which.js
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module.exports = which
which.sync = whichSync
var path = require("path")
, fs
, COLON = process.platform === "win32" ? ";" : ":"
, isExe
, fs = require("fs")
if (process.platform == "win32") {
// On windows, there is no good way to check that a file is executable
isExe = function isExe () { return true }
} else {
isExe = function isExe (mod, uid, gid) {
//console.error(mod, uid, gid);
//console.error("isExe?", (mod & 0111).toString(8))
var ret = (mod & 0001)
|| (mod & 0010) && process.getgid && gid === process.getgid()
|| (mod & 0010) && process.getuid && 0 === process.getuid()
|| (mod & 0100) && process.getuid && uid === process.getuid()
|| (mod & 0100) && process.getuid && 0 === process.getuid()
//console.error("isExe?", ret)
return ret
}
}
function which (cmd, cb) {
if (isAbsolute(cmd)) return cb(null, cmd)
var pathEnv = (process.env.PATH || "").split(COLON)
, pathExt = [""]
if (process.platform === "win32") {
pathEnv.push(process.cwd())
pathExt = (process.env.PATHEXT || ".EXE").split(COLON)
if (cmd.indexOf(".") !== -1) pathExt.unshift("")
}
//console.error("pathEnv", pathEnv)
;(function F (i, l) {
if (i === l) return cb(new Error("not found: "+cmd))
var p = path.resolve(pathEnv[i], cmd)
;(function E (ii, ll) {
if (ii === ll) return F(i + 1, l)
var ext = pathExt[ii]
//console.error(p + ext)
fs.stat(p + ext, function (er, stat) {
if (!er &&
stat &&
stat.isFile() &&
isExe(stat.mode, stat.uid, stat.gid)) {
//console.error("yes, exe!", p + ext)
return cb(null, p + ext)
}
return E(ii + 1, ll)
})
})(0, pathExt.length)
})(0, pathEnv.length)
}
function whichSync (cmd) {
if (isAbsolute(cmd)) return cmd
var pathEnv = (process.env.PATH || "").split(COLON)
, pathExt = [""]
if (process.platform === "win32") {
pathEnv.push(process.cwd())
pathExt = (process.env.PATHEXT || ".EXE").split(COLON)
if (cmd.indexOf(".") !== -1) pathExt.unshift("")
}
for (var i = 0, l = pathEnv.length; i < l; i ++) {
var p = path.join(pathEnv[i], cmd)
for (var j = 0, ll = pathExt.length; j < ll; j ++) {
var cur = p + pathExt[j]
var stat
try { stat = fs.statSync(cur) } catch (ex) {}
if (stat &&
stat.isFile() &&
isExe(stat.mode, stat.uid, stat.gid)) return cur
}
}
throw new Error("not found: "+cmd)
}
var isAbsolute = process.platform === "win32" ? absWin : absUnix
function absWin (p) {
if (absUnix(p)) return true
// pull off the device/UNC bit from a windows path.
// from node's lib/path.js
var splitDeviceRe =
/^([a-zA-Z]:|[\\\/]{2}[^\\\/]+[\\\/][^\\\/]+)?([\\\/])?/
, result = splitDeviceRe.exec(p)
, device = result[1] || ''
, isUnc = device && device.charAt(1) !== ':'
, isAbsolute = !!result[2] || isUnc // UNC paths are always absolute
return isAbsolute
}
function absUnix (p) {
return p.charAt(0) === "/" || p === ""
}