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//! Patterns telling us certain facts about current syntax element, they are used in completion context
use syntax::{
algo::non_trivia_sibling,
ast::{self, LoopBodyOwner},
match_ast, AstNode, Direction, NodeOrToken, SyntaxElement,
SyntaxKind::{self, *},
SyntaxNode, SyntaxToken, T,
};
#[cfg(test)]
use crate::test_utils::{check_pattern_is_applicable, check_pattern_is_not_applicable};
/// Direct parent container of the cursor position
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub(crate) enum ImmediateLocation {
Impl,
Trait,
RecordField,
RefExpr,
IdentPat,
BlockExpr,
ItemList,
}
pub(crate) fn determine_location(tok: SyntaxToken) -> Option<ImmediateLocation> {
// First "expand" the element we are completing to its maximum so that we can check in what
// context it immediately lies. This for example means if the token is a NameRef at the end of
// a path, we want to look at where the path is in the tree.
let node = match tok.parent().and_then(ast::NameLike::cast)? {
ast::NameLike::NameRef(name_ref) => {
if let Some(segment) = name_ref.syntax().parent().and_then(ast::PathSegment::cast) {
let p = segment.parent_path();
if p.parent_path().is_none() {
p.syntax()
.ancestors()
.take_while(|it| it.text_range() == p.syntax().text_range())
.last()?
} else {
return None;
}
} else {
return None;
}
}
it @ ast::NameLike::Name(_) | it @ ast::NameLike::Lifetime(_) => it.syntax().clone(),
};
let parent = match node.parent() {
Some(parent) => parent,
// SourceFile
None => {
return match node.kind() {
MACRO_ITEMS | SOURCE_FILE => Some(ImmediateLocation::ItemList),
_ => None,
}
}
};
let res = match_ast! {
match parent {
ast::IdentPat(_it) => ImmediateLocation::IdentPat,
ast::BlockExpr(_it) => ImmediateLocation::BlockExpr,
ast::SourceFile(_it) => ImmediateLocation::ItemList,
ast::ItemList(_it) => ImmediateLocation::ItemList,
ast::RefExpr(_it) => ImmediateLocation::RefExpr,
ast::RecordField(_it) => ImmediateLocation::RecordField,
ast::AssocItemList(it) => match it.syntax().parent().map(|it| it.kind()) {
Some(IMPL) => ImmediateLocation::Impl,
Some(TRAIT) => ImmediateLocation::Trait,
_ => return None,
},
_ => return None,
}
};
Some(res)
}
#[cfg(test)]
fn check_location(code: &str, loc: ImmediateLocation) {
check_pattern_is_applicable(code, |e| {
assert_eq!(determine_location(e.into_token().expect("Expected a token")), Some(loc));
true
});
}
#[test]
fn test_has_trait_parent() {
check_location(r"trait A { f$0 }", ImmediateLocation::Trait);
}
#[test]
fn test_has_impl_parent() {
check_location(r"impl A { f$0 }", ImmediateLocation::Impl);
}
#[test]
fn test_has_field_list_parent() {
check_location(r"struct Foo { f$0 }", ImmediateLocation::RecordField);
check_location(r"struct Foo { f$0 pub f: i32}", ImmediateLocation::RecordField);
}
#[test]
fn test_has_block_expr_parent() {
check_location(r"fn my_fn() { let a = 2; f$0 }", ImmediateLocation::BlockExpr);
}
#[test]
fn test_has_ident_pat_parent() {
check_location(r"fn my_fn(m$0) {}", ImmediateLocation::IdentPat);
check_location(r"fn my_fn() { let m$0 }", ImmediateLocation::IdentPat);
check_location(r"fn my_fn(&m$0) {}", ImmediateLocation::IdentPat);
check_location(r"fn my_fn() { let &m$0 }", ImmediateLocation::IdentPat);
}
#[test]
fn test_has_ref_expr_parent() {
check_location(r"fn my_fn() { let x = &m$0 foo; }", ImmediateLocation::RefExpr);
}
#[test]
fn test_has_item_list_or_source_file_parent() {
check_location(r"i$0", ImmediateLocation::ItemList);
check_location(r"mod foo { f$0 }", ImmediateLocation::ItemList);
}
pub(crate) fn inside_impl_trait_block(element: SyntaxElement) -> bool {
// Here we search `impl` keyword up through the all ancestors, unlike in `has_impl_parent`,
// where we only check the first parent with different text range.
element
.ancestors()
.find(|it| it.kind() == IMPL)
.map(|it| ast::Impl::cast(it).unwrap())
.map(|it| it.trait_().is_some())
.unwrap_or(false)
}
#[test]
fn test_inside_impl_trait_block() {
check_pattern_is_applicable(r"impl Foo for Bar { f$0 }", inside_impl_trait_block);
check_pattern_is_applicable(r"impl Foo for Bar { fn f$0 }", inside_impl_trait_block);
check_pattern_is_not_applicable(r"impl A { f$0 }", inside_impl_trait_block);
check_pattern_is_not_applicable(r"impl A { fn f$0 }", inside_impl_trait_block);
}
pub(crate) fn is_match_arm(element: SyntaxElement) -> bool {
not_same_range_ancestor(element.clone()).filter(|it| it.kind() == MATCH_ARM).is_some()
&& previous_sibling_or_ancestor_sibling(element)
.and_then(|it| it.into_token())
.filter(|it| it.kind() == FAT_ARROW)
.is_some()
}
#[test]
fn test_is_match_arm() {
check_pattern_is_applicable(r"fn my_fn() { match () { () => m$0 } }", is_match_arm);
}
pub(crate) fn previous_token(element: SyntaxElement) -> Option<SyntaxToken> {
element.into_token().and_then(|it| previous_non_trivia_token(it))
}
/// Check if the token previous to the previous one is `for`.
/// For example, `for _ i$0` => true.
pub(crate) fn for_is_prev2(element: SyntaxElement) -> bool {
element
.into_token()
.and_then(|it| previous_non_trivia_token(it))
.and_then(|it| previous_non_trivia_token(it))
.filter(|it| it.kind() == T![for])
.is_some()
}
#[test]
fn test_for_is_prev2() {
check_pattern_is_applicable(r"for i i$0", for_is_prev2);
}
pub(crate) fn has_prev_sibling(element: SyntaxElement, kind: SyntaxKind) -> bool {
previous_sibling_or_ancestor_sibling(element).filter(|it| it.kind() == kind).is_some()
}
#[test]
fn test_has_impl_as_prev_sibling() {
check_pattern_is_applicable(r"impl A w$0 {}", |it| has_prev_sibling(it, IMPL));
}
pub(crate) fn is_in_loop_body(element: SyntaxElement) -> bool {
element
.ancestors()
.take_while(|it| it.kind() != FN && it.kind() != CLOSURE_EXPR)
.find_map(|it| {
let loop_body = match_ast! {
match it {
ast::ForExpr(it) => it.loop_body(),
ast::WhileExpr(it) => it.loop_body(),
ast::LoopExpr(it) => it.loop_body(),
_ => None,
}
};
loop_body.filter(|it| it.syntax().text_range().contains_range(element.text_range()))
})
.is_some()
}
pub(crate) fn not_same_range_ancestor(element: SyntaxElement) -> Option<SyntaxNode> {
element.ancestors().skip_while(|it| it.text_range() == element.text_range()).next()
}
fn previous_non_trivia_token(token: SyntaxToken) -> Option<SyntaxToken> {
let mut token = token.prev_token();
while let Some(inner) = token.clone() {
if !inner.kind().is_trivia() {
return Some(inner);
} else {
token = inner.prev_token();
}
}
None
}
fn previous_sibling_or_ancestor_sibling(element: SyntaxElement) -> Option<SyntaxElement> {
let token_sibling = non_trivia_sibling(element.clone(), Direction::Prev);
if let Some(sibling) = token_sibling {
Some(sibling)
} else {
// if not trying to find first ancestor which has such a sibling
let range = element.text_range();
let top_node = element.ancestors().take_while(|it| it.text_range() == range).last()?;
let prev_sibling_node = top_node.ancestors().find(|it| {
non_trivia_sibling(NodeOrToken::Node(it.to_owned()), Direction::Prev).is_some()
})?;
non_trivia_sibling(NodeOrToken::Node(prev_sibling_node), Direction::Prev)
}
}
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