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/*
* Copyright 2014, gRPC Authors All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.grpc.protobuf.lite;
import com.google.common.io.ByteStreams;
import com.google.protobuf.CodedOutputStream;
import com.google.protobuf.MessageLite;
import com.google.protobuf.Parser;
import io.grpc.Drainable;
import io.grpc.KnownLength;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.annotation.Nullable;
/**
* An {@link InputStream} backed by a protobuf.
*/
class ProtoInputStream extends InputStream implements Drainable, KnownLength {
// ProtoInputStream is first initialized with a *message*. *partial* is initially null.
// Once there has been a read operation on this stream, *message* is serialized to *partial* and
// set to null.
@Nullable private MessageLite message;
private final Parser<?> parser;
@Nullable private ByteArrayInputStream partial;
public ProtoInputStream(MessageLite message, Parser<?> parser) {
this.message = message;
this.parser = parser;
}
@Override
public int drainTo(OutputStream target) throws IOException {
int written;
if (message != null) {
written = message.getSerializedSize();
message.writeTo(target);
message = null;
} else if (partial != null) {
written = (int) ByteStreams.copy(partial, target);
partial = null;
} else {
written = 0;
}
return written;
}
@Override
public int read() throws IOException {
if (message != null) {
partial = new ByteArrayInputStream(message.toByteArray());
message = null;
}
if (partial != null) {
return partial.read();
}
return -1;
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
if (message != null) {
int size = message.getSerializedSize();
if (size == 0) {
message = null;
partial = null;
return -1;
}
if (len >= size) {
// This is the only case that is zero-copy.
CodedOutputStream stream = CodedOutputStream.newInstance(b, off, size);
message.writeTo(stream);
stream.flush();
stream.checkNoSpaceLeft();
message = null;
partial = null;
return size;
}
partial = new ByteArrayInputStream(message.toByteArray());
message = null;
}
if (partial != null) {
return partial.read(b, off, len);
}
return -1;
}
@Override
public int available() throws IOException {
if (message != null) {
return message.getSerializedSize();
} else if (partial != null) {
return partial.available();
}
return 0;
}
MessageLite message() {
if (message == null) {
throw new IllegalStateException("message not available");
}
return message;
}
Parser<?> parser() {
return parser;
}
}
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