notebookDiff.ts

/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

import { DetailedLineRangeMapping } from '../../../util/vs/editor/common/diff/rangeMapping';


export type CellDiffInfo = {
	originalCellIndex: number;
	modifiedCellIndex: number;
	type: 'unchanged';
} |
{
	originalCellIndex: number;
	type: 'delete';
} |
{
	modifiedCellIndex: number;
	type: 'insert';
};

export function computeDiff(originalModel: string[], modifiedModel: string[], cellChanges: readonly DetailedLineRangeMapping[]) {
	const cellDiffInfo: CellDiffInfo[] = [];
	let originalCellIndex = 0;
	let modifiedCellIndex = 0;

	for (let i = 0; i < cellChanges.length; i++) {
		const change = cellChanges[i];
		// common cells

		for (let j = 0; j < change.original.startLineNumber - 1 - originalCellIndex; j++) {
			cellDiffInfo.push({
				originalCellIndex: originalCellIndex + j,
				modifiedCellIndex: modifiedCellIndex + j,
				type: 'unchanged'
			});
		}

		const modifiedLCS = computeModifiedLCS(originalModel, modifiedModel, change);

		cellDiffInfo.push(...modifiedLCS);
		originalCellIndex = change.original.startLineNumber - 1 + change.original.length;
		modifiedCellIndex = change.modified.startLineNumber - 1 + change.modified.length;
	}

	for (let i = originalCellIndex; i < originalModel.length; i++) {
		cellDiffInfo.push({
			originalCellIndex: i,
			modifiedCellIndex: i - originalCellIndex + modifiedCellIndex,
			type: 'unchanged'
		});
	}

	return cellDiffInfo;
}

function computeModifiedLCS(original: string[], modified: string[], change: DetailedLineRangeMapping) {
	const result: CellDiffInfo[] = [];
	// modified cells
	const modifiedLen = Math.min(change.original.length, change.modified.length);

	for (let j = 0; j < modifiedLen; j++) {
		const originalCell = original[change.original.startLineNumber - 1 + j];
		const modifiedCell = modified[change.modified.startLineNumber - 1 + j];
		if (originalCell !== modifiedCell) {
			result.push({
				originalCellIndex: change.original.startLineNumber - 1 + j,
				type: 'delete'
			});
			result.push({
				modifiedCellIndex: change.modified.startLineNumber - 1 + j,
				type: 'insert'
			});
		} else {
			result.push({
				originalCellIndex: change.original.startLineNumber - 1 + j,
				modifiedCellIndex: change.modified.startLineNumber - 1 + j,
				type: 'unchanged'
			});
		}
	}

	for (let j = modifiedLen; j < change.original.length; j++) {
		// deletion
		result.push({
			originalCellIndex: change.original.startLineNumber - 1 + j,
			type: 'delete'
		});
	}

	for (let j = modifiedLen; j < change.modified.length; j++) {
		result.push({
			modifiedCellIndex: change.modified.startLineNumber - 1 + j,
			type: 'insert'
		});
	}

	return result;
}