From e3e11b1a90bf45f846aab7e88539e0f627dbbc9e Mon Sep 17 00:00:00 2001 From: Daniel Imms <2193314+Tyriar@users.noreply.github.com> Date: Fri, 14 Mar 2025 10:26:30 -0700 Subject: [PATCH] Reflow on resize using similar logic to conpty This aligns reflowing much closer to how conpty does it. This was always an issue but only became a big issue recently because conpty 1.22+ opts to passthrough sequences rather than reprinting aggressively. This means that the conpty buffer being in sync with the xterm.js buffer is more important, otherwise the cursor will show up in a seemingly random position. The existing reflow appears to differ somewhat in conpty, like it seems to reflow at the word level, not the character level like xterm.js, but refining that closer if not worth the effort since conpty may end up relying on the terminal's buffer in the future[1]. Fixes #5319 Fixes #3513 Related #4231 Related microsoft/vscode#241978 [1]: https://github.com/microsoft/terminal/blob/main/doc/specs/%2313000%20-%20In-process%20ConPTY.md --- package.json | 2 +- src/common/buffer/Buffer.ts | 75 ++++++++++++++++++++++++++++++++++++- 2 files changed, 75 insertions(+), 2 deletions(-) diff --git a/package.json b/package.json index 6b3f6910..6ed4f2bb 100644 --- a/package.json +++ b/package.json @@ -95,7 +95,7 @@ "jsdom": "^18.0.1", "mocha": "^10.1.0", "mustache": "^4.2.0", - "node-pty": "1.1.0-beta19", + "node-pty": "^1.1.0-beta31", "nyc": "^15.1.0", "source-map-loader": "^3.0.0", "source-map-support": "^0.5.20", diff --git a/src/common/buffer/Buffer.ts b/src/common/buffer/Buffer.ts index 81ab156b..af4b240f 100644 --- a/src/common/buffer/Buffer.ts +++ b/src/common/buffer/Buffer.ts @@ -320,7 +320,37 @@ export class Buffer implements IBuffer { if (toRemove.length > 0) { const newLayoutResult = reflowLargerCreateNewLayout(this.lines, toRemove); reflowLargerApplyNewLayout(this.lines, newLayoutResult.layout); + + // For conpty, it has its own copy of the buffer _without scrollback_ internally. Its behavior + // when reflowing larger is to insert empty lines at the bottom of the buffer as when lines + // unwrap conpty's view cannot pull scrollback down, so it adds empty lines at the end. + let removedInViewport = 0; + const isWindowsMode = this._optionsService.rawOptions.windowsMode || this._optionsService.rawOptions.windowsPty.backend !== undefined || this._optionsService.rawOptions.windowsPty.buildNumber !== undefined; + if (isWindowsMode) { + for (let i = (toRemove.length / 2) - 1; i >= 0; i--) { + if (toRemove[i * 2 + 0] > this.ybase + removedInViewport) { + removedInViewport += toRemove[i * 2 + 1]; + } + } + } + this._reflowLargerAdjustViewport(newCols, newRows, newLayoutResult.countRemoved); + + // Apply empty lines for any removed in viewport for conpty. + if (isWindowsMode) { + if (removedInViewport > 0) { + for (let i = 0; i < removedInViewport; i++) { + // 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, this.getNullCell(DEFAULT_ATTR_DATA))); + } + if (this.ybase === this.ydisp) { + this.ydisp += removedInViewport; + } + this.ybase += removedInViewport; + this.y -= removedInViewport; + } + } } } @@ -352,7 +382,7 @@ export class Buffer implements IBuffer { const nullCell = this.getNullCell(DEFAULT_ATTR_DATA); // Gather all BufferLines that need to be inserted into the Buffer here so that they can be // batched up and only committed once - const toInsert = []; + const toInsert: { start: number, newLines: IBufferLine[] }[] = []; let countToInsert = 0; // Go backwards as many lines may be trimmed and this will avoid considering them for (let y = this.lines.length - 1; y >= 0; y--) { @@ -467,6 +497,20 @@ export class Buffer implements IBuffer { this.savedY = Math.min(this.savedY + linesToAdd, this.ybase + newRows - 1); } + // For conpty, it has its own copy of the buffer _without scrollback_ internally. Its behavior + // when reflowing smaller is to reflow all lines inside the viewport, and removing empty or + // whitespace only lines from the bottom, until non-whitespace is hit in order to prevent + // content from being pushed into the scrollback. + let addedInViewport = 0; + const isWindowsMode = this._optionsService.rawOptions.windowsMode || this._optionsService.rawOptions.windowsPty.backend !== undefined || this._optionsService.rawOptions.windowsPty.buildNumber !== undefined; + if (isWindowsMode) { + for (let i = toInsert.length - 1; i >= 0; i--) { + if (toInsert[i].start > this.ybase + addedInViewport) { + addedInViewport += toInsert[i].newLines.length; + } + } + } + // Rearrange lines in the buffer if there are any insertions, this is done at the end rather // than earlier so that it's a single O(n) pass through the buffer, instead of O(n^2) from many // costly calls to CircularList.splice. @@ -520,6 +564,35 @@ export class Buffer implements IBuffer { this.lines.onTrimEmitter.fire(amountToTrim); } } + + // Apply empty lines to remove calculated earlier for conpty. + if (isWindowsMode) { + if (addedInViewport > 0) { + let emptyLinesAtBottom = 0; + for (let i = this.lines.length - 1; i >= this.ybase + this.y; i--) { + const line = this.lines.get(i) as BufferLine; + if (line.isWrapped || line.getTrimmedLength() > 0) { + break; + } + emptyLinesAtBottom++; + } + const emptyLinesToRemove = Math.min(addedInViewport, emptyLinesAtBottom); + if (emptyLinesToRemove > 0) { + for (let i = 0; i < emptyLinesToRemove; i++) { + this.lines.pop(); + } + if (this.ybase === this.ydisp) { + this.ydisp -= emptyLinesToRemove; + } + this.ybase -= emptyLinesToRemove; + this.y += emptyLinesToRemove; + this.lines.onDeleteEmitter.fire({ + index: this.lines.length - emptyLinesToRemove, + amount: emptyLinesToRemove + }); + } + } + } } /**