Implement Download folder path retrieval on OS X

The current implementation returns the DocumentLocation folder.
Since now only cocoa is supported, we can use NSFileManager to get the
correct path.

[ChangeLog][QtCore][OS X] Now QStandardPaths returns the correct path
for the DownloadLocation.

Change-Id: Ic0ea3ebf8585a1e34a7b43c734df78fd3949d4d4
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/io/io.pri

@@ -148,9 +148,8 @@ win32 {
                 HEADERS += io/qfilesystemwatcher_fsevents_p.h
             }
             macx {
-                SOURCES += \
-                    io/qstorageinfo_mac.cpp \
-                    io/qstandardpaths_mac.cpp
+                SOURCES += io/qstorageinfo_mac.cpp
+                OBJECTIVE_SOURCES += io/qstandardpaths_mac.mm
                 LIBS += -framework DiskArbitration -framework IOKit
             } else:ios {
                 OBJECTIVE_SOURCES += io/qstandardpaths_ios.mm

src/corelib/io/qstandardpaths.cpp

@@ -195,7 +195,7 @@ QT_BEGIN_NAMESPACE
          \li "~/Library/Preferences"
          \li "C:/Users/<USER>/AppData/Local", "C:/ProgramData"
     \row \li DownloadLocation
-         \li "~/Documents"
+         \li "~/Downloads"
          \li "C:/Users/<USER>/Documents"
     \row \li GenericCacheLocation
          \li "~/Library/Caches", "/Library/Caches"

src/corelib/io/qstandardpaths_mac.mm

@@ -33,6 +33,7 @@
 
 #include "qstandardpaths.h"
 #include <qdir.h>
+#include <qurl.h>
 #include <private/qcore_mac_p.h>
 
 #ifndef QT_BOOTSTRAPPED
@@ -55,8 +56,6 @@ OSType translateLocation(QStandardPaths::StandardLocation type)
         return kPreferencesFolderType;
     case QStandardPaths::DesktopLocation:
         return kDesktopFolderType;
-    case QStandardPaths::DownloadLocation: // needs NSSearchPathForDirectoriesInDomains with NSDownloadsDirectory
-                                           // which needs an objective-C *.mm file...
     case QStandardPaths::DocumentsLocation:
         return kDocumentsFolderType;
     case QStandardPaths::FontsLocation:
@@ -113,6 +112,15 @@ static void appendOrganizationAndApp(QString &path)
 
 static QString macLocation(QStandardPaths::StandardLocation type, short domain)
 {
+    // https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSFileManager_Class/index.html
+    if (type == QStandardPaths::DownloadLocation) {
+        NSFileManager *fileManager = [NSFileManager defaultManager];
+        NSURL *url = [fileManager URLForDirectory:NSDownloadsDirectory inDomain:NSUserDomainMask appropriateForURL:nil create:NO error:nil];
+        if (!url)
+            return QString();
+        return QString::fromNSString([url path]);
+    }
+
     // http://developer.apple.com/documentation/Carbon/Reference/Folder_Manager/Reference/reference.html
     FSRef ref;
     OSErr err = FSFindFolder(domain, translateLocation(type), false, &ref);

src/tools/bootstrap/bootstrap.pro

@@ -132,12 +132,13 @@ win32:SOURCES += ../../corelib/io/qfilesystemengine_win.cpp \
 mac {
    SOURCES += ../../corelib/kernel/qcoreapplication_mac.cpp \
               ../../corelib/kernel/qcore_mac.cpp
-   LIBS += -framework CoreServices
+   LIBS += -framework CoreServices -framework Foundation
 }
 
 macx {
-    SOURCES += \
-        ../../corelib/io/qstandardpaths_mac.cpp
+    OBJECTIVE_SOURCES += \
+        ../../corelib/tools/qstring_mac.mm \
+        ../../corelib/io/qstandardpaths_mac.mm
 } else:unix {
     SOURCES += \
         ../../corelib/io/qstandardpaths_unix.cpp