mirror of
https://github.com/xuxiaobo-bobo/boda_jsEnv.git
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121 lines
3.5 KiB
JavaScript
121 lines
3.5 KiB
JavaScript
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var fs = require('fs');
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var path = require('path');
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var cst = require('../../constants.js')
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// XP's system default value for `PATHEXT` system variable, just in case it's not
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// set on Windows.
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var XP_DEFAULT_PATHEXT = '.com;.exe;.bat;.cmd;.vbs;.vbe;.js;.jse;.wsf;.wsh';
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// For earlier versions of NodeJS that doesn't have a list of constants (< v6)
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var FILE_EXECUTABLE_MODE = 1;
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function statFollowLinks() {
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return fs.statSync.apply(fs, arguments);
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}
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function isWindowsPlatform() {
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return cst.IS_WINDOWS;
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}
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// Cross-platform method for splitting environment `PATH` variables
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function splitPath(p) {
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return p ? p.split(path.delimiter) : [];
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}
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// Tests are running all cases for this func but it stays uncovered by codecov due to unknown reason
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/* istanbul ignore next */
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function isExecutable(pathName) {
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try {
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// TODO(node-support): replace with fs.constants.X_OK once remove support for node < v6
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fs.accessSync(pathName, FILE_EXECUTABLE_MODE);
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} catch (err) {
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return false;
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}
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return true;
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}
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function checkPath(pathName) {
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return fs.existsSync(pathName) && !statFollowLinks(pathName).isDirectory()
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&& (isWindowsPlatform() || isExecutable(pathName));
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}
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//@
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//@ ### which(command)
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//@
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//@ Examples:
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//@
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//@ ```javascript
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//@ var nodeExec = which('node');
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//@ ```
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//@
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//@ Searches for `command` in the system's `PATH`. On Windows, this uses the
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//@ `PATHEXT` variable to append the extension if it's not already executable.
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//@ Returns a [ShellString](#shellstringstr) containing the absolute path to
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//@ `command`.
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function _which(cmd) {
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if (!cmd) console.error('must specify command');
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var options = {}
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var isWindows = isWindowsPlatform();
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var pathArray = splitPath(process.env.PATH);
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var queryMatches = [];
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// No relative/absolute paths provided?
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if (cmd.indexOf('/') === -1) {
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// Assume that there are no extensions to append to queries (this is the
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// case for unix)
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var pathExtArray = [''];
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if (isWindows) {
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// In case the PATHEXT variable is somehow not set (e.g.
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// child_process.spawn with an empty environment), use the XP default.
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var pathExtEnv = process.env.PATHEXT || XP_DEFAULT_PATHEXT;
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pathExtArray = splitPath(pathExtEnv.toUpperCase());
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}
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// Search for command in PATH
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for (var k = 0; k < pathArray.length; k++) {
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// already found it
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if (queryMatches.length > 0 && !options.all) break;
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var attempt = path.resolve(pathArray[k], cmd);
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if (isWindows) {
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attempt = attempt.toUpperCase();
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}
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var match = attempt.match(/\.[^<>:"/|?*.]+$/);
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if (match && pathExtArray.indexOf(match[0]) >= 0) { // this is Windows-only
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// The user typed a query with the file extension, like
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// `which('node.exe')`
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if (checkPath(attempt)) {
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queryMatches.push(attempt);
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break;
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}
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} else { // All-platforms
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// Cycle through the PATHEXT array, and check each extension
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// Note: the array is always [''] on Unix
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for (var i = 0; i < pathExtArray.length; i++) {
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var ext = pathExtArray[i];
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var newAttempt = attempt + ext;
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if (checkPath(newAttempt)) {
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queryMatches.push(newAttempt);
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break;
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}
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}
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}
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}
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} else if (checkPath(cmd)) { // a valid absolute or relative path
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queryMatches.push(path.resolve(cmd));
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}
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if (queryMatches.length > 0) {
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return options.all ? queryMatches : queryMatches[0];
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}
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return options.all ? [] : null;
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}
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module.exports = _which;
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