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Move cache into Buffer owned object, use WeakRefs

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This allows O(1) clearing of the cache, a single TTL timer and we
can avoid making BufferLine's Disposable
This commit is contained in:
Daniel Imms
2026-05-02 05:32:43 -07:00
parent 7615cd210a
commit 52d4b2719c
10 changed files with 219 additions and 40 deletions
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src/common/buffer/Buffer.ts
+33 -4
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@@ -8,6 +8,7 @@ import { IdleTaskQueue } from 'common/TaskQueue';
import { IAttributeData, IBufferLine, ICellData, ICharset } from 'common/Types';
import { ExtendedAttrs } from 'common/buffer/AttributeData';
import { BufferLine, DEFAULT_ATTR_DATA } from 'common/buffer/BufferLine';
import { BufferLineStringCache } from 'common/buffer/BufferLineStringCache';
import { getWrappedLineTrimmedLength, reflowLargerApplyNewLayout, reflowLargerCreateNewLayout, reflowLargerGetLinesToRemove, reflowSmallerGetNewLineLengths } from 'common/buffer/BufferReflow';
import { CellData } from 'common/buffer/CellData';
import { NULL_CELL_CHAR, NULL_CELL_CODE, NULL_CELL_WIDTH, WHITESPACE_CELL_CHAR, WHITESPACE_CELL_CODE, WHITESPACE_CELL_WIDTH } from 'common/buffer/Constants';
@@ -17,6 +18,7 @@ import { DEFAULT_CHARSET } from 'common/data/Charsets';
import { IBufferService, ILogService, IOptionsService } from 'common/services/Services';
export const MAX_BUFFER_SIZE = 4294967295; // 2^32 - 1
const STRING_CACHE_CLEAR_DELAY_MS = 50;
/**
* This class represents a terminal buffer (an internal state of the terminal), where the
@@ -50,6 +52,8 @@ export class Buffer implements IBuffer {
private _isClearing: boolean = false;
private _memoryCleanupQueue: InstanceType<typeof IdleTaskQueue>;
private _memoryCleanupPosition = 0;
private readonly _stringCache: BufferLineStringCache;
private _stringCacheClearTimeout: ReturnType<typeof setTimeout> | undefined;
constructor(
private _hasScrollback: boolean,
@@ -64,6 +68,7 @@ export class Buffer implements IBuffer {
this.scrollBottom = this._rows - 1;
this.setupTabStops();
this._memoryCleanupQueue = new IdleTaskQueue(this._logService);
this._stringCache = new BufferLineStringCache(() => this._scheduleStringCacheCleanup());
}
public getNullCell(attr?: IAttributeData): ICellData {
@@ -93,7 +98,7 @@ export class Buffer implements IBuffer {
}
public getBlankLine(attr: IAttributeData, isWrapped?: boolean): IBufferLine {
return new BufferLine(this._bufferService.cols, this.getNullCell(attr), isWrapped);
return new BufferLine(this._stringCache, this._bufferService.cols, this.getNullCell(attr), isWrapped);
}
public get hasScrollback(): boolean {
@@ -138,6 +143,7 @@ export class Buffer implements IBuffer {
* Clears the buffer to it's initial state, discarding all previous data.
*/
public clear(): void {
this._resetStringCache();
this.ydisp = 0;
this.ybase = 0;
this.y = 0;
@@ -156,6 +162,7 @@ export class Buffer implements IBuffer {
public resize(newCols: number, newRows: number): void {
// store reference to null cell with default attrs
const nullCell = this.getNullCell(DEFAULT_ATTR_DATA);
this._resetStringCache();
// count bufferlines with overly big memory to be cleaned afterwards
let dirtyMemoryLines = 0;
@@ -190,7 +197,7 @@ export class Buffer implements IBuffer {
if (this._optionsService.rawOptions.windowsPty.backend !== undefined || this._optionsService.rawOptions.windowsPty.buildNumber !== undefined) {
// Just add the new missing rows on Windows as conpty reprints the screen with it's
// view of the world. Once a line enters scrollback for conpty it remains there
this.lines.push(new BufferLine(newCols, nullCell));
this.lines.push(new BufferLine(this._stringCache, newCols, nullCell, false));
} else {
if (this.ybase > 0 && this.lines.length <= this.ybase + this.y + addToY + 1) {
// There is room above the buffer and there are no empty elements below the line,
@@ -204,7 +211,7 @@ export class Buffer implements IBuffer {
} else {
// Add a blank line if there is no buffer left at the top to scroll to, or if there
// are blank lines after the cursor
this.lines.push(new BufferLine(newCols, nullCell));
this.lines.push(new BufferLine(this._stringCache, newCols, nullCell, false));
}
}
}
@@ -303,6 +310,28 @@ export class Buffer implements IBuffer {
return normalRun;
}
private _scheduleStringCacheCleanup(): void {
if (this._stringCacheClearTimeout !== undefined) {
clearTimeout(this._stringCacheClearTimeout);
}
this._stringCacheClearTimeout = setTimeout(() => {
this._stringCacheClearTimeout = undefined;
this._clearStringCache();
}, STRING_CACHE_CLEAR_DELAY_MS);
}
private _resetStringCache(): void {
if (this._stringCacheClearTimeout !== undefined) {
clearTimeout(this._stringCacheClearTimeout);
this._stringCacheClearTimeout = undefined;
}
this._clearStringCache();
}
private _clearStringCache(): void {
this._stringCache.clear();
}
private get _isReflowEnabled(): boolean {
const windowsPty = this._optionsService.rawOptions.windowsPty;
if (windowsPty && windowsPty.buildNumber) {
@@ -345,7 +374,7 @@ export class Buffer implements IBuffer {
}
if (this.lines.length < newRows) {
// Add an extra row at the bottom of the viewport
this.lines.push(new BufferLine(newCols, nullCell));
this.lines.push(new BufferLine(this._stringCache, newCols, nullCell, false));
}
} else {
if (this.ydisp === this.ybase) {