Bug 1361330 - Part 2: Move MemoryOutputStream to a generic place; r=asuth

dom/filehandle/ActorsParent.cpp

@@ -17,6 +17,7 @@
 #include "mozilla/dom/indexedDB/PBackgroundIDBDatabaseParent.h"
 #include "mozilla/dom/IPCBlobUtils.h"
 #include "mozilla/dom/ipc/PendingIPCBlobParent.h"
+#include "mozilla/dom/quota/MemoryOutputStream.h"
 #include "nsAutoPtr.h"
 #include "nsComponentManagerUtils.h"
 #include "nsDebug.h"
@@ -48,6 +49,7 @@
 namespace mozilla {
 namespace dom {
 
+using namespace mozilla::dom::quota;
 using namespace mozilla::ipc;
 
 namespace {
@@ -632,8 +634,6 @@ class ReadOp final
 {
   friend class FileHandle;
 
-  class MemoryOutputStream;
-
   const FileRequestReadParams mParams;
 
 private:
@@ -651,34 +651,6 @@ private:
   GetResponse(FileRequestResponse& aResponse) override;
 };
 
-class ReadOp::MemoryOutputStream final
-  : public nsIOutputStream
-{
-  nsCString mData;
-  uint64_t mOffset;
-
-public:
-  static already_AddRefed<MemoryOutputStream>
-  Create(uint64_t aSize);
-
-  const nsCString&
-  Data() const
-  {
-    return mData;
-  }
-
-private:
-  MemoryOutputStream()
-  : mOffset(0)
-  { }
-
-  virtual ~MemoryOutputStream()
-  { }
-
-  NS_DECL_THREADSAFE_ISUPPORTS
-  NS_DECL_NSIOUTPUTSTREAM
-};
-
 class WriteOp final
   : public CopyFileHandleOp
 {
@@ -2404,96 +2376,6 @@ ReadOp::GetResponse(FileRequestResponse& aResponse)
   aResponse = FileRequestReadResponse(stream->Data());
 }
 
-// static
-already_AddRefed<ReadOp::MemoryOutputStream>
-ReadOp::
-MemoryOutputStream::Create(uint64_t aSize)
-{
-  MOZ_ASSERT(aSize, "Passed zero size!");
-
-  if (NS_WARN_IF(aSize > UINT32_MAX)) {
-    return nullptr;
-  }
-
-  RefPtr<MemoryOutputStream> stream = new MemoryOutputStream();
-
-  char* dummy;
-  uint32_t length = stream->mData.GetMutableData(&dummy, aSize, fallible);
-  if (NS_WARN_IF(length != aSize)) {
-    return nullptr;
-  }
-
-  return stream.forget();
-}
-
-NS_IMPL_ISUPPORTS(ReadOp::MemoryOutputStream, nsIOutputStream)
-
-NS_IMETHODIMP
-ReadOp::
-MemoryOutputStream::Close()
-{
-  mData.Truncate(mOffset);
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-ReadOp::
-MemoryOutputStream::Write(const char* aBuf, uint32_t aCount, uint32_t* _retval)
-{
-  return WriteSegments(NS_CopySegmentToBuffer, (char*)aBuf, aCount, _retval);
-}
-
-NS_IMETHODIMP
-ReadOp::
-MemoryOutputStream::Flush()
-{
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-ReadOp::
-MemoryOutputStream::WriteFrom(nsIInputStream* aFromStream, uint32_t aCount,
-                              uint32_t* _retval)
-{
-  return NS_ERROR_NOT_IMPLEMENTED;
-}
-
-NS_IMETHODIMP
-ReadOp::
-MemoryOutputStream::WriteSegments(nsReadSegmentFun aReader, void* aClosure,
-                                  uint32_t aCount, uint32_t* _retval)
-{
-  NS_ASSERTION(mData.Length() >= mOffset, "Bad stream state!");
-
-  uint32_t maxCount = mData.Length() - mOffset;
-  if (maxCount == 0) {
-    *_retval = 0;
-    return NS_OK;
-  }
-
-  if (aCount > maxCount) {
-    aCount = maxCount;
-  }
-
-  nsresult rv = aReader(this, aClosure, mData.BeginWriting() + mOffset, 0,
-                        aCount, _retval);
-  if (NS_SUCCEEDED(rv)) {
-    NS_ASSERTION(*_retval <= aCount,
-                 "Reader should not read more than we asked it to read!");
-    mOffset += *_retval;
-  }
-
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-ReadOp::
-MemoryOutputStream::IsNonBlocking(bool* _retval)
-{
-  *_retval = false;
-  return NS_OK;
-}
-
 WriteOp::WriteOp(FileHandle* aFileHandle,
                  const FileRequestParams& aParams)
   : CopyFileHandleOp(aFileHandle)

dom/quota/MemoryOutputStream.cpp

@@ -0,0 +1,100 @@
+/* -*- 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 "MemoryOutputStream.h"
+
+#include "nsStreamUtils.h"
+
+namespace mozilla {
+namespace dom {
+namespace quota {
+
+// static
+already_AddRefed<MemoryOutputStream>
+MemoryOutputStream::Create(uint64_t aSize)
+{
+  MOZ_ASSERT(aSize, "Passed zero size!");
+
+  if (NS_WARN_IF(aSize > UINT32_MAX)) {
+    return nullptr;
+  }
+
+  RefPtr<MemoryOutputStream> stream = new MemoryOutputStream();
+
+  char* dummy;
+  uint32_t length = stream->mData.GetMutableData(&dummy, aSize, fallible);
+  if (NS_WARN_IF(length != aSize)) {
+    return nullptr;
+  }
+
+  return stream.forget();
+}
+
+NS_IMPL_ISUPPORTS(MemoryOutputStream, nsIOutputStream)
+
+NS_IMETHODIMP
+MemoryOutputStream::Close()
+{
+  mData.Truncate(mOffset);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+MemoryOutputStream::Write(const char* aBuf, uint32_t aCount, uint32_t* _retval)
+{
+  return WriteSegments(NS_CopySegmentToBuffer, (char*)aBuf, aCount, _retval);
+}
+
+NS_IMETHODIMP
+MemoryOutputStream::Flush()
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+MemoryOutputStream::WriteFrom(nsIInputStream* aFromStream, uint32_t aCount,
+                              uint32_t* _retval)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+MemoryOutputStream::WriteSegments(nsReadSegmentFun aReader, void* aClosure,
+                                  uint32_t aCount, uint32_t* _retval)
+{
+  MOZ_ASSERT(mData.Length() >= mOffset, "Bad stream state!");
+
+  uint32_t maxCount = mData.Length() - mOffset;
+  if (maxCount == 0) {
+    *_retval = 0;
+    return NS_OK;
+  }
+
+  if (aCount > maxCount) {
+    aCount = maxCount;
+  }
+
+  nsresult rv = aReader(this, aClosure, mData.BeginWriting() + mOffset, 0,
+                        aCount, _retval);
+  if (NS_SUCCEEDED(rv)) {
+    MOZ_ASSERT(*_retval <= aCount,
+               "Reader should not read more than we asked it to read!");
+    mOffset += *_retval;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+MemoryOutputStream::IsNonBlocking(bool* _retval)
+{
+  *_retval = false;
+  return NS_OK;
+}
+
+} // namespace quota
+} // namespace dom
+} // namespace mozilla

dom/quota/MemoryOutputStream.h

@@ -0,0 +1,58 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_quota_MemoryOutputStream_h
+#define mozilla_dom_quota_MemoryOutputStream_h
+
+#include "nsIOutputStream.h"
+
+namespace mozilla {
+namespace dom {
+namespace quota {
+
+// An output stream so you can read your potentially-async input stream into
+// a contiguous buffer in the form of an nsCString using NS_AsyncCopy.
+// Back when streams were more synchronous and people didn't know blocking I/O
+// was bad, if you wanted to read a stream into a flat buffer, you could use
+// NS_ReadInputStreamToString/NS_ReadInputStreamToBuffer.  But those don't work
+// with async streams. This can be used to replace hand-rolled Read/AsyncWait()
+// loops.  Because you specify the expected size up front, the nsCString buffer
+// is pre-allocated so wasteful reallocations can be avoided.  However,
+// nsCString currently may over-allocate and this can be problematic on 32-bit
+// windows until we're rid of that build configuration.
+class MemoryOutputStream final
+  : public nsIOutputStream
+{
+  nsCString mData;
+  uint64_t mOffset;
+
+public:
+  static already_AddRefed<MemoryOutputStream>
+  Create(uint64_t aSize);
+
+  const nsCString&
+  Data() const
+  {
+    return mData;
+  }
+
+private:
+  MemoryOutputStream()
+  : mOffset(0)
+  { }
+
+  virtual ~MemoryOutputStream()
+  { }
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIOUTPUTSTREAM
+};
+
+} // namespace quota
+} // namespace dom
+} // namespace mozilla
+
+#endif /* mozilla_dom_quota_MemoryOutputStream_h */

dom/quota/moz.build

@@ -32,6 +32,7 @@ EXPORTS.mozilla.dom.quota += [
     'ActorsParent.h',
     'Client.h',
     'FileStreams.h',
+    'MemoryOutputStream.h',
     'OriginScope.h',
     'PersistenceType.h',
     'QuotaCommon.h',
@@ -46,6 +47,7 @@ UNIFIED_SOURCES += [
     'ActorsChild.cpp',
     'ActorsParent.cpp',
     'FileStreams.cpp',
+    'MemoryOutputStream.cpp',
     'QuotaManagerService.cpp',
     'QuotaRequests.cpp',
     'QuotaResults.cpp',