export function applyCodeCoverageToAllEditors()

in src/goCover.ts [217:306]
58 lines of code
12 McCabe index (conditional complexity)

export function applyCodeCoverageToAllEditors(coverProfilePath: string, dir?: string): Promise<void> {
	const v = new Promise<void>((resolve, reject) => {
		try {
			const showCounts = getGoConfig().get('coverShowCounts') as boolean;
			const coveragePath = new Map<string, CoverageData>(); // <filename> from the cover profile to the coverage data.

			// Clear existing coverage files
			clearCoverage();

			// collect the packages named in the coverage file
			const seenPaths = new Set<string>();
			// for now read synchronously and hope for no errors
			const contents = fs.readFileSync(coverProfilePath).toString();
			contents.split('\n').forEach((line) => {
				// go test coverageprofile generates output:
				//    filename:StartLine.StartColumn,EndLine.EndColumn Hits CoverCount
				// where the filename is either the import path + '/' + base file name, or
				// the actual file path (either absolute or starting with .)
				// See https://golang.org/issues/40251.
				//
				// The first line will be like "mode: set" which we will ignore.
				// TODO: port https://golang.org/cl/179377 for faster parsing.

				const parse = line.match(/^(\S+)\:(\d+)\.(\d+)\,(\d+)\.(\d+)\s(\d+)\s(\d+)/);
				if (!parse) {
					return;
				}

				let filename = parse[1];
				if (filename.startsWith('.' + path.sep)) {
					// If it's a relative file path, convert it to an absolute path.
					// From now on, we can assume that it's a real file name if it is
					// an absolute path.
					filename = path.resolve(filename);
				}
				// If this is not a real file name, that's package_path + file name,
				// Record it in seenPaths for `go list` call to resolve package path ->
				// directory mapping.
				if (!path.isAbsolute(filename)) {
					const lastSlash = filename.lastIndexOf('/');
					if (lastSlash !== -1) {
						seenPaths.add(filename.slice(0, lastSlash));
					}
				}

				// and fill in coveragePath
				const coverage = coveragePath.get(parse[1]) || emptyCoverageData();
				// When line directive is used this information is artificial and
				// the source code file can be non-existent or wrong (go.dev/issues/41222).
				// There is no perfect way to guess whether the line/col in coverage profile
				// is bogus. At least, we know that 0 or negative values are not true line/col.
				const startLine = parseInt(parse[2], 10);
				const startCol = parseInt(parse[3], 10);
				const endLine = parseInt(parse[4], 10);
				const endCol = parseInt(parse[5], 10);
				if (startLine < 1 || startCol < 1 || endLine < 1 || endCol < 1) {
					return;
				}
				const range = new vscode.Range(
					// Convert lines and columns to 0-based
					startLine - 1,
					startCol - 1,
					endLine - 1,
					endCol - 1
				);

				const counts = parseInt(parse[7], 10);
				// If is Covered (CoverCount > 0)
				if (counts > 0) {
					coverage.coveredOptions.push(...elaborate(range, counts, showCounts));
				} else {
					coverage.uncoveredOptions.push(...elaborate(range, counts, showCounts));
				}

				coveragePath.set(filename, coverage);
			});

			getImportPathToFolder([...seenPaths], dir).then((pathsToDirs) => {
				createCoverageData(pathsToDirs, coveragePath);
				setDecorators();
				vscode.window.visibleTextEditors.forEach(applyCodeCoverage);
				resolve();
			});
		} catch (e) {
			vscode.window.showInformationMessage((e as any).msg);
			reject(e);
		}
	});
	return v;
}