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Bug 1315913 - Part 1: Move nsFrameMessenger structured clone Build/Unpack into StructuredCloneData and expand to support PBackground. r=baku

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This commit is contained in:
Andrew Sutherland 2016-11-07 08:38:02 -05:00
parent b1840b3633
commit 7390cfe98f
4 changed files with 523 additions and 136 deletions
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134
dom/base/nsFrameMessageManager.cpp
View File

@ -202,108 +202,12 @@ NS_INTERFACE_MAP_END
NS_IMPL_CYCLE_COLLECTING_ADDREF(nsFrameMessageManager)
NS_IMPL_CYCLE_COLLECTING_RELEASE(nsFrameMessageManager)
enum ActorFlavorEnum {
Parent = 0,
Child
};
template <ActorFlavorEnum>
struct BlobTraits
{ };
template <>
struct BlobTraits<Parent>
{
typedef mozilla::dom::BlobParent BlobType;
typedef mozilla::dom::PBlobParent ProtocolType;
typedef mozilla::dom::nsIContentParent ConcreteContentManagerType;
};
template <>
struct BlobTraits<Child>
{
typedef mozilla::dom::BlobChild BlobType;
typedef mozilla::dom::PBlobChild ProtocolType;
typedef mozilla::dom::nsIContentChild ConcreteContentManagerType;
};
template<ActorFlavorEnum>
struct DataBlobs
{ };
template<>
struct DataBlobs<Parent>
{
typedef BlobTraits<Parent>::ProtocolType ProtocolType;
static InfallibleTArray<ProtocolType*>& Blobs(ClonedMessageData& aData)
{
return aData.blobsParent();
}
static const InfallibleTArray<ProtocolType*>& Blobs(const ClonedMessageData& aData)
{
return aData.blobsParent();
}
};
template<>
struct DataBlobs<Child>
{
typedef BlobTraits<Child>::ProtocolType ProtocolType;
static InfallibleTArray<ProtocolType*>& Blobs(ClonedMessageData& aData)
{
return aData.blobsChild();
}
static const InfallibleTArray<ProtocolType*>& Blobs(const ClonedMessageData& aData)
{
return aData.blobsChild();
}
};
template<ActorFlavorEnum Flavor>
static bool
BuildClonedMessageData(typename BlobTraits<Flavor>::ConcreteContentManagerType* aManager,
StructuredCloneData& aData,
ClonedMessageData& aClonedData)
{
SerializedStructuredCloneBuffer& buffer = aClonedData.data();
auto iter = aData.Data().Iter();
size_t size = aData.Data().Size();
bool success;
buffer.data = aData.Data().Borrow<js::SystemAllocPolicy>(iter, size, &success);
if (NS_WARN_IF(!success)) {
return false;
}
aClonedData.identfiers().AppendElements(aData.PortIdentifiers());
const nsTArray<RefPtr<BlobImpl>>& blobImpls = aData.BlobImpls();
if (!blobImpls.IsEmpty()) {
typedef typename BlobTraits<Flavor>::ProtocolType ProtocolType;
InfallibleTArray<ProtocolType*>& blobList = DataBlobs<Flavor>::Blobs(aClonedData);
uint32_t length = blobImpls.Length();
blobList.SetCapacity(length);
for (uint32_t i = 0; i < length; ++i) {
typename BlobTraits<Flavor>::BlobType* protocolActor =
aManager->GetOrCreateActorForBlobImpl(blobImpls[i]);
if (!protocolActor) {
return false;
}
blobList.AppendElement(protocolActor);
}
}
return true;
}
bool
MessageManagerCallback::BuildClonedMessageDataForParent(nsIContentParent* aParent,
StructuredCloneData& aData,
ClonedMessageData& aClonedData)
{
return BuildClonedMessageData<Parent>(aParent, aData, aClonedData);
return aData.BuildClonedMessageDataForParent(aParent, aClonedData);
}
bool
@ -311,51 +215,21 @@ MessageManagerCallback::BuildClonedMessageDataForChild(nsIContentChild* aChild,
StructuredCloneData& aData,
ClonedMessageData& aClonedData)
{
return BuildClonedMessageData<Child>(aChild, aData, aClonedData);
}
template<ActorFlavorEnum Flavor>
static void
UnpackClonedMessageData(const ClonedMessageData& aClonedData,
StructuredCloneData& aData)
{
const SerializedStructuredCloneBuffer& buffer = aClonedData.data();
typedef typename BlobTraits<Flavor>::ProtocolType ProtocolType;
const InfallibleTArray<ProtocolType*>& blobs = DataBlobs<Flavor>::Blobs(aClonedData);
const InfallibleTArray<MessagePortIdentifier>& identifiers = aClonedData.identfiers();
aData.UseExternalData(buffer.data);
aData.PortIdentifiers().AppendElements(identifiers);
if (!blobs.IsEmpty()) {
uint32_t length = blobs.Length();
aData.BlobImpls().SetCapacity(length);
for (uint32_t i = 0; i < length; ++i) {
auto* blob =
static_cast<typename BlobTraits<Flavor>::BlobType*>(blobs[i]);
MOZ_ASSERT(blob);
RefPtr<BlobImpl> blobImpl = blob->GetBlobImpl();
MOZ_ASSERT(blobImpl);
aData.BlobImpls().AppendElement(blobImpl);
}
}
return aData.BuildClonedMessageDataForChild(aChild, aClonedData);
}
void
mozilla::dom::ipc::UnpackClonedMessageDataForParent(const ClonedMessageData& aClonedData,
StructuredCloneData& aData)
{
UnpackClonedMessageData<Parent>(aClonedData, aData);
aData.BorrowFromClonedMessageDataForParent(aClonedData);
}
void
mozilla::dom::ipc::UnpackClonedMessageDataForChild(const ClonedMessageData& aClonedData,
StructuredCloneData& aData)
{
UnpackClonedMessageData<Child>(aClonedData, aData);
aData.BorrowFromClonedMessageDataForChild(aClonedData);
}
bool

6
dom/ipc/DOMTypes.ipdlh
View File

@ -32,6 +32,12 @@ struct MessagePortIdentifier
bool neutered;
};
/**
* Cross-process representation for postMessage() style payloads where Blobs may
* be referenced/"cloned" and (optionally) messageports transferred. Use
* StructuredCloneData in your code to convert between this wire representation
* and the StructuredCloneData StructuredCloneHolder-subclass.
*/
struct ClonedMessageData
{
SerializedStructuredCloneBuffer data;

357
dom/ipc/StructuredCloneData.cpp
View File

@ -40,7 +40,9 @@ StructuredCloneData::Copy(const StructuredCloneData& aData)
NS_ENSURE_TRUE(mSharedData, false);
}
PortIdentifiers().AppendElements(aData.PortIdentifiers());
if (mSupportsTransferring) {
PortIdentifiers().AppendElements(aData.PortIdentifiers());
}
MOZ_ASSERT(BlobImpls().IsEmpty());
BlobImpls().AppendElements(aData.BlobImpls());
@ -96,6 +98,340 @@ StructuredCloneData::Write(JSContext* aCx,
mInitialized = true;
}
enum ActorFlavorEnum {
Parent = 0,
Child,
};
enum ManagerFlavorEnum {
ContentProtocol = 0,
BackgroundProtocol
};
template <ActorFlavorEnum>
struct BlobTraits
{ };
template <>
struct BlobTraits<Parent>
{
typedef mozilla::dom::BlobParent BlobType;
typedef mozilla::dom::PBlobParent ProtocolType;
};
template <>
struct BlobTraits<Child>
{
typedef mozilla::dom::BlobChild BlobType;
typedef mozilla::dom::PBlobChild ProtocolType;
};
template <ActorFlavorEnum, ManagerFlavorEnum>
struct ParentManagerTraits
{ };
template<>
struct ParentManagerTraits<Parent, ContentProtocol>
{
typedef mozilla::dom::nsIContentParent ConcreteContentManagerType;
};
template<>
struct ParentManagerTraits<Child, ContentProtocol>
{
typedef mozilla::dom::nsIContentChild ConcreteContentManagerType;
};
template<>
struct ParentManagerTraits<Parent, BackgroundProtocol>
{
typedef mozilla::ipc::PBackgroundParent ConcreteContentManagerType;
};
template<>
struct ParentManagerTraits<Child, BackgroundProtocol>
{
typedef mozilla::ipc::PBackgroundChild ConcreteContentManagerType;
};
template<ActorFlavorEnum>
struct DataBlobs
{ };
template<>
struct DataBlobs<Parent>
{
typedef BlobTraits<Parent>::ProtocolType ProtocolType;
static InfallibleTArray<ProtocolType*>& Blobs(ClonedMessageData& aData)
{
return aData.blobsParent();
}
static const InfallibleTArray<ProtocolType*>& Blobs(const ClonedMessageData& aData)
{
return aData.blobsParent();
}
};
template<>
struct DataBlobs<Child>
{
typedef BlobTraits<Child>::ProtocolType ProtocolType;
static InfallibleTArray<ProtocolType*>& Blobs(ClonedMessageData& aData)
{
return aData.blobsChild();
}
static const InfallibleTArray<ProtocolType*>& Blobs(const ClonedMessageData& aData)
{
return aData.blobsChild();
}
};
template<ActorFlavorEnum Flavor, ManagerFlavorEnum ManagerFlavor>
static bool
BuildClonedMessageData(typename ParentManagerTraits<Flavor, ManagerFlavor>::ConcreteContentManagerType* aManager,
StructuredCloneData& aData,
ClonedMessageData& aClonedData)
{
SerializedStructuredCloneBuffer& buffer = aClonedData.data();
auto iter = aData.Data().Iter();
size_t size = aData.Data().Size();
bool success;
buffer.data = aData.Data().Borrow<js::SystemAllocPolicy>(iter, size, &success);
if (NS_WARN_IF(!success)) {
return false;
}
if (aData.SupportsTransferring()) {
aClonedData.identfiers().AppendElements(aData.PortIdentifiers());
}
const nsTArray<RefPtr<BlobImpl>>& blobImpls = aData.BlobImpls();
if (!blobImpls.IsEmpty()) {
typedef typename BlobTraits<Flavor>::BlobType BlobType;
typedef typename BlobTraits<Flavor>::ProtocolType ProtocolType;
InfallibleTArray<ProtocolType*>& blobList = DataBlobs<Flavor>::Blobs(aClonedData);
uint32_t length = blobImpls.Length();
blobList.SetCapacity(length);
for (uint32_t i = 0; i < length; ++i) {
BlobType* protocolActor = BlobType::GetOrCreate(aManager, blobImpls[i]);
if (!protocolActor) {
return false;
}
blobList.AppendElement(protocolActor);
}
}
return true;
}
bool
StructuredCloneData::BuildClonedMessageDataForParent(
nsIContentParent* aParent,
ClonedMessageData& aClonedData)
{
return BuildClonedMessageData<Parent, ContentProtocol>(aParent, *this, aClonedData);
}
bool
StructuredCloneData::BuildClonedMessageDataForChild(
nsIContentChild* aChild,
ClonedMessageData& aClonedData)
{
return BuildClonedMessageData<Child, ContentProtocol>(aChild, *this, aClonedData);
}
bool
StructuredCloneData::BuildClonedMessageDataForBackgroundParent(
PBackgroundParent* aParent,
ClonedMessageData& aClonedData)
{
return BuildClonedMessageData<Parent, BackgroundProtocol>(aParent, *this, aClonedData);
}
bool
StructuredCloneData::BuildClonedMessageDataForBackgroundChild(
PBackgroundChild* aChild,
ClonedMessageData& aClonedData)
{
return BuildClonedMessageData<Child, BackgroundProtocol>(aChild, *this, aClonedData);
}
// See the StructuredCloneData class block comment for the meanings of each val.
enum MemoryFlavorEnum {
BorrowMemory = 0,
CopyMemory,
StealMemory
};
template<MemoryFlavorEnum>
struct MemoryTraits
{ };
template<>
struct MemoryTraits<BorrowMemory>
{
typedef const mozilla::dom::ClonedMessageData ClonedMessageType;
static void ProvideBuffer(const ClonedMessageData& aClonedData,
StructuredCloneData& aData)
{
const SerializedStructuredCloneBuffer& buffer = aClonedData.data();
aData.UseExternalData(buffer.data);
}
};
template<>
struct MemoryTraits<CopyMemory>
{
typedef const mozilla::dom::ClonedMessageData ClonedMessageType;
static void ProvideBuffer(const ClonedMessageData& aClonedData,
StructuredCloneData& aData)
{
const SerializedStructuredCloneBuffer& buffer = aClonedData.data();
aData.CopyExternalData(buffer.data);
}
};
template<>
struct MemoryTraits<StealMemory>
{
// note: not const!
typedef mozilla::dom::ClonedMessageData ClonedMessageType;
static void ProvideBuffer(ClonedMessageData& aClonedData,
StructuredCloneData& aData)
{
SerializedStructuredCloneBuffer& buffer = aClonedData.data();
aData.StealExternalData(buffer.data);
}
};
// Note that there isn't actually a difference between Parent/BackgroundParent
// and Child/BackgroundChild in this implementation. The calling methods,
// however, do maintain the distinction for code-reading purposes and are backed
// by assertions to enforce there is no misuse.
template<MemoryFlavorEnum MemoryFlavor, ActorFlavorEnum Flavor>
static void
UnpackClonedMessageData(typename MemoryTraits<MemoryFlavor>::ClonedMessageType& aClonedData,
StructuredCloneData& aData)
{
typedef typename BlobTraits<Flavor>::ProtocolType ProtocolType;
const InfallibleTArray<ProtocolType*>& blobs = DataBlobs<Flavor>::Blobs(aClonedData);
const InfallibleTArray<MessagePortIdentifier>& identifiers = aClonedData.identfiers();
MemoryTraits<MemoryFlavor>::ProvideBuffer(aClonedData, aData);
if (aData.SupportsTransferring()) {
aData.PortIdentifiers().AppendElements(identifiers);
}
if (!blobs.IsEmpty()) {
uint32_t length = blobs.Length();
aData.BlobImpls().SetCapacity(length);
for (uint32_t i = 0; i < length; ++i) {
auto* blob =
static_cast<typename BlobTraits<Flavor>::BlobType*>(blobs[i]);
MOZ_ASSERT(blob);
RefPtr<BlobImpl> blobImpl = blob->GetBlobImpl();
MOZ_ASSERT(blobImpl);
aData.BlobImpls().AppendElement(blobImpl);
}
}
}
void
StructuredCloneData::BorrowFromClonedMessageDataForParent(const ClonedMessageData& aClonedData)
{
// PContent parent is always main thread and actor constraints demand we're
// likewise on that thread.
MOZ_ASSERT(NS_IsMainThread());
UnpackClonedMessageData<BorrowMemory, Parent>(aClonedData, *this);
}
void
StructuredCloneData::BorrowFromClonedMessageDataForChild(const ClonedMessageData& aClonedData)
{
// PContent child is always main thread and actor constraints demand we're
// likewise on that thread.
MOZ_ASSERT(NS_IsMainThread());
UnpackClonedMessageData<BorrowMemory, Child>(aClonedData, *this);
}
void
StructuredCloneData::BorrowFromClonedMessageDataForBackgroundParent(const ClonedMessageData& aClonedData)
{
MOZ_ASSERT(IsOnBackgroundThread());
UnpackClonedMessageData<BorrowMemory, Parent>(aClonedData, *this);
}
void
StructuredCloneData::BorrowFromClonedMessageDataForBackgroundChild(const ClonedMessageData& aClonedData)
{
// No thread assertion; BackgroundChild can happen on any thread.
UnpackClonedMessageData<BorrowMemory, Child>(aClonedData, *this);
}
void
StructuredCloneData::CopyFromClonedMessageDataForParent(const ClonedMessageData& aClonedData)
{
MOZ_ASSERT(NS_IsMainThread());
UnpackClonedMessageData<CopyMemory, Parent>(aClonedData, *this);
}
void
StructuredCloneData::CopyFromClonedMessageDataForChild(const ClonedMessageData& aClonedData)
{
MOZ_ASSERT(NS_IsMainThread());
UnpackClonedMessageData<CopyMemory, Child>(aClonedData, *this);
}
void
StructuredCloneData::CopyFromClonedMessageDataForBackgroundParent(const ClonedMessageData& aClonedData)
{
MOZ_ASSERT(IsOnBackgroundThread());
UnpackClonedMessageData<BorrowMemory, Parent>(aClonedData, *this);
}
void
StructuredCloneData::CopyFromClonedMessageDataForBackgroundChild(const ClonedMessageData& aClonedData)
{
UnpackClonedMessageData<CopyMemory, Child>(aClonedData, *this);
}
void
StructuredCloneData::StealFromClonedMessageDataForParent(ClonedMessageData& aClonedData)
{
MOZ_ASSERT(NS_IsMainThread());
UnpackClonedMessageData<StealMemory, Parent>(aClonedData, *this);
}
void
StructuredCloneData::StealFromClonedMessageDataForChild(ClonedMessageData& aClonedData)
{
MOZ_ASSERT(NS_IsMainThread());
UnpackClonedMessageData<StealMemory, Child>(aClonedData, *this);
}
void
StructuredCloneData::StealFromClonedMessageDataForBackgroundParent(ClonedMessageData& aClonedData)
{
MOZ_ASSERT(IsOnBackgroundThread());
UnpackClonedMessageData<StealMemory, Parent>(aClonedData, *this);
}
void
StructuredCloneData::StealFromClonedMessageDataForBackgroundChild(ClonedMessageData& aClonedData)
{
UnpackClonedMessageData<StealMemory, Child>(aClonedData, *this);
}
void
StructuredCloneData::WriteIPCParams(IPC::Message* aMsg) const
{
@ -128,6 +464,25 @@ StructuredCloneData::CopyExternalData(const char* aData,
return true;
}
bool
StructuredCloneData::CopyExternalData(const JSStructuredCloneData& aData)
{
MOZ_ASSERT(!mInitialized);
mSharedData = SharedJSAllocatedData::CreateFromExternalData(aData);
NS_ENSURE_TRUE(mSharedData, false);
mInitialized = true;
return true;
}
bool
StructuredCloneData::StealExternalData(JSStructuredCloneData& aData)
{
MOZ_ASSERT(!mInitialized);
mSharedData = new SharedJSAllocatedData(Move(aData));
mInitialized = true;
return true;
}
} // namespace ipc
} // namespace dom
} // namespace mozilla

162
dom/ipc/StructuredCloneData.h
View File

@ -18,9 +18,30 @@ class Message;
class PickleIterator;
namespace mozilla {
namespace dom {
namespace ipc {
class PBackgroundChild;
class PBackgroundParent;
} // namespace ipc
namespace dom {
class nsIContentChild;
class nsIContentParent;
namespace ipc {
/**
* Wraps the non-reference-counted JSStructuredCloneData class to have a
* reference count so that multiple StructuredCloneData instances can reference
* a single underlying serialized representation.
*
* As used by StructuredCloneData, it is an invariant that our
* JSStructuredCloneData owns its buffers. (For the non-owning case,
* StructuredCloneData uses mExternalData which holds a BufferList::Borrow()ed
* read-only view of the data.)
*/
class SharedJSAllocatedData final
{
public:
@ -63,14 +84,74 @@ private:
JSStructuredCloneData mData;
};
/**
* IPC-aware StructuredCloneHolder subclass that serves as both a helper class
* for dealing with message data (blobs, transferables) and also an IPDL
* data-type in cases where message data is not needed. If your use-case does
* not (potentially) involve IPC, then you should use StructuredCloneHolder or
* one of its other subclasses instead.
*
* ## Usage ##
*
* The general recipe for using this class is:
* - In your IPDL definition, use the ClonedMessageData type whenever you want
* to send a structured clone that may include blobs or transferables such as
* message ports.
* - To send the data, instantiate a StructuredCloneData instance and Write()
* into it like a normal structure clone. When you are ready to send the
* ClonedMessageData-bearing IPC message, use the appropriate
* BuildClonedMessageDataFor{Parent,Child,BackgroundParent,BackgroundChild}
* method to populate the ClonedMessageData and then send it before your
* StructuredCloneData instance is destroyed. (Buffer borrowing is used
* under-the-hood to avoid duplicating the serialized data, requiring this.)
* - To receive the data, instantiate a StructuredCloneData and use the
* appropriate {Borrow,Copy,Steal}FromClonedMessageDataFor{Parent,Child,
* BackgroundParent,BackgroundChild} method. See the memory management
* section for more info.
*
* Variations:
* - If transferables are not allowed (ex: BroadcastChannel), then use the
* StructuredCloneDataNoTransfers subclass instead of StructuredCloneData.
*
* ## Memory Management ##
*
* Serialized structured clone representations can be quite large. So it's best
* to avoid wasteful duplication. When Write()ing into the StructuredCloneData,
* you don't need to worry about this[1], but when you already have serialized
* structured clone data you plan to Read(), you do need to. Similarly, if
* you're using StructuredCloneData as an IPDL type, it efficiently unmarshals.
*
* The from-ClonedMessageData memory management strategies available are:
* - Borrow: Create a JSStructuredCloneData that holds a non-owning, read-only
* BufferList::Borrow()ed copy of the source. Your StructuredCloneData needs
* to be destroyed before the source is. Commonly used when the
* StructuredCloneData instance is stack-allocated (and Read() is used before
* the function returns).
* - Copy: Makes a reference-counted copy of the source JSStructuredCloneData,
* making it safe for the StructuredCloneData to outlive the source data.
* - Steal: Steal the buffers from the underlying JSStructuredCloneData so that
* it's safe for the StructuredCloneData to outlive the source data. This is
* safe to use with IPC-provided ClonedMessageData instances because
* JSStructuredCloneData's IPC ParamTraits::Read method uses ExtractBuffers,
* returning a fatal false if unable to extract. (And
* SerializedStructuredCloneBuffer wraps/defers to it.) But if it's possible
* the ClonedMessageData came from a different source that might have borrowed
* the buffers itself, then things will crash. That would be a pretty crazy
* implementation; if you see one, change it to use SharedJSAllocatedData.
*
* 1: Specifically, in the Write() case an owning SharedJSAllocatedData is
* created efficiently (by stealing from StructuredCloneHolder). The
* BuildClonedMessageDataFor* method can be called at any time and it will
* borrow the underlying memory. While it would be even better if
* SerializedStructuredCloneBuffer could hold a SharedJSAllocatedData ref,
* there's no reason you can't wait to BuildClonedMessageDataFor* until you
* need to make the IPC Send* call.
*/
class StructuredCloneData : public StructuredCloneHolder
{
public:
StructuredCloneData()
: StructuredCloneHolder(StructuredCloneHolder::CloningSupported,
StructuredCloneHolder::TransferringSupported,
StructuredCloneHolder::StructuredCloneScope::DifferentProcess)
, mInitialized(false)
: StructuredCloneData(StructuredCloneHolder::TransferringSupported)
{}
StructuredCloneData(const StructuredCloneData&) = delete;
@ -111,6 +192,41 @@ public:
JS::Handle<JS::Value> aTransfers,
ErrorResult &aRv);
// Actor-varying methods to convert the structured clone stored in this holder
// by a previous call to Write() into ClonedMessageData IPC representation.
// (Blobs are represented in IPC by PBlob actors, so we need the parent to be
// able to create them.)
bool BuildClonedMessageDataForParent(nsIContentParent* aParent,
ClonedMessageData& aClonedData);
bool BuildClonedMessageDataForChild(nsIContentChild* aChild,
ClonedMessageData& aClonedData);
bool BuildClonedMessageDataForBackgroundParent(mozilla::ipc::PBackgroundParent* aParent,
ClonedMessageData& aClonedData);
bool BuildClonedMessageDataForBackgroundChild(mozilla::ipc::PBackgroundChild* aChild,
ClonedMessageData& aClonedData);
// Actor-varying and memory-management-strategy-varying methods to initialize
// this holder from a ClonedMessageData representation.
void BorrowFromClonedMessageDataForParent(const ClonedMessageData& aClonedData);
void BorrowFromClonedMessageDataForChild(const ClonedMessageData& aClonedData);
void BorrowFromClonedMessageDataForBackgroundParent(const ClonedMessageData& aClonedData);
void BorrowFromClonedMessageDataForBackgroundChild(const ClonedMessageData& aClonedData);
void CopyFromClonedMessageDataForParent(const ClonedMessageData& aClonedData);
void CopyFromClonedMessageDataForChild(const ClonedMessageData& aClonedData);
void CopyFromClonedMessageDataForBackgroundParent(const ClonedMessageData& aClonedData);
void CopyFromClonedMessageDataForBackgroundChild(const ClonedMessageData& aClonedData);
// The steal variants of course take a non-const ClonedMessageData.
void StealFromClonedMessageDataForParent(ClonedMessageData& aClonedData);
void StealFromClonedMessageDataForChild(ClonedMessageData& aClonedData);
void StealFromClonedMessageDataForBackgroundParent(ClonedMessageData& aClonedData);
void StealFromClonedMessageDataForBackgroundChild(ClonedMessageData& aClonedData);
// Initialize this instance, borrowing the contents of the given
// JSStructuredCloneData. You are responsible for ensuring that this
// StructuredCloneData instance is destroyed before aData is destroyed.
bool UseExternalData(const JSStructuredCloneData& aData)
{
auto iter = aData.Iter();
@ -121,7 +237,19 @@ public:
return success;
}
// Initialize this instance by copying the given data that probably came from
// nsStructuredClone doing a base64 decode. Don't use this.
bool CopyExternalData(const char* aData, size_t aDataLength);
// Initialize this instance by copying the contents of an existing
// JSStructuredCloneData. Use when this StructuredCloneData instance may
// outlive aData.
bool CopyExternalData(const JSStructuredCloneData& aData);
// Initialize this instance by stealing the contents of aData via Move
// constructor, clearing the original aData as a side-effect. This is only
// safe if aData owns the underlying buffers. This is the case for instances
// provided by IPC to Recv calls.
bool StealExternalData(JSStructuredCloneData& aData);
JSStructuredCloneData& Data()
{
@ -143,16 +271,40 @@ public:
return mSharedData;
}
bool SupportsTransferring()
{
return mSupportsTransferring;
}
// For IPC serialization
void WriteIPCParams(IPC::Message* aMessage) const;
bool ReadIPCParams(const IPC::Message* aMessage, PickleIterator* aIter);
protected:
explicit StructuredCloneData(TransferringSupport aSupportsTransferring)
: StructuredCloneHolder(StructuredCloneHolder::CloningSupported,
aSupportsTransferring,
StructuredCloneHolder::StructuredCloneScope::DifferentProcess)
, mInitialized(false)
{}
private:
JSStructuredCloneData mExternalData;
RefPtr<SharedJSAllocatedData> mSharedData;
bool mInitialized;
};
/**
* For use when transferring should not be supported.
*/
class StructuredCloneDataNoTransfers : public StructuredCloneData {
public:
StructuredCloneDataNoTransfers()
: StructuredCloneData(StructuredCloneHolder::TransferringNotSupported)
{}
};
} // namespace ipc
} // namespace dom
} // namespace mozilla