summaryrefslogtreecommitdiff
path: root/dom/cache/ReadStream.cpp
blob: efce027a19d123460c464fdb0f5470796e8b40c1 (plain)
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
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
/* -*- 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 "mozilla/dom/cache/ReadStream.h"

#include "mozilla/Unused.h"
#include "mozilla/dom/cache/CacheStreamControlChild.h"
#include "mozilla/dom/cache/CacheStreamControlParent.h"
#include "mozilla/dom/cache/CacheTypes.h"
#include "mozilla/ipc/IPCStreamUtils.h"
#include "mozilla/SnappyUncompressInputStream.h"
#include "nsIAsyncInputStream.h"
#include "nsTArray.h"

namespace mozilla {
namespace dom {
namespace cache {

using mozilla::Unused;
using mozilla::ipc::AutoIPCStream;
using mozilla::ipc::IPCStream;

// ----------------------------------------------------------------------------

// The inner stream class.  This is where all of the real work is done.  As
// an invariant Inner::Close() must be called before ~Inner().  This is
// guaranteed by our outer ReadStream class.
class ReadStream::Inner final : public ReadStream::Controllable
{
public:
  Inner(StreamControl* aControl, const nsID& aId,
        nsIInputStream* aStream);

  void
  Serialize(CacheReadStreamOrVoid* aReadStreamOut,
            nsTArray<UniquePtr<AutoIPCStream>>& aStreamCleanupList,
            ErrorResult& aRv);

  void
  Serialize(CacheReadStream* aReadStreamOut,
            nsTArray<UniquePtr<AutoIPCStream>>& aStreamCleanupList,
            ErrorResult& aRv);

  // ReadStream::Controllable methods
  virtual void
  CloseStream() override;

  virtual void
  CloseStreamWithoutReporting() override;

  virtual bool
  MatchId(const nsID& aId) const override;

  virtual bool
  HasEverBeenRead() const override;

  // Simulate nsIInputStream methods, but we don't actually inherit from it
  nsresult
  Close();

  nsresult
  Available(uint64_t *aNumAvailableOut);

  nsresult
  Read(char *aBuf, uint32_t aCount, uint32_t *aNumReadOut);

  nsresult
  ReadSegments(nsWriteSegmentFun aWriter, void *aClosure, uint32_t aCount,
               uint32_t *aNumReadOut);

  nsresult
  IsNonBlocking(bool *aNonBlockingOut);

private:
  class NoteClosedRunnable;
  class ForgetRunnable;

  ~Inner();

  void
  NoteClosed();

  void
  Forget();

  void
  NoteClosedOnOwningThread();

  void
  ForgetOnOwningThread();

  // Weak ref to the stream control actor.  The actor will always call either
  // CloseStream() or CloseStreamWithoutReporting() before it's destroyed.  The
  // weak ref is cleared in the resulting NoteClosedOnOwningThread() or
  // ForgetOnOwningThread() method call.
  StreamControl* mControl;

  const nsID mId;
  nsCOMPtr<nsIThread> mOwningThread;

  enum State
  {
    Open,
    Closed,
    NumStates
  };
  Atomic<State> mState;
  Atomic<bool> mHasEverBeenRead;


  // The wrapped stream objects may not be threadsafe.  We need to be able
  // to close a stream on our owning thread while an IO thread is simultaneously
  // reading the same stream.  Therefore, protect all access to these stream
  // objects with a mutex.
  Mutex mMutex;
  nsCOMPtr<nsIInputStream> mStream;
  nsCOMPtr<nsIInputStream> mSnappyStream;

  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(cache::ReadStream::Inner, override)
};

// ----------------------------------------------------------------------------

// Runnable to notify actors that the ReadStream has closed.  This must
// be done on the thread associated with the PBackground actor.  Must be
// cancelable to execute on Worker threads (which can occur when the
// ReadStream is constructed on a child process Worker thread).
class ReadStream::Inner::NoteClosedRunnable final : public CancelableRunnable
{
public:
  explicit NoteClosedRunnable(ReadStream::Inner* aStream)
    : mStream(aStream)
  { }

  NS_IMETHOD Run() override
  {
    mStream->NoteClosedOnOwningThread();
    mStream = nullptr;
    return NS_OK;
  }

  // Note, we must proceed with the Run() method since our actor will not
  // clean itself up until we note that the stream is closed.
  nsresult Cancel() override
  {
    Run();
    return NS_OK;
  }

private:
  ~NoteClosedRunnable() { }

  RefPtr<ReadStream::Inner> mStream;
};

// ----------------------------------------------------------------------------

// Runnable to clear actors without reporting that the ReadStream has
// closed.  Since this can trigger actor destruction, we need to do
// it on the thread associated with the PBackground actor.  Must be
// cancelable to execute on Worker threads (which can occur when the
// ReadStream is constructed on a child process Worker thread).
class ReadStream::Inner::ForgetRunnable final : public CancelableRunnable
{
public:
  explicit ForgetRunnable(ReadStream::Inner* aStream)
    : mStream(aStream)
  { }

  NS_IMETHOD Run() override
  {
    mStream->ForgetOnOwningThread();
    mStream = nullptr;
    return NS_OK;
  }

  // Note, we must proceed with the Run() method so that we properly
  // call RemoveListener on the actor.
  nsresult Cancel() override
  {
    Run();
    return NS_OK;
  }

private:
  ~ForgetRunnable() { }

  RefPtr<ReadStream::Inner> mStream;
};

// ----------------------------------------------------------------------------

ReadStream::Inner::Inner(StreamControl* aControl, const nsID& aId,
                         nsIInputStream* aStream)
  : mControl(aControl)
  , mId(aId)
  , mOwningThread(NS_GetCurrentThread())
  , mState(Open)
  , mHasEverBeenRead(false)
  , mMutex("dom::cache::ReadStream")
  , mStream(aStream)
  , mSnappyStream(new SnappyUncompressInputStream(aStream))
{
  MOZ_DIAGNOSTIC_ASSERT(mStream);
  MOZ_DIAGNOSTIC_ASSERT(mControl);
  mControl->AddReadStream(this);
}

void
ReadStream::Inner::Serialize(CacheReadStreamOrVoid* aReadStreamOut,
                             nsTArray<UniquePtr<AutoIPCStream>>& aStreamCleanupList,
                             ErrorResult& aRv)
{
  MOZ_ASSERT(NS_GetCurrentThread() == mOwningThread);
  MOZ_DIAGNOSTIC_ASSERT(aReadStreamOut);
  *aReadStreamOut = CacheReadStream();
  Serialize(&aReadStreamOut->get_CacheReadStream(), aStreamCleanupList, aRv);
}

void
ReadStream::Inner::Serialize(CacheReadStream* aReadStreamOut,
                             nsTArray<UniquePtr<AutoIPCStream>>& aStreamCleanupList,
                             ErrorResult& aRv)
{
  MOZ_ASSERT(NS_GetCurrentThread() == mOwningThread);
  MOZ_DIAGNOSTIC_ASSERT(aReadStreamOut);

  if (mState != Open) {
    aRv.ThrowTypeError<MSG_CACHE_STREAM_CLOSED>();
    return;
  }

  MOZ_DIAGNOSTIC_ASSERT(mControl);

  aReadStreamOut->id() = mId;
  mControl->SerializeControl(aReadStreamOut);

  {
    MutexAutoLock lock(mMutex);
    mControl->SerializeStream(aReadStreamOut, mStream, aStreamCleanupList);
  }

  MOZ_DIAGNOSTIC_ASSERT(aReadStreamOut->stream().type() ==
                        IPCStream::TInputStreamParamsWithFds);

  // We're passing ownership across the IPC barrier with the control, so
  // do not signal that the stream is closed here.
  Forget();
}

void
ReadStream::Inner::CloseStream()
{
  MOZ_ASSERT(NS_GetCurrentThread() == mOwningThread);
  Close();
}

void
ReadStream::Inner::CloseStreamWithoutReporting()
{
  MOZ_ASSERT(NS_GetCurrentThread() == mOwningThread);
  Forget();
}

bool
ReadStream::Inner::MatchId(const nsID& aId) const
{
  MOZ_ASSERT(NS_GetCurrentThread() == mOwningThread);
  return mId.Equals(aId);
}

bool
ReadStream::Inner::HasEverBeenRead() const
{
  MOZ_ASSERT(NS_GetCurrentThread() == mOwningThread);
  return mHasEverBeenRead;
}

nsresult
ReadStream::Inner::Close()
{
  // stream ops can happen on any thread
  nsresult rv = NS_OK;
  {
    MutexAutoLock lock(mMutex);
    rv = mSnappyStream->Close();
  }
  NoteClosed();
  return rv;
}

nsresult
ReadStream::Inner::Available(uint64_t* aNumAvailableOut)
{
  // stream ops can happen on any thread
  nsresult rv = NS_OK;
  {
    MutexAutoLock lock(mMutex);
    rv = mSnappyStream->Available(aNumAvailableOut);
  }

  if (NS_FAILED(rv)) {
    Close();
  }

  return rv;
}

nsresult
ReadStream::Inner::Read(char* aBuf, uint32_t aCount, uint32_t* aNumReadOut)
{
  // stream ops can happen on any thread
  MOZ_DIAGNOSTIC_ASSERT(aNumReadOut);

  nsresult rv = NS_OK;
  {
    MutexAutoLock lock(mMutex);
    rv = mSnappyStream->Read(aBuf, aCount, aNumReadOut);
  }

  if ((NS_FAILED(rv) && rv != NS_BASE_STREAM_WOULD_BLOCK) ||
      *aNumReadOut == 0) {
    Close();
  }

  mHasEverBeenRead = true;

  return rv;
}

nsresult
ReadStream::Inner::ReadSegments(nsWriteSegmentFun aWriter, void* aClosure,
                                uint32_t aCount, uint32_t* aNumReadOut)
{
  // stream ops can happen on any thread
  MOZ_DIAGNOSTIC_ASSERT(aNumReadOut);

  if (aCount) {
    mHasEverBeenRead = true;
  }


  nsresult rv = NS_OK;
  {
    MutexAutoLock lock(mMutex);
    rv = mSnappyStream->ReadSegments(aWriter, aClosure, aCount, aNumReadOut);
  }

  if ((NS_FAILED(rv) && rv != NS_BASE_STREAM_WOULD_BLOCK &&
                        rv != NS_ERROR_NOT_IMPLEMENTED) || *aNumReadOut == 0) {
    Close();
  }

  // Verify bytes were actually read before marking as being ever read.  For
  // example, code can test if the stream supports ReadSegments() by calling
  // this method with a dummy callback which doesn't read anything.  We don't
  // want to trigger on that.
  if (*aNumReadOut) {
    mHasEverBeenRead = true;
  }

  return rv;
}

nsresult
ReadStream::Inner::IsNonBlocking(bool* aNonBlockingOut)
{
  // stream ops can happen on any thread
  MutexAutoLock lock(mMutex);
  return mSnappyStream->IsNonBlocking(aNonBlockingOut);
}

ReadStream::Inner::~Inner()
{
  // Any thread
  MOZ_DIAGNOSTIC_ASSERT(mState == Closed);
  MOZ_DIAGNOSTIC_ASSERT(!mControl);
}

void
ReadStream::Inner::NoteClosed()
{
  // Any thread
  if (mState == Closed) {
    return;
  }

  if (NS_GetCurrentThread() == mOwningThread) {
    NoteClosedOnOwningThread();
    return;
  }

  nsCOMPtr<nsIRunnable> runnable = new NoteClosedRunnable(this);
  MOZ_ALWAYS_SUCCEEDS(
    mOwningThread->Dispatch(runnable, nsIThread::DISPATCH_NORMAL));
}

void
ReadStream::Inner::Forget()
{
  // Any thread
  if (mState == Closed) {
    return;
  }

  if (NS_GetCurrentThread() == mOwningThread) {
    ForgetOnOwningThread();
    return;
  }

  nsCOMPtr<nsIRunnable> runnable = new ForgetRunnable(this);
  MOZ_ALWAYS_SUCCEEDS(
    mOwningThread->Dispatch(runnable, nsIThread::DISPATCH_NORMAL));
}

void
ReadStream::Inner::NoteClosedOnOwningThread()
{
  MOZ_ASSERT(NS_GetCurrentThread() == mOwningThread);

  // Mark closed and do nothing if we were already closed
  if (!mState.compareExchange(Open, Closed)) {
    return;
  }

  MOZ_DIAGNOSTIC_ASSERT(mControl);
  mControl->NoteClosed(this, mId);
  mControl = nullptr;
}

void
ReadStream::Inner::ForgetOnOwningThread()
{
  MOZ_ASSERT(NS_GetCurrentThread() == mOwningThread);

  // Mark closed and do nothing if we were already closed
  if (!mState.compareExchange(Open, Closed)) {
    return;
  }

  MOZ_DIAGNOSTIC_ASSERT(mControl);
  mControl->ForgetReadStream(this);
  mControl = nullptr;
}

// ----------------------------------------------------------------------------

NS_IMPL_ISUPPORTS(cache::ReadStream, nsIInputStream, ReadStream);

// static
already_AddRefed<ReadStream>
ReadStream::Create(const CacheReadStreamOrVoid& aReadStreamOrVoid)
{
  if (aReadStreamOrVoid.type() == CacheReadStreamOrVoid::Tvoid_t) {
    return nullptr;
  }

  return Create(aReadStreamOrVoid.get_CacheReadStream());
}

// static
already_AddRefed<ReadStream>
ReadStream::Create(const CacheReadStream& aReadStream)
{
  // The parameter may or may not be for a Cache created stream.  The way we
  // tell is by looking at the stream control actor.  If the actor exists,
  // then we know the Cache created it.
  if (!aReadStream.controlChild() && !aReadStream.controlParent()) {
    return nullptr;
  }

  MOZ_DIAGNOSTIC_ASSERT(aReadStream.stream().type() ==
                        IPCStream::TInputStreamParamsWithFds);

  // Control is guaranteed to survive this method as ActorDestroy() cannot
  // run on this thread until we complete.
  StreamControl* control;
  if (aReadStream.controlChild()) {
    auto actor = static_cast<CacheStreamControlChild*>(aReadStream.controlChild());
    control = actor;
  } else {
    auto actor = static_cast<CacheStreamControlParent*>(aReadStream.controlParent());
    control = actor;
  }
  MOZ_DIAGNOSTIC_ASSERT(control);

  nsCOMPtr<nsIInputStream> stream = DeserializeIPCStream(aReadStream.stream());
  MOZ_DIAGNOSTIC_ASSERT(stream);

  // Currently we expect all cache read streams to be blocking file streams.
#if !defined(RELEASE_OR_BETA)
  nsCOMPtr<nsIAsyncInputStream> asyncStream = do_QueryInterface(stream);
  MOZ_DIAGNOSTIC_ASSERT(!asyncStream);
#endif

  RefPtr<Inner> inner = new Inner(control, aReadStream.id(), stream);
  RefPtr<ReadStream> ref = new ReadStream(inner);
  return ref.forget();
}

// static
already_AddRefed<ReadStream>
ReadStream::Create(PCacheStreamControlParent* aControl, const nsID& aId,
                   nsIInputStream* aStream)
{
  MOZ_DIAGNOSTIC_ASSERT(aControl);
  auto actor = static_cast<CacheStreamControlParent*>(aControl);
  RefPtr<Inner> inner = new Inner(actor, aId, aStream);
  RefPtr<ReadStream> ref = new ReadStream(inner);
  return ref.forget();
}

void
ReadStream::Serialize(CacheReadStreamOrVoid* aReadStreamOut,
                      nsTArray<UniquePtr<AutoIPCStream>>& aStreamCleanupList,
                      ErrorResult& aRv)
{
  mInner->Serialize(aReadStreamOut, aStreamCleanupList, aRv);
}

void
ReadStream::Serialize(CacheReadStream* aReadStreamOut,
                      nsTArray<UniquePtr<AutoIPCStream>>& aStreamCleanupList,
                      ErrorResult& aRv)
{
  mInner->Serialize(aReadStreamOut, aStreamCleanupList, aRv);
}

ReadStream::ReadStream(ReadStream::Inner* aInner)
  : mInner(aInner)
{
  MOZ_DIAGNOSTIC_ASSERT(mInner);
}

ReadStream::~ReadStream()
{
  // Explicitly close the inner stream so that it does not have to
  // deal with implicitly closing at destruction time.
  mInner->Close();
}

NS_IMETHODIMP
ReadStream::Close()
{
  return mInner->Close();
}

NS_IMETHODIMP
ReadStream::Available(uint64_t* aNumAvailableOut)
{
  return mInner->Available(aNumAvailableOut);
}

NS_IMETHODIMP
ReadStream::Read(char* aBuf, uint32_t aCount, uint32_t* aNumReadOut)
{
  return mInner->Read(aBuf, aCount, aNumReadOut);
}

NS_IMETHODIMP
ReadStream::ReadSegments(nsWriteSegmentFun aWriter, void* aClosure,
                         uint32_t aCount, uint32_t* aNumReadOut)
{
  return mInner->ReadSegments(aWriter, aClosure, aCount, aNumReadOut);
}

NS_IMETHODIMP
ReadStream::IsNonBlocking(bool* aNonBlockingOut)
{
  return mInner->IsNonBlocking(aNonBlockingOut);
}

} // namespace cache
} // namespace dom
} // namespace mozilla