Source/WebCore/platform/network/cf/FormDataStreamCFNet.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2005-2017 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
  *     documentation and/or other materials provided with the distribution.
  * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
  *     its contributors may be used to endorse or promote products derived
  *     from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "config.h"
 #include "FormDataStreamCFNet.h"

 #include "BlobData.h"
 #include "BlobRegistry.h"
 #include "FormData.h"
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <wtf/Assertions.h>
 #include <wtf/FileSystem.h>
 #include <wtf/HashMap.h>
 #include <wtf/MainThread.h>
 #include <wtf/RetainPtr.h>
 #include <wtf/SchedulePair.h>
 #include <wtf/StdLibExtras.h>
 #include <wtf/Threading.h>

 static const SInt32 fileNotFoundError = -43;

 #if PLATFORM(COCOA)
 extern "C" void CFURLRequestSetHTTPRequestBody(CFMutableURLRequestRef mutableHTTPRequest, CFDataRef httpBody);
 extern "C" void CFURLRequestSetHTTPHeaderFieldValue(CFMutableURLRequestRef mutableHTTPRequest, CFStringRef httpHeaderField, CFStringRef httpHeaderFieldValue);
 extern "C" void CFURLRequestSetHTTPRequestBodyStream(CFMutableURLRequestRef req, CFReadStreamRef bodyStream);
 #elif PLATFORM(WIN)
 #include <CFNetwork/CFURLRequest.h>
 #endif

 typedef struct {
     CFIndex version; /* == 1 */
     void *(*create)(CFReadStreamRef stream, void *info);
     void (*finalize)(CFReadStreamRef stream, void *info);
     CFStringRef (*copyDescription)(CFReadStreamRef stream, void *info);
     Boolean (*open)(CFReadStreamRef stream, CFStreamError *error, Boolean *openComplete, void *info);
     Boolean (*openCompleted)(CFReadStreamRef stream, CFStreamError *error, void *info);
     CFIndex (*read)(CFReadStreamRef stream, UInt8 *buffer, CFIndex bufferLength, CFStreamError *error, Boolean *atEOF, void *info);
     const UInt8 *(*getBuffer)(CFReadStreamRef stream, CFIndex maxBytesToRead, CFIndex *numBytesRead, CFStreamError *error, Boolean *atEOF, void *info);
     Boolean (*canRead)(CFReadStreamRef stream, void *info);
     void (*close)(CFReadStreamRef stream, void *info);
     CFTypeRef (*copyProperty)(CFReadStreamRef stream, CFStringRef propertyName, void *info);
     Boolean (*setProperty)(CFReadStreamRef stream, CFStringRef propertyName, CFTypeRef propertyValue, void *info);
     void (*requestEvents)(CFReadStreamRef stream, CFOptionFlags streamEvents, void *info);
     void (*schedule)(CFReadStreamRef stream, CFRunLoopRef runLoop, CFStringRef runLoopMode, void *info);
     void (*unschedule)(CFReadStreamRef stream, CFRunLoopRef runLoop, CFStringRef runLoopMode, void *info);
 } CFReadStreamCallBacksV1;

 #if PLATFORM(WIN)
 #define EXTERN extern "C" __declspec(dllimport)
 #else
 #define EXTERN extern "C"
 #endif

 EXTERN void CFReadStreamSignalEvent(CFReadStreamRef stream, CFStreamEventType event, const void *error);
 EXTERN CFReadStreamRef CFReadStreamCreate(CFAllocatorRef alloc, const void *callbacks, void *info);

 namespace WebCore {

 static void formEventCallback(CFReadStreamRef stream, CFStreamEventType type, void* context);

 static CFStringRef formDataPointerPropertyName = CFSTR("WebKitFormDataPointer");

 CFStringRef formDataStreamLengthPropertyName()
 {
     return CFSTR("WebKitFormDataStreamLength");
 }

 struct FormCreationContext {
     FormDataForUpload data;
     unsigned long long streamLength;
 };

 struct FormStreamFields {
     FormStreamFields(FormDataForUpload&& data)
         : data(WTFMove(data)) { }

     FormDataForUpload data;
     SchedulePairHashSet scheduledRunLoopPairs;
     Vector<FormDataElement> remainingElements; // in reverse order
     CFReadStreamRef currentStream { nullptr };
     long long currentStreamRangeLength { BlobDataItem::toEndOfFile };
     MallocPtr<char> currentData;
     CFReadStreamRef formStream { nullptr };
     unsigned long long streamLength { 0 };
     unsigned long long bytesSent { 0 };
     Lock streamIsBeingOpenedOrClosedLock;
 };

 static void closeCurrentStream(FormStreamFields* form)
 {
     ASSERT(form->streamIsBeingOpenedOrClosedLock.isHeld());

     if (form->currentStream) {
         CFReadStreamClose(form->currentStream);
         CFReadStreamSetClient(form->currentStream, kCFStreamEventNone, 0, 0);
         CFRelease(form->currentStream);
         form->currentStream = 0;
         form->currentStreamRangeLength = BlobDataItem::toEndOfFile;
     }

     form->currentData = nullptr;
 }

 // Return false if we cannot advance the stream. Currently the only possible failure is that the underlying file has been removed or changed since File.slice.
 static bool advanceCurrentStream(FormStreamFields* form)
 {
     ASSERT(form->streamIsBeingOpenedOrClosedLock.isHeld());

     closeCurrentStream(form);

     if (form->remainingElements.isEmpty())
         return true;

     // Create the new stream.
     FormDataElement& nextInput = form->remainingElements.last();

     bool success = switchOn(nextInput.data,
         [form] (Vector<char>& bytes) {
             size_t size = bytes.size();
             MallocPtr<char> data = bytes.releaseBuffer();
             form->currentStream = CFReadStreamCreateWithBytesNoCopy(0, reinterpret_cast<const UInt8*>(data.get()), size, kCFAllocatorNull);
             form->currentData = WTFMove(data);
             return true;
         }, [form] (const FormDataElement::EncodedFileData& fileData) {
             // Check if the file has been changed.
             if (!fileData.fileModificationTimeMatchesExpectation())
                 return false;

             const String& path = fileData.filename;
             form->currentStream = CFReadStreamCreateWithFile(0, FileSystem::pathAsURL(path).get());
             if (!form->currentStream) {
                 // The file must have been removed or become unreadable.
                 return false;
             }
             if (fileData.fileStart > 0) {
                 RetainPtr<CFNumberRef> position = adoptCF(CFNumberCreate(0, kCFNumberLongLongType, &fileData.fileStart));
                 CFReadStreamSetProperty(form->currentStream, kCFStreamPropertyFileCurrentOffset, position.get());
             }
             form->currentStreamRangeLength = fileData.fileLength;
             return true;
         }, [] (const FormDataElement::EncodedBlobData&) {
             ASSERT_NOT_REACHED();
             return false;
         }
     );

     if (!success)
         return false;

     form->remainingElements.removeLast();

     // Set up the callback.
     CFStreamClientContext context = { 0, form, 0, 0, 0 };
     CFReadStreamSetClient(form->currentStream, kCFStreamEventHasBytesAvailable | kCFStreamEventErrorOccurred | kCFStreamEventEndEncountered,
         formEventCallback, &context);

     // Schedule with the current set of run loops.
     SchedulePairHashSet::iterator end = form->scheduledRunLoopPairs.end();
     for (SchedulePairHashSet::iterator it = form->scheduledRunLoopPairs.begin(); it != end; ++it)
         CFReadStreamScheduleWithRunLoop(form->currentStream, (*it)->runLoop(), (*it)->mode());

     return true;
 }

 static bool openNextStream(FormStreamFields* form)
 {
     // CFReadStreamOpen() can cause this function to be re-entered from another thread before it returns.
     // One example when this can occur is when the stream being opened has no data. See <rdar://problem/23550269>.
     LockHolder locker(form->streamIsBeingOpenedOrClosedLock);

     // Skip over any streams we can't open.
     if (!advanceCurrentStream(form))
         return false;
     while (form->currentStream && !CFReadStreamOpen(form->currentStream)) {
         if (!advanceCurrentStream(form))
             return false;
     }
     return true;
 }

 static void* formCreate(CFReadStreamRef stream, void* context)
 {
     FormCreationContext* formContext = static_cast<FormCreationContext*>(context);

     FormStreamFields* newInfo = new FormStreamFields(WTFMove(formContext->data));
     newInfo->formStream = stream; // Don't retain. That would create a reference cycle.
     newInfo->streamLength = formContext->streamLength;

     callOnMainThread([formContext] {
         delete formContext;
     });

     // Append in reverse order since we remove elements from the end.
     size_t size = newInfo->data.data().elements().size();
     newInfo->remainingElements.reserveInitialCapacity(size);
     for (size_t i = 0; i < size; ++i)
         newInfo->remainingElements.uncheckedAppend(newInfo->data.data().elements()[size - i - 1]);

     return newInfo;
 }

 static void formFinalize(CFReadStreamRef stream, void* context)
 {
     FormStreamFields* form = static_cast<FormStreamFields*>(context);
     ASSERT_UNUSED(stream, form->formStream == stream);

     callOnMainThread([form] {
         {
             LockHolder locker(form->streamIsBeingOpenedOrClosedLock);
             closeCurrentStream(form);
         }
         delete form;
     });
 }

 static Boolean formOpen(CFReadStreamRef, CFStreamError* error, Boolean* openComplete, void* context)
 {
     FormStreamFields* form = static_cast<FormStreamFields*>(context);

     bool opened = openNextStream(form);

     *openComplete = opened;
     error->error = opened ? 0 :
 #if PLATFORM(WIN)
         ENOENT;
 #else
         fileNotFoundError;
 #endif
     return opened;
 }

 static CFIndex formRead(CFReadStreamRef, UInt8* buffer, CFIndex bufferLength, CFStreamError* error, Boolean* atEOF, void* context)
 {
     FormStreamFields* form = static_cast<FormStreamFields*>(context);

     while (form->currentStream) {
         CFIndex bytesToRead = bufferLength;
         if (form->currentStreamRangeLength != BlobDataItem::toEndOfFile && form->currentStreamRangeLength < bytesToRead)
             bytesToRead = static_cast<CFIndex>(form->currentStreamRangeLength);
         CFIndex bytesRead = CFReadStreamRead(form->currentStream, buffer, bytesToRead);
         if (bytesRead < 0) {
             *error = CFReadStreamGetError(form->currentStream);
             return -1;
         }
         if (bytesRead > 0) {
             error->error = 0;
             *atEOF = FALSE;
             form->bytesSent += bytesRead;
             if (form->currentStreamRangeLength != BlobDataItem::toEndOfFile)
                 form->currentStreamRangeLength -= bytesRead;

             return bytesRead;
         }
         openNextStream(form);
     }

     error->error = 0;
     *atEOF = TRUE;
     return 0;
 }

 static Boolean formCanRead(CFReadStreamRef stream, void* context)
 {
     FormStreamFields* form = static_cast<FormStreamFields*>(context);

     while (form->currentStream && CFReadStreamGetStatus(form->currentStream) == kCFStreamStatusAtEnd)
         openNextStream(form);

     if (!form->currentStream) {
         CFReadStreamSignalEvent(stream, kCFStreamEventEndEncountered, 0);
         return FALSE;
     }
     return CFReadStreamHasBytesAvailable(form->currentStream);
 }

 static void formClose(CFReadStreamRef, void* context)
 {
     FormStreamFields* form = static_cast<FormStreamFields*>(context);
     LockHolder locker(form->streamIsBeingOpenedOrClosedLock);

     closeCurrentStream(form);
 }

 static CFTypeRef formCopyProperty(CFReadStreamRef, CFStringRef propertyName, void *context)
 {
     FormStreamFields* form = static_cast<FormStreamFields*>(context);

     if (kCFCompareEqualTo == CFStringCompare(propertyName, formDataPointerPropertyName, 0)) {
         long long formDataAsNumber = static_cast<long long>(reinterpret_cast<intptr_t>(&form->data.data()));
         return CFNumberCreate(0, kCFNumberLongLongType, &formDataAsNumber);
     }

     if (kCFCompareEqualTo == CFStringCompare(propertyName, formDataStreamLengthPropertyName(), 0))
         return CFStringCreateWithFormat(0, 0, CFSTR("%llu"), form->streamLength);

     return 0;
 }

 static void formSchedule(CFReadStreamRef, CFRunLoopRef runLoop, CFStringRef runLoopMode, void* context)
 {
     FormStreamFields* form = static_cast<FormStreamFields*>(context);

     if (form->currentStream)
         CFReadStreamScheduleWithRunLoop(form->currentStream, runLoop, runLoopMode);
     form->scheduledRunLoopPairs.add(SchedulePair::create(runLoop, runLoopMode));
 }

 static void formUnschedule(CFReadStreamRef, CFRunLoopRef runLoop, CFStringRef runLoopMode, void* context)
 {
     FormStreamFields* form = static_cast<FormStreamFields*>(context);

     if (form->currentStream)
         CFReadStreamUnscheduleFromRunLoop(form->currentStream, runLoop, runLoopMode);
     form->scheduledRunLoopPairs.remove(SchedulePair::create(runLoop, runLoopMode));
 }

 static void formEventCallback(CFReadStreamRef stream, CFStreamEventType type, void* context)
 {
     FormStreamFields* form = static_cast<FormStreamFields*>(context);

     switch (type) {
     case kCFStreamEventHasBytesAvailable:
         CFReadStreamSignalEvent(form->formStream, kCFStreamEventHasBytesAvailable, 0);
         break;
     case kCFStreamEventErrorOccurred: {
         CFStreamError readStreamError = CFReadStreamGetError(stream);
         CFReadStreamSignalEvent(form->formStream, kCFStreamEventErrorOccurred, &readStreamError);
         break;
     }
     case kCFStreamEventEndEncountered:
         openNextStream(form);
         if (!form->currentStream)
             CFReadStreamSignalEvent(form->formStream, kCFStreamEventEndEncountered, 0);
         break;
     case kCFStreamEventNone:
         LOG_ERROR("unexpected kCFStreamEventNone");
         break;
     case kCFStreamEventOpenCompleted:
         LOG_ERROR("unexpected kCFStreamEventOpenCompleted");
         break;
     case kCFStreamEventCanAcceptBytes:
         LOG_ERROR("unexpected kCFStreamEventCanAcceptBytes");
         break;
     }
 }

 RetainPtr<CFReadStreamRef> createHTTPBodyCFReadStream(FormData& formData)
 {
     auto resolvedFormData = formData.resolveBlobReferences(blobRegistry().blobRegistryImpl());
     auto dataForUpload = resolvedFormData->prepareForUpload();

     // Precompute the content length so CFNetwork doesn't use chunked mode.
     unsigned long long length = 0;
     for (auto& element : dataForUpload.data().elements())
         length += element.lengthInBytes(blobRegistry().blobRegistryImpl());

     FormCreationContext* formContext = new FormCreationContext { WTFMove(dataForUpload), length };
     CFReadStreamCallBacksV1 callBacks = { 1, formCreate, formFinalize, nullptr, formOpen, nullptr, formRead, nullptr, formCanRead, formClose, formCopyProperty, nullptr, nullptr, formSchedule, formUnschedule };
     return adoptCF(CFReadStreamCreate(nullptr, static_cast<const void*>(&callBacks), formContext));
 }

 void setHTTPBody(CFMutableURLRequestRef request, FormData* formData)
 {
     if (!formData)
         return;

     // Handle the common special case of one piece of form data, with no files.
     auto& elements = formData->elements();
     if (elements.size() == 1 && !formData->alwaysStream()) {
         if (auto* vector = WTF::get_if<Vector<char>>(elements[0].data)) {
             auto data = adoptCF(CFDataCreate(nullptr, reinterpret_cast<const UInt8*>(vector->data()), vector->size()));
             CFURLRequestSetHTTPRequestBody(request, data.get());
             return;
         }
     }

     CFURLRequestSetHTTPRequestBodyStream(request, createHTTPBodyCFReadStream(*formData).get());
 }

 FormData* httpBodyFromStream(CFReadStreamRef stream)
 {
     if (!stream)
         return nullptr;

     // Passing the pointer as property appears to be the only way to associate a stream with FormData.
     // A new stream is always created in CFURLRequestCopyHTTPRequestBodyStream (or -[NSURLRequest HTTPBodyStream]),
     // so a side HashMap wouldn't work.
     // Even the stream's context pointer is different from the one we returned from formCreate().

     RetainPtr<CFNumberRef> formDataPointerAsCFNumber = adoptCF(static_cast<CFNumberRef>(CFReadStreamCopyProperty(stream, formDataPointerPropertyName)));
     if (!formDataPointerAsCFNumber)
         return nullptr;

     long formDataPointerAsNumber;
     if (!CFNumberGetValue(formDataPointerAsCFNumber.get(), kCFNumberLongType, &formDataPointerAsNumber))
         return nullptr;

     return reinterpret_cast<FormData*>(static_cast<intptr_t>(formDataPointerAsNumber));
 }

 } // namespace WebCore
	/*
	* Copyright (C) 2005-2017 Apple Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	* 3. Neither the name of Apple Inc. ("Apple") nor the names of
	* its contributors may be used to endorse or promote products derived
	* from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
	* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
	* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
	* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
	* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "config.h"
	#include "FormDataStreamCFNet.h"

	#include "BlobData.h"
	#include "BlobRegistry.h"
	#include "FormData.h"
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <wtf/Assertions.h>
	#include <wtf/FileSystem.h>
	#include <wtf/HashMap.h>
	#include <wtf/MainThread.h>
	#include <wtf/RetainPtr.h>
	#include <wtf/SchedulePair.h>
	#include <wtf/StdLibExtras.h>
	#include <wtf/Threading.h>

	static const SInt32 fileNotFoundError = -43;

	#if PLATFORM(COCOA)
	extern "C" void CFURLRequestSetHTTPRequestBody(CFMutableURLRequestRef mutableHTTPRequest, CFDataRef httpBody);
	extern "C" void CFURLRequestSetHTTPHeaderFieldValue(CFMutableURLRequestRef mutableHTTPRequest, CFStringRef httpHeaderField, CFStringRef httpHeaderFieldValue);
	extern "C" void CFURLRequestSetHTTPRequestBodyStream(CFMutableURLRequestRef req, CFReadStreamRef bodyStream);
	#elif PLATFORM(WIN)
	#include <CFNetwork/CFURLRequest.h>
	#endif

	typedef struct {
	CFIndex version; /* == 1 */
	void (create)(CFReadStreamRef stream, void *info);
	void (finalize)(CFReadStreamRef stream, void info);
	CFStringRef (copyDescription)(CFReadStreamRef stream, void info);
	Boolean (open)(CFReadStreamRef stream, CFStreamError error, Boolean openComplete, void info);
	Boolean (openCompleted)(CFReadStreamRef stream, CFStreamError error, void *info);
	CFIndex (read)(CFReadStreamRef stream, UInt8 buffer, CFIndex bufferLength, CFStreamError error, Boolean atEOF, void *info);
	const UInt8 (getBuffer)(CFReadStreamRef stream, CFIndex maxBytesToRead, CFIndex numBytesRead, CFStreamError error, Boolean atEOF, void info);
	Boolean (canRead)(CFReadStreamRef stream, void info);
	void (close)(CFReadStreamRef stream, void info);
	CFTypeRef (copyProperty)(CFReadStreamRef stream, CFStringRef propertyName, void info);
	Boolean (setProperty)(CFReadStreamRef stream, CFStringRef propertyName, CFTypeRef propertyValue, void info);
	void (requestEvents)(CFReadStreamRef stream, CFOptionFlags streamEvents, void info);
	void (schedule)(CFReadStreamRef stream, CFRunLoopRef runLoop, CFStringRef runLoopMode, void info);
	void (unschedule)(CFReadStreamRef stream, CFRunLoopRef runLoop, CFStringRef runLoopMode, void info);
	} CFReadStreamCallBacksV1;

	#if PLATFORM(WIN)
	#define EXTERN extern "C" __declspec(dllimport)
	#else
	#define EXTERN extern "C"
	#endif

	EXTERN void CFReadStreamSignalEvent(CFReadStreamRef stream, CFStreamEventType event, const void *error);
	EXTERN CFReadStreamRef CFReadStreamCreate(CFAllocatorRef alloc, const void callbacks, void info);

	namespace WebCore {

	static void formEventCallback(CFReadStreamRef stream, CFStreamEventType type, void* context);

	static CFStringRef formDataPointerPropertyName = CFSTR("WebKitFormDataPointer");

	CFStringRef formDataStreamLengthPropertyName()
	{
	return CFSTR("WebKitFormDataStreamLength");
	}

	struct FormCreationContext {
	FormDataForUpload data;
	unsigned long long streamLength;
	};

	struct FormStreamFields {
	FormStreamFields(FormDataForUpload&& data)
	: data(WTFMove(data)) { }

	FormDataForUpload data;
	SchedulePairHashSet scheduledRunLoopPairs;
	Vector<FormDataElement> remainingElements; // in reverse order
	CFReadStreamRef currentStream { nullptr };
	long long currentStreamRangeLength { BlobDataItem::toEndOfFile };
	MallocPtr<char> currentData;
	CFReadStreamRef formStream { nullptr };
	unsigned long long streamLength { 0 };
	unsigned long long bytesSent { 0 };
	Lock streamIsBeingOpenedOrClosedLock;
	};

	static void closeCurrentStream(FormStreamFields* form)
	{
	ASSERT(form->streamIsBeingOpenedOrClosedLock.isHeld());

	if (form->currentStream) {
	CFReadStreamClose(form->currentStream);
	CFReadStreamSetClient(form->currentStream, kCFStreamEventNone, 0, 0);
	CFRelease(form->currentStream);
	form->currentStream = 0;
	form->currentStreamRangeLength = BlobDataItem::toEndOfFile;
	}

	form->currentData = nullptr;
	}

	// Return false if we cannot advance the stream. Currently the only possible failure is that the underlying file has been removed or changed since File.slice.
	static bool advanceCurrentStream(FormStreamFields* form)
	{
	ASSERT(form->streamIsBeingOpenedOrClosedLock.isHeld());

	closeCurrentStream(form);

	if (form->remainingElements.isEmpty())
	return true;

	// Create the new stream.
	FormDataElement& nextInput = form->remainingElements.last();

	bool success = switchOn(nextInput.data,
	[form] (Vector<char>& bytes) {
	size_t size = bytes.size();
	MallocPtr<char> data = bytes.releaseBuffer();
	form->currentStream = CFReadStreamCreateWithBytesNoCopy(0, reinterpret_cast<const UInt8*>(data.get()), size, kCFAllocatorNull);
	form->currentData = WTFMove(data);
	return true;
	}, [form] (const FormDataElement::EncodedFileData& fileData) {
	// Check if the file has been changed.
	if (!fileData.fileModificationTimeMatchesExpectation())
	return false;

	const String& path = fileData.filename;
	form->currentStream = CFReadStreamCreateWithFile(0, FileSystem::pathAsURL(path).get());
	if (!form->currentStream) {
	// The file must have been removed or become unreadable.
	return false;
	}
	if (fileData.fileStart > 0) {
	RetainPtr<CFNumberRef> position = adoptCF(CFNumberCreate(0, kCFNumberLongLongType, &fileData.fileStart));
	CFReadStreamSetProperty(form->currentStream, kCFStreamPropertyFileCurrentOffset, position.get());
	}
	form->currentStreamRangeLength = fileData.fileLength;
	return true;
	}, [] (const FormDataElement::EncodedBlobData&) {
	ASSERT_NOT_REACHED();
	return false;
	}
	);

	if (!success)
	return false;

	form->remainingElements.removeLast();

	// Set up the callback.
	CFStreamClientContext context = { 0, form, 0, 0, 0 };
	CFReadStreamSetClient(form->currentStream, kCFStreamEventHasBytesAvailable \| kCFStreamEventErrorOccurred \| kCFStreamEventEndEncountered,
	formEventCallback, &context);

	// Schedule with the current set of run loops.
	SchedulePairHashSet::iterator end = form->scheduledRunLoopPairs.end();
	for (SchedulePairHashSet::iterator it = form->scheduledRunLoopPairs.begin(); it != end; ++it)
	CFReadStreamScheduleWithRunLoop(form->currentStream, (it)->runLoop(), (it)->mode());

	return true;
	}

	static bool openNextStream(FormStreamFields* form)
	{
	// CFReadStreamOpen() can cause this function to be re-entered from another thread before it returns.
	// One example when this can occur is when the stream being opened has no data. See <rdar://problem/23550269>.
	LockHolder locker(form->streamIsBeingOpenedOrClosedLock);

	// Skip over any streams we can't open.
	if (!advanceCurrentStream(form))
	return false;
	while (form->currentStream && !CFReadStreamOpen(form->currentStream)) {
	if (!advanceCurrentStream(form))
	return false;
	}
	return true;
	}

	static void* formCreate(CFReadStreamRef stream, void* context)
	{
	FormCreationContext* formContext = static_cast<FormCreationContext*>(context);

	FormStreamFields* newInfo = new FormStreamFields(WTFMove(formContext->data));
	newInfo->formStream = stream; // Don't retain. That would create a reference cycle.
	newInfo->streamLength = formContext->streamLength;

	callOnMainThread([formContext] {
	delete formContext;
	});

	// Append in reverse order since we remove elements from the end.
	size_t size = newInfo->data.data().elements().size();
	newInfo->remainingElements.reserveInitialCapacity(size);
	for (size_t i = 0; i < size; ++i)
	newInfo->remainingElements.uncheckedAppend(newInfo->data.data().elements()[size - i - 1]);

	return newInfo;
	}

	static void formFinalize(CFReadStreamRef stream, void* context)
	{
	FormStreamFields* form = static_cast<FormStreamFields*>(context);
	ASSERT_UNUSED(stream, form->formStream == stream);

	callOnMainThread([form] {
	{
	LockHolder locker(form->streamIsBeingOpenedOrClosedLock);
	closeCurrentStream(form);
	}
	delete form;
	});
	}

	static Boolean formOpen(CFReadStreamRef, CFStreamError* error, Boolean* openComplete, void* context)
	{
	FormStreamFields* form = static_cast<FormStreamFields*>(context);

	bool opened = openNextStream(form);

	*openComplete = opened;
	error->error = opened ? 0 :
	#if PLATFORM(WIN)
	ENOENT;
	#else
	fileNotFoundError;
	#endif
	return opened;
	}

	static CFIndex formRead(CFReadStreamRef, UInt8* buffer, CFIndex bufferLength, CFStreamError* error, Boolean* atEOF, void* context)
	{
	FormStreamFields* form = static_cast<FormStreamFields*>(context);

	while (form->currentStream) {
	CFIndex bytesToRead = bufferLength;
	if (form->currentStreamRangeLength != BlobDataItem::toEndOfFile && form->currentStreamRangeLength < bytesToRead)
	bytesToRead = static_cast<CFIndex>(form->currentStreamRangeLength);
	CFIndex bytesRead = CFReadStreamRead(form->currentStream, buffer, bytesToRead);
	if (bytesRead < 0) {
	*error = CFReadStreamGetError(form->currentStream);
	return -1;
	}
	if (bytesRead > 0) {
	error->error = 0;
	*atEOF = FALSE;
	form->bytesSent += bytesRead;
	if (form->currentStreamRangeLength != BlobDataItem::toEndOfFile)
	form->currentStreamRangeLength -= bytesRead;

	return bytesRead;
	}
	openNextStream(form);
	}

	error->error = 0;
	*atEOF = TRUE;
	return 0;
	}

	static Boolean formCanRead(CFReadStreamRef stream, void* context)
	{
	FormStreamFields* form = static_cast<FormStreamFields*>(context);

	while (form->currentStream && CFReadStreamGetStatus(form->currentStream) == kCFStreamStatusAtEnd)
	openNextStream(form);

	if (!form->currentStream) {
	CFReadStreamSignalEvent(stream, kCFStreamEventEndEncountered, 0);
	return FALSE;
	}
	return CFReadStreamHasBytesAvailable(form->currentStream);
	}

	static void formClose(CFReadStreamRef, void* context)
	{
	FormStreamFields* form = static_cast<FormStreamFields*>(context);
	LockHolder locker(form->streamIsBeingOpenedOrClosedLock);

	closeCurrentStream(form);
	}

	static CFTypeRef formCopyProperty(CFReadStreamRef, CFStringRef propertyName, void *context)
	{
	FormStreamFields* form = static_cast<FormStreamFields*>(context);

	if (kCFCompareEqualTo == CFStringCompare(propertyName, formDataPointerPropertyName, 0)) {
	long long formDataAsNumber = static_cast<long long>(reinterpret_cast<intptr_t>(&form->data.data()));
	return CFNumberCreate(0, kCFNumberLongLongType, &formDataAsNumber);
	}

	if (kCFCompareEqualTo == CFStringCompare(propertyName, formDataStreamLengthPropertyName(), 0))
	return CFStringCreateWithFormat(0, 0, CFSTR("%llu"), form->streamLength);

	return 0;
	}

	static void formSchedule(CFReadStreamRef, CFRunLoopRef runLoop, CFStringRef runLoopMode, void* context)
	{
	FormStreamFields* form = static_cast<FormStreamFields*>(context);

	if (form->currentStream)
	CFReadStreamScheduleWithRunLoop(form->currentStream, runLoop, runLoopMode);
	form->scheduledRunLoopPairs.add(SchedulePair::create(runLoop, runLoopMode));
	}

	static void formUnschedule(CFReadStreamRef, CFRunLoopRef runLoop, CFStringRef runLoopMode, void* context)
	{
	FormStreamFields* form = static_cast<FormStreamFields*>(context);

	if (form->currentStream)
	CFReadStreamUnscheduleFromRunLoop(form->currentStream, runLoop, runLoopMode);
	form->scheduledRunLoopPairs.remove(SchedulePair::create(runLoop, runLoopMode));
	}

	static void formEventCallback(CFReadStreamRef stream, CFStreamEventType type, void* context)
	{
	FormStreamFields* form = static_cast<FormStreamFields*>(context);

	switch (type) {
	case kCFStreamEventHasBytesAvailable:
	CFReadStreamSignalEvent(form->formStream, kCFStreamEventHasBytesAvailable, 0);
	break;
	case kCFStreamEventErrorOccurred: {
	CFStreamError readStreamError = CFReadStreamGetError(stream);
	CFReadStreamSignalEvent(form->formStream, kCFStreamEventErrorOccurred, &readStreamError);
	break;
	}
	case kCFStreamEventEndEncountered:
	openNextStream(form);
	if (!form->currentStream)
	CFReadStreamSignalEvent(form->formStream, kCFStreamEventEndEncountered, 0);
	break;
	case kCFStreamEventNone:
	LOG_ERROR("unexpected kCFStreamEventNone");
	break;
	case kCFStreamEventOpenCompleted:
	LOG_ERROR("unexpected kCFStreamEventOpenCompleted");
	break;
	case kCFStreamEventCanAcceptBytes:
	LOG_ERROR("unexpected kCFStreamEventCanAcceptBytes");
	break;
	}
	}

	RetainPtr<CFReadStreamRef> createHTTPBodyCFReadStream(FormData& formData)
	{
	auto resolvedFormData = formData.resolveBlobReferences(blobRegistry().blobRegistryImpl());
	auto dataForUpload = resolvedFormData->prepareForUpload();

	// Precompute the content length so CFNetwork doesn't use chunked mode.
	unsigned long long length = 0;
	for (auto& element : dataForUpload.data().elements())
	length += element.lengthInBytes(blobRegistry().blobRegistryImpl());

	FormCreationContext* formContext = new FormCreationContext { WTFMove(dataForUpload), length };
	CFReadStreamCallBacksV1 callBacks = { 1, formCreate, formFinalize, nullptr, formOpen, nullptr, formRead, nullptr, formCanRead, formClose, formCopyProperty, nullptr, nullptr, formSchedule, formUnschedule };
	return adoptCF(CFReadStreamCreate(nullptr, static_cast<const void*>(&callBacks), formContext));
	}

	void setHTTPBody(CFMutableURLRequestRef request, FormData* formData)
	{
	if (!formData)
	return;

	// Handle the common special case of one piece of form data, with no files.
	auto& elements = formData->elements();
	if (elements.size() == 1 && !formData->alwaysStream()) {
	if (auto* vector = WTF::get_if<Vector<char>>(elements[0].data)) {
	auto data = adoptCF(CFDataCreate(nullptr, reinterpret_cast<const UInt8*>(vector->data()), vector->size()));
	CFURLRequestSetHTTPRequestBody(request, data.get());
	return;
	}
	}

	CFURLRequestSetHTTPRequestBodyStream(request, createHTTPBodyCFReadStream(*formData).get());
	}

	FormData* httpBodyFromStream(CFReadStreamRef stream)
	{
	if (!stream)
	return nullptr;

	// Passing the pointer as property appears to be the only way to associate a stream with FormData.
	// A new stream is always created in CFURLRequestCopyHTTPRequestBodyStream (or -[NSURLRequest HTTPBodyStream]),
	// so a side HashMap wouldn't work.
	// Even the stream's context pointer is different from the one we returned from formCreate().

	RetainPtr<CFNumberRef> formDataPointerAsCFNumber = adoptCF(static_cast<CFNumberRef>(CFReadStreamCopyProperty(stream, formDataPointerPropertyName)));
	if (!formDataPointerAsCFNumber)
	return nullptr;

	long formDataPointerAsNumber;
	if (!CFNumberGetValue(formDataPointerAsCFNumber.get(), kCFNumberLongType, &formDataPointerAsNumber))
	return nullptr;

	return reinterpret_cast<FormData*>(static_cast<intptr_t>(formDataPointerAsNumber));
	}

	} // namespace WebCore