SerialPortPumps.h - mozsearch

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim:set ts=2 sw=2 sts=2 et cindent: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_dom_SerialPortPumps_h

#define mozilla_dom_SerialPortPumps_h

#include "mozilla/dom/SerialPlatformService.h"

#include "nsIAsyncInputStream.h"

#include "nsIAsyncOutputStream.h"

#include "nsThreadUtils.h"

namespace mozilla::dom {

constexpr uint32_t kMinSerialPortPumpSize = 16384;

}  // namespace mozilla::dom

namespace mozilla::dom::webserial {

// Reads data from the serial device and writes it into a local nsIPipe.

// Runs on the IO thread. An NS_AsyncCopy bridges the nsIPipe to the

// DataPipeSender on a separate thread (DataPipeSender::Write() can block).

// Uses AsyncWait for backpressure when the local pipe is full.

class SerialPortReadPump final : public Runnable,

                                 public nsIOutputStreamCallback {

 public:

  NS_DECL_ISUPPORTS_INHERITED

  SerialPortReadPump(const nsString& aPortId, nsIAsyncOutputStream* aOutput);

  void Stop();

  NS_IMETHOD Run() override;

  NS_IMETHOD OnOutputStreamReady(nsIAsyncOutputStream* aStream) override;

 private:

  ~SerialPortReadPump() = default;

  nsString mPortId;

  nsCOMPtr<nsIAsyncOutputStream> mOutput;

  Atomic<bool> mStopped{false};

  nsTArray<uint8_t> mPendingData;

  uint32_t mPendingOffset = 0;

};

// Reads data from a DataPipeReceiver (JS writes) and writes it to the serial

// device. Runs on the IO thread. Uses AsyncWait to be notified when data is

// available in the pipe.

class SerialPortWritePump final : public nsIInputStreamCallback {

 public:

  NS_DECL_THREADSAFE_ISUPPORTS

  SerialPortWritePump(const nsString& aPortId, nsIAsyncInputStream* aInput);

  void Start();

  void Stop();

  // Register a runnable to invoke when the input pipe is fully closed (all

  // data consumed and written to the device). If the pipe is already closed

  // the runnable fires synchronously. Only one callback may be registered;

  // a second call replaces the previous one.

  void OnPipeClosed(nsCOMPtr<nsIRunnable>&& aCallback);

  bool IsPipeClosed() const { return mPipeClosed; }

  NS_IMETHOD OnInputStreamReady(nsIAsyncInputStream* aStream) override;

 private:

  ~SerialPortWritePump() = default;

  nsString mPortId;

  nsCOMPtr<nsIAsyncInputStream> mInput;

  Atomic<bool> mStopped{false};

  // Only accessed from the SerialPlatformService's IO thread

  bool mPipeClosed = false;

  nsCOMPtr<nsIRunnable> mClosedCallback;

};

}  // namespace mozilla::dom::webserial

#endif  // mozilla_dom_SerialPortPumps_h