Merge #196

196: Hover: Show documentation r=matklad a=kjeremy

Closes #186 

Co-authored-by: Jeremy A. Kolb <[email protected]>

Author: bors[bot]

crates/ra_analysis/src/imp.rs

@@ -364,6 +364,16 @@ impl AnalysisImpl {
         ret
     }
 
+    pub fn doc_comment_for(
+        &self,
+        file_id: FileId,
+        symbol: FileSymbol,
+    ) -> Cancelable<Option<String>> {
+        let file = self.db.file_syntax(file_id);
+
+        Ok(symbol.docs(&file))
+    }
+
     pub fn diagnostics(&self, file_id: FileId) -> Cancelable<Vec<Diagnostic>> {
         let module_tree = self.module_tree(file_id)?;
         let syntax = self.db.file_syntax(file_id);

crates/ra_analysis/src/lib.rs

@@ -258,6 +258,13 @@ impl Analysis {
     pub fn find_all_refs(&self, position: FilePosition) -> Cancelable<Vec<(FileId, TextRange)>> {
         Ok(self.imp.find_all_refs(position))
     }
+    pub fn doc_comment_for(
+        &self,
+        file_id: FileId,
+        symbol: FileSymbol,
+    ) -> Cancelable<Option<String>> {
+        self.imp.doc_comment_for(file_id, symbol)
+    }
     pub fn parent_module(&self, position: FilePosition) -> Cancelable<Vec<(FileId, FileSymbol)>> {
         self.imp.parent_module(position)
     }

crates/ra_editor/src/symbols.rs

@@ -2,7 +2,7 @@ use crate::TextRange;
 
 use ra_syntax::{
     algo::visit::{visitor, Visitor},
-    ast::{self, NameOwner},
+    ast::{self, DocCommentsOwner, NameOwner},
     AstNode, File, SmolStr, SyntaxKind, SyntaxNodeRef, WalkEvent,
 };
 
@@ -22,6 +22,36 @@ pub struct FileSymbol {
     pub kind: SyntaxKind,
 }
 
+impl FileSymbol {
+    pub fn docs(&self, file: &File) -> Option<String> {
+        file.syntax()
+            .descendants()
+            .filter(|node| node.kind() == self.kind && node.range() == self.node_range)
+            .filter_map(|node: SyntaxNodeRef| {
+                fn doc_comments<'a, N: DocCommentsOwner<'a>>(node: N) -> Option<String> {
+                    let comments = node.doc_comment_text();
+                    if comments.is_empty() {
+                        None
+                    } else {
+                        Some(comments)
+                    }
+                }
+
+                visitor()
+                    .visit(doc_comments::<ast::FnDef>)
+                    .visit(doc_comments::<ast::StructDef>)
+                    .visit(doc_comments::<ast::EnumDef>)
+                    .visit(doc_comments::<ast::TraitDef>)
+                    .visit(doc_comments::<ast::Module>)
+                    .visit(doc_comments::<ast::TypeDef>)
+                    .visit(doc_comments::<ast::ConstDef>)
+                    .visit(doc_comments::<ast::StaticDef>)
+                    .accept(node)?
+            })
+            .nth(0)
+    }
+}
+
 pub fn file_symbols(file: &File) -> Vec<FileSymbol> {
     file.syntax().descendants().filter_map(to_symbol).collect()
 }

crates/ra_lsp_server/src/caps.rs

@@ -16,7 +16,7 @@ pub fn server_capabilities() -> ServerCapabilities {
                 save: None,
             },
         )),
-        hover_provider: None,
+        hover_provider: Some(true),
         completion_provider: Some(CompletionOptions {
             resolve_provider: None,
             trigger_characters: None,

crates/ra_lsp_server/src/main_loop/handlers.rs

@@ -4,9 +4,9 @@ use gen_lsp_server::ErrorCode;
 use languageserver_types::{
     CodeActionResponse, Command, CompletionItem, CompletionItemKind, Diagnostic,
     DiagnosticSeverity, DocumentSymbol, Documentation, FoldingRange, FoldingRangeKind,
-    FoldingRangeParams, InsertTextFormat, Location, MarkupContent, MarkupKind, Position,
+    FoldingRangeParams, InsertTextFormat, Location, MarkupContent, MarkupKind, MarkedString, Position,
     PrepareRenameResponse, RenameParams, SymbolInformation, TextDocumentIdentifier, TextEdit,
-    WorkspaceEdit, ParameterInformation, SignatureInformation,
+    WorkspaceEdit, ParameterInformation, SignatureInformation, Hover, HoverContents,
 };
 use ra_analysis::{FileId, FoldKind, Query, RunnableKind, FilePosition};
 use ra_syntax::text_utils::contains_offset_nonstrict;
@@ -478,6 +478,30 @@ pub fn handle_signature_help(
     }
 }
 
+pub fn handle_hover(
+    world: ServerWorld,
+    params: req::TextDocumentPositionParams,
+) -> Result<Option<Hover>> {
+    let position = params.try_conv_with(&world)?;
+    let line_index = world.analysis().file_line_index(position.file_id);
+
+    for (file_id, symbol) in world.analysis().approximately_resolve_symbol(position)? {
+        let range = symbol.node_range.conv_with(&line_index);
+        let comment = world.analysis.doc_comment_for(file_id, symbol)?;
+
+        if comment.is_some() {
+            let contents = HoverContents::Scalar(MarkedString::String(comment.unwrap()));
+
+            return Ok(Some(Hover {
+                contents,
+                range: Some(range),
+            }));
+        }
+    }
+
+    Ok(None)
+}
+
 pub fn handle_prepare_rename(
     world: ServerWorld,
     params: req::TextDocumentPositionParams,

crates/ra_lsp_server/src/main_loop/mod.rs

@@ -259,6 +259,7 @@ fn on_request(
         .on::<req::CodeActionRequest>(handlers::handle_code_action)?
         .on::<req::FoldingRangeRequest>(handlers::handle_folding_range)?
         .on::<req::SignatureHelpRequest>(handlers::handle_signature_help)?
+        .on::<req::HoverRequest>(handlers::handle_hover)?
         .on::<req::PrepareRenameRequest>(handlers::handle_prepare_rename)?
         .on::<req::Rename>(handlers::handle_rename)?
         .on::<req::References>(handlers::handle_references)?

crates/ra_syntax/src/ast/generated.rs

@@ -608,6 +608,7 @@ impl<R: TreeRoot<RaTypes>> ConstDefNode<R> {
 impl<'a> ast::NameOwner<'a> for ConstDef<'a> {}
 impl<'a> ast::TypeParamsOwner<'a> for ConstDef<'a> {}
 impl<'a> ast::AttrsOwner<'a> for ConstDef<'a> {}
+impl<'a> ast::DocCommentsOwner<'a> for ConstDef<'a> {}
 impl<'a> ConstDef<'a> {}
 
 // ContinueExpr
@@ -722,6 +723,7 @@ impl<R: TreeRoot<RaTypes>> EnumDefNode<R> {
 impl<'a> ast::NameOwner<'a> for EnumDef<'a> {}
 impl<'a> ast::TypeParamsOwner<'a> for EnumDef<'a> {}
 impl<'a> ast::AttrsOwner<'a> for EnumDef<'a> {}
+impl<'a> ast::DocCommentsOwner<'a> for EnumDef<'a> {}
 impl<'a> EnumDef<'a> {}
 
 // Expr
@@ -1886,6 +1888,7 @@ impl<R: TreeRoot<RaTypes>> ModuleNode<R> {
 
 impl<'a> ast::NameOwner<'a> for Module<'a> {}
 impl<'a> ast::AttrsOwner<'a> for Module<'a> {}
+impl<'a> ast::DocCommentsOwner<'a> for Module<'a> {}
 impl<'a> Module<'a> {
     pub fn item_list(self) -> Option<ItemList<'a>> {
         super::child_opt(self)
@@ -3205,6 +3208,7 @@ impl<R: TreeRoot<RaTypes>> StaticDefNode<R> {
 impl<'a> ast::NameOwner<'a> for StaticDef<'a> {}
 impl<'a> ast::TypeParamsOwner<'a> for StaticDef<'a> {}
 impl<'a> ast::AttrsOwner<'a> for StaticDef<'a> {}
+impl<'a> ast::DocCommentsOwner<'a> for StaticDef<'a> {}
 impl<'a> StaticDef<'a> {}
 
 // Stmt
@@ -3270,6 +3274,7 @@ impl<R: TreeRoot<RaTypes>> StructDefNode<R> {
 impl<'a> ast::NameOwner<'a> for StructDef<'a> {}
 impl<'a> ast::TypeParamsOwner<'a> for StructDef<'a> {}
 impl<'a> ast::AttrsOwner<'a> for StructDef<'a> {}
+impl<'a> ast::DocCommentsOwner<'a> for StructDef<'a> {}
 impl<'a> StructDef<'a> {
     pub fn fields(self) -> impl Iterator<Item = NamedFieldDef<'a>> + 'a {
         super::children(self)
@@ -3424,6 +3429,7 @@ impl<R: TreeRoot<RaTypes>> TraitDefNode<R> {
 
 impl<'a> ast::NameOwner<'a> for TraitDef<'a> {}
 impl<'a> ast::AttrsOwner<'a> for TraitDef<'a> {}
+impl<'a> ast::DocCommentsOwner<'a> for TraitDef<'a> {}
 impl<'a> TraitDef<'a> {}
 
 // TryExpr
@@ -3649,6 +3655,7 @@ impl<R: TreeRoot<RaTypes>> TypeDefNode<R> {
 impl<'a> ast::NameOwner<'a> for TypeDef<'a> {}
 impl<'a> ast::TypeParamsOwner<'a> for TypeDef<'a> {}
 impl<'a> ast::AttrsOwner<'a> for TypeDef<'a> {}
+impl<'a> ast::DocCommentsOwner<'a> for TypeDef<'a> {}
 impl<'a> TypeDef<'a> {}
 
 // TypeParam

crates/ra_syntax/src/grammar.ron

@@ -260,6 +260,7 @@ Grammar(
                 "NameOwner",
                 "TypeParamsOwner",
                 "AttrsOwner",
+                "DocCommentsOwner"
             ],
             collections: [
                 ["fields", "NamedFieldDef"]
@@ -270,10 +271,11 @@ Grammar(
             "NameOwner",
             "TypeParamsOwner",
             "AttrsOwner",
+            "DocCommentsOwner"
         ] ),
-        "TraitDef": ( traits: ["NameOwner", "AttrsOwner"] ),
+        "TraitDef": ( traits: ["NameOwner", "AttrsOwner", "DocCommentsOwner"] ),
         "Module": (
-            traits: ["NameOwner", "AttrsOwner" ],
+            traits: ["NameOwner", "AttrsOwner", "DocCommentsOwner" ],
             options: [ "ItemList" ]
         ),
         "ItemList": (
@@ -283,16 +285,19 @@ Grammar(
             "NameOwner",
             "TypeParamsOwner",
             "AttrsOwner",
+            "DocCommentsOwner"
         ] ),
         "StaticDef": ( traits: [
             "NameOwner",
             "TypeParamsOwner",
             "AttrsOwner",
+            "DocCommentsOwner"
         ] ),
         "TypeDef": ( traits: [
             "NameOwner",
             "TypeParamsOwner",
             "AttrsOwner",
+            "DocCommentsOwner"
         ] ),
         "ImplItem": (),