8 files changed, 195 insertions, 9 deletions

diff --git a/crates/gen_lsp_server/Cargo.toml b/crates/gen_lsp_server/Cargo.toml
index 4eb508fc0..6580ba6e4 100644
--- a/crates/gen_lsp_server/Cargo.toml
+++ b/crates/gen_lsp_server/Cargo.toml
@@ -4,7 +4,7 @@ version = "0.1.0"
 authors = ["Aleksey Kladov <[email protected]>"]
 
 [dependencies]
-languageserver-types = "0.50.0"
+languageserver-types = "0.51.0"
 log = "0.4.3"
 
 failure = "0.1.2"
diff --git a/crates/ra_analysis/src/lib.rs b/crates/ra_analysis/src/lib.rs
index 4da55ab26..b4c7db476 100644
--- a/crates/ra_analysis/src/lib.rs
+++ b/crates/ra_analysis/src/lib.rs
@@ -34,6 +34,7 @@ use imp::{AnalysisImpl, AnalysisHostImpl, FileResolverImp};
 pub use ra_editor::{
     StructureNode, LineIndex, FileSymbol,
     Runnable, RunnableKind, HighlightedRange, CompletionItem,
+    Fold, FoldKind
 };
 pub use job::{JobToken, JobHandle};
 
@@ -224,6 +225,10 @@ impl Analysis {
     pub fn diagnostics(&self, file_id: FileId) -> Vec<Diagnostic> {
         self.imp.diagnostics(file_id)
     }
+    pub fn folding_ranges(&self, file_id: FileId) -> Vec<Fold> {
+        let file = self.imp.file_syntax(file_id);
+        ra_editor::folding_ranges(&file)
+    }
 }
 
 #[derive(Debug)]
diff --git a/crates/ra_editor/src/folding_ranges.rs b/crates/ra_editor/src/folding_ranges.rs
new file mode 100644
index 000000000..817da28d1
--- /dev/null
+++ b/crates/ra_editor/src/folding_ranges.rs
@@ -0,0 +1,142 @@
+use std::collections::HashSet;
+
+use ra_syntax::{
+    File, TextRange, SyntaxNodeRef,
+    SyntaxKind,
+    algo::{walk, Direction, siblings},
+};
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum FoldKind {
+    Comment,
+    Imports,
+}
+
+#[derive(Debug)]
+pub struct Fold {
+    pub range: TextRange,
+    pub kind: FoldKind,
+}
+
+pub fn folding_ranges(file: &File) -> Vec<Fold> {
+    let syntax = file.syntax();
+
+    let mut res = vec![];
+    let mut visited = HashSet::new();
+
+    for node in walk::preorder(syntax) {
+        if visited.contains(&node) {
+            continue;
+        }
+
+        let range_and_kind = match node.kind() {
+            SyntaxKind::COMMENT => (
+                contiguous_range_for(SyntaxKind::COMMENT, node, &mut visited),
+                Some(FoldKind::Comment),
+            ),
+            SyntaxKind::USE_ITEM => (
+                contiguous_range_for(SyntaxKind::USE_ITEM, node, &mut visited),
+                Some(FoldKind::Imports),
+            ),
+            _ => (None, None),
+        };
+
+        match range_and_kind {
+            (Some(range), Some(kind)) => {
+                res.push(Fold {
+                    range: range,
+                    kind: kind
+                });
+            }
+            _ => {}
+        }
+    }
+
+    res
+}
+
+fn contiguous_range_for<'a>(
+    kind: SyntaxKind,
+    node: SyntaxNodeRef<'a>,
+    visited: &mut HashSet<SyntaxNodeRef<'a>>,
+) -> Option<TextRange> {
+    visited.insert(node);
+
+    let left = node;
+    let mut right = node;
+    for node in siblings(node, Direction::Forward) {
+        visited.insert(node);
+        match node.kind() {
+            SyntaxKind::WHITESPACE if !node.leaf_text().unwrap().as_str().contains("\n\n") => (),
+            k => {
+                if k == kind {
+                    right = node
+                } else {
+                    break;
+                }
+            }
+        }
+    }
+    if left != right {
+        Some(TextRange::from_to(
+            left.range().start(),
+            right.range().end(),
+        ))
+    } else {
+        None
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_fold_comments() {
+        let text = r#"
+// Hello
+// this is a multiline
+// comment
+//
+
+// But this is not
+
+fn main() {
+    // We should
+    // also
+    // fold
+    // this one.
+}"#;
+
+        let file = File::parse(&text);
+        let folds = folding_ranges(&file);
+        assert_eq!(folds.len(), 2);
+        assert_eq!(folds[0].range.start(), 1.into());
+        assert_eq!(folds[0].range.end(), 46.into());
+        assert_eq!(folds[0].kind, FoldKind::Comment);
+
+        assert_eq!(folds[1].range.start(), 84.into());
+        assert_eq!(folds[1].range.end(), 137.into());
+        assert_eq!(folds[1].kind, FoldKind::Comment);
+    }
+
+    #[test]
+    fn test_fold_imports() {
+        let text = r#"
+use std::str;
+use std::vec;
+use std::io as iop;
+
+fn main() {
+}"#;
+
+        let file = File::parse(&text);
+        let folds = folding_ranges(&file);
+        assert_eq!(folds.len(), 1);
+        assert_eq!(folds[0].range.start(), 1.into());
+        assert_eq!(folds[0].range.end(), 48.into());
+        assert_eq!(folds[0].kind, FoldKind::Imports);
+    }
+
+
+}
\ No newline at end of file
diff --git a/crates/ra_editor/src/lib.rs b/crates/ra_editor/src/lib.rs
index 78ed34c7c..de929d73a 100644
--- a/crates/ra_editor/src/lib.rs
+++ b/crates/ra_editor/src/lib.rs
@@ -10,6 +10,7 @@ mod extend_selection;
 mod symbols;
 mod line_index;
 mod edit;
+mod folding_ranges;
 mod code_actions;
 mod typing;
 mod completion;
@@ -36,6 +37,7 @@ pub use self::{
     },
     typing::{join_lines, on_eq_typed},
     completion::{scope_completion, CompletionItem},
+    folding_ranges::{Fold, FoldKind, folding_ranges}
 };
 
 #[derive(Debug)]
diff --git a/crates/ra_lsp_server/Cargo.toml b/crates/ra_lsp_server/Cargo.toml
index b851f70e1..32463e499 100644
--- a/crates/ra_lsp_server/Cargo.toml
+++ b/crates/ra_lsp_server/Cargo.toml
@@ -15,7 +15,7 @@ crossbeam-channel = "0.2.4"
 flexi_logger = "0.9.1"
 log = "0.4.3"
 url_serde = "0.2.0"
-languageserver-types = "0.50.0"
+languageserver-types = "0.51.0"
 walkdir = "2.2.0"
 im = "12.0.0"
 cargo_metadata = "0.6.0"
diff --git a/crates/ra_lsp_server/src/caps.rs b/crates/ra_lsp_server/src/caps.rs
index 7456aea8a..3c628f29c 100644
--- a/crates/ra_lsp_server/src/caps.rs
+++ b/crates/ra_lsp_server/src/caps.rs
@@ -1,5 +1,7 @@
 use languageserver_types::{
     ServerCapabilities,
+    CodeActionProviderCapability,
+    FoldingRangeProviderCapability,
     TextDocumentSyncCapability,
     TextDocumentSyncOptions,
     TextDocumentSyncKind,
@@ -32,7 +34,7 @@ pub fn server_capabilities() -> ServerCapabilities {
         document_highlight_provider: None,
         document_symbol_provider: Some(true),
         workspace_symbol_provider: Some(true),
-        code_action_provider: Some(true),
+        code_action_provider: Some(CodeActionProviderCapability::Simple(true)),
         code_lens_provider: None,
         document_formatting_provider: None,
         document_range_formatting_provider: None,
@@ -40,10 +42,12 @@ pub fn server_capabilities() -> ServerCapabilities {
             first_trigger_character: "=".to_string(),
             more_trigger_character: None,
         }),
+        folding_range_provider: Some(FoldingRangeProviderCapability::Simple(true)),
         rename_provider: None,
         color_provider: None,
         execute_command_provider: Some(ExecuteCommandOptions {
             commands: vec!["apply_code_action".to_string()],
         }),
+        workspace: None,
     }
 }
diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index b2ebc9cdc..51061543c 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -1,15 +1,16 @@
-use std::collections::HashMap;
+use std::collections::{HashMap};
 
 use languageserver_types::{
     Diagnostic, DiagnosticSeverity, DocumentSymbol,
-    Command, TextDocumentIdentifier,
+    CodeActionResponse, Command, TextDocumentIdentifier,
     SymbolInformation, Position, Location, TextEdit,
     CompletionItem, InsertTextFormat, CompletionItemKind,
+    FoldingRange, FoldingRangeParams, FoldingRangeKind
 };
 use serde_json::to_value;
-use ra_analysis::{Query, FileId, RunnableKind, JobToken};
+use ra_analysis::{Query, FileId, RunnableKind, JobToken, FoldKind};
 use ra_syntax::{
-    text_utils::contains_offset_nonstrict,
+    text_utils::contains_offset_nonstrict
 };
 
 use ::{
@@ -177,6 +178,7 @@ pub fn handle_workspace_symbol(
                     world, &line_index
                 )?,
                 container_name: None,
+                deprecated: None,
             };
             res.push(info);
         };
@@ -365,11 +367,41 @@ pub fn handle_completion(
     Ok(Some(req::CompletionResponse::Array(items)))
 }
 
+pub fn handle_folding_range(
+    world: ServerWorld,
+    params: FoldingRangeParams,
+    _token: JobToken,
+) -> Result<Option<Vec<FoldingRange>>> {
+    let file_id = params.text_document.try_conv_with(&world)?;
+    let line_index = world.analysis().file_line_index(file_id);
+
+    let res = Some(world.analysis()
+        .folding_ranges(file_id)
+        .into_iter()
+        .map(|fold| {
+            let kind = match fold.kind {
+                FoldKind::Comment => FoldingRangeKind::Comment,
+                FoldKind::Imports => FoldingRangeKind::Imports
+            };
+            let range = fold.range.conv_with(&line_index);
+            FoldingRange {
+                start_line: range.start.line,
+                start_character: Some(range.start.character),
+                end_line: range.end.line,
+                end_character: Some(range.start.character),
+                kind: Some(kind)
+            }
+        })
+        .collect());
+
+    Ok(res)
+}
+
 pub fn handle_code_action(
     world: ServerWorld,
     params: req::CodeActionParams,
     _token: JobToken,
-) -> Result<Option<Vec<Command>>> {
+) -> Result<Option<CodeActionResponse>> {
     let file_id = params.text_document.try_conv_with(&world)?;
     let line_index = world.analysis().file_line_index(file_id);
     let range = params.range.conv_with(&line_index);
@@ -392,7 +424,7 @@ pub fn handle_code_action(
         res.push(cmd);
     }
 
-    Ok(Some(res))
+    Ok(Some(CodeActionResponse::Commands(res)))
 }
 
 pub fn publish_diagnostics(
diff --git a/crates/ra_lsp_server/src/main_loop/mod.rs b/crates/ra_lsp_server/src/main_loop/mod.rs
index 2b2279e97..abc58b70e 100644
--- a/crates/ra_lsp_server/src/main_loop/mod.rs
+++ b/crates/ra_lsp_server/src/main_loop/mod.rs
@@ -253,6 +253,7 @@ fn on_request(
         .on::<req::DecorationsRequest>(handlers::handle_decorations)?
         .on::<req::Completion>(handlers::handle_completion)?
         .on::<req::CodeActionRequest>(handlers::handle_code_action)?
+        .on::<req::FoldingRangeRequest>(handlers::handle_folding_range)?
         .finish();
     match req {
         Ok((id, handle)) => {