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Improve pre/post nodes extraction #48

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Jul 13, 2023
Merged

Improve pre/post nodes extraction #48

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ee1a630
doc: add some TODO related to regex->regex-automata
vthib Jul 10, 2023
ae4653b
feat: improve generation of pre/post nodes after literals extraction
vthib Jun 7, 2023
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1 change: 1 addition & 0 deletions boreal/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,7 @@ codespan-reporting = "0.11"
aho-corasick = "1.0"
memchr = "2.5"
# Remove unicode feature
# TODO: regex only enables dfa-onepass, and not all of dfa. Check which option we want.
regex-automata = { version = "0.3", default-features = false, features = ["std", "syntax", "perf", "meta", "nfa", "dfa", "hybrid"] }
# No default features to disable unicode, we do not need it
regex-syntax = { version = "0.7", default-features = false }
Expand Down
101 changes: 41 additions & 60 deletions boreal/src/compiler/variable/literals.rs
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Expand Up @@ -173,7 +173,9 @@ impl LiteralsExtractor {
pub fn into_literals_details(mut self, original_node: &Node) -> LiteralsDetails {
self.close();

let (pre_ast, post_ast) = self.set.build_pre_post_ast(original_node);
let (pre_ast, post_ast) = self
.set
.build_pre_post_ast(original_node, self.current_position);

LiteralsDetails {
literals: self.set.literals,
Expand All @@ -191,6 +193,7 @@ struct LiteralSet {

/// Starting position of the literals (including the first bytes of the literals).
start_position: usize,

/// Ending position of the literals (excluding the last bytes of the literals).
end_position: usize,

Expand All @@ -212,48 +215,21 @@ impl LiteralSet {
}
}

fn add_literals_ast(&self, nodes: &mut Vec<Node>) {
match &self.literals[..] {
[] => (),
[literal] => {
nodes.extend(literal.iter().copied().map(Node::Literal));
}
literals => {
nodes.push(Node::Group(Box::new(Node::Alternation(
literals
.iter()
.map(|literal| {
Node::Concat(literal.iter().copied().map(Node::Literal).collect())
})
.collect(),
))));
}
}
}

fn build_pre_post_ast(&self, original_node: &Node) -> (Option<Node>, Option<Node>) {
fn build_pre_post_ast(
&self,
original_node: &Node,
last_position: usize,
) -> (Option<Node>, Option<Node>) {
if self.literals.is_empty() {
return (None, None);
}

let visitor = PrePostExtractor::new(self.start_position, self.end_position);
let (pre_node, post_node) = visit(original_node, visitor);

let pre_node = pre_node.map(|pre| {
let mut pre_nodes = Vec::new();
pre_nodes.push(pre);
self.add_literals_ast(&mut pre_nodes);
pre_nodes.push(Node::Assertion(AssertionKind::EndLine));
Node::Concat(pre_nodes)
});
let post_node = post_node.map(|post| {
let mut post_nodes = Vec::new();
self.add_literals_ast(&mut post_nodes);
post_nodes.push(post);
Node::Concat(post_nodes)
});

(pre_node, post_node)
let visitor = PrePostExtractor::new(self.start_position, self.end_position, last_position);
let (pre, post) = visit(original_node, visitor);
(
pre.map(|pre| Node::Concat(vec![pre, Node::Assertion(AssertionKind::EndLine)])),
post,
)
}
}

Expand Down Expand Up @@ -281,13 +257,15 @@ struct PrePostExtractor {
start_position: usize,
/// End position of the extracted literals.
end_position: usize,
/// Last position of the regex.
last_position: usize,

/// Current position during the visit of the original AST.
current_position: usize,
}

impl PrePostExtractor {
fn new(start_position: usize, end_position: usize) -> Self {
fn new(start_position: usize, end_position: usize, last_position: usize) -> Self {
Self {
pre_stack: Vec::new(),
post_stack: Vec::new(),
Expand All @@ -298,6 +276,7 @@ impl PrePostExtractor {
current_position: 0,
start_position,
end_position,
last_position,
}
}

Expand All @@ -307,9 +286,10 @@ impl PrePostExtractor {
}

fn add_pre_post_node(&mut self, node: &Node) {
if self.current_position < self.start_position {
if self.current_position < self.end_position && self.start_position > 0 {
self.add_node(node.clone(), false);
} else if self.current_position >= self.end_position {
}
if self.current_position >= self.start_position && self.end_position != self.last_position {
self.add_node(node.clone(), true);
}
}
Expand Down Expand Up @@ -502,7 +482,7 @@ mod tests {
"{ AB ( 11 | 12 ) 13 ( 1? | 14 ) }",
&[b"\xAB\x11\x13", b"\xAB\x12\x13"],
"",
r"(\xab\x11\x13|\xab\x12\x13)([\x10-\x1f]|\x14)",
r"\xab(\x11|\x12)\x13([\x10-\x1f]|\x14)",
);

// Test imbrication of alternations
Expand Down Expand Up @@ -551,11 +531,7 @@ mod tests {
b"\x12\x22\x32\x42\x52",
],
"",
"(\\x11!1AQ|\\x11!1AR|\\x11!1BQ|\\x11!1BR|\\x11!2AQ|\\x11!2AR|\\x11!2BQ|\\x11!2BR|\
\\x11\"1AQ|\\x11\"1AR|\\x11\"1BQ|\\x11\"1BR|\\x11\"2AQ|\\x11\"2AR|\\x11\"2BQ|\
\\x11\"2BR|\\x12!1AQ|\\x12!1AR|\\x12!1BQ|\\x12!1BR|\\x12!2AQ|\\x12!2AR|\\x12!2BQ|\
\\x12!2BR|\\x12\"1AQ|\\x12\"1AR|\\x12\"1BQ|\\x12\"1BR|\\x12\"2AQ|\\x12\"2AR|\
\\x12\"2BQ|\\x12\"2BR)(a|b)(q|r)\\x88",
"(\\x11|\\x12)(!|\")(1|2)(A|B)(Q|R)(a|b)(q|r)\\x88",
);
test(
"{ ( 11 | 12 ) ( 21 | 22 ) 33 ( 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 ) }",
Expand All @@ -566,7 +542,7 @@ mod tests {
b"\x12\x22\x33",
],
"",
r#"(\x11!3|\x11"3|\x12!3|\x12"3)(\x01|\x02|\x03|\x04|\x05|\x06|\x07|\x08|\x09|\x10)"#,
r#"(\x11|\x12)(!|")3(\x01|\x02|\x03|\x04|\x05|\x06|\x07|\x08|\x09|\x10)"#,
);

// TODO: to improve, there are diminishing returns in computing the longest literals.
Expand Down Expand Up @@ -651,7 +627,7 @@ mod tests {
test(
"{ 61 ?? ( 62 63 | 64) 65 }",
&[b"\x62\x63\x65", b"\x64\x65"],
r"a.(bce|de)$",
r"a.(bc|d)e$",
"",
);
}
Expand Down Expand Up @@ -684,34 +660,39 @@ mod tests {
// Literal on the left side of a group
test("abc(a+)b", &[b"abc"], "", "abc(a+)b");
// Literal spanning inside a group
test("ab(ca+)b", &[b"abc"], "", "abc(a+)b");
test("ab(ca+)b", &[b"abc"], "", "ab(ca+)b");
// Literal spanning up to the end of a group
test("ab(c)a+b", &[b"abc"], "", "abca+b");
test("ab(c)a+b", &[b"abc"], "", "ab(c)a+b");
// Literal spanning in and out of a group
test("a(b)ca+b", &[b"abc"], "", "abca+b");
test("a(b)ca+b", &[b"abc"], "", "a(b)ca+b");

// Literal on the right side of a group
test("b(a+)abc", &[b"abc"], "b(a+)abc$", "");
// Literal spanning inside a group
test("b(a+a)bc", &[b"abc"], "b(a+)abc$", "");
test("b(a+a)bc", &[b"abc"], "b(a+a)bc$", "");
// Literal starting in a group
test("ba+(ab)c", &[b"abc"], "ba+abc$", "");
test("ba+(ab)c", &[b"abc"], "ba+(ab)c$", "");
// Literal spanning in and out of a group
test("ba+a(bc)", &[b"abc"], "ba+abc$", "");
test("ba+a(bc)", &[b"abc"], "ba+a(bc)$", "");

// A few tests on closing nodes
test("a.+bcd{2}e", &[b"bc"], "a.+bc$", "bcd{2}e");
test("a.+bc.e", &[b"bc"], "a.+bc$", "bc.e");
test("a.+bc\\B.e", &[b"bc"], "a.+bc$", "bc\\B.e");
test("a.+bc[aA]e", &[b"bc"], "a.+bc$", "bc[aA]e");
test("a.+bc()de", &[b"bcde"], "a.+bcde$", "");
test("a.+bc()de", &[b"bcde"], "a.+bc()de$", "");

test("a+(b.c)(d)(ef)g+", &[b"cdef"], "a+(b.)cdef$", "cdefg+");
test(
"a+(b.c)(d)(ef)g+",
&[b"cdef"],
"a+(b.c)(d)(ef)$",
"(c)(d)(ef)g+",
);

test(
"a((b(c)((d)()(e(g+h)ij)))kl)m",
&[b"hijklm"],
"a((b(c)((d)()(e(g+)))))hijklm$",
"a((b(c)((d)()(e(g+h)ij)))kl)m$",
"",
);

Expand All @@ -728,6 +709,6 @@ mod tests {

test_type_traits_non_clonable(LiteralsExtractor::new());
test_type_traits_non_clonable(LiteralSet::default());
test_type_traits_non_clonable(PrePostExtractor::new(0, 0));
test_type_traits_non_clonable(PrePostExtractor::new(0, 0, 0));
}
}