95 lines
2.5 KiB
JavaScript
95 lines
2.5 KiB
JavaScript
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import {get} from './get.js';
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/**
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* Get the list of children and grandchildren pids of the given PID.
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* @param {number|string} pid A PID. If -1 will return all the pids.
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* @param {object} [options] Optional options object.
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* @param {boolean} [options.root=false] Include the provided PID in the list.
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* @param {boolean} [options.advanced=false] Returns a list of objects in the
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* format {ppid: X, pid: Y}.
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* @param {Function} callback callback(err, list) Called when the list is ready.
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*/
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export function pidtreeCallback(pid, options, callback) {
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if (typeof options === 'function') {
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callback = options;
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options = {};
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}
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if (typeof options !== 'object' || options === null) {
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options = {};
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}
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pid = Number.parseInt(pid, 10);
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if (Number.isNaN(pid) || pid < -1) {
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callback(new TypeError('The pid provided is invalid'));
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return;
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}
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get((error, list) => {
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if (error) {
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callback(error);
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return;
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}
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// If the user wants the whole list just return it.
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if (pid === -1) {
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const all = list.map((entry) =>
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options.advanced ? {ppid: entry[0], pid: entry[1]} : entry[1],
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);
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callback(null, all);
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return;
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}
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let root;
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for (const entry of list) {
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if (entry[1] === pid) {
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root = options.advanced ? {ppid: entry[0], pid} : pid;
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break;
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}
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if (entry[0] === pid) {
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// Special pids like 0 on *nix.
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root = options.advanced ? {pid} : pid;
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}
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}
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if (root === undefined) {
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callback(new Error('No matching pid found'));
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return;
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}
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// Build the adjacency Hash Map (pid -> [children of pid]).
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const tree = {};
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for (const [parentPid, childPid] of list) {
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if (tree[parentPid]) {
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tree[parentPid].push(childPid);
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} else {
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tree[parentPid] = [childPid];
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}
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}
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// Starting from the PID provided by the user, traverse the tree using the
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// adjacency Hash Map until the whole subtree is visited. Each pid
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// encountered while visiting is added to the pids array.
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const pids = [root];
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let index = 0;
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while (index < pids.length) {
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const current = options.advanced ? pids[index].pid : pids[index];
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index++;
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const children = tree[current];
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if (!children) continue;
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for (const childPid of children) {
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pids.push(options.advanced ? {ppid: current, pid: childPid} : childPid);
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}
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delete tree[current];
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}
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if (!options.root) {
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pids.shift(); // Remove root.
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}
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callback(null, pids);
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});
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}
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