private doOpen()

in src/vs/code/electron-main/windows.ts [528:748]
146 lines of code
42 McCabe index (conditional complexity)

	private doOpen(
		openConfig: IOpenConfiguration,
		workspacesToOpen: IWorkspacePathToOpen[],
		foldersToOpen: IFolderPathToOpen[],
		emptyToRestore: IEmptyWindowBackupInfo[],
		emptyToOpen: number,
		fileInputs: IFileInputs | undefined,
		foldersToAdd: IFolderPathToOpen[]
	) {
		const usedWindows: ICodeWindow[] = [];

		// Settings can decide if files/folders open in new window or not
		let { openFolderInNewWindow, openFilesInNewWindow } = this.shouldOpenNewWindow(openConfig);

		// Handle folders to add by looking for the last active workspace (not on initial startup)
		if (!openConfig.initialStartup && foldersToAdd.length > 0) {
			const authority = foldersToAdd[0].remoteAuthority;
			const lastActiveWindow = this.getLastActiveWindowForAuthority(authority);
			if (lastActiveWindow) {
				usedWindows.push(this.doAddFoldersToExistingWindow(lastActiveWindow, foldersToAdd.map(f => f.folderUri)));
			}
		}

		// Handle files to open/diff or to create when we dont open a folder and we do not restore any folder/untitled from hot-exit
		const potentialWindowsCount = foldersToOpen.length + workspacesToOpen.length + emptyToRestore.length;
		if (potentialWindowsCount === 0 && fileInputs) {

			// Find suitable window or folder path to open files in
			const fileToCheck = fileInputs.filesToOpenOrCreate[0] || fileInputs.filesToDiff[0];

			// only look at the windows with correct authority
			const windows = WindowsManager.WINDOWS.filter(w => w.remoteAuthority === fileInputs!.remoteAuthority);

			const bestWindowOrFolder = findBestWindowOrFolderForFile({
				windows,
				newWindow: openFilesInNewWindow,
				context: openConfig.context,
				fileUri: fileToCheck && fileToCheck.fileUri,
				localWorkspaceResolver: workspace => workspace.configPath.scheme === Schemas.file ? this.workspacesMainService.resolveLocalWorkspaceSync(workspace.configPath) : null
			});

			// We found a window to open the files in
			if (bestWindowOrFolder instanceof CodeWindow) {

				// Window is workspace
				if (bestWindowOrFolder.openedWorkspace) {
					workspacesToOpen.push({ workspace: bestWindowOrFolder.openedWorkspace, remoteAuthority: bestWindowOrFolder.remoteAuthority });
				}

				// Window is single folder
				else if (bestWindowOrFolder.openedFolderUri) {
					foldersToOpen.push({ folderUri: bestWindowOrFolder.openedFolderUri, remoteAuthority: bestWindowOrFolder.remoteAuthority });
				}

				// Window is empty
				else {

					// Do open files
					usedWindows.push(this.doOpenFilesInExistingWindow(openConfig, bestWindowOrFolder, fileInputs));

					// Reset these because we handled them
					fileInputs = undefined;
				}
			}

			// Finally, if no window or folder is found, just open the files in an empty window
			else {
				usedWindows.push(this.openInBrowserWindow({
					userEnv: openConfig.userEnv,
					cli: openConfig.cli,
					initialStartup: openConfig.initialStartup,
					fileInputs,
					forceNewWindow: true,
					remoteAuthority: fileInputs.remoteAuthority,
					forceNewTabbedWindow: openConfig.forceNewTabbedWindow
				}));

				// Reset these because we handled them
				fileInputs = undefined;
			}
		}

		// Handle workspaces to open (instructed and to restore)
		const allWorkspacesToOpen = arrays.distinct(workspacesToOpen, workspace => workspace.workspace.id); // prevent duplicates
		if (allWorkspacesToOpen.length > 0) {

			// Check for existing instances
			const windowsOnWorkspace = arrays.coalesce(allWorkspacesToOpen.map(workspaceToOpen => findWindowOnWorkspace(WindowsManager.WINDOWS, workspaceToOpen.workspace)));
			if (windowsOnWorkspace.length > 0) {
				const windowOnWorkspace = windowsOnWorkspace[0];
				const fileInputsForWindow = (fileInputs && fileInputs.remoteAuthority === windowOnWorkspace.remoteAuthority) ? fileInputs : undefined;

				// Do open files
				usedWindows.push(this.doOpenFilesInExistingWindow(openConfig, windowOnWorkspace, fileInputsForWindow));

				// Reset these because we handled them
				if (fileInputsForWindow) {
					fileInputs = undefined;
				}

				openFolderInNewWindow = true; // any other folders to open must open in new window then
			}

			// Open remaining ones
			allWorkspacesToOpen.forEach(workspaceToOpen => {
				if (windowsOnWorkspace.some(win => win.openedWorkspace!.id === workspaceToOpen.workspace.id)) {
					return; // ignore folders that are already open
				}

				const remoteAuthority = workspaceToOpen.remoteAuthority;
				const fileInputsForWindow = (fileInputs && fileInputs.remoteAuthority === remoteAuthority) ? fileInputs : undefined;

				// Do open folder
				usedWindows.push(this.doOpenFolderOrWorkspace(openConfig, workspaceToOpen, openFolderInNewWindow, fileInputsForWindow));

				// Reset these because we handled them
				if (fileInputsForWindow) {
					fileInputs = undefined;
				}

				openFolderInNewWindow = true; // any other folders to open must open in new window then
			});
		}

		// Handle folders to open (instructed and to restore)
		const allFoldersToOpen = arrays.distinct(foldersToOpen, folder => getComparisonKey(folder.folderUri)); // prevent duplicates
		if (allFoldersToOpen.length > 0) {

			// Check for existing instances
			const windowsOnFolderPath = arrays.coalesce(allFoldersToOpen.map(folderToOpen => findWindowOnWorkspace(WindowsManager.WINDOWS, folderToOpen.folderUri)));
			if (windowsOnFolderPath.length > 0) {
				const windowOnFolderPath = windowsOnFolderPath[0];
				const fileInputsForWindow = fileInputs && fileInputs.remoteAuthority === windowOnFolderPath.remoteAuthority ? fileInputs : undefined;

				// Do open files
				usedWindows.push(this.doOpenFilesInExistingWindow(openConfig, windowOnFolderPath, fileInputsForWindow));

				// Reset these because we handled them
				if (fileInputsForWindow) {
					fileInputs = undefined;
				}

				openFolderInNewWindow = true; // any other folders to open must open in new window then
			}

			// Open remaining ones
			allFoldersToOpen.forEach(folderToOpen => {

				if (windowsOnFolderPath.some(win => isEqual(win.openedFolderUri, folderToOpen.folderUri))) {
					return; // ignore folders that are already open
				}

				const remoteAuthority = folderToOpen.remoteAuthority;
				const fileInputsForWindow = (fileInputs && fileInputs.remoteAuthority === remoteAuthority) ? fileInputs : undefined;

				// Do open folder
				usedWindows.push(this.doOpenFolderOrWorkspace(openConfig, folderToOpen, openFolderInNewWindow, fileInputsForWindow));

				// Reset these because we handled them
				if (fileInputsForWindow) {
					fileInputs = undefined;
				}

				openFolderInNewWindow = true; // any other folders to open must open in new window then
			});
		}

		// Handle empty to restore
		const allEmptyToRestore = arrays.distinct(emptyToRestore, info => info.backupFolder); // prevent duplicates
		if (allEmptyToRestore.length > 0) {
			allEmptyToRestore.forEach(emptyWindowBackupInfo => {
				const remoteAuthority = emptyWindowBackupInfo.remoteAuthority;
				const fileInputsForWindow = (fileInputs && fileInputs.remoteAuthority === remoteAuthority) ? fileInputs : undefined;

				usedWindows.push(this.openInBrowserWindow({
					userEnv: openConfig.userEnv,
					cli: openConfig.cli,
					initialStartup: openConfig.initialStartup,
					fileInputs: fileInputsForWindow,
					remoteAuthority,
					forceNewWindow: true,
					forceNewTabbedWindow: openConfig.forceNewTabbedWindow,
					emptyWindowBackupInfo
				}));

				// Reset these because we handled them
				if (fileInputsForWindow) {
					fileInputs = undefined;
				}

				openFolderInNewWindow = true; // any other folders to open must open in new window then
			});
		}

		// Handle empty to open (only if no other window opened)
		if (usedWindows.length === 0 || fileInputs) {
			if (fileInputs && !emptyToOpen) {
				emptyToOpen++;
			}

			const remoteAuthority = fileInputs ? fileInputs.remoteAuthority : (openConfig.cli && openConfig.cli.remote || undefined);

			for (let i = 0; i < emptyToOpen; i++) {
				usedWindows.push(this.openInBrowserWindow({
					userEnv: openConfig.userEnv,
					cli: openConfig.cli,
					initialStartup: openConfig.initialStartup,
					remoteAuthority,
					forceNewWindow: openFolderInNewWindow,
					forceNewTabbedWindow: openConfig.forceNewTabbedWindow,
					fileInputs
				}));

				// Reset these because we handled them
				fileInputs = undefined;
				openFolderInNewWindow = true; // any other window to open must open in new window then
			}
		}

		return arrays.distinct(usedWindows);
	}