/* 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/. */

#include "nsStreamLoader.h"
#include "nsIInputStream.h"
#include "nsIChannel.h"
#include "nsError.h"
#include "mozilla/ProfilerLabels.h"

#include <limits>

namespace mozilla {
namespace net {

nsStreamLoader::nsStreamLoader() = default;

NS_IMETHODIMP
nsStreamLoader::Init(nsIStreamLoaderObserver* aStreamObserver,
                     nsIRequestObserver* aRequestObserver) {
  NS_ENSURE_ARG_POINTER(aStreamObserver);
  mObserver = aStreamObserver;
  mRequestObserver = aRequestObserver;
  return NS_OK;
}

nsresult nsStreamLoader::Create(REFNSIID aIID, void** aResult) {
  RefPtr<nsStreamLoader> it = new nsStreamLoader();
  return it->QueryInterface(aIID, aResult);
}

NS_IMPL_ISUPPORTS(nsStreamLoader, nsIStreamLoader, nsIRequestObserver,
                  nsIStreamListener, nsIThreadRetargetableStreamListener)

NS_IMETHODIMP
nsStreamLoader::GetNumBytesRead(uint32_t* aNumBytes) {
  *aNumBytes = mBytesRead;
  return NS_OK;
}

NS_IMETHODIMP
nsStreamLoader::GetRequest(nsIRequest** aRequest) {
  nsCOMPtr<nsIRequest> req = mRequest;
  req.forget(aRequest);
  return NS_OK;
}

NS_IMETHODIMP
nsStreamLoader::OnStartRequest(nsIRequest* request) {
  nsCOMPtr<nsIChannel> chan(do_QueryInterface(request));
  if (chan) {
    int64_t contentLength = -1;
    chan->GetContentLength(&contentLength);
    if (contentLength >= 0) {
      // On 64bit platforms size of uint64_t coincides with the size of size_t,
      // so we want to compare with the minimum from size_t and int64_t.
      if (static_cast<uint64_t>(contentLength) >
          std::min(std::numeric_limits<size_t>::max(),
                   static_cast<size_t>(std::numeric_limits<int64_t>::max()))) {
        // Too big to fit into size_t, so let's bail.
        return NS_ERROR_OUT_OF_MEMORY;
      }
      // preallocate buffer
      if (!mData.initCapacity(contentLength)) {
        return NS_ERROR_OUT_OF_MEMORY;
      }
    }
  }
  if (nsCOMPtr<nsIRequestObserver> requestObserver = mRequestObserver) {
    requestObserver->OnStartRequest(request);
  }
  return NS_OK;
}

NS_IMETHODIMP
nsStreamLoader::OnStopRequest(nsIRequest* request, nsresult aStatus) {
  AUTO_PROFILER_LABEL("nsStreamLoader::OnStopRequest", NETWORK);

  if (mObserver) {
    // provide nsIStreamLoader::request during call to OnStreamComplete
    mRequest = request;
    size_t length = mData.length();
    uint8_t* elems = mData.extractOrCopyRawBuffer();
    nsresult rv =
        mObserver->OnStreamComplete(this, mContext, aStatus, length, elems);
    if (rv != NS_SUCCESS_ADOPTED_DATA) {
      // The observer didn't take ownership of the extracted data buffer, so
      // put it back into mData.
      mData.replaceRawBuffer(elems, length);
    }
    // done.. cleanup
    ReleaseData();
    mRequest = nullptr;
    mObserver = nullptr;
  }

  if (nsCOMPtr<nsIRequestObserver> requestObserver = mRequestObserver) {
    requestObserver->OnStopRequest(request, aStatus);
    mRequestObserver = nullptr;
  }

  return NS_OK;
}

nsresult nsStreamLoader::WriteSegmentFun(nsIInputStream* inStr, void* closure,
                                         const char* fromSegment,
                                         uint32_t toOffset, uint32_t count,
                                         uint32_t* writeCount) {
  nsStreamLoader* self = (nsStreamLoader*)closure;

  if (!self->mData.append(fromSegment, count)) {
    self->mData.clearAndFree();
    return NS_ERROR_OUT_OF_MEMORY;
  }

  *writeCount = count;
  return NS_OK;
}

NS_IMETHODIMP
nsStreamLoader::OnDataAvailable(nsIRequest* request, nsIInputStream* inStr,
                                uint64_t sourceOffset, uint32_t count) {
  uint32_t countRead;
  nsresult rv = inStr->ReadSegments(WriteSegmentFun, this, count, &countRead);
  NS_ENSURE_SUCCESS(rv, rv);
  mBytesRead += countRead;
  return NS_OK;
}

void nsStreamLoader::ReleaseData() { mData.clearAndFree(); }

NS_IMETHODIMP
nsStreamLoader::CheckListenerChain() { return NS_OK; }

NS_IMETHODIMP
nsStreamLoader::OnDataFinished(nsresult) { return NS_OK; }

}  // namespace net
}  // namespace mozilla