DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Header

Mercurial (1aeaa33a64f9)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 "FileReaderSync.h"

#include "jsfriendapi.h"
#include "mozilla/Unused.h"
#include "mozilla/Base64.h"
#include "mozilla/dom/File.h"
#include "mozilla/Encoding.h"
#include "mozilla/dom/FileReaderSyncBinding.h"
#include "nsCExternalHandlerService.h"
#include "nsComponentManagerUtils.h"
#include "nsCOMPtr.h"
#include "nsDOMClassInfoID.h"
#include "nsError.h"
#include "nsIConverterInputStream.h"
#include "nsIInputStream.h"
#include "nsIMultiplexInputStream.h"
#include "nsStreamUtils.h"
#include "nsStringStream.h"
#include "nsISupportsImpl.h"
#include "nsNetUtil.h"
#include "nsServiceManagerUtils.h"
#include "nsIAsyncInputStream.h"
#include "mozilla/dom/WorkerPrivate.h"
#include "mozilla/dom/WorkerRunnable.h"

using namespace mozilla;
using namespace mozilla::dom;
using mozilla::dom::GlobalObject;
using mozilla::dom::Optional;

// static
already_AddRefed<FileReaderSync> FileReaderSync::Constructor(
    const GlobalObject& aGlobal, ErrorResult& aRv) {
  RefPtr<FileReaderSync> frs = new FileReaderSync();

  return frs.forget();
}

bool FileReaderSync::WrapObject(JSContext* aCx,
                                JS::Handle<JSObject*> aGivenProto,
                                JS::MutableHandle<JSObject*> aReflector) {
  return FileReaderSyncBinding::Wrap(aCx, this, aGivenProto, aReflector);
}

void FileReaderSync::ReadAsArrayBuffer(JSContext* aCx,
                                       JS::Handle<JSObject*> aScopeObj,
                                       Blob& aBlob,
                                       JS::MutableHandle<JSObject*> aRetval,
                                       ErrorResult& aRv) {
  uint64_t blobSize = aBlob.GetSize(aRv);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  UniquePtr<char[], JS::FreePolicy> bufferData(js_pod_malloc<char>(blobSize));
  if (!bufferData) {
    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
    return;
  }

  nsCOMPtr<nsIInputStream> stream;
  aBlob.CreateInputStream(getter_AddRefs(stream), aRv);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  uint32_t numRead;
  aRv = SyncRead(stream, bufferData.get(), blobSize, &numRead);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  // The file is changed in the meantime?
  if (numRead != blobSize) {
    aRv.Throw(NS_ERROR_FAILURE);
    return;
  }

  JSObject* arrayBuffer =
      JS_NewArrayBufferWithContents(aCx, blobSize, bufferData.get());
  if (!arrayBuffer) {
    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
    return;
  }
  // arrayBuffer takes the ownership when it is not null. Otherwise we
  // need to release it explicitly.
  mozilla::Unused << bufferData.release();

  aRetval.set(arrayBuffer);
}

void FileReaderSync::ReadAsBinaryString(Blob& aBlob, nsAString& aResult,
                                        ErrorResult& aRv) {
  nsCOMPtr<nsIInputStream> stream;
  aBlob.CreateInputStream(getter_AddRefs(stream), aRv);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  uint32_t numRead;
  do {
    char readBuf[4096];
    aRv = SyncRead(stream, readBuf, sizeof(readBuf), &numRead);
    if (NS_WARN_IF(aRv.Failed())) {
      return;
    }

    uint32_t oldLength = aResult.Length();
    AppendASCIItoUTF16(Substring(readBuf, readBuf + numRead), aResult);
    if (aResult.Length() - oldLength != numRead) {
      aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
      return;
    }
  } while (numRead > 0);
}

void FileReaderSync::ReadAsText(Blob& aBlob,
                                const Optional<nsAString>& aEncoding,
                                nsAString& aResult, ErrorResult& aRv) {
  nsCOMPtr<nsIInputStream> stream;
  aBlob.CreateInputStream(getter_AddRefs(stream), aRv);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  nsCString sniffBuf;
  if (!sniffBuf.SetLength(3, fallible)) {
    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
    return;
  }

  uint32_t numRead = 0;
  aRv = SyncRead(stream, sniffBuf.BeginWriting(), sniffBuf.Length(), &numRead);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  // No data, we don't need to continue.
  if (numRead == 0) {
    aResult.Truncate();
    return;
  }

  // Try the API argument.
  const Encoding* encoding =
      aEncoding.WasPassed() ? Encoding::ForLabel(aEncoding.Value()) : nullptr;
  if (!encoding) {
    // API argument failed. Try the type property of the blob.
    nsAutoString type16;
    aBlob.GetType(type16);
    NS_ConvertUTF16toUTF8 type(type16);
    nsAutoCString specifiedCharset;
    bool haveCharset;
    int32_t charsetStart, charsetEnd;
    NS_ExtractCharsetFromContentType(type, specifiedCharset, &haveCharset,
                                     &charsetStart, &charsetEnd);
    encoding = Encoding::ForLabel(specifiedCharset);
    if (!encoding) {
      // Type property failed. Use UTF-8.
      encoding = UTF_8_ENCODING;
    }
  }

  if (numRead < sniffBuf.Length()) {
    sniffBuf.Truncate(numRead);
  }

  // Let's recreate the full stream using a:
  // multiplexStream(syncStream + original stream)
  // In theory, we could try to see if the inputStream is a nsISeekableStream,
  // but this doesn't work correctly for nsPipe3 - See bug 1349570.

  nsCOMPtr<nsIMultiplexInputStream> multiplexStream =
      do_CreateInstance("@mozilla.org/io/multiplex-input-stream;1");
  if (NS_WARN_IF(!multiplexStream)) {
    aRv.Throw(NS_ERROR_FAILURE);
    return;
  }

  nsCOMPtr<nsIInputStream> sniffStringStream;
  aRv = NS_NewCStringInputStream(getter_AddRefs(sniffStringStream), sniffBuf);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  aRv = multiplexStream->AppendStream(sniffStringStream);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  uint64_t blobSize = aBlob.GetSize(aRv);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  nsCOMPtr<nsIInputStream> syncStream;
  aRv = ConvertAsyncToSyncStream(blobSize - sniffBuf.Length(), stream.forget(),
                                 getter_AddRefs(syncStream));
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  // ConvertAsyncToSyncStream returns a null syncStream if the stream has been
  // already closed or there is nothing to read.
  if (syncStream) {
    aRv = multiplexStream->AppendStream(syncStream);
    if (NS_WARN_IF(aRv.Failed())) {
      return;
    }
  }

  nsAutoCString charset;
  encoding->Name(charset);

  nsCOMPtr<nsIInputStream> multiplex(do_QueryInterface(multiplexStream));
  aRv = ConvertStream(multiplex, charset.get(), aResult);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }
}

void FileReaderSync::ReadAsDataURL(Blob& aBlob, nsAString& aResult,
                                   ErrorResult& aRv) {
  nsAutoString scratchResult;
  scratchResult.AssignLiteral("data:");

  nsString contentType;
  aBlob.GetType(contentType);

  if (contentType.IsEmpty()) {
    scratchResult.AppendLiteral("application/octet-stream");
  } else {
    scratchResult.Append(contentType);
  }
  scratchResult.AppendLiteral(";base64,");

  nsCOMPtr<nsIInputStream> stream;
  aBlob.CreateInputStream(getter_AddRefs(stream), aRv);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  uint64_t blobSize = aBlob.GetSize(aRv);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  nsCOMPtr<nsIInputStream> syncStream;
  aRv = ConvertAsyncToSyncStream(blobSize, stream.forget(),
                                 getter_AddRefs(syncStream));
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  MOZ_ASSERT(syncStream);

  uint64_t size;
  aRv = syncStream->Available(&size);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  // The file is changed in the meantime?
  if (blobSize != size) {
    return;
  }

  nsAutoString encodedData;
  aRv = Base64EncodeInputStream(syncStream, encodedData, size);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  scratchResult.Append(encodedData);

  aResult = scratchResult;
}

nsresult FileReaderSync::ConvertStream(nsIInputStream* aStream,
                                       const char* aCharset,
                                       nsAString& aResult) {
  nsCOMPtr<nsIConverterInputStream> converterStream =
      do_CreateInstance("@mozilla.org/intl/converter-input-stream;1");
  NS_ENSURE_TRUE(converterStream, NS_ERROR_FAILURE);

  nsresult rv = converterStream->Init(
      aStream, aCharset, 8192,
      nsIConverterInputStream::DEFAULT_REPLACEMENT_CHARACTER);
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIUnicharInputStream> unicharStream =
      do_QueryInterface(converterStream);
  NS_ENSURE_TRUE(unicharStream, NS_ERROR_FAILURE);

  uint32_t numChars;
  nsString result;
  while (NS_SUCCEEDED(unicharStream->ReadString(8192, result, &numChars)) &&
         numChars > 0) {
    uint32_t oldLength = aResult.Length();
    aResult.Append(result);
    if (aResult.Length() - oldLength != result.Length()) {
      return NS_ERROR_OUT_OF_MEMORY;
    }
  }

  return rv;
}

namespace {

// This runnable is used to terminate the sync event loop.
class ReadReadyRunnable final : public WorkerSyncRunnable {
 public:
  ReadReadyRunnable(WorkerPrivate* aWorkerPrivate,
                    nsIEventTarget* aSyncLoopTarget)
      : WorkerSyncRunnable(aWorkerPrivate, aSyncLoopTarget) {}

  bool WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override {
    aWorkerPrivate->AssertIsOnWorkerThread();
    MOZ_ASSERT(mSyncLoopTarget);

    nsCOMPtr<nsIEventTarget> syncLoopTarget;
    mSyncLoopTarget.swap(syncLoopTarget);

    aWorkerPrivate->StopSyncLoop(syncLoopTarget, true);
    return true;
  }

 private:
  ~ReadReadyRunnable() {}
};

// This class implements nsIInputStreamCallback and it will be called when the
// stream is ready to be read.
class ReadCallback final : public nsIInputStreamCallback {
 public:
  NS_DECL_THREADSAFE_ISUPPORTS

  ReadCallback(WorkerPrivate* aWorkerPrivate, nsIEventTarget* aEventTarget)
      : mWorkerPrivate(aWorkerPrivate), mEventTarget(aEventTarget) {}

  NS_IMETHOD
  OnInputStreamReady(nsIAsyncInputStream* aStream) override {
    // I/O Thread. Now we need to block the sync event loop.
    RefPtr<ReadReadyRunnable> runnable =
        new ReadReadyRunnable(mWorkerPrivate, mEventTarget);
    return mEventTarget->Dispatch(runnable.forget(), NS_DISPATCH_NORMAL);
  }

 private:
  ~ReadCallback() {}

  // The worker is kept alive because of the sync event loop.
  WorkerPrivate* mWorkerPrivate;
  nsCOMPtr<nsIEventTarget> mEventTarget;
};

NS_IMPL_ADDREF(ReadCallback);
NS_IMPL_RELEASE(ReadCallback);

NS_INTERFACE_MAP_BEGIN(ReadCallback)
  NS_INTERFACE_MAP_ENTRY(nsIInputStreamCallback)
  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIInputStreamCallback)
NS_INTERFACE_MAP_END

}  // namespace

nsresult FileReaderSync::SyncRead(nsIInputStream* aStream, char* aBuffer,
                                  uint32_t aBufferSize, uint32_t* aRead) {
  MOZ_ASSERT(aStream);
  MOZ_ASSERT(aBuffer);
  MOZ_ASSERT(aRead);

  // Let's try to read, directly.
  nsresult rv = aStream->Read(aBuffer, aBufferSize, aRead);

  // Nothing else to read.
  if (rv == NS_BASE_STREAM_CLOSED || (NS_SUCCEEDED(rv) && *aRead == 0)) {
    return NS_OK;
  }

  // An error.
  if (NS_FAILED(rv) && rv != NS_BASE_STREAM_WOULD_BLOCK) {
    return rv;
  }

  // All good.
  if (NS_SUCCEEDED(rv)) {
    // Not enough data, let's read recursively.
    if (*aRead != aBufferSize) {
      uint32_t byteRead = 0;
      rv = SyncRead(aStream, aBuffer + *aRead, aBufferSize - *aRead, &byteRead);
      if (NS_WARN_IF(NS_FAILED(rv))) {
        return rv;
      }

      *aRead += byteRead;
    }

    return NS_OK;
  }

  // We need to proceed async.
  nsCOMPtr<nsIAsyncInputStream> asyncStream = do_QueryInterface(aStream);
  if (!asyncStream) {
    return rv;
  }

  WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
  MOZ_ASSERT(workerPrivate);

  AutoSyncLoopHolder syncLoop(workerPrivate, Closing);

  nsCOMPtr<nsIEventTarget> syncLoopTarget = syncLoop.GetEventTarget();
  if (!syncLoopTarget) {
    // SyncLoop creation can fail if the worker is shutting down.
    return NS_ERROR_DOM_INVALID_STATE_ERR;
  }

  RefPtr<ReadCallback> callback =
      new ReadCallback(workerPrivate, syncLoopTarget);

  nsCOMPtr<nsIEventTarget> target =
      do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID);
  MOZ_ASSERT(target);

  rv = asyncStream->AsyncWait(callback, 0, aBufferSize, target);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  if (!syncLoop.Run()) {
    return NS_ERROR_DOM_INVALID_STATE_ERR;
  }

  // Now, we can try to read again.
  return SyncRead(aStream, aBuffer, aBufferSize, aRead);
}

nsresult FileReaderSync::ConvertAsyncToSyncStream(
    uint64_t aStreamSize, already_AddRefed<nsIInputStream> aAsyncStream,
    nsIInputStream** aSyncStream) {
  nsCOMPtr<nsIInputStream> asyncInputStream = Move(aAsyncStream);

  // If the stream is not async, we just need it to be bufferable.
  nsCOMPtr<nsIAsyncInputStream> asyncStream =
      do_QueryInterface(asyncInputStream);
  if (!asyncStream) {
    return NS_NewBufferedInputStream(aSyncStream, asyncInputStream.forget(),
                                     4096);
  }

  nsAutoCString buffer;
  if (!buffer.SetLength(aStreamSize, fallible)) {
    return NS_ERROR_OUT_OF_MEMORY;
  }

  uint32_t read;
  nsresult rv =
      SyncRead(asyncInputStream, buffer.BeginWriting(), aStreamSize, &read);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  if (read != aStreamSize) {
    return NS_ERROR_FAILURE;
  }

  rv = NS_NewCStringInputStream(aSyncStream, buffer);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  return NS_OK;
}