ResetTest.kt

/*
 * Copyright (C) 2020 Square, Inc.
 *
 * 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 okhttp3.internal.ws

import okio.Buffer
import okio.DeflaterSink
import okio.InflaterSource
import org.assertj.core.api.Assertions.assertThat
import org.junit.Test
import java.util.zip.Deflater
import java.util.zip.Inflater

class ResetTest {
  private val deflatedBuffer = Buffer()
  private val deflater = Deflater()
  private val deflaterSink = DeflaterSink(deflatedBuffer, deflater)

  private val inflaterBuffer = Buffer()
  private val inflater = Inflater()
  private val inflaterSource = InflaterSource(inflaterBuffer, inflater)

  @Test
  fun inflaterResets() {
    val deflatedMessages = mutableListOf<Buffer>()

    deflatedMessages += deflateMessage("abc".repeat(100))
    deflater.reset()

    deflatedMessages += deflateMessage("def".repeat(100))
    deflater.reset()

    assertThat(inflateMessage(deflatedMessages.removeAt(0)))
        .isEqualTo("abc".repeat(100))
    inflater.reset()

    assertThat(inflateMessage(deflatedMessages.removeAt(0)))
        .isEqualTo("def".repeat(100))
    inflater.reset()
  }

  @Test
  fun inflaterDoesNotReset() {
    val deflatedMessages = mutableListOf<Buffer>()

    deflatedMessages += deflateMessage("abc".repeat(100))
    deflater.reset()

    deflatedMessages += deflateMessage("def".repeat(100))
    deflater.reset()

    assertThat(inflateMessage(deflatedMessages.removeAt(0)))
        .isEqualTo("abc".repeat(100))

    assertThat(inflateMessage(deflatedMessages.removeAt(0)))
        .isEqualTo("def".repeat(100))
  }

  private fun deflateMessage(message: String): Buffer {
    val contentBuffer = Buffer().writeUtf8(message)
    deflaterSink.write(contentBuffer, contentBuffer.size)
    deflaterSink.flush()
    return Buffer().also { it.writeAll(deflatedBuffer) }
  }

  private fun inflateMessage(message: Buffer): String {
    val targetSize = inflater.bytesRead + message.size

    inflaterBuffer.writeAll(message)
    val result = Buffer()
    while (inflater.bytesRead < targetSize) {
      check(inflaterSource.read(result, Long.MAX_VALUE) != -1L)
    }
    return result.readUtf8()
  }
}

The inflaterResets() test passes.

The inflaterDoesNotReset() test fails like this:

java.io.IOException: java.util.zip.DataFormatException: invalid stored block lengths
	at okio.InflaterSource.read(InflaterSource.kt:77)
	at okhttp3.internal.ws.ResetTest.inflateMessage(ResetTest.kt:69)
	at okhttp3.internal.ws.ResetTest.inflaterDoesNotReset(ResetTest.kt:52)
Caused by: java.util.zip.DataFormatException: invalid stored block lengths
	at java.base/java.util.zip.Inflater.inflateBytesBytes(Native Method)
	at java.base/java.util.zip.Inflater.inflate(Inflater.java:385)
	at okio.InflaterSource.read(InflaterSource.kt:60)
	... 27 more