Lobashov_Ivan_PIBD-21_IP/Lab3/node_modules/pidtree/lib/pidtree.js
2024-01-10 22:39:31 +04:00

105 lines
2.6 KiB
JavaScript

'use strict';
var getAll = require('./get');
/**
* Get the list of children and grandchildren pids of the given PID.
* @param {Number|String} PID A PID. If -1 will return all the pids.
* @param {Object} [options] Optional options object.
* @param {Boolean} [options.root=false] Include the provided PID in the list.
* @param {Boolean} [options.advanced=false] Returns a list of objects in the
* format {pid: X, ppid: Y}.
* @param {Function} callback(err, list) Called when the list is ready.
*/
function list(PID, options, callback) {
if (typeof options === 'function') {
callback = options;
options = {};
}
if (typeof options !== 'object') {
options = {};
}
PID = parseInt(PID, 10);
if (isNaN(PID) || PID < -1) {
callback(new TypeError('The pid provided is invalid'));
return;
}
getAll(function(err, list) {
if (err) {
callback(err);
return;
}
// If the user wants the whole list just return it
if (PID === -1) {
for (var i = 0; i < list.length; i++) {
list[i] = options.advanced
? {ppid: list[i][0], pid: list[i][1]}
: (list[i] = list[i][1]);
}
callback(null, list);
return;
}
var root;
for (var l = 0; l < list.length; l++) {
if (list[l][1] === PID) {
root = options.advanced ? {ppid: list[l][0], pid: PID} : PID;
break;
}
if (list[l][0] === PID) {
root = options.advanced ? {pid: PID} : PID; // Special pids like 0 on *nix
}
}
if (!root) {
callback(new Error('No maching pid found'));
return;
}
// Build the adiacency Hash Map (pid -> [children of pid])
var tree = {};
while (list.length > 0) {
var element = list.pop();
if (tree[element[0]]) {
tree[element[0]].push(element[1]);
} else {
tree[element[0]] = [element[1]];
}
}
// Starting by the PID provided by the user, traverse the tree using the
// adiacency Hash Map until the whole subtree is visited.
// Each pid encountered while visiting is added to the pids array.
var idx = 0;
var pids = [root];
while (idx < pids.length) {
var curpid = options.advanced ? pids[idx++].pid : pids[idx++];
if (!tree[curpid]) continue;
var length = tree[curpid].length;
for (var j = 0; j < length; j++) {
pids.push(
options.advanced
? {ppid: curpid, pid: tree[curpid][j]}
: tree[curpid][j]
);
}
delete tree[curpid];
}
if (!options.root) {
pids.shift(); // Remove root
}
callback(null, pids);
});
}
module.exports = list;