In a coding interview you're asked to build, in 30 minutes, an ImageManager that fetches an image by URL and returns it from cache if it's been fetched before. How would you handle several cells requesting the same URL at the same time?
A manager wrapped in an actor looks up NSCache, then a dictionary of in-flight Tasks, then disk, then the network, and if the same URL is already downloading it waits on that Task instead of starting a new request, coalescing the requests.
ConcurrencyShort answerAdvanced
In a message list screen, each cell downloads its profile image asynchronously and caches…
#nscache #actor
CS fundamentals and algorithmsShort answerAdvanced
You need to write an in-memory image cache with LRU eviction yourself. Which data…
#image-cache #nscache
PersistenceShort answerBasics
NSCache exists, so why do image libraries write their own LRU cache?
#image-cache #nscache
iOS system designShort answerAdvanced
If you had to build an image loading library like SDWebImage or Kingfisher yourself, how…
#image-cache #cancellation