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Implemented infinite loop detector

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yhirose 2020-01-24 00:37:21 -05:00
parent 2c5d2b55cc
commit c5e356d804
2 changed files with 269 additions and 24 deletions
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188
peglib.h
View File

@ -24,6 +24,7 @@
#include <initializer_list>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <mutex>
@ -1702,8 +1703,6 @@ struct AssignIDToDefinition : public Ope::Visitor
struct IsLiteralToken : public Ope::Visitor
{
IsLiteralToken() : result_(false) {}
void visit(PrioritizedChoice& ope) override {
for (auto op: ope.opes_) {
if (!IsLiteralToken::check(*op)) {
@ -1724,13 +1723,11 @@ struct IsLiteralToken : public Ope::Visitor
}
private:
bool result_;
bool result_ = false;
};
struct TokenChecker : public Ope::Visitor
{
TokenChecker() : has_token_boundary_(false), has_rule_(false) {}
void visit(Sequence& ope) override {
for (auto op: ope.opes_) {
op->accept(*this);
@ -1763,13 +1760,12 @@ struct TokenChecker : public Ope::Visitor
}
private:
bool has_token_boundary_;
bool has_rule_;
bool has_token_boundary_ = false;
bool has_rule_ = false;
};
struct DetectLeftRecursion : public Ope::Visitor {
DetectLeftRecursion(const std::string& name)
: error_s(nullptr), name_(name), done_(false) {}
DetectLeftRecursion(const std::string& name) : name_(name) {}
void visit(Sequence& ope) override {
for (auto op: ope.opes_) {
@ -1811,12 +1807,122 @@ struct DetectLeftRecursion : public Ope::Visitor {
void visit(Whitespace& ope) override { ope.ope_->accept(*this); }
void visit(BackReference& /*ope*/) override { done_ = true; }
const char* error_s;
const char* error_s = nullptr;
private:
std::string name_;
std::set<std::string> refs_;
bool done_;
bool done_ = false;
};
struct HasEmptyElement : public Ope::Visitor
{
HasEmptyElement(std::list<std::pair<const char*, std::string>>& refs): refs_(refs) {}
void visit(Sequence& ope) override {
bool save_is_empty = false;
const char* save_error_s = nullptr;
std::string save_error_name;
for (auto op: ope.opes_) {
op->accept(*this);
if (!is_empty) { return; }
save_is_empty = is_empty;
save_error_s = error_s;
save_error_name = error_name;
is_empty = false;
error_name.clear();
}
is_empty = save_is_empty;
error_s = save_error_s;
error_name = save_error_name;
}
void visit(PrioritizedChoice& ope) override {
for (auto op: ope.opes_) {
op->accept(*this);
if (is_empty) { return; }
}
}
void visit(ZeroOrMore& /*ope*/) override { set_error(); }
void visit(OneOrMore& ope) override { ope.ope_->accept(*this); }
void visit(Option& /*ope*/) override { set_error(); }
void visit(AndPredicate& /*ope*/) override { set_error(); }
void visit(NotPredicate& /*ope*/) override { set_error(); }
void visit(CaptureScope& ope) override { ope.ope_->accept(*this); }
void visit(Capture& ope) override { ope.ope_->accept(*this); }
void visit(TokenBoundary& ope) override { ope.ope_->accept(*this); }
void visit(Ignore& ope) override { ope.ope_->accept(*this); }
void visit(WeakHolder& ope) override { ope.weak_.lock()->accept(*this); }
void visit(Holder& ope) override { ope.ope_->accept(*this); }
void visit(Reference& ope) override;
void visit(Whitespace& ope) override { ope.ope_->accept(*this); }
bool is_empty = false;
const char* error_s = nullptr;
std::string error_name;
private:
void set_error() {
is_empty = true;
error_s = refs_.back().first;
error_name = refs_.back().second;
}
std::list<std::pair<const char*, std::string>>& refs_;
};
struct DetectInfiniteLoop : public Ope::Visitor
{
DetectInfiniteLoop(const char* s, const std::string& name) {
refs_.emplace_back(s, name);
}
void visit(Sequence& ope) override {
for (auto op: ope.opes_) {
op->accept(*this);
if (has_error) { return; }
}
}
void visit(PrioritizedChoice& ope) override {
for (auto op: ope.opes_) {
op->accept(*this);
if (has_error) { return; }
}
}
void visit(ZeroOrMore& ope) override {
HasEmptyElement vis(refs_);
ope.ope_->accept(vis);
if (vis.is_empty) {
has_error = true;
error_s = vis.error_s;
error_name = vis.error_name;
}
}
void visit(OneOrMore& ope) override {
HasEmptyElement vis(refs_);
ope.ope_->accept(vis);
if (vis.is_empty) {
has_error = true;
error_s = vis.error_s;
error_name = vis.error_name;
}
}
void visit(Option& ope) override { ope.ope_->accept(*this); }
void visit(AndPredicate& ope) override { ope.ope_->accept(*this); }
void visit(NotPredicate& ope) override { ope.ope_->accept(*this); }
void visit(CaptureScope& ope) override { ope.ope_->accept(*this); }
void visit(Capture& ope) override { ope.ope_->accept(*this); }
void visit(TokenBoundary& ope) override { ope.ope_->accept(*this); }
void visit(Ignore& ope) override { ope.ope_->accept(*this); }
void visit(WeakHolder& ope) override { ope.weak_.lock()->accept(*this); }
void visit(Holder& ope) override { ope.ope_->accept(*this); }
void visit(Reference& ope) override;
void visit(Whitespace& ope) override { ope.ope_->accept(*this); }
bool has_error = false;
const char* error_s = nullptr;
std::string error_name;
private:
std::list<std::pair<const char*, std::string>> refs_;
};
struct ReferenceChecker : public Ope::Visitor {
@ -1941,8 +2047,6 @@ private:
struct IsPrioritizedChoice : public Ope::Visitor
{
IsPrioritizedChoice() : result_(false) {}
void visit(PrioritizedChoice& /*ope*/) override {
result_ = true;
}
@ -1954,7 +2058,7 @@ struct IsPrioritizedChoice : public Ope::Visitor
}
private:
bool result_;
bool result_ = false;
};
/*
@ -2425,6 +2529,36 @@ inline void DetectLeftRecursion::visit(Reference& ope) {
done_ = true;
}
inline void HasEmptyElement::visit(Reference& ope) {
auto it = std::find_if(refs_.begin(), refs_.end(), [&](const auto& ref) {
return ope.name_ == ref.second;
});
if (it != refs_.end()) {
return;
}
if (ope.rule_) {
refs_.emplace_back(ope.s_, ope.name_);
ope.rule_->accept(*this);
refs_.pop_back();
}
}
inline void DetectInfiniteLoop::visit(Reference& ope) {
auto it = std::find_if(refs_.begin(), refs_.end(), [&](const auto& ref) {
return ope.name_ == ref.second;
});
if (it != refs_.end()) {
return;
}
if (ope.rule_) {
refs_.emplace_back(ope.s_, ope.name_);
ope.rule_->accept(*this);
refs_.pop_back();
}
}
inline void ReferenceChecker::visit(Reference& ope) {
auto it = std::find(params_.begin(), params_.end(), ope.name_);
if (it != params_.end()) {
@ -2531,6 +2665,7 @@ private:
struct Data {
std::shared_ptr<Grammar> grammar;
std::string start;
const char* start_pos = nullptr;
std::vector<std::pair<std::string, const char*>> duplicates;
Data(): grammar(std::make_shared<Grammar>()) {}
@ -2648,6 +2783,7 @@ private:
if (data.start.empty()) {
data.start = name;
data.start_pos = sv.c_str();
}
} else {
data.duplicates.emplace_back(name, sv.c_str());
@ -2931,7 +3067,20 @@ private:
}
// Set root definition
start = data.start;
auto& start_rule = (*data.grammar)[data.start];
// Check infinite loop
{
DetectInfiniteLoop vis(data.start_pos, data.start);
start_rule.accept(vis);
if (vis.has_error) {
if (log) {
auto line = line_info(s, vis.error_s);
log(line.first, line.second, "infinite loop is detected in '" + vis.error_name + "'.");
}
return nullptr;
}
}
// Automatic whitespace skipping
if (grammar.count(WHITESPACE_DEFINITION_NAME)) {
@ -2943,16 +3092,17 @@ private:
}
}
auto& rule = (*data.grammar)[start];
rule.whitespaceOpe = wsp((*data.grammar)[WHITESPACE_DEFINITION_NAME].get_core_operator());
start_rule.whitespaceOpe = wsp((*data.grammar)[WHITESPACE_DEFINITION_NAME].get_core_operator());
}
// Word expression
if (grammar.count(WORD_DEFINITION_NAME)) {
auto& rule = (*data.grammar)[start];
rule.wordOpe = (*data.grammar)[WORD_DEFINITION_NAME].get_core_operator();
start_rule.wordOpe = (*data.grammar)[WORD_DEFINITION_NAME].get_core_operator();
}
// Set root definition
start = data.start;
return data.grammar;
}

105
test/test.cc
View File

@ -36,6 +36,101 @@ TEST_CASE("Empty syntax test", "[general]")
REQUIRE(ret == false);
}
TEST_CASE("Infinite loop 1", "[infinite loop]")
{
peg::parser pg(R"(
ROOT <- WH TOKEN* WH
TOKEN <- [a-z0-9]*
WH <- [ \t]*
)");
REQUIRE(!pg);
}
TEST_CASE("Infinite loop 2", "[infinite loop]")
{
peg::parser pg(R"(
ROOT <- WH TOKEN+ WH
TOKEN <- [a-z0-9]*
WH <- [ \t]*
)");
REQUIRE(!pg);
}
TEST_CASE("Infinite loop 3", "[infinite loop]")
{
peg::parser pg(R"(
ROOT <- WH TOKEN* WH
TOKEN <- !'word1'
WH <- [ \t]*
)");
REQUIRE(!pg);
}
TEST_CASE("Infinite loop 4", "[infinite loop]")
{
peg::parser pg(R"(
ROOT <- WH TOKEN* WH
TOKEN <- &'word1'
WH <- [ \t]*
)");
REQUIRE(!pg);
}
TEST_CASE("Infinite loop 5", "[infinite loop]")
{
peg::parser pg(R"(
Numbers <- Number*
Number <- [0-9]+ / Spacing
Spacing <- ' ' / '\t' / '\n' / EOF # EOF is empty
EOF <- !.
)");
REQUIRE(!pg);
}
TEST_CASE("Not infinite 1", "[infinite loop]")
{
peg::parser pg(R"(
Numbers <- Number* EOF
Number <- [0-9]+ / Spacing
Spacing <- ' ' / '\t' / '\n'
EOF <- !.
)");
REQUIRE(!!pg); // OK
}
TEST_CASE("Not infinite 2", "[infinite loop]")
{
peg::parser pg(R"(
ROOT <- _ ('[' TAG_NAME ']' _)*
# In a sequence operator, if there is at least one non-empty element, we can treat it as non-empty
TAG_NAME <- (!']' .)+
_ <- [ \t]*
)");
REQUIRE(!!pg); // OK
}
TEST_CASE("Not infinite 3", "[infinite loop]")
{
peg::parser pg(R"(
EXPRESSION <- _ TERM (TERM_OPERATOR TERM)*
TERM <- FACTOR (FACTOR_OPERATOR FACTOR)*
FACTOR <- NUMBER / '(' _ EXPRESSION ')' _ # Recursive...
TERM_OPERATOR <- < [-+] > _
FACTOR_OPERATOR <- < [/*] > _
NUMBER <- < [0-9]+ > _
_ <- [ \t\r\n]*
)");
REQUIRE(!!pg); // OK
}
TEST_CASE("Action taking non const Semantic Values parameter", "[general]")
{
peg::parser parser(R"(
@ -61,11 +156,11 @@ TEST_CASE("Action taking non const Semantic Values parameter", "[general]")
TEST_CASE("String capture test", "[general]")
{
peg::parser parser(
" ROOT <- _ ('[' TAG_NAME ']' _)* "
" TAG_NAME <- (!']' .)+ "
" _ <- [ \t]* "
);
peg::parser parser(R"(
ROOT <- _ ('[' TAG_NAME ']' _)*
TAG_NAME <- (!']' .)+
_ <- [ \t]*
)");
std::vector<std::string> tags;