.end()) {
// stripped query -> AST
frontend::opencypher::Parser parser(stripped.query());
auto low_level_tree = parser.tree();
auto parser = [&] {
// Be careful about unlocking since parser can throw.
std::unique_lock<SpinLock>(antlr_lock_);
return std::make_unique<frontend::opencypher::Parser>(
stripped.query());
}();
auto low_level_tree = parser->tree();
// AST -> high level tree
frontend::CypherMainVisitor visitor(ctx);
@ -185,6 +194,13 @@ class Interpreter {
private:
ConcurrentMap<HashType, CachedAst> ast_cache_;
// Antlr has singleton instance that is shared between threads. It is
// protected by locks inside of antlr. Unfortunately, they are not protected
// in a very good way. Once we have antlr version without race conditions we
// can remove this lock. This will probably never happen since antlr
// developers introduce more bugs in each version. Fortunately, we have cache
// so this lock probably won't impact performance much...
SpinLock antlr_lock_;
};
} // namespace query