feat(autoedit): refactor renderer code to simplify iteration on decor… (

#6163)

The PR refactors the current autoedits renderer to use a common schema
for which Decorations can use.
Idea is to make it easy for anyone to try to implement a new decoration
type without knowing the details on diff computation.

vscode/src/autoedits/autoedits-provider.ts

@@ -22,7 +22,8 @@ import { OpenAIAdapter } from './adapters/openai'
 import { autoeditsLogger } from './logger'
 import type { AutoeditsModelAdapter } from './prompt-provider'
 import type { CodeToReplaceData } from './prompt-utils'
-import { AutoEditsRendererManager } from './renderer'
+import { DefaultDecorator } from './renderer/decorators/default-decorator'
+import { AutoEditsRendererManager } from './renderer/manager'
 import {
     adjustPredictionIfInlineCompletionPossible,
     extractInlineCompletionFromRewrittenCode,
@@ -75,7 +76,9 @@ export class AutoeditsProvider implements vscode.InlineCompletionItemProvider, v
             contextRankingStrategy: ContextRankingStrategy.TimeBased,
             dataCollectionEnabled: false,
         })
-        this.rendererManager = new AutoEditsRendererManager()
+        this.rendererManager = new AutoEditsRendererManager(
+            (editor: vscode.TextEditor) => new DefaultDecorator(editor)
+        )
         this.onSelectionChangeDebounced = debounce(
             (event: vscode.TextEditorSelectionChangeEvent) => this.autoeditOnSelectionChange(event),
             ONSELECTION_CHANGE_DEFAULT_DEBOUNCE_INTERVAL_MS

vscode/src/autoedits/renderer/decorators/base.ts

@@ -0,0 +1,70 @@
+import type * as vscode from 'vscode'
+import type { ModifiedRange } from '../diff-utils'
+
+/**
+ * Represents a decorator that manages VS Code editor decorations for auto-edit suggestions.
+ *
+ * This interface defines the contract for displaying and managing decorative elements
+ * that visualize proposed text changes in the editor.
+ *
+ * Lifecycle:
+ * - Single instance should be created per decoration session and disposed of when the decorations
+ *   are no longer needed.
+ * - Always call dispose() when the decorator is no longer needed to clean up resources.
+ * - Dispose should always clear the decorations.
+ *
+ * Usage Pattern:
+ * ```typescript
+ * const decorator = createAutoeditsDecorator(...);
+ * try {
+ *   decorator.setDecorations(decorationInfo);
+ *   ...
+ * } finally {
+ *   decorator.clearDecorations();
+ *   decorator.dispose();
+ * }
+ * ```
+ */
+export interface AutoeditsDecorator extends vscode.Disposable {
+    /**
+     * Applies decorations to the editor based on the provided decoration information.
+     *
+     * @param decorationInformation Contains the line-by-line information about text changes
+     *        and how they should be decorated in the editor.
+     */
+    setDecorations(decorationInformation: DecorationInformation): void
+}
+
+/**
+ * Represents the different types of line decorations that can be applied.
+ */
+export enum DecorationLineType {
+    /** Line has been modified from its original state */
+    Modified = 0,
+    /** New line has been added */
+    Added = 1,
+    /** Line has been removed */
+    Removed = 2,
+    /** Line remains unchanged */
+    Unchanged = 3,
+}
+
+export interface DecorationLineInformation {
+    lineType: DecorationLineType
+    // Line number in the original text. The line number can be null if the line was added.
+    oldLineNumber: number | null
+    // Line number in the new predicted text. The line number can be null if the line was removed.
+    newLineNumber: number | null
+    // The text of the line in the original text.
+    oldText: string
+    // The text of the line in the new predicted text.
+    newText: string
+    // The ranges of text that were modified in the line.
+    modifiedRanges: ModifiedRange[]
+}
+
+export interface DecorationInformation {
+    lines: DecorationLineInformation[]
+    oldLines: string[]
+    newLines: string[]
+}

vscode/src/autoedits/renderer/decorators/common.ts

@@ -0,0 +1,51 @@
+import { type DecorationLineInformation, DecorationLineType } from './base'
+
+/**
+ * Checks if the only changes for modified lines are additions of text
+ */
+export function isOnlyAddingTextForModifiedLines(
+    decorationInformation: DecorationLineInformation[]
+): boolean {
+    for (const line of decorationInformation) {
+        if (line.lineType !== DecorationLineType.Modified) {
+            continue
+        }
+        if (line.modifiedRanges.some(range => range.from1 !== range.to1)) {
+            return false
+        }
+    }
+    return true
+}
+
+export function splitLineDecorationIntoLineTypes(decorationInformation: DecorationLineInformation[]): {
+    modifiedLines: DecorationLineInformation[]
+    removedLines: DecorationLineInformation[]
+    addedLines: DecorationLineInformation[]
+    unchangedLines: DecorationLineInformation[]
+} {
+    const result = {
+        modifiedLines: [] as DecorationLineInformation[],
+        removedLines: [] as DecorationLineInformation[],
+        addedLines: [] as DecorationLineInformation[],
+        unchangedLines: [] as DecorationLineInformation[],
+    }
+
+    for (const line of decorationInformation) {
+        switch (line.lineType) {
+            case DecorationLineType.Modified:
+                result.modifiedLines.push(line)
+                break
+            case DecorationLineType.Removed:
+                result.removedLines.push(line)
+                break
+            case DecorationLineType.Added:
+                result.addedLines.push(line)
+                break
+            case DecorationLineType.Unchanged:
+                result.unchangedLines.push(line)
+                break
+        }
+    }
+
+    return result
+}

vscode/src/autoedits/renderer.test.ts → vscode/src/autoedits/renderer/decorators/default-decorator.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest'
-import { _replaceLeadingTrailingChars } from './renderer'
+import { _replaceLeadingTrailingChars } from './default-decorator'
 
 describe('replaceLeadingTrailingChars', () => {
     it('replaces leading and trailing spaces with tabs', () => {