Initial commit for Chrome metainstaller on Mac.

chrome/installer/mac/app/downloader.m

+// Copyright (c) 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import <Foundation/Foundation.h>
+#import "downloader.h"
+#import "parser.h"
+
+NSURL* getChromeImageURL(NSData* someData) {
+  Parser *parser = [[Parser alloc] init];
+  [parser parseXML:someData];
+  [parser appendFilenameToURL];
+
+  NSArray *downloadLinks = [NSArray arrayWithArray: parser.chromeDownloadURLs];

[Elly Fong-Jones, 2016/06/24 17:26:01]

no space after colon

+  NSString *chromeURLString = [downloadLinks firstObject];

[Elly Fong-Jones, 2016/06/24 17:26:01]

can downloadLinks ever be empty? What if parser fails?

+
+  return [NSURL URLWithString: chromeURLString];
+}
+
+NSData* downloadChromeAsData(NSURL* chromeURL) {
+  return [NSData dataWithContentsOfURL:chromeURL];

[Elly Fong-Jones, 2016/06/24 17:26:01]

[NSData dataWithContentsOfURL:] will do the entire download synchronously on the
UI thread, so the entire app will be non-responsive while this call is running,
which could be quite some time. There's a note in the documentation for that
method about this problem.

I think we need to do an asynchronous download using [NSURLSession
downloadTaskWithURL:] instead.

+}
+
+NSString* getDownloadsFilePath() {
+  NSArray *downloadPaths = NSSearchPathForDirectoriesInDomains(
+      NSDownloadsDirectory, NSUserDomainMask, YES);
+  NSString *downloadDirectory = [downloadPaths objectAtIndex:0];
+  NSString *filePath = [NSString stringWithFormat:@"%@/%@",
+                        downloadDirectory, @"GoogleChrome.dmg"];

[Elly Fong-Jones, 2016/06/24 17:26:01]

I think it would be nicer to use [NSString pathWithComponents:] here instead.

+  return filePath;
+}
+
+void writeDataToDisk(NSData* topSecretData) {

[Elly Fong-Jones, 2016/06/24 17:26:01]

is it really top secret? :)

+  if (topSecretData) {
+    NSString *filePath = getDownloadsFilePath();
+    [topSecretData writeToFile:filePath atomically:YES];
+    NSLog(@"File was downloaded to %@.", filePath);
+  } else {
+    NSLog(@"Error downloading file.");
+  }
+}