import okhttp3.internal.http2.Http2.frameLogWindowUpdate
import okhttp3.internal.writeMedium
import okio.Buffer
import okio.BufferedSink

/** Writes HTTP/2 transport frames. */
@Suppress("NAME_SHADOWING")
class Http2Writer(
  private val sink: BufferedSink,
  private val client: Boolean,
) : Closeable {
  internal val lock: ReentrantLock = ReentrantLock()

  private val hpackBuffer: Buffer = Buffer()

import kotlin.contracts.InvocationKind
import kotlin.contracts.contract
import okhttp3.Dispatcher
import okhttp3.internal.http2.Http2Connection
import okhttp3.internal.http2.Http2Stream
import okhttp3.internal.http2.Http2Writer

/**
 * Centralisation of central locks according to docs/contribute/concurrency.md
 */
internal object Locks {
  inline fun <T> Dispatcher.withLock(action: () -> T): T {

    val newMaxFrameSize = 16777215
    val writer = Http2Writer(Buffer(), true)
    writer.applyAndAckSettings(Settings().set(Settings.MAX_FRAME_SIZE, newMaxFrameSize))
    assertThat(writer.maxDataLength()).isEqualTo(newMaxFrameSize)
    writer.frameHeader(0, newMaxFrameSize, Http2.TYPE_DATA, FLAG_NONE)
  }

  @Test fun streamIdHasReservedBit() {
    val writer = Http2Writer(Buffer(), true)
    assertFailsWith<IllegalArgumentException> {

#### Http2Writer

Socket writes are guarded by the Http2Writer. Only one stream can write at a time so that messages are not interleaved. Writes are either made by application-layer threads or the do-stuff-later pool.

### Holding multiple locks

You're allowed to take the Http2Connection lock while holding the Http2Writer lock. But not vice-versa. Because taking the Http2Writer lock can block.

    this.client = client
    writer = Http2Writer(bytesOut, client)
  }

  fun acceptFrame() {
    frameCount++
  }

  /** Maximum length of an outbound data frame.  */
  fun maxOutboundDataLength(): Int = writer.maxDataLength()

  /** Count of frames sent or received.  */
  fun frameCount(): Int = frameCount

  fun sendFrame(): Http2Writer {
    outFrames.add(OutFrame(frameCount++, bytesOut.size, false))

HSPLokhttp3/internal/http2/Http2Writer;-><clinit>()V
HSPLokhttp3/internal/http2/Http2Writer;-><init>(Lokio/BufferedSink;Z)V
HSPLokhttp3/internal/http2/Http2Writer;->applyAndAckSettings(Lokhttp3/internal/http2/Settings;)V
HSPLokhttp3/internal/http2/Http2Writer;->close()V
HSPLokhttp3/internal/http2/Http2Writer;->data(ZILokio/Buffer;I)V
HSPLokhttp3/internal/http2/Http2Writer;->flush()V

  var writeBytesMaximum: Long = peerSettings.initialWindowSize.toLong()
    private set

  internal val socket: Socket = builder.socket
  val writer = Http2Writer(builder.sink, client)

  // Visible for testing
  val readerRunnable = ReaderRunnable(Http2Reader(builder.source, client))

  // Guarded by this.
  private val currentPushRequests = mutableSetOf<Int>()