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|
use libsyntax2::{
File, TextUnit, AstNode,
ast::self,
algo::{
ancestors,
},
};
use {
AtomEdit, find_node_at_offset,
scope::{FnScopes, ModuleScope},
};
#[derive(Debug)]
pub struct
CompletionItem {
pub name: String,
pub snippet: Option<String>
}
pub fn scope_completion(file: &File, offset: TextUnit) -> Option<Vec<CompletionItem>> {
// Insert a fake ident to get a valid parse tree
let file = {
let edit = AtomEdit::insert(offset, "intellijRulezz".to_string());
// Don't bother with completion if incremental reparse fails
file.incremental_reparse(&edit)?
};
let name_ref = find_node_at_offset::<ast::NameRef>(file.syntax(), offset)?;
if !is_ident_expr(name_ref) {
return None;
}
let mut res = Vec::new();
if let Some(fn_def) = ancestors(name_ref.syntax()).filter_map(ast::FnDef::cast).next() {
complete_keywords(&file, Some(fn_def), name_ref, &mut res);
let scopes = FnScopes::new(fn_def);
complete_fn(name_ref, &scopes, &mut res);
} else {
complete_keywords(&file, None, name_ref, &mut res);
}
if let Some(root) = ancestors(name_ref.syntax()).filter_map(ast::Root::cast).next() {
let scope = ModuleScope::new(root);
res.extend(
scope.entries().iter()
.map(|entry| CompletionItem {
name: entry.name().to_string(),
snippet: None,
})
)
}
Some(res)
}
fn is_ident_expr(name_ref: ast::NameRef) -> bool {
match ancestors(name_ref.syntax()).filter_map(ast::Expr::cast).next() {
None => false,
Some(expr) => {
expr.syntax().range() == name_ref.syntax().range()
}
}
}
fn complete_keywords(file: &File, fn_def: Option<ast::FnDef>, name_ref: ast::NameRef, acc: &mut Vec<CompletionItem>) {
acc.push(keyword("if", "if $0 { }"));
acc.push(keyword("match", "match $0 { }"));
acc.push(keyword("while", "while $0 { }"));
acc.push(keyword("loop", "loop {$0}"));
if let Some(off) = name_ref.syntax().range().start().checked_sub(2.into()) {
if let Some(if_expr) = find_node_at_offset::<ast::IfExpr>(file.syntax(), off) {
if if_expr.syntax().range().end() < name_ref.syntax().range().start() {
acc.push(keyword("else", "else {$0}"));
acc.push(keyword("else if", "else if $0 { }"));
}
}
}
// if let Some(fn_def) = fn_def {
// acc.push(keyword("return", ""))
// }
fn keyword(kw: &str, snip: &str) -> CompletionItem {
CompletionItem {
name: kw.to_string(),
snippet: Some(snip.to_string()),
}
}
}
fn complete_fn(name_ref: ast::NameRef, scopes: &FnScopes, acc: &mut Vec<CompletionItem>) {
acc.extend(
scopes.scope_chain(name_ref.syntax())
.flat_map(|scope| scopes.entries(scope).iter())
.map(|entry| CompletionItem {
name: entry.name().to_string(),
snippet: None,
})
)
}
#[cfg(test)]
mod tests {
use super::*;
use test_utils::{assert_eq_dbg, extract_offset};
fn check_scope_completion(code: &str, expected_completions: &str) {
let (off, code) = extract_offset(&code);
let file = File::parse(&code);
let completions = scope_completion(&file, off)
.unwrap()
.into_iter()
.filter(|c| c.snippet.is_none())
.collect::<Vec<_>>();
assert_eq_dbg(expected_completions, &completions);
}
fn check_snippet_completion(code: &str, expected_completions: &str) {
let (off, code) = extract_offset(&code);
let file = File::parse(&code);
let completions = scope_completion(&file, off)
.unwrap()
.into_iter()
.filter(|c| c.snippet.is_some())
.collect::<Vec<_>>();
assert_eq_dbg(expected_completions, &completions);
}
#[test]
fn test_completion_let_scope() {
check_scope_completion(r"
fn quux(x: i32) {
let y = 92;
1 + <|>;
let z = ();
}
", r#"[CompletionItem { name: "y", snippet: None },
CompletionItem { name: "x", snippet: None },
CompletionItem { name: "quux", snippet: None }]"#);
}
#[test]
fn test_completion_if_let_scope() {
check_scope_completion(r"
fn quux() {
if let Some(x) = foo() {
let y = 92;
};
if let Some(a) = bar() {
let b = 62;
1 + <|>
}
}
", r#"[CompletionItem { name: "b", snippet: None },
CompletionItem { name: "a", snippet: None },
CompletionItem { name: "quux", snippet: None }]"#);
}
#[test]
fn test_completion_for_scope() {
check_scope_completion(r"
fn quux() {
for x in &[1, 2, 3] {
<|>
}
}
", r#"[CompletionItem { name: "x", snippet: None },
CompletionItem { name: "quux", snippet: None }]"#);
}
#[test]
fn test_completion_mod_scope() {
check_scope_completion(r"
struct Foo;
enum Baz {}
fn quux() {
<|>
}
", r#"[CompletionItem { name: "Foo", snippet: None },
CompletionItem { name: "Baz", snippet: None },
CompletionItem { name: "quux", snippet: None }]"#);
}
#[test]
fn test_completion_kewords() {
check_snippet_completion(r"
fn quux() {
<|>
}
", r#"[CompletionItem { name: "if", snippet: Some("if $0 { }") },
CompletionItem { name: "match", snippet: Some("match $0 { }") },
CompletionItem { name: "while", snippet: Some("while $0 { }") },
CompletionItem { name: "loop", snippet: Some("loop {$0}") }]"#);
}
#[test]
fn test_completion_else() {
check_snippet_completion(r"
fn quux() {
if true {
()
} <|>
}
", r#"[CompletionItem { name: "if", snippet: Some("if $0 { }") },
CompletionItem { name: "match", snippet: Some("match $0 { }") },
CompletionItem { name: "while", snippet: Some("while $0 { }") },
CompletionItem { name: "loop", snippet: Some("loop {$0}") },
CompletionItem { name: "else", snippet: Some("else {$0}") },
CompletionItem { name: "else if", snippet: Some("else if $0 { }") }]"#);
}
}
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