08-27-周三_17-09-29

node_modules/fs-extra/lib/streams/create-output-stream.js

@@ -0,0 +1,43 @@
+var path = require('path')
+var fs = require('fs')
+var mkdir = require('../mkdirs')
+var WriteStream = fs.WriteStream
+
+function createOutputStream (file, options) {
+  var dirExists = false
+  var dir = path.dirname(file)
+  options = options || {}
+
+  // if fd is set with an actual number, file is created, hence directory is too
+  if (options.fd) {
+    return fs.createWriteStream(file, options)
+  } else {
+    // this hacks the WriteStream constructor from calling open()
+    options.fd = -1
+  }
+
+  var ws = new WriteStream(file, options)
+
+  var oldOpen = ws.open
+  ws.open = function () {
+    ws.fd = null // set actual fd
+    if (dirExists) return oldOpen.call(ws)
+
+    // this only runs once on first write
+    mkdir.mkdirs(dir, function (err) {
+      if (err) {
+        ws.destroy()
+        ws.emit('error', err)
+        return
+      }
+      dirExists = true
+      oldOpen.call(ws)
+    })
+  }
+
+  ws.open()
+
+  return ws
+}
+
+module.exports = createOutputStream