Store a boolean on whether the cache is trimmed

src/common/buffer/BufferLine.test.ts

@@ -16,20 +16,20 @@ class TestBufferLine extends BufferLine {
     return this._combined;
   }
 
-  public get cachedCanonicalString(): string | undefined {
-    return this._cachedCanonicalString;
+  public get cachedString(): string | undefined {
+    return this._cachedString;
   }
 
-  public set cachedCanonicalString(value: string | undefined) {
-    this._cachedCanonicalString = value;
+  public set cachedString(value: string | undefined) {
+    this._cachedString = value;
   }
 
-  public get cachedCanonicalTrimmedString(): string | undefined {
-    return this._cachedCanonicalTrimmedString;
+  public get isCachedStringTrimmed(): boolean {
+    return this._isCachedStringTrimmed;
   }
 
-  public set cachedCanonicalTrimmedString(value: string | undefined) {
-    this._cachedCanonicalTrimmedString = value;
+  public set isCachedStringTrimmed(value: boolean) {
+    this._isCachedStringTrimmed = value;
   }
 
   public toArray(): CharData[] {
@@ -833,26 +833,32 @@ describe('BufferLine', function(): void {
       // Trimmed-only canonical request should cache the trimmed value.
       const trimmed = line.translateToString(true, undefined, undefined, undefined);
       assert.equal(trimmed, 'abc');
-      assert.equal(line.cachedCanonicalTrimmedString, 'abc');
+      assert.equal(line.cachedString, 'abc');
+      assert.equal(line.isCachedStringTrimmed, true);
 
-      // Non-trimmed canonical request should cache the full value and free trimmed cache.
+      // Non-trimmed canonical request should refresh cache with the full value.
       const translated = line.translateToString(false, undefined, undefined, undefined);
       assert.equal(translated, 'abc  ');
-      assert.equal(line.cachedCanonicalString, 'abc  ');
-      assert.equal(line.cachedCanonicalTrimmedString, undefined);
+      assert.equal(line.cachedString, 'abc  ');
+      assert.equal(line.isCachedStringTrimmed, false);
 
-      // Once non-trimmed is cached, trimmed should be derived from trimEnd() (not re-cached).
+      // Once non-trimmed is cached, trimmed should be derived via trimEnd().
       assert.equal(line.translateToString(true, undefined, undefined, undefined), 'abc');
-      assert.equal(line.cachedCanonicalTrimmedString, undefined);
+      assert.equal(line.cachedString, 'abc  ');
+      assert.equal(line.isCachedStringTrimmed, false);
 
-      line.cachedCanonicalString = 'cached-non-trimmed  ';
-      line.cachedCanonicalTrimmedString = 'cached-trimmed';
+      line.cachedString = 'cached-non-trimmed  ';
+      line.isCachedStringTrimmed = false;
       assert.equal(line.translateToString(false, undefined, undefined, undefined), 'cached-non-trimmed  ');
-      assert.equal(line.translateToString(true, undefined, undefined, undefined), 'cached-trimmed');
-
-      line.cachedCanonicalTrimmedString = undefined;
       assert.equal(line.translateToString(true, undefined, undefined, undefined), 'cached-non-trimmed');
 
+      line.cachedString = 'cached-trimmed';
+      line.isCachedStringTrimmed = true;
+      assert.equal(line.translateToString(true, undefined, undefined, undefined), 'cached-trimmed');
+      assert.equal(line.translateToString(false, undefined, undefined, undefined), 'abc  ');
+      assert.equal(line.cachedString, 'abc  ');
+      assert.equal(line.isCachedStringTrimmed, false);
+
       // Any optional translation argument should bypass cache.
       assert.equal(line.translateToString(false, 0, 2, undefined), 'ab');
       assert.equal(line.translateToString(true, 0, 2, undefined), 'ab');
@@ -863,13 +869,14 @@ describe('BufferLine', function(): void {
         const line = new TestBufferLine(5);
         line.fill(createCellData(1, 'a', 1));
         line.translateToString(true, undefined, undefined, undefined);
-        assert.equal(line.cachedCanonicalTrimmedString, 'aaaaa');
+        assert.equal(line.cachedString, 'aaaaa');
+        assert.equal(line.isCachedStringTrimmed, true);
         line.translateToString(false, undefined, undefined, undefined);
-        assert.equal(line.cachedCanonicalString, 'aaaaa');
-        assert.equal(line.cachedCanonicalTrimmedString, undefined);
+        assert.equal(line.cachedString, 'aaaaa');
+        assert.equal(line.isCachedStringTrimmed, false);
         mutate(line);
-        assert.equal(line.cachedCanonicalString, undefined);
-        assert.equal(line.cachedCanonicalTrimmedString, undefined);
+        assert.equal(line.cachedString, undefined);
+        assert.equal(line.isCachedStringTrimmed, false);
       };
 
       assertCacheInvalidated(line => line.set(0, [0, 'b', 1, 'b'.charCodeAt(0)]));

src/common/buffer/BufferLine.ts

@@ -63,9 +63,8 @@ export class BufferLine implements IBufferLine {
   protected _data: Uint32Array;
   protected _combined: {[index: number]: string} = {};
   protected _extendedAttrs: {[index: number]: IExtendedAttrs | undefined} = {};
-  // Cache for canonical full-line translations.
-  protected _cachedCanonicalString: string | undefined;
-  protected _cachedCanonicalTrimmedString: string | undefined;
+  protected _cachedString: string | undefined;
+  protected _isCachedStringTrimmed: boolean = false;
   public length: number;
 
   constructor(cols: number, fillCellData?: ICellData, public isWrapped: boolean = false) {
@@ -537,9 +536,13 @@ export class BufferLine implements IBufferLine {
    */
   public translateToString(trimRight?: boolean, startCol?: number, endCol?: number, outColumns?: number[]): string {
     const isCanonicalRequest = (startCol === undefined || startCol === 0) && endCol === undefined && outColumns === undefined;
-    const cachedResult = trimRight ? this._cachedCanonicalTrimmedString ?? this._cachedCanonicalString?.trimEnd() : this._cachedCanonicalString;
-    if (isCanonicalRequest && cachedResult !== undefined) {
-      return cachedResult;
+    if (isCanonicalRequest && this._cachedString !== undefined) {
+      if (trimRight) {
+        return this._isCachedStringTrimmed ? this._cachedString : this._cachedString.trimEnd();
+      }
+      if (!this._isCachedStringTrimmed) {
+        return this._cachedString;
+      }
     }
     startCol = startCol ?? 0;
     endCol = endCol ?? this.length;
@@ -566,19 +569,14 @@ export class BufferLine implements IBufferLine {
       outColumns.push(startCol);
     }
     if (isCanonicalRequest) {
-      if (trimRight) {
-        this._cachedCanonicalTrimmedString = result;
-      } else {
-        this._cachedCanonicalString = result;
-        // Free the trimmed string as trimEnd() will be used to save memory
-        this._cachedCanonicalTrimmedString = undefined;
-      }
+      this._cachedString = result;
+      this._isCachedStringTrimmed = !!trimRight;
     }
     return result;
   }
 
   private _invalidateStringCache(): void {
-    this._cachedCanonicalString = undefined;
-    this._cachedCanonicalTrimmedString = undefined;
+    this._cachedString = undefined;
+    this._isCachedStringTrimmed = false;
   }
 }