CodeMapper support

src/harness/client.ts

@@ -789,6 +789,8 @@ export class SessionClient implements LanguageService {
         });
     }
 
+    mapCode = notImplemented;
+
     private createFileLocationOrRangeRequestArgs(positionOrRange: number | TextRange, fileName: string): protocol.FileLocationOrRangeRequestArgs {
         return typeof positionOrRange === "number"
             ? this.createFileLocationRequestArgs(fileName, positionOrRange)

src/harness/fourslashImpl.ts

@@ -4510,6 +4510,57 @@ export class TestState {
 
         this.verifyCurrentFileContent(newFileContent);
     }
+
+    public baselineMapCode(
+        ranges: Range[][],
+        changes: string[] = [],
+    ): void {
+        const fileName = this.activeFile.fileName;
+        const focusLocations = ranges.map(r =>
+            r.map(({ pos, end }) => {
+                return { start: pos, length: end - pos };
+            })
+        );
+        let before = this.getFileContent(fileName);
+        const edits = this.languageService.mapCode(
+            fileName,
+            // We trim the leading whitespace stuff just so our test cases can be more readable.
+            changes,
+            focusLocations,
+            this.formatCodeSettings,
+            {},
+        );
+        this.applyChanges(edits);
+        focusLocations.forEach(r => {
+            r.sort((a, b) => a.start - b.start);
+        });
+        focusLocations.sort((a, b) => a[0].start - b[0].start);
+        for (const subLoc of focusLocations) {
+            for (const { start, length } of subLoc) {
+                let offset = 0;
+                for (const sl2 of focusLocations) {
+                    for (const { start: s2, length: l2 } of sl2) {
+                        if (s2 < start) {
+                            offset += 4;
+                            if ((s2 + l2) > start) {
+                                offset -= 2;
+                            }
+                        }
+                    }
+                }
+                before = before.slice(0, start + offset) + "[|" + before.slice(start + offset, start + offset + length) + "|]" + before.slice(start + offset + length);
+            }
+        }
+        const after = this.getFileContent(fileName);
+        const baseline = `
+// === ORIGINAL ===
+${before}
+// === INCOMING CHANGES ===
+${changes.join("\n// ---\n")}
+// === MAPPED ===
+${after}`;
+        this.baseline("mapCode", baseline, ".mapCode.ts");
+    }
 }
 
 function updateTextRangeForTextChanges({ pos, end }: ts.TextRange, textChanges: readonly ts.TextChange[]): ts.TextRange {

src/harness/fourslashInterfaceImpl.ts

@@ -239,6 +239,10 @@ export class VerifyNegatable {
     public uncommentSelection(newFileContent: string) {
         this.state.uncommentSelection(newFileContent);
     }
+
+    public baselineMapCode(ranges: FourSlash.Range[][], changes: string[] = []): void {
+        this.state.baselineMapCode(ranges, changes);
+    }
 }
 
 export class Verify extends VerifyNegatable {

src/server/protocol.ts

@@ -200,6 +200,7 @@ export const enum CommandTypes {
     ProvideCallHierarchyOutgoingCalls = "provideCallHierarchyOutgoingCalls",
     ProvideInlayHints = "provideInlayHints",
     WatchChange = "watchChange",
+    MapCode = "mapCode",
 }
 
 /**
@@ -2342,6 +2343,38 @@ export interface InlayHintsResponse extends Response {
     body?: InlayHintItem[];
 }
 
+export interface MapCodeRequestArgs extends FileRequestArgs {
+    /**
+     * The files and changes to try and apply/map.
+     */
+    mapping: MapCodeRequestDocumentMapping;
+}
+
+export interface MapCodeRequestDocumentMapping {
+    /**
+     * The specific code to map/insert/replace in the file.
+     */
+    contents: string[];
+
+    /**
+     * Areas of "focus" to inform the code mapper with. For example, cursor
+     * location, current selection, viewport, etc. Nested arrays denote
+     * priority: toplevel arrays are more important than inner arrays, and
+     * inner array priorities are based on items within that array. Items
+     * earlier in the arrays have higher priority.
+     */
+    focusLocations?: TextSpan[][];
+}
+
+export interface MapCodeRequest extends FileRequest {
+    command: CommandTypes.MapCode;
+    arguments: MapCodeRequestArgs;
+}
+
+export interface MapCodeResponse extends Response {
+    body: readonly FileCodeEdits[];
+}
+
 /**
  * Synchronous request for semantic diagnostics of one file.
  */

src/server/session.ts

@@ -1906,6 +1906,26 @@ export class Session<TMessage = string> implements EventSender {
         });
     }
 
+    private mapCode(args: protocol.MapCodeRequestArgs): protocol.FileCodeEdits[] {
+        const formatOptions = this.getHostFormatOptions();
+        const preferences = this.getHostPreferences();
+        const { file, languageService } = this.getFileAndLanguageServiceForSyntacticOperation(args);
+        const scriptInfo = this.projectService.getScriptInfoForNormalizedPath(file)!;
+        const focusLocations = args.mapping.focusLocations?.map(spans => {
+            return spans.map(loc => {
+                const start = scriptInfo.lineOffsetToPosition(loc.start.line, loc.start.offset);
+                const end = scriptInfo.lineOffsetToPosition(loc.end.line, loc.end.offset);
+                return {
+                    start,
+                    length: end - start,
+                };
+            });
+        });
+
+        const changes = languageService.mapCode(file, args.mapping.contents, focusLocations, formatOptions, preferences);
+        return this.mapTextChangesToCodeEdits(changes);
+    }
+
     private setCompilerOptionsForInferredProjects(args: protocol.SetCompilerOptionsForInferredProjectsArgs): void {
         this.projectService.setCompilerOptionsForInferredProjects(args.options, args.projectRootPath);
     }
@@ -3610,6 +3630,9 @@ export class Session<TMessage = string> implements EventSender {
         [protocol.CommandTypes.ProvideInlayHints]: (request: protocol.InlayHintsRequest) => {
             return this.requiredResponse(this.provideInlayHints(request.arguments));
         },
+        [protocol.CommandTypes.MapCode]: (request: protocol.MapCodeRequest) => {
+            return this.requiredResponse(this.mapCode(request.arguments));
+        },
     }));
 
     public addProtocolHandler(command: string, handler: (request: protocol.Request) => HandlerResponse) {

src/services/_namespaces/ts.MapCode.ts

@@ -0,0 +1,3 @@
+/* Generated file to emulate the ts.MapCode namespace. */
+
+export * from "../mapCode.js";

src/services/_namespaces/ts.ts

@@ -33,6 +33,8 @@ export { GoToDefinition };
 import * as InlayHints from "./ts.InlayHints.js";
 export { InlayHints };
 import * as JsDoc from "./ts.JsDoc.js";
+import * as MapCode from "./ts.MapCode.js";
+export { MapCode };
 export { JsDoc };
 import * as NavigateTo from "./ts.NavigateTo.js";
 export { NavigateTo };