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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package jdk.incubator.http.internal.hpack;
import java.nio.ByteBuffer;
/**
* Delivers results of the {@link Decoder#decode(ByteBuffer, boolean,
* DecodingCallback) decoding operation}.
*
* <p> Methods of the callback are never called by a decoder with any of the
* arguments being {@code null}.
*
* @apiNote
*
* <p> The callback provides methods for all possible <a
* href="https://tools.ietf.org/html/rfc7541#section-6">binary
* representations</a>. This could be useful for implementing an intermediary,
* logging, debugging, etc.
*
* <p> The callback is an interface in order to interoperate with lambdas (in
* the most common use case):
* <pre>{@code
* DecodingCallback callback = (name, value) -> System.out.println(name + ", " + value);
* }</pre>
*
* <p> Names and values are {@link CharSequence}s rather than {@link String}s in
* order to allow users to decide whether or not they need to create objects. A
* {@code CharSequence} might be used in-place, for example, to be appended to
* an {@link Appendable} (e.g. {@link StringBuilder}) and then discarded.
*
* <p> That said, if a passed {@code CharSequence} needs to outlast the method
* call, it needs to be copied.
*
* @since 9
*/
@FunctionalInterface
public interface DecodingCallback {
/**
* A method the more specific methods of the callback forward their calls
* to.
*
* @param name
* header name
* @param value
* header value
*/
void onDecoded(CharSequence name, CharSequence value);
/**
* A more finer-grained version of {@link #onDecoded(CharSequence,
* CharSequence)} that also reports on value sensitivity.
*
* <p> Value sensitivity must be considered, for example, when implementing
* an intermediary. A {@code value} is sensitive if it was represented as <a
* href="https://tools.ietf.org/html/rfc7541#section-6.2.3">Literal Header
* Field Never Indexed</a>.
*
* <p> It is required that intermediaries MUST use the {@linkplain
* Encoder#header(CharSequence, CharSequence, boolean) same representation}
* for encoding this header field in order to protect its value which is not
* to be put at risk by compressing it.
*
* @implSpec
*
* <p> The default implementation invokes {@code onDecoded(name, value)}.
*
* @param name
* header name
* @param value
* header value
* @param sensitive
* whether or not the value is sensitive
*
* @see #onLiteralNeverIndexed(int, CharSequence, CharSequence, boolean)
* @see #onLiteralNeverIndexed(CharSequence, boolean, CharSequence, boolean)
*/
default void onDecoded(CharSequence name, CharSequence value,
boolean sensitive) {
onDecoded(name, value);
}
/**
* An <a href="https://tools.ietf.org/html/rfc7541#section-6.1">Indexed
* Header Field</a> decoded.
*
* @implSpec
*
* <p> The default implementation invokes
* {@code onDecoded(name, value, false)}.
*
* @param index
* index of an entry in the table
* @param name
* header name
* @param value
* header value
*/
default void onIndexed(int index, CharSequence name, CharSequence value) {
onDecoded(name, value, false);
}
/**
* A <a href="https://tools.ietf.org/html/rfc7541#section-6.2.2">Literal
* Header Field without Indexing</a> decoded, where a {@code name} was
* referred by an {@code index}.
*
* @implSpec
*
* <p> The default implementation invokes
* {@code onDecoded(name, value, false)}.
*
* @param index
* index of an entry in the table
* @param name
* header name
* @param value
* header value
* @param valueHuffman
* if the {@code value} was Huffman encoded
*/
default void onLiteral(int index, CharSequence name,
CharSequence value, boolean valueHuffman) {
onDecoded(name, value, false);
}
/**
* A <a href="https://tools.ietf.org/html/rfc7541#section-6.2.2">Literal
* Header Field without Indexing</a> decoded, where both a {@code name} and
* a {@code value} were literal.
*
* @implSpec
*
* <p> The default implementation invokes
* {@code onDecoded(name, value, false)}.
*
* @param name
* header name
* @param nameHuffman
* if the {@code name} was Huffman encoded
* @param value
* header value
* @param valueHuffman
* if the {@code value} was Huffman encoded
*/
default void onLiteral(CharSequence name, boolean nameHuffman,
CharSequence value, boolean valueHuffman) {
onDecoded(name, value, false);
}
/**
* A <a href="https://tools.ietf.org/html/rfc7541#section-6.2.3">Literal
* Header Field Never Indexed</a> decoded, where a {@code name}
* was referred by an {@code index}.
*
* @implSpec
*
* <p> The default implementation invokes
* {@code onDecoded(name, value, true)}.
*
* @param index
* index of an entry in the table
* @param name
* header name
* @param value
* header value
* @param valueHuffman
* if the {@code value} was Huffman encoded
*/
default void onLiteralNeverIndexed(int index, CharSequence name,
CharSequence value,
boolean valueHuffman) {
onDecoded(name, value, true);
}
/**
* A <a href="https://tools.ietf.org/html/rfc7541#section-6.2.3">Literal
* Header Field Never Indexed</a> decoded, where both a {@code
* name} and a {@code value} were literal.
*
* @implSpec
*
* <p> The default implementation invokes
* {@code onDecoded(name, value, true)}.
*
* @param name
* header name
* @param nameHuffman
* if the {@code name} was Huffman encoded
* @param value
* header value
* @param valueHuffman
* if the {@code value} was Huffman encoded
*/
default void onLiteralNeverIndexed(CharSequence name, boolean nameHuffman,
CharSequence value, boolean valueHuffman) {
onDecoded(name, value, true);
}
/**
* A <a href="https://tools.ietf.org/html/rfc7541#section-6.2.1">Literal
* Header Field with Incremental Indexing</a> decoded, where a {@code name}
* was referred by an {@code index}.
*
* @implSpec
*
* <p> The default implementation invokes
* {@code onDecoded(name, value, false)}.
*
* @param index
* index of an entry in the table
* @param name
* header name
* @param value
* header value
* @param valueHuffman
* if the {@code value} was Huffman encoded
*/
default void onLiteralWithIndexing(int index,
CharSequence name,
CharSequence value, boolean valueHuffman) {
onDecoded(name, value, false);
}
/**
* A <a href="https://tools.ietf.org/html/rfc7541#section-6.2.1">Literal
* Header Field with Incremental Indexing</a> decoded, where both a {@code
* name} and a {@code value} were literal.
*
* @implSpec
*
* <p> The default implementation invokes
* {@code onDecoded(name, value, false)}.
*
* @param name
* header name
* @param nameHuffman
* if the {@code name} was Huffman encoded
* @param value
* header value
* @param valueHuffman
* if the {@code value} was Huffman encoded
*/
default void onLiteralWithIndexing(CharSequence name, boolean nameHuffman,
CharSequence value, boolean valueHuffman) {
onDecoded(name, value, false);
}
/**
* A <a href="https://tools.ietf.org/html/rfc7541#section-6.3">Dynamic Table
* Size Update</a> decoded.
*
* @implSpec
*
* <p> The default implementation does nothing.
*
* @param capacity
* new capacity of the header table
*/
default void onSizeUpdate(int capacity) { }
}