CGFontCreateWithDataProvider hangs in airplane mode

Question

When I make a call to CGFontCreateWithDataProvider while in airplane mode, my apps freeze. Not in airplane mode, it works fine. The font is s

Answer 1

I found the answer after a bit more searching.

According to the following bug report: https://alpha.app.net/jaredsinclair/post/18555292

If there’s no network connection, CGFontCreateWithDataProvider() hangs in a semaphore trap if it’s called during appDidFinishLaunchingWithOptions. Calling it in the next run loop works without hanging.

As noted in the same post, calling

[UIFont familyNames]

before CGFontCreateWithDataProvider()

resolves the issue. My code now looks like this and works as expected:

+ (void)registerIconFontWithURL:(NSURL *)url
{
    NSAssert([[NSFileManager defaultManager] fileExistsAtPath:[url path]], @"Font file doesn't exist");
    CGDataProviderRef fontDataProvider = CGDataProviderCreateWithURL((__bridge CFURLRef)url);

    //THE NEXT LINE IS RELEVANT PART
    [UIFont familyNames];

    CGFontRef newFont = CGFontCreateWithDataProvider(fontDataProvider);
    CGDataProviderRelease(fontDataProvider);
    CFErrorRef error;
    CTFontManagerRegisterGraphicsFont(newFont, &error);
    CGFontRelease(newFont);
}