export function getFoldingRanges()

in src/services/jsonFolding.ts [9:126]
108 lines of code
41 McCabe index (conditional complexity)

export function getFoldingRanges(document: TextDocument, context?: FoldingRangesContext): FoldingRange[] {
	const ranges: FoldingRange[] = [];
	const nestingLevels: number[] = [];
	const stack: FoldingRange[] = [];
	let prevStart = -1;
	const scanner = createScanner(document.getText(), false);
	let token = scanner.scan();

	function addRange(range: FoldingRange) {
		ranges.push(range);
		nestingLevels.push(stack.length);
	}

	while (token !== SyntaxKind.EOF) {
		switch (token) {
			case SyntaxKind.OpenBraceToken:
			case SyntaxKind.OpenBracketToken: {
				const startLine = document.positionAt(scanner.getTokenOffset()).line;
				const range = { startLine, endLine: startLine, kind: token === SyntaxKind.OpenBraceToken ? 'object' : 'array' };
				stack.push(range);
				break;
			}
			case SyntaxKind.CloseBraceToken:
			case SyntaxKind.CloseBracketToken: {
				const kind = token === SyntaxKind.CloseBraceToken ? 'object' : 'array';
				if (stack.length > 0 && stack[stack.length - 1].kind === kind) {
					const range = stack.pop();
					const line = document.positionAt(scanner.getTokenOffset()).line;
					if (range && line > range.startLine + 1 && prevStart !== range.startLine) {
						range.endLine = line - 1;
						addRange(range);
						prevStart = range.startLine;
					}
				}
				break;
			}

			case SyntaxKind.BlockCommentTrivia: {
				const startLine = document.positionAt(scanner.getTokenOffset()).line;
				const endLine = document.positionAt(scanner.getTokenOffset() + scanner.getTokenLength()).line;
				if (scanner.getTokenError() === ScanError.UnexpectedEndOfComment && startLine + 1 < document.lineCount) {
					scanner.setPosition(document.offsetAt(Position.create(startLine + 1, 0)));
				} else {
					if (startLine < endLine) {
						addRange({ startLine, endLine, kind: FoldingRangeKind.Comment });
						prevStart = startLine;
					}
				}
				break;
			}

			case SyntaxKind.LineCommentTrivia: {
				const text = document.getText().substr(scanner.getTokenOffset(), scanner.getTokenLength());
				const m = text.match(/^\/\/\s*#(region\b)|(endregion\b)/);
				if (m) {
					const line = document.positionAt(scanner.getTokenOffset()).line;
					if (m[1]) { // start pattern match
						const range = { startLine: line, endLine: line, kind: FoldingRangeKind.Region };
						stack.push(range);
					} else {
						let i = stack.length - 1;
						while (i >= 0 && stack[i].kind !== FoldingRangeKind.Region) {
							i--;
						}
						if (i >= 0) {
							const range = stack[i];
							stack.length = i;
							if (line > range.startLine && prevStart !== range.startLine) {
								range.endLine = line;
								addRange(range);
								prevStart = range.startLine;
							}
						}
					}
				}
				break;
			}

		}
		token = scanner.scan();
	}
	const rangeLimit = context && context.rangeLimit;
	if (typeof rangeLimit !== 'number' || ranges.length <= rangeLimit) {
		return ranges;
	}
	if (context && context.onRangeLimitExceeded) {
		context.onRangeLimitExceeded(document.uri);
	}

	const counts: number[] = [];
	for (let level of nestingLevels) {
		if (level < 30) {
			counts[level] = (counts[level] || 0) + 1;
		}
	}
	let entries = 0;
	let maxLevel = 0;
	for (let i = 0; i < counts.length; i++) {
		const n = counts[i];
		if (n) {
			if (n + entries > rangeLimit) {
				maxLevel = i;
				break;
			}
			entries += n;
		}
	}
	const result = [];
	for (let i = 0; i < ranges.length; i++) {
		const level = nestingLevels[i];
		if (typeof level === 'number') {
			if (level < maxLevel || (level === maxLevel && entries++ < rangeLimit)) {
				result.push(ranges[i]);
			}
		}
	}
	return result;
}