Add getPlatform function (microsoft#374)

* Add `getPlatform` function

* Clean up

Author: brcrista

node/Strings/resources.resjson/en-US/resources.resjson

@@ -29,5 +29,6 @@
   "loc.messages.LIB_PathHasNullByte": "Path cannot contain null bytes",
   "loc.messages.LIB_OperationFailed": "Failed %s: %s",
   "loc.messages.LIB_UseFirstGlobMatch": "Multiple workspace matches. using first.",
-  "loc.messages.LIB_MergeTestResultNotSupported": "Merging test results from multiple files to one test run is not supported on this version of build agent for OSX/Linux, each test result file will be published as a separate test run in VSO/TFS."
+  "loc.messages.LIB_MergeTestResultNotSupported": "Merging test results from multiple files to one test run is not supported on this version of build agent for OSX/Linux, each test result file will be published as a separate test run in VSO/TFS.",
+  "loc.messages.LIB_PlatformNotSupported": "Platform not supported: %s"
 }

node/lib.json

@@ -30,6 +30,7 @@
     "LIB_PathHasNullByte": "Path cannot contain null bytes",
     "LIB_OperationFailed": "Failed %s: %s",
     "LIB_UseFirstGlobMatch": "Multiple workspace matches. using first.",
-    "LIB_MergeTestResultNotSupported": "Merging test results from multiple files to one test run is not supported on this version of build agent for OSX/Linux, each test result file will be published as a separate test run in VSO/TFS."
+    "LIB_MergeTestResultNotSupported": "Merging test results from multiple files to one test run is not supported on this version of build agent for OSX/Linux, each test result file will be published as a separate test run in VSO/TFS.",
+    "LIB_PlatformNotSupported": "Platform not supported: %s"
   } 
 }

node/task.ts

@@ -4,11 +4,9 @@ import fs = require('fs');
 import path = require('path');
 import os = require('os');
 import minimatch = require('minimatch');
-import util = require('util');
 import im = require('./internal');
 import tcm = require('./taskcommand');
 import trm = require('./toolrunner');
-import vm = require('./vault');
 import semver = require('semver');
 
 export enum TaskResult {
@@ -45,6 +43,13 @@ export enum FieldType {
     Url
 }
 
+/** Platforms supported by our build agent */
+export enum Platform {
+    Windows,
+    MacOS,
+    Linux
+}
+
 //-----------------------------------------------------
 // General Helpers
 //-----------------------------------------------------
@@ -563,6 +568,7 @@ export function writeFile(file: string, data: string | Buffer, options?: string
 }
 
 /**
+ * @deprecated Use `getPlatform`
  * Useful for determining the host operating system.
  * see [os.type](https://nodejs.org/api/os.html#os_os_type)
  * 
@@ -572,6 +578,20 @@ export function osType(): string {
     return os.type();
 }
 
+/**
+ * Determine the operating system the build agent is running on.
+ * @returns {Platform}
+ * @throws {Error} Platform is not supported by our agent
+ */
+export function getPlatform(): Platform {
+    switch (process.platform) {
+        case 'win32': return Platform.Windows;
+        case 'darwin': return Platform.MacOS;
+        case 'linux': return Platform.Linux;
+        default: throw Error(loc('LIB_PlatformNotSupported', process.platform));
+    }
+}
+
 /**
  * Returns the process's current working directory.
  * see [process.cwd](https://nodejs.org/api/process.html#process_process_cwd)