add support for windows(minimum support Windows Vista)

lib/index.js

@@ -1,5 +1,7 @@
 var exec = require('child_process').exec
-var parse = require('./parse')
+var parsePosix = require('./parse-posix')
+var parseWin = require('./parse-win')
+var path = require('path')
 
 module.exports = function df(aOptions, aCallback) {
     var options
@@ -32,10 +34,25 @@ module.exports = function df(aOptions, aCallback) {
     // It should invoke callback with `err` but it's a breaking change
 
     // TODO: should fail if unit is not a string
-
-    var command = 'df -kP'
-    if (options.file) {
-        command += ' ' + options.file
+    var command = null;
+    var isWin = process.platform === 'win32'
+    var file = options.file
+    if (isWin) {
+        var disk = null
+        command = 'wmic LOGICALDISK '
+        if (file) {
+            file = path.win32.normalize(file)
+            disk = path.parse(file).root.slice(0, -1)
+            command += disk
+        } else {
+            command += ' where "DRIVETYPE=3"'
+        }
+        command += ' get name, filesystem, size, freespace'
+    } else {
+        var command = 'df -kP'
+        if (file) {
+            command += ' ' + file
+        }
     }
 
     exec(command, function(err, stdout, stderr) {
@@ -49,7 +66,12 @@ module.exports = function df(aOptions, aCallback) {
             return
         }
 
-        var entries = parse(stdout, options)
+        var entries = null;
+        if (isWin) {
+            entries = parseWin(stdout, options)
+        } else {
+            entries = parsePosix(stdout, options)
+        }
 
         callback(null, entries)
     })

lib/parse-win.js

@@ -0,0 +1,50 @@
+var format = require('./format')
+var calcMultiplier = require('./calcMultiplier')
+
+module.exports = function (stdout, options) {
+    // TODO: this should be removed because it never happens.
+    // Nonetheless, I want to consider it a breaking changed that's to be made after releasing 0.1.4
+    if (!stdout) {
+        return void 0
+    }
+
+    // TODO: `options.prefixMultiplier` should become `options.unit`
+    // I should deprecate the use of `options.prefixMultiplier` in 0.1.4
+    var multiplier = calcMultiplier(options.prefixMultiplier)
+    var precision = options.precision
+    // TODO: `options.isDisplayPrefixMultiplier` should become `options.showUnit`
+    // I should deprecate the use of options.isDisplayPrefixMultiplier in 0.1.4
+    var unit = options.isDisplayPrefixMultiplier ? options.prefixMultiplier : null
+
+    return stdout
+        .trim()
+        .split(/\r\r\n/) // split into rows
+        .slice(1) // strip column headers away
+        .map(function (row) {
+            var columns = row
+                .trim()
+                // one or more whitespaces followed by one or more digits
+                // must be interpreted as column delimiter
+                .replace(/\s+(\d+)/g, '\t$1')
+                // one or more whitespaces followed by a letter
+                // must be interpreted as column delimiter
+                .replace(/\s+([a-zA-Z])/g, '\t$1')
+                // comma followed by one or more whitespaces must be
+                // interpreted as the last column delimiter
+                .replace(/(\:)\s+/g, '$1\t')
+                // split into columns
+                .split(/\t/)
+            var size = parseInt(columns[3], 10)
+            var free = parseInt(columns[1], 10)
+            var used = size - free
+            var capacity = 1 - free / size
+            return {
+                filesystem: columns[0],
+                size: format(size, multiplier, precision, unit),
+                used: format(used, multiplier, precision, unit),
+                available: format(free, multiplier, precision, unit),
+                capacity: precision ? capacity.toFixed(precision) : capacity,
+                mount: columns[2],
+            }
+        })
+}