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package com.bumptech.glide.load;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import com.bumptech.glide.load.engine.Resource;
import java.io.IOException;
/**
* An interface for decoding resources.
*
* @param The type the resource will be decoded from (File, InputStream etc).
* @param The type of the decoded resource (Bitmap, Drawable etc).
*/
public interface ResourceDecoder {
/**
* Returns {@code true} if this decoder is capable of decoding the given source with the given
* options, and {@code false} otherwise.
*
* Decoders should make a best effort attempt to quickly determine if they are likely to be
* able to decode data, but should not attempt to completely read the given data. A typical
* implementation would check the file headers verify they match content the decoder expects to
* handle (i.e. a GIF decoder should verify that the image contains the GIF header block.
*
*
Decoders that return {@code true} from {@code handles} may still return {@code null} from
* {@link #decode(Object, int, int, Options)} if the data is partial or formatted incorrectly.
*/
boolean handles(@NonNull T source, @NonNull Options options) throws IOException;
/**
* Returns a decoded resource from the given data or null if no resource could be decoded.
*
*
The {@code source} is managed by the caller, there's no need to close it. The returned
* {@link Resource} will be {@link Resource#recycle() released} when the engine sees fit.
*
*
Note - The {@code width} and {@code height} arguments are hints only, there is no
* requirement that the decoded resource exactly match the given dimensions. A typical use case
* would be to use the target dimensions to determine how much to downsample Bitmaps by to avoid
* overly large allocations.
*
* @param source The data the resource should be decoded from.
* @param width The ideal width in pixels of the decoded resource, or {@link
* com.bumptech.glide.request.target.Target#SIZE_ORIGINAL} to indicate the original resource
* width.
* @param height The ideal height in pixels of the decoded resource, or {@link
* com.bumptech.glide.request.target.Target#SIZE_ORIGINAL} to indicate the original resource
* height.
* @param options A map of string keys to objects that may or may not contain options available to
* this particular implementation. Implementations should not assume that any or all of their
* option keys are present. However, implementations may assume that if one of their option
* keys is present, it's value is non-null and is of the expected type.
* @throws IOException typically only if the {@code source} ({@link java.io.InputStream}, {@link
* android.os.ParcelFileDescriptor} etc) throws while being read.
* @throws OutOfMemoryError is sometimes thrown if the the request produces an overly large result
* due to some combination of source size, requested size, source format and requested format.
* Callers do/must handle this error and implementations can throw this error.
* @throws RuntimeException is thrown by a variety of decoding libraries, including various
* Android libraries. Callers do/must handle this error and implementations can throw this
* exception or, preferably, more detailed subclasses.
*/
@Nullable
Resource decode(@NonNull T source, int width, int height, @NonNull Options options)
throws IOException;
}