Transition OnEnter to WorkspaceSnippetEdit

This also changes our handiling of snippet edits on the client side.
`editor.insertSnippet` unfortunately forces indentation, which we
really don't want to have to deal with. So, let's just implement our
manual hacky way of dealing with a simple subset of snippets we
actually use in rust-analyzer

8 files changed, 97 insertions, 90 deletions

diff --git a/crates/ra_ide/src/typing/on_enter.rs b/crates/ra_ide/src/typing/on_enter.rs
index 78a40cc94..85be14ad3 100644
--- a/crates/ra_ide/src/typing/on_enter.rs
+++ b/crates/ra_ide/src/typing/on_enter.rs
@@ -38,17 +38,15 @@ pub(crate) fn on_enter(db: &RootDatabase, position: FilePosition) -> Option<Sour
     }
 
     let indent = node_indent(&file, comment.syntax())?;
-    let inserted = format!("\n{}{} ", indent, prefix);
-    let cursor_position = position.offset + TextSize::of(&inserted);
+    let inserted = format!("\n{}{} $0", indent, prefix);
     let edit = TextEdit::insert(position.offset, inserted);
 
-    Some(
-        SourceChange::source_file_edit(
-            "On enter",
-            SourceFileEdit { edit, file_id: position.file_id },
-        )
-        .with_cursor(FilePosition { offset: cursor_position, file_id: position.file_id }),
-    )
+    let mut res = SourceChange::source_file_edit(
+        "On enter",
+        SourceFileEdit { edit, file_id: position.file_id },
+    );
+    res.is_snippet = true;
+    Some(res)
 }
 
 fn followed_by_comment(comment: &ast::Comment) -> bool {
@@ -84,7 +82,7 @@ fn node_indent(file: &SourceFile, token: &SyntaxToken) -> Option<SmolStr> {
 
 #[cfg(test)]
 mod tests {
-    use test_utils::{add_cursor, assert_eq_text, extract_offset};
+    use test_utils::{assert_eq_text, extract_offset};
 
     use crate::mock_analysis::single_file;
 
@@ -98,7 +96,6 @@ mod tests {
         assert_eq!(result.source_file_edits.len(), 1);
         let mut actual = before.to_string();
         result.source_file_edits[0].edit.apply(&mut actual);
-        let actual = add_cursor(&actual, result.cursor_position.unwrap().offset);
         Some(actual)
     }
 
@@ -121,7 +118,7 @@ fn foo() {
 ",
             r"
 /// Some docs
-/// <|>
+/// $0
 fn foo() {
 }
 ",
@@ -137,7 +134,7 @@ impl S {
             r"
 impl S {
     /// Some
-    /// <|> docs.
+    /// $0 docs.
     fn foo() {}
 }
 ",
@@ -151,7 +148,7 @@ fn foo() {
 ",
             r"
 ///
-/// <|> Some docs
+/// $0 Some docs
 fn foo() {
 }
 ",
@@ -175,7 +172,7 @@ fn main() {
             r"
 fn main() {
     // Fix
-    // <|> me
+    // $0 me
     let x = 1 + 1;
 }
 ",
@@ -195,7 +192,7 @@ fn main() {
             r"
 fn main() {
     // Fix
-    // <|>
+    // $0
     // me
     let x = 1 + 1;
 }
diff --git a/crates/rust-analyzer/src/lsp_ext.rs b/crates/rust-analyzer/src/lsp_ext.rs
index f75a26eb7..3c7bd609d 100644
--- a/crates/rust-analyzer/src/lsp_ext.rs
+++ b/crates/rust-analyzer/src/lsp_ext.rs
@@ -102,7 +102,7 @@ pub enum OnEnter {}
 
 impl Request for OnEnter {
     type Params = lsp_types::TextDocumentPositionParams;
-    type Result = Option<SourceChange>;
+    type Result = Option<SnippetWorkspaceEdit>;
     const METHOD: &'static str = "rust-analyzer/onEnter";
 }
 
diff --git a/crates/rust-analyzer/src/main_loop/handlers.rs b/crates/rust-analyzer/src/main_loop/handlers.rs
index be6a0aece..fcf08cd79 100644
--- a/crates/rust-analyzer/src/main_loop/handlers.rs
+++ b/crates/rust-analyzer/src/main_loop/handlers.rs
@@ -159,12 +159,12 @@ pub fn handle_join_lines(
 pub fn handle_on_enter(
     world: WorldSnapshot,
     params: lsp_types::TextDocumentPositionParams,
-) -> Result<Option<lsp_ext::SourceChange>> {
+) -> Result<Option<lsp_ext::SnippetWorkspaceEdit>> {
     let _p = profile("handle_on_enter");
     let position = from_proto::file_position(&world, params)?;
     match world.analysis().on_enter(position)? {
         None => Ok(None),
-        Some(source_change) => to_proto::source_change(&world, source_change).map(Some),
+        Some(source_change) => to_proto::snippet_workspace_edit(&world, source_change).map(Some),
     }
 }
 
diff --git a/crates/rust-analyzer/tests/heavy_tests/main.rs b/crates/rust-analyzer/tests/heavy_tests/main.rs
index 74676b3ee..4e94c37e1 100644
--- a/crates/rust-analyzer/tests/heavy_tests/main.rs
+++ b/crates/rust-analyzer/tests/heavy_tests/main.rs
@@ -474,27 +474,21 @@ fn main() {{}}
             position: Position { line: 0, character: 5 },
         },
         json!({
-          "cursorPosition": {
-            "position": { "character": 4, "line": 1 },
-            "textDocument": { "uri": "file:///[..]src/m0.rs" }
-          },
-          "label": "On enter",
-          "workspaceEdit": {
-            "documentChanges": [
-              {
-                "edits": [
-                  {
-                    "newText": "\n/// ",
-                    "range": {
-                      "end": { "character": 5, "line": 0 },
-                      "start": { "character": 5, "line": 0 }
-                    }
+          "documentChanges": [
+            {
+              "edits": [
+                {
+                  "insertTextFormat": 2,
+                  "newText": "\n/// $0",
+                  "range": {
+                    "end": { "character": 5, "line": 0 },
+                    "start": { "character": 5, "line": 0 }
                   }
-                ],
-                "textDocument": { "uri": "file:///[..]src/m0.rs", "version": null }
-              }
-            ]
-          }
+                }
+              ],
+              "textDocument": { "uri": "file:///[..]src/m0.rs", "version": null }
+            }
+          ]
         }),
     );
     let elapsed = start.elapsed();
@@ -526,27 +520,21 @@ version = \"0.0.0\"
             position: Position { line: 0, character: 8 },
         },
         json!({
-          "cursorPosition": {
-            "position": { "line": 1, "character": 4 },
-            "textDocument": { "uri": "file:///[..]src/main.rs" }
-          },
-          "label": "On enter",
-          "workspaceEdit": {
-            "documentChanges": [
-              {
-                "edits": [
-                  {
-                    "newText": "\r\n/// ",
-                    "range": {
-                      "end": { "line": 0, "character": 8 },
-                      "start": { "line": 0, "character": 8 }
-                    }
+          "documentChanges": [
+            {
+              "edits": [
+                {
+                  "insertTextFormat": 2,
+                  "newText": "\r\n/// $0",
+                  "range": {
+                    "end": { "line": 0, "character": 8 },
+                    "start": { "line": 0, "character": 8 }
                   }
-                ],
-                "textDocument": { "uri": "file:///[..]src/main.rs", "version": null }
-              }
-            ]
-          }
+                }
+              ],
+              "textDocument": { "uri": "file:///[..]src/main.rs", "version": null }
+            }
+          ]
         }),
     );
 }
diff --git a/editors/code/src/commands/index.ts b/editors/code/src/commands/index.ts
index 0937b495c..e5ed77e32 100644
--- a/editors/code/src/commands/index.ts
+++ b/editors/code/src/commands/index.ts
@@ -53,36 +53,57 @@ export function selectAndApplySourceChange(ctx: Ctx): Cmd {
     };
 }
 
-export function applySnippetWorkspaceEdit(_ctx: Ctx): Cmd {
+export function applySnippetWorkspaceEditCommand(_ctx: Ctx): Cmd {
     return async (edit: vscode.WorkspaceEdit) => {
-        assert(edit.entries().length === 1, `bad ws edit: ${JSON.stringify(edit)}`);
-        const [uri, edits] = edit.entries()[0];
+        await applySnippetWorkspaceEdit(edit);
+    };
+}
+
+export async function applySnippetWorkspaceEdit(edit: vscode.WorkspaceEdit) {
+    assert(edit.entries().length === 1, `bad ws edit: ${JSON.stringify(edit)}`);
+    const [uri, edits] = edit.entries()[0];
 
-        const editor = vscode.window.visibleTextEditors.find((it) => it.document.uri.toString() === uri.toString());
-        if (!editor) return;
+    const editor = vscode.window.visibleTextEditors.find((it) => it.document.uri.toString() === uri.toString());
+    if (!editor) return;
 
-        let editWithSnippet: vscode.TextEdit | undefined = undefined;
-        let lineDelta = 0;
-        await editor.edit((builder) => {
-            for (const indel of edits) {
-                const isSnippet = indel.newText.indexOf('$0') !== -1 || indel.newText.indexOf('${') !== -1;
-                if (isSnippet) {
-                    editWithSnippet = indel;
-                } else {
-                    if (!editWithSnippet) {
-                        lineDelta = (indel.newText.match(/\n/g) || []).length - (indel.range.end.line - indel.range.start.line);
-                    }
-                    builder.replace(indel.range, indel.newText);
-                }
+    let selection: vscode.Selection | undefined = undefined;
+    let lineDelta = 0;
+    await editor.edit((builder) => {
+        for (const indel of edits) {
+            const parsed = parseSnippet(indel.newText);
+            if (parsed) {
+                const [newText, [placeholderStart, placeholderLength]] = parsed;
+                const prefix = newText.substr(0, placeholderStart);
+                const lastNewline = prefix.lastIndexOf('\n');
+
+                const startLine = indel.range.start.line + lineDelta + countLines(prefix);
+                const startColumn = lastNewline === -1 ?
+                    indel.range.start.character + placeholderStart
+                    : prefix.length - lastNewline - 1;
+                const endColumn = startColumn + placeholderLength;
+                selection = new vscode.Selection(
+                    new vscode.Position(startLine, startColumn),
+                    new vscode.Position(startLine, endColumn),
+                );
+                builder.replace(indel.range, newText);
+            } else {
+                lineDelta = countLines(indel.newText) - (indel.range.end.line - indel.range.start.line);
+                builder.replace(indel.range, indel.newText);
             }
-        });
-        if (editWithSnippet) {
-            const snip = editWithSnippet as vscode.TextEdit;
-            const range = snip.range.with(
-                snip.range.start.with(snip.range.start.line + lineDelta),
-                snip.range.end.with(snip.range.end.line + lineDelta),
-            );
-            await editor.insertSnippet(new vscode.SnippetString(snip.newText), range);
         }
-    };
+    });
+    if (selection) editor.selection = selection;
+}
+
+function parseSnippet(snip: string): [string, [number, number]] | undefined {
+    const m = snip.match(/\$(0|\{0:([^}]*)\})/);
+    if (!m) return undefined;
+    const placeholder = m[2] ?? "";
+    const range: [number, number] = [m.index!!, placeholder.length];
+    const insert = snip.replace(m[0], placeholder);
+    return [insert, range];
+}
+
+function countLines(text: string): number {
+    return (text.match(/\n/g) || []).length;
 }
diff --git a/editors/code/src/commands/on_enter.ts b/editors/code/src/commands/on_enter.ts
index 285849db7..a7871c31e 100644
--- a/editors/code/src/commands/on_enter.ts
+++ b/editors/code/src/commands/on_enter.ts
@@ -1,8 +1,8 @@
 import * as vscode from 'vscode';
 import * as ra from '../rust-analyzer-api';
 
-import { applySourceChange } from '../source_change';
 import { Cmd, Ctx } from '../ctx';
+import { applySnippetWorkspaceEdit } from '.';
 
 async function handleKeypress(ctx: Ctx) {
     const editor = ctx.activeRustEditor;
@@ -21,7 +21,8 @@ async function handleKeypress(ctx: Ctx) {
     });
     if (!change) return false;
 
-    await applySourceChange(ctx, change);
+    const workspaceEdit = client.protocol2CodeConverter.asWorkspaceEdit(change);
+    await applySnippetWorkspaceEdit(workspaceEdit);
     return true;
 }
 
diff --git a/editors/code/src/main.ts b/editors/code/src/main.ts
index ac3bb365e..8b0a9d870 100644
--- a/editors/code/src/main.ts
+++ b/editors/code/src/main.ts
@@ -91,7 +91,7 @@ export async function activate(context: vscode.ExtensionContext) {
     ctx.registerCommand('debugSingle', commands.debugSingle);
     ctx.registerCommand('showReferences', commands.showReferences);
     ctx.registerCommand('applySourceChange', commands.applySourceChange);
-    ctx.registerCommand('applySnippetWorkspaceEdit', commands.applySnippetWorkspaceEdit);
+    ctx.registerCommand('applySnippetWorkspaceEdit', commands.applySnippetWorkspaceEditCommand);
     ctx.registerCommand('selectAndApplySourceChange', commands.selectAndApplySourceChange);
 
     ctx.pushCleanup(activateTaskProvider(workspaceFolder));
diff --git a/editors/code/src/rust-analyzer-api.ts b/editors/code/src/rust-analyzer-api.ts
index 400ac3714..3b83b10e3 100644
--- a/editors/code/src/rust-analyzer-api.ts
+++ b/editors/code/src/rust-analyzer-api.ts
@@ -69,7 +69,7 @@ export interface JoinLinesParams {
 export const joinLines = request<JoinLinesParams, SourceChange>("joinLines");
 
 
-export const onEnter = request<lc.TextDocumentPositionParams, Option<SourceChange>>("onEnter");
+export const onEnter = request<lc.TextDocumentPositionParams, Option<lc.WorkspaceEdit>>("onEnter");
 
 export interface RunnablesParams {
     textDocument: lc.TextDocumentIdentifier;