dom/file/TemporaryFileBlobImpl.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "TemporaryFileBlobImpl.h"
   8
   9 #include "RemoteLazyInputStreamThread.h"
  10 #include "mozilla/ErrorResult.h"
  11 #include "nsFileStreams.h"
  12 #include "nsIFile.h"
  13 #include "nsIFileStreams.h"
  14 #include "nsNetUtil.h"
  15 #include "nsThreadUtils.h"
  16 #include "nsXULAppAPI.h"
  17
  18 using namespace mozilla::ipc;
  19
  20 namespace mozilla::dom {
  21
  22 namespace {
  23
  24 // Here the flags needed in order to keep the temporary file opened.
  25 // 1. REOPEN_ON_REWIND -> otherwise the stream is not serializable more than
  26 //                        once.
  27 // 2. no DEFER_OPEN -> the file must be kept open on windows in order to be
  28 //                     deleted when used.
  29 // 3. no CLOSE_ON_EOF -> the file will be closed by the DTOR. No needs. Also
  30 //                       because the inputStream will not be read directly.
  31 // 4. no SHARE_DELETE -> We don't want to allow this file to be deleted.
  32 const uint32_t sTemporaryFileStreamFlags = nsIFileInputStream::REOPEN_ON_REWIND;
  33
  34 class TemporaryFileInputStream final : public nsFileInputStream {
  35  public:
  36   static nsresult Create(nsIFile* aFile, nsIInputStream** aInputStream) {
  37     MOZ_ASSERT(aFile);
  38     MOZ_ASSERT(aInputStream);
  39     MOZ_ASSERT(XRE_IsParentProcess());
  40
  41     RefPtr<TemporaryFileInputStream> stream =
  42         new TemporaryFileInputStream(aFile);
  43
  44     nsresult rv = stream->Init(aFile, -1, -1, sTemporaryFileStreamFlags);
  45     if (NS_WARN_IF(NS_FAILED(rv))) {
  46       return rv;
  47     }
  48
  49     stream.forget(aInputStream);
  50     return NS_OK;
  51   }
  52
  53   void Serialize(InputStreamParams& aParams, uint32_t aMaxSize,
  54                  uint32_t* aSizeUsed) override {
  55     MOZ_CRASH("This inputStream cannot be serialized.");
  56   }
  57
  58   bool Deserialize(const InputStreamParams& aParams) override {
  59     MOZ_CRASH("This inputStream cannot be deserialized.");
  60     return false;
  61   }
  62
  63  private:
  64   explicit TemporaryFileInputStream(nsIFile* aFile) : mFile(aFile) {
  65     MOZ_ASSERT(XRE_IsParentProcess());
  66   }
  67
  68   ~TemporaryFileInputStream() override {
  69     // Let's delete the file on the RemoteLazyInputStream Thread.
  70     RefPtr<RemoteLazyInputStreamThread> thread =
  71         RemoteLazyInputStreamThread::GetOrCreate();
  72     if (NS_WARN_IF(!thread)) {
  73       return;
  74     }
  75
  76     nsCOMPtr<nsIFile> file = std::move(mFile);
  77     thread->Dispatch(
  78         NS_NewRunnableFunction("TemporaryFileInputStream::Runnable",
  79                                [file]() { file->Remove(false); }));
  80   }
  81
  82   nsCOMPtr<nsIFile> mFile;
  83 };
  84
  85 }  // namespace
  86
  87 TemporaryFileBlobImpl::TemporaryFileBlobImpl(nsIFile* aFile,
  88                                              const nsAString& aContentType)
  89     : FileBlobImpl(aFile, u""_ns, aContentType)
  90 #ifdef DEBUG
  91       ,
  92       mInputStreamCreated(false)
  93 #endif
  94 {
  95   MOZ_ASSERT(XRE_IsParentProcess());
  96
  97   // This must be considered a blob.
  98   mIsFile = false;
  99 }
 100
 101 TemporaryFileBlobImpl::~TemporaryFileBlobImpl() {
 102   MOZ_ASSERT(mInputStreamCreated);
 103 }
 104
 105 already_AddRefed<BlobImpl> TemporaryFileBlobImpl::CreateSlice(
 106     uint64_t aStart, uint64_t aLength, const nsAString& aContentType,
 107     ErrorResult& aRv) const {
 108   MOZ_CRASH("This BlobImpl is not meant to be sliced!");
 109   return nullptr;
 110 }
 111
 112 void TemporaryFileBlobImpl::CreateInputStream(nsIInputStream** aStream,
 113                                               ErrorResult& aRv) const {
 114 #ifdef DEBUG
 115   MOZ_ASSERT(!mInputStreamCreated);
 116   // CreateInputStream can be called only once.
 117   mInputStreamCreated = true;
 118 #endif
 119
 120   aRv = TemporaryFileInputStream::Create(mFile, aStream);
 121   if (NS_WARN_IF(aRv.Failed())) {
 122     return;
 123   }
 124 }
 125
 126 }  // namespace mozilla::dom