Remove iterators from IDecorationService

They're too low performance for typical use cases

Fixes #4079

addons/xterm-addon-canvas/src/BaseRenderLayer.ts

@@ -404,12 +404,11 @@ export abstract class BaseRenderLayer implements IRenderLayer {
 
     // Don't try cache the glyph if it uses any decoration foreground/background override.
     let hasOverrides = false;
-    for (const d of this._decorationService.getDecorationsAtCell(x, y)) {
+    this._decorationService.forEachDecorationAtCell(x, y, undefined, d => {
       if (d.backgroundColorRGB || d.foregroundColorRGB) {
         hasOverrides = true;
-        break;
       }
-    }
+    });
 
     const atlasDidDraw = hasOverrides ? false : this._charAtlas?.draw(this._ctx, this._currentGlyphIdentifier, x * this._scaledCellWidth + this._scaledCharLeft, y * this._scaledCellHeight + this._scaledCharTop);
 
@@ -519,9 +518,9 @@ export abstract class BaseRenderLayer implements IRenderLayer {
     let bgOverride: number | undefined;
     let fgOverride: number | undefined;
     let isTop = false;
-    for (const d of this._decorationService.getDecorationsAtCell(x, y)) {
+    this._decorationService.forEachDecorationAtCell(x, y, undefined, d => {
       if (d.options.layer !== 'top' && isTop) {
-        continue;
+        return;
       }
       if (d.backgroundColorRGB) {
         bgOverride = d.backgroundColorRGB.rgba;
@@ -530,7 +529,7 @@ export abstract class BaseRenderLayer implements IRenderLayer {
         fgOverride = d.foregroundColorRGB.rgba;
       }
       isTop = d.options.layer === 'top';
-    }
+    });
 
     // Apply selection foreground if applicable
     if (!isTop) {

addons/xterm-addon-canvas/src/TextRenderLayer.ts

@@ -187,15 +187,15 @@ export class TextRenderLayer extends BaseRenderLayer {
       // Get any decoration foreground/background overrides, this must be fetched before the early
       // exist but applied after inverse
       let isTop = false;
-      for (const d of this._decorationService.getDecorationsAtCell(x, this._bufferService.buffer.ydisp + y)) {
+      this._decorationService.forEachDecorationAtCell(x, this._bufferService.buffer.ydisp + y, undefined, d => {
         if (d.options.layer !== 'top' && isTop) {
-          continue;
+          return;
         }
         if (d.backgroundColorRGB) {
           nextFillStyle = d.backgroundColorRGB.css;
         }
         isTop = d.options.layer === 'top';
-      }
+      });
 
       if (prevFillStyle === null) {
         // This is either the first iteration, or the default background was set. Either way, we

src/browser/renderer/dom/DomRendererRowFactory.ts

@@ -204,9 +204,9 @@ export class DomRendererRowFactory {
       let bgOverride: IColor | undefined;
       let fgOverride: IColor | undefined;
       let isTop = false;
-      for (const d of this._decorationService.getDecorationsAtCell(x, row)) {
+      this._decorationService.forEachDecorationAtCell(x, row, undefined, d => {
         if (d.options.layer !== 'top' && isTop) {
-          continue;
+          return;
         }
         if (d.backgroundColorRGB) {
           bgColorMode = Attributes.CM_RGB;
@@ -219,7 +219,7 @@ export class DomRendererRowFactory {
           fgOverride = d.foregroundColorRGB;
         }
         isTop = d.options.layer === 'top';
-      }
+      });
 
       // Apply selection foreground if applicable
       const isInSelection = this._isCellInSelection(x, row);

src/common/TestUtils.test.ts

@@ -161,8 +161,6 @@ export class MockDecorationService implements IDecorationService {
   public onDecorationRemoved = new EventEmitter<IInternalDecoration>().event;
   public registerDecoration(decorationOptions: IDecorationOptions): IDecoration | undefined { return undefined; }
   public reset(): void { }
-  public *getDecorationsAtLine(line: number): IterableIterator<IInternalDecoration> { }
-  public *getDecorationsAtCell(x: number, line: number): IterableIterator<IInternalDecoration> { }
   public forEachDecorationAtCell(x: number, line: number, layer: 'bottom' | 'top' | undefined, callback: (decoration: IInternalDecoration) => void): void { }
   public dispose(): void { }
 }

src/common/services/DecorationService.ts

@@ -62,10 +62,6 @@ export class DecorationService extends Disposable implements IDecorationService
     this._decorations.clear();
   }
 
-  public *getDecorationsAtLine(line: number): IterableIterator<IInternalDecoration> {
-    return this._decorations.getKeyIterator(line);
-  }
-
   public *getDecorationsAtCell(x: number, line: number, layer?: 'bottom' | 'top'): IterableIterator<IInternalDecoration> {
     let xmin = 0;
     let xmax = 0;

src/common/services/Services.ts

@@ -304,13 +304,9 @@ export interface IDecorationService extends IDisposable {
   readonly onDecorationRemoved: IEvent<IInternalDecoration>;
   registerDecoration(decorationOptions: IDecorationOptions): IDecoration | undefined;
   reset(): void;
-  /** Iterates over the decorations at a line (in no particular order). */
-  getDecorationsAtLine(line: number): IterableIterator<IInternalDecoration>;
-  /** Iterates over the decorations at a cell (in no particular order). */
-  getDecorationsAtCell(x: number, line: number, layer?: 'bottom' | 'top'): IterableIterator<IInternalDecoration>;
   /**
-   * Trigger a callback over the decoration at a cell (in no particular order). This is a high
-   * performance, but less ergonomic, version of {@link getDecorationsAtCell}.
+   * Trigger a callback over the decoration at a cell (in no particular order). This uses a callback
+   * instead of an iterator as it's typically used in hot code paths.
    */
   forEachDecorationAtCell(x: number, line: number, layer: 'bottom' | 'top' | undefined, callback: (decoration: IInternalDecoration) => void): void;
 }