X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=crates%2Fide_db%2Fsrc%2Fhelpers.rs;h=f6a1a5521836a8a1e41e258a217bae04301be4ed;hb=3018ffd85e6921ba57d4340f666269ec85e58902;hp=66798ea3a69aa310d50d50d4d5f9a187457da640;hpb=c2be91dcd826e1529ac6ac431b3f871ec72abebc;p=rust.git

diff --git a/crates/ide_db/src/helpers.rs b/crates/ide_db/src/helpers.rs
index 66798ea3a69..f6a1a552183 100644
--- a/crates/ide_db/src/helpers.rs
+++ b/crates/ide_db/src/helpers.rs
@@ -1,16 +1,28 @@
 //! A module with ide helpers for high-level ide features.
-pub mod insert_use;
+pub mod famous_defs;
+pub mod generated_lints;
 pub mod import_assets;
+pub mod insert_use;
+pub mod merge_imports;
+pub mod node_ext;
+pub mod rust_doc;
 
-use std::collections::VecDeque;
+use std::{collections::VecDeque, iter};
 
 use base_db::FileId;
 use either::Either;
-use hir::{Crate, Enum, ItemInNs, MacroDef, Module, ModuleDef, Name, ScopeDef, Semantics, Trait};
-use syntax::ast::{self, make};
+use hir::{ItemInNs, MacroDef, ModuleDef, Name, PathResolution, Semantics};
+use itertools::Itertools;
+use syntax::{
+    ast::{self, make, HasLoopBody, Ident},
+    AstNode, AstToken, Direction, SyntaxElement, SyntaxKind, SyntaxToken, TokenAtOffset, WalkEvent,
+    T,
+};
 
 use crate::RootDatabase;
 
+pub use self::famous_defs::FamousDefs;
+
 pub fn item_name(db: &RootDatabase, item: ItemInNs) -> Option<Name> {
     match item {
         ItemInNs::Types(module_def_id) => ModuleDef::from(module_def_id).name(db),
@@ -19,6 +31,69 @@ pub fn item_name(db: &RootDatabase, item: ItemInNs) -> Option<Name> {
     }
 }
 
+/// Parses and returns the derive path at the cursor position in the given attribute, if it is a derive.
+/// This special case is required because the derive macro is a compiler builtin that discards the input derives.
+///
+/// The returned path is synthesized from TokenTree tokens and as such cannot be used with the [`Semantics`].
+pub fn get_path_in_derive_attr(
+    sema: &hir::Semantics<RootDatabase>,
+    attr: &ast::Attr,
+    cursor: &Ident,
+) -> Option<ast::Path> {
+    let cursor = cursor.syntax();
+    let path = attr.path()?;
+    let tt = attr.token_tree()?;
+    if !tt.syntax().text_range().contains_range(cursor.text_range()) {
+        return None;
+    }
+    let scope = sema.scope(attr.syntax());
+    let resolved_attr = sema.resolve_path(&path)?;
+    let derive = FamousDefs(sema, scope.krate()).core_macros_builtin_derive()?;
+    if PathResolution::Macro(derive) != resolved_attr {
+        return None;
+    }
+
+    let first = cursor
+        .siblings_with_tokens(Direction::Prev)
+        .filter_map(SyntaxElement::into_token)
+        .take_while(|tok| tok.kind() != T!['('] && tok.kind() != T![,])
+        .last()?;
+    let path_tokens = first
+        .siblings_with_tokens(Direction::Next)
+        .filter_map(SyntaxElement::into_token)
+        .take_while(|tok| tok != cursor);
+
+    ast::Path::parse(&path_tokens.chain(iter::once(cursor.clone())).join("")).ok()
+}
+
+/// Parses and resolves the path at the cursor position in the given attribute, if it is a derive.
+/// This special case is required because the derive macro is a compiler builtin that discards the input derives.
+pub fn try_resolve_derive_input(
+    sema: &hir::Semantics<RootDatabase>,
+    attr: &ast::Attr,
+    cursor: &Ident,
+) -> Option<PathResolution> {
+    let path = get_path_in_derive_attr(sema, attr, cursor)?;
+    let scope = sema.scope(attr.syntax());
+    // FIXME: This double resolve shouldn't be necessary
+    // It's only here so we prefer macros over other namespaces
+    match scope.speculative_resolve_as_mac(&path) {
+        Some(mac) if mac.kind() == hir::MacroKind::Derive => Some(PathResolution::Macro(mac)),
+        Some(_) => return None,
+        None => scope
+            .speculative_resolve(&path)
+            .filter(|res| matches!(res, PathResolution::Def(ModuleDef::Module(_)))),
+    }
+}
+
+/// Picks the token with the highest rank returned by the passed in function.
+pub fn pick_best_token(
+    tokens: TokenAtOffset<SyntaxToken>,
+    f: impl Fn(SyntaxKind) -> usize,
+) -> Option<SyntaxToken> {
+    tokens.max_by_key(move |t| f(t.kind()))
+}
+
 /// Converts the mod path struct into its ast representation.
 pub fn mod_path_to_ast(path: &hir::ModPath) -> ast::Path {
     let _p = profile::span("mod_path_to_ast");
@@ -67,104 +142,6 @@ pub fn visit_file_defs(
     module.impl_defs(db).into_iter().for_each(|impl_| cb(Either::Right(impl_)));
 }
 
-/// Helps with finding well-know things inside the standard library. This is
-/// somewhat similar to the known paths infra inside hir, but it different; We
-/// want to make sure that IDE specific paths don't become interesting inside
-/// the compiler itself as well.
-pub struct FamousDefs<'a, 'b>(pub &'a Semantics<'b, RootDatabase>, pub Option<Crate>);
-
-#[allow(non_snake_case)]
-impl FamousDefs<'_, '_> {
-    pub const FIXTURE: &'static str = include_str!("helpers/famous_defs_fixture.rs");
-
-    pub fn std(&self) -> Option<Crate> {
-        self.find_crate("std")
-    }
-
-    pub fn core(&self) -> Option<Crate> {
-        self.find_crate("core")
-    }
-
-    pub fn core_cmp_Ord(&self) -> Option<Trait> {
-        self.find_trait("core:cmp:Ord")
-    }
-
-    pub fn core_convert_From(&self) -> Option<Trait> {
-        self.find_trait("core:convert:From")
-    }
-
-    pub fn core_convert_Into(&self) -> Option<Trait> {
-        self.find_trait("core:convert:Into")
-    }
-
-    pub fn core_option_Option(&self) -> Option<Enum> {
-        self.find_enum("core:option:Option")
-    }
-
-    pub fn core_default_Default(&self) -> Option<Trait> {
-        self.find_trait("core:default:Default")
-    }
-
-    pub fn core_iter_Iterator(&self) -> Option<Trait> {
-        self.find_trait("core:iter:traits:iterator:Iterator")
-    }
-
-    pub fn core_iter(&self) -> Option<Module> {
-        self.find_module("core:iter")
-    }
-
-    fn find_trait(&self, path: &str) -> Option<Trait> {
-        match self.find_def(path)? {
-            hir::ScopeDef::ModuleDef(hir::ModuleDef::Trait(it)) => Some(it),
-            _ => None,
-        }
-    }
-
-    fn find_enum(&self, path: &str) -> Option<Enum> {
-        match self.find_def(path)? {
-            hir::ScopeDef::ModuleDef(hir::ModuleDef::Adt(hir::Adt::Enum(it))) => Some(it),
-            _ => None,
-        }
-    }
-
-    fn find_module(&self, path: &str) -> Option<Module> {
-        match self.find_def(path)? {
-            hir::ScopeDef::ModuleDef(hir::ModuleDef::Module(it)) => Some(it),
-            _ => None,
-        }
-    }
-
-    fn find_crate(&self, name: &str) -> Option<Crate> {
-        let krate = self.1?;
-        let db = self.0.db;
-        let res =
-            krate.dependencies(db).into_iter().find(|dep| dep.name.to_string() == name)?.krate;
-        Some(res)
-    }
-
-    fn find_def(&self, path: &str) -> Option<ScopeDef> {
-        let db = self.0.db;
-        let mut path = path.split(':');
-        let trait_ = path.next_back()?;
-        let std_crate = path.next()?;
-        let std_crate = self.find_crate(std_crate)?;
-        let mut module = std_crate.root_module(db);
-        for segment in path {
-            module = module.children(db).find_map(|child| {
-                let name = child.name(db)?;
-                if name.to_string() == segment {
-                    Some(child)
-                } else {
-                    None
-                }
-            })?;
-        }
-        let def =
-            module.scope(db, None).into_iter().find(|(name, _def)| name.to_string() == trait_)?.1;
-        Some(def)
-    }
-}
-
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct SnippetCap {
     _private: (),
@@ -179,3 +156,130 @@ pub const fn new(allow_snippets: bool) -> Option<SnippetCap> {
         }
     }
 }
+
+/// Calls `cb` on each expression inside `expr` that is at "tail position".
+/// Does not walk into `break` or `return` expressions.
+/// Note that modifying the tree while iterating it will cause undefined iteration which might
+/// potentially results in an out of bounds panic.
+pub fn for_each_tail_expr(expr: &ast::Expr, cb: &mut dyn FnMut(&ast::Expr)) {
+    match expr {
+        ast::Expr::BlockExpr(b) => {
+            match b.modifier() {
+                Some(
+                    ast::BlockModifier::Async(_)
+                    | ast::BlockModifier::Try(_)
+                    | ast::BlockModifier::Const(_),
+                ) => return cb(expr),
+
+                Some(ast::BlockModifier::Label(label)) => {
+                    for_each_break_expr(Some(label), b.stmt_list(), &mut |b| {
+                        cb(&ast::Expr::BreakExpr(b))
+                    });
+                }
+                Some(ast::BlockModifier::Unsafe(_)) => (),
+                None => (),
+            }
+            if let Some(stmt_list) = b.stmt_list() {
+                if let Some(e) = stmt_list.tail_expr() {
+                    for_each_tail_expr(&e, cb);
+                }
+            }
+        }
+        ast::Expr::IfExpr(if_) => {
+            let mut if_ = if_.clone();
+            loop {
+                if let Some(block) = if_.then_branch() {
+                    for_each_tail_expr(&ast::Expr::BlockExpr(block), cb);
+                }
+                match if_.else_branch() {
+                    Some(ast::ElseBranch::IfExpr(it)) => if_ = it,
+                    Some(ast::ElseBranch::Block(block)) => {
+                        for_each_tail_expr(&ast::Expr::BlockExpr(block), cb);
+                        break;
+                    }
+                    None => break,
+                }
+            }
+        }
+        ast::Expr::LoopExpr(l) => {
+            for_each_break_expr(l.label(), l.loop_body().and_then(|it| it.stmt_list()), &mut |b| {
+                cb(&ast::Expr::BreakExpr(b))
+            })
+        }
+        ast::Expr::MatchExpr(m) => {
+            if let Some(arms) = m.match_arm_list() {
+                arms.arms().filter_map(|arm| arm.expr()).for_each(|e| for_each_tail_expr(&e, cb));
+            }
+        }
+        ast::Expr::ArrayExpr(_)
+        | ast::Expr::AwaitExpr(_)
+        | ast::Expr::BinExpr(_)
+        | ast::Expr::BoxExpr(_)
+        | ast::Expr::BreakExpr(_)
+        | ast::Expr::CallExpr(_)
+        | ast::Expr::CastExpr(_)
+        | ast::Expr::ClosureExpr(_)
+        | ast::Expr::ContinueExpr(_)
+        | ast::Expr::FieldExpr(_)
+        | ast::Expr::ForExpr(_)
+        | ast::Expr::IndexExpr(_)
+        | ast::Expr::Literal(_)
+        | ast::Expr::MacroCall(_)
+        | ast::Expr::MacroStmts(_)
+        | ast::Expr::MethodCallExpr(_)
+        | ast::Expr::ParenExpr(_)
+        | ast::Expr::PathExpr(_)
+        | ast::Expr::PrefixExpr(_)
+        | ast::Expr::RangeExpr(_)
+        | ast::Expr::RecordExpr(_)
+        | ast::Expr::RefExpr(_)
+        | ast::Expr::ReturnExpr(_)
+        | ast::Expr::TryExpr(_)
+        | ast::Expr::TupleExpr(_)
+        | ast::Expr::WhileExpr(_)
+        | ast::Expr::YieldExpr(_) => cb(expr),
+    }
+}
+
+/// Calls `cb` on each break expr inside of `body` that is applicable for the given label.
+pub fn for_each_break_expr(
+    label: Option<ast::Label>,
+    body: Option<ast::StmtList>,
+    cb: &mut dyn FnMut(ast::BreakExpr),
+) {
+    let label = label.and_then(|lbl| lbl.lifetime());
+    let mut depth = 0;
+    if let Some(b) = body {
+        let preorder = &mut b.syntax().preorder();
+        let ev_as_expr = |ev| match ev {
+            WalkEvent::Enter(it) => Some(WalkEvent::Enter(ast::Expr::cast(it)?)),
+            WalkEvent::Leave(it) => Some(WalkEvent::Leave(ast::Expr::cast(it)?)),
+        };
+        let eq_label = |lt: Option<ast::Lifetime>| {
+            lt.zip(label.as_ref()).map_or(false, |(lt, lbl)| lt.text() == lbl.text())
+        };
+        while let Some(node) = preorder.find_map(ev_as_expr) {
+            match node {
+                WalkEvent::Enter(expr) => match expr {
+                    ast::Expr::LoopExpr(_) | ast::Expr::WhileExpr(_) | ast::Expr::ForExpr(_) => {
+                        depth += 1
+                    }
+                    ast::Expr::BlockExpr(e) if e.label().is_some() => depth += 1,
+                    ast::Expr::BreakExpr(b)
+                        if (depth == 0 && b.lifetime().is_none()) || eq_label(b.lifetime()) =>
+                    {
+                        cb(b);
+                    }
+                    _ => (),
+                },
+                WalkEvent::Leave(expr) => match expr {
+                    ast::Expr::LoopExpr(_) | ast::Expr::WhileExpr(_) | ast::Expr::ForExpr(_) => {
+                        depth -= 1
+                    }
+                    ast::Expr::BlockExpr(e) if e.label().is_some() => depth -= 1,
+                    _ => (),
+                },
+            }
+        }
+    }
+}