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package com.netease.cloud.internal;


import com.netease.cloud.exception.AbortedException;
import com.netease.cloud.util.IOUtils;
import org.apache.commons.logging.LogFactory;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

public abstract class SdkInputStream extends FilterInputStream implements Releasable {
    /**
     * Creates a FilterInputStream
     * by assigning the  argument in
     * to the field this.in so as
     * to remember it for later use.
     *
     * @param in the underlying input stream, or null if
     *           this instance is to be created without an underlying stream.
     */
    protected SdkInputStream(InputStream in) {
        super(in);
    }

    /**
     * Returns the underlying input stream, if any, from the subclass; or null
     * if there is no underlying input stream.
     */
    abstract protected InputStream getWrappedInputStream();

    /**
    * Returns true if the current operation should abort; false otherwise.
    * Note the interrupted status of the thread is cleared by this method.
    */
   protected static boolean shouldAbort() {
       return Thread.interrupted();
   }

    /**
     * Aborts with subclass specific abortion logic executed if needed.
     * Note the interrupted status of the thread is cleared by this method.
     * @throws AbortedException if found necessary.
     */
    protected final void abortIfNeeded() {
        if (shouldAbort()) {
            try {
                abort();    // execute subclass specific abortion logic
            } catch (IOException e) {
                LogFactory.getLog(getClass()).debug("FYI", e);
            }
            throw new AbortedException();
        }
    }

    /**
     * Can be used to provide abortion logic prior to throwing the
     * AbortedException. No-op by default.
     */
    protected void abort() throws IOException {
        // no-op by default, but subclass such as NOSObjectInputStream may override
    }

    /**
     * WARNING: Subclass that overrides this method must NOT call
     * super.release() or else it would lead to infinite loop.
     * 
     * {@inheritDoc}
     */
    @Override
    public void release() {
        // Don't call IOUtils.release(in, null) or else could lead to infinite loop
        IOUtils.closeQuietly(this, null);
        InputStream in = getWrappedInputStream();
        if (in instanceof Releasable) {
            // This allows any underlying stream that has the close operation
            // disabled to be truly released
            Releasable r = (Releasable)in;
            r.release();
        }
    }
}