Adds support for webrtc::test::ResourcePath on iOS

webrtc/test/testsupport/iosfileutils.mm

+/*
+ *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#import <Foundation/Foundation.h>
+#include <string.h>
+
+#include "webrtc/base/checks.h"
+#include "webrtc/typedefs.h"
+
+std::string IOSResourcePath(std::string name, std::string extension) {
+  // Extract name of file and exclude any added path.
+  // Example: name: "audio_coding/testfile32kHz" => file_name: "testfile32kHz".
+  std::size_t pos = name.find_last_of("/");
+  DCHECK_NE(pos, std::string::npos);
+  std::string file_name = name.substr(pos + 1);
+  // Convert from UTF8 to NSString objects.
+  NSString* nameString =

[henrika_webrtc, 2015/06/11 10:50:31]

Could you please comment on the memory handling details here. Must I release
these? Not sure on how ARC is enabled. Thanks.

[henrika_webrtc, 2015/06/11 12:27:56]

Perhaps I should do:

[[[NSString alloc] initWithUTF8String:file_name.c_str()] autorelease];

instead

[henrika_webrtc, 2015/06/11 13:10:59]

sorry, or perhaps use the factory method stringWithUTF8String instead,

NSString* str = [NSString stringWithUTF8String:file_name.c_str()]

[tkchin_webrtc, 2015/06/12 01:30:26]

You should enable ARC in GYP file. Use:
            'xcode_settings': {
              'CLANG_ENABLE_OBJC_ARC': 'YES',
            },

It may be worth guarding the file from non-ARC use:
#if !defined(__has_feature) || !__has_feature(objc_arc)
#error "This file requires ARC support."
#endif

Under ARC you never call retain/release/autorelease on objects. However, in here
you will need an autoreleasepool since there is no pool created in the test main
function. You can either add the autoreleasepool in the main function for the
test binary, or just here like follows:

@autoreleasepool {
   NSString* ....
}

See this for proper conversions between NSString* and std::string
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/libjin...

[henrika_webrtc, 2015/06/12 12:52:11]

Thanks. Done changes but might have missed some details.

It is not clear to me why your StdStringFromNSString is better than the existing
pathString.UTF8String. Care to elaborate.

[tkchin_webrtc, 2015/06/12 17:43:35]

In this case it doesn't matter. StdStringFromNSString does a copy, whereas
pathString.UTF8String does not, and accessing its bytes after NSString* is
dealloc-ed will cause issues.

[henrika_webrtc, 2015/06/15 08:46:29]

Thanks. Have shifted to using your methods.

+      [[NSString alloc] initWithUTF8String:file_name.c_str()];
+  NSString* typeString =
+      [[NSString alloc] initWithUTF8String:extension.c_str()];
+  // Get full pathname for the resource identified by the name and extension.
+  NSString* pathString = [[NSBundle mainBundle] pathForResource: nameString
+                                                         ofType: typeString];
+  // Return a null-terminated UTF8 representation of |pathString|.
+  return pathString.UTF8String;
+}