When is an Image Cache removed from disk in fresco android?

Question

I need to know how long a cached version of URI would be on the disk in fresco cache?

Answer 1

As it is written at http://frescolib.org/docs/caching.html#trimming-the-caches:

When configuring the image pipeline, you can set the maximum size of each of the caches. But there are times when you might want to go lower than that. For instance, your application might have caches for other kinds of data that might need more space and crowd out Fresco's. Or you might be checking to see if the device as a whole is running out of storage space.

Fresco's caches implement the DiskTrimmable or MemoryTrimmable interfaces. These are hooks into which your app can tell them to do emergency evictions.

Your application can then configure the pipeline with objects implementing the DiskTrimmableRegistry and MemoryTrimmableRegistry interfaces.

These objects must keep a list of trimmables. They must use app-specific logic to determine when memory or disk space must be preserved. They then notify the trimmable objects to carry out their trims.

So, if you don't specify DiskTrimmable or MemoryTrimmable while configuration your ImagePipeline will be using default DiskTrimmable, MemoryTrimmable. So, after looking for default values in sources i found this:

private static DiskCacheConfig getDefaultMainDiskCacheConfig(final Context context) {
    return DiskCacheConfig.newBuilder()
        .setBaseDirectoryPathSupplier(
            new Supplier<File>() {
              @Override
              public File get() {
                return context.getApplicationContext().getCacheDir();
              }
            })
        .setBaseDirectoryName("image_cache")
        .setMaxCacheSize(40 * ByteConstants.MB)
        .setMaxCacheSizeOnLowDiskSpace(10 * ByteConstants.MB)
        .setMaxCacheSizeOnVeryLowDiskSpace(2 * ByteConstants.MB)
        .build();
  }

So conclusion is next: when the memory is full (40 ByteConstants.MB or 10 ByteConstants.MB or 2 ByteConstants.MB) - Fresco will delete old records and write new records(images). Maybe Fresco use this method.