Initial commit for Chrome metainstaller on Mac.

chrome/installer/mac/app/Downloader.m

Index: chrome/installer/mac/app/Downloader.m
diff --git a/chrome/installer/mac/app/Downloader.m b/chrome/installer/mac/app/Downloader.m
new file mode 100644
index 0000000000000000000000000000000000000000..857897ab934878287b7b4e8a1c2d97d1619445b7
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+++ b/chrome/installer/mac/app/Downloader.m
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+// Copyright 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 "DownloadDelegate.h"
+#import "Downloader.h"
+#import "NetworkCommunication.h"
+#import "OmahaXMLParser.h"
+
+@implementation Downloader
+
+// TODO: make this overrideable with commandline argument? or enviro variable
++ (NSString*)getDownloadsFilePath {
+  NSArray* downloadPaths = NSSearchPathForDirectoriesInDomains(
+      NSDownloadsDirectory, NSUserDomainMask, YES);
+  NSString* filePathToDownloads = [downloadPaths objectAtIndex:0];
+  NSArray* filenameComposition = @[ filePathToDownloads, @"GoogleChrome.dmg" ];
+  NSString* completeFilePath =
+      [NSString pathWithComponents:filenameComposition];
+  return completeFilePath;
+}
+
+// The URLs extracted from parseXML are incomplete and need the filename (which
+// is the same for all the links) appended to the end. Iterates through
+// chromeIncompleteDownloadURLs_ and appends chromeImageFilename_ to each URL.
+- (NSMutableArray*)appendFilename:(NSString*)filename
+                           toURLs:(NSArray*)incompleteURLs {
+  NSMutableArray* completeURLs = [[NSMutableArray alloc] init];
+
+  for (NSString* URL in incompleteURLs) {
+    [completeURLs addObject:[NSURL URLWithString:filename
+                                   relativeToURL:[NSURL URLWithString:URL]]];
+  }
+  return completeURLs;
+}
+
+// Extract URLs and the filename from the omahaResponseXML. Then complete the
+// URLs by appending filename and returns the first complete URL.
+- (NSURL*)getChromeImageURLFromOmahaResponse:(NSData*)omahaResponseXML {
+  NSError* err = nil;
+
+  OmahaXMLParser* parser = [[OmahaXMLParser alloc] init];
+  NSArray* incompleteURLs = [parser parseXML:omahaResponseXML error:&err];
+
+  if ([incompleteURLs count] < 1) {
+    // TODO: Error handling and implement way to verify URL is working. Error
+    // information saved in "err".
+  }
+
+  NSMutableArray* completeURLs =
+      [self appendFilename:parser.chromeImageFilename toURLs:incompleteURLs];
+
+  NSURL* chromeURL = [completeURLs firstObject];
+  return chromeURL;
+}
+
+// Downloads contents of chromeURL to downloads folders and delegates the work
+// to the DownloadDelegate class.
+- (BOOL)writeChromeImageToDownloadsDirectory:(NSURL*)chromeURL {
+  DownloadDelegate* delegate = [[DownloadDelegate alloc] init];
+  NetworkCommunication* downloadTask =
+      [[NetworkCommunication alloc] initWithDelegate:delegate];
+
+  // TODO: What if file already exists?
+  [downloadTask createRequestWithUrlAsString:[chromeURL absoluteString]
+                                  andXMLBody:nil];
+  [downloadTask sendDownloadRequest];
+
+  NSFileManager* manager = [[NSFileManager alloc] init];
+  return [manager fileExistsAtPath:[Downloader getDownloadsFilePath]];
+}
+
+// Pieces together the getting the URL portion and downloading the contents of
+// URL portion.
+- (BOOL)downloadChromeImageToDownloadsDirectory:(NSData*)omahaResponseXML {
+  NSURL* chromeURL = [self getChromeImageURLFromOmahaResponse:omahaResponseXML];
+  BOOL writeWasSuccessful =
+      [self writeChromeImageToDownloadsDirectory:chromeURL];
+  return writeWasSuccessful;
+}
+
+@end