Introduce FormDataBytesConsumer

third_party/WebKit/Source/modules/fetch/FormDataBytesConsumer.cpp

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "modules/fetch/FormDataBytesConsumer.h"
+
+#include "core/dom/DOMArrayBuffer.h"
+#include "core/dom/DOMArrayBufferView.h"
+#include "modules/fetch/BlobBytesConsumer.h"
+#include "platform/blob/BlobData.h"
+#include "platform/network/EncodedFormData.h"
+#include "wtf/Vector.h"
+#include "wtf/text/TextCodec.h"
+#include "wtf/text/TextEncoding.h"
+#include "wtf/text/WTFString.h"
+
+namespace blink {
+
+namespace {
+
+bool isSimple(const EncodedFormData* formData)

[hiroshige, 2016/09/15 09:47:33]

Memo: this is dup of isSimple() in FetchFormDataConsumerHandle.cpp.
This isn't a problem provided FetchFormDataConsumerHandle.cpp will be deleted
soon.

[yhirano, 2016/09/16 03:10:32]

Acknowledged.

+{
+    for (const auto& element : formData->elements()) {
+        if (element.m_type != FormDataElement::data)
+            return false;
+    }
+    return true;
+}
+
+class SimpleFormDataBytesConsumer : public BytesConsumer {
+public:
+    explicit SimpleFormDataBytesConsumer(PassRefPtr<EncodedFormData> formData)
+        : m_formData(formData)
+    {
+    }
+
+    // BytesConsumer implementation
+    Result beginRead(const char** buffer, size_t* available) override
+    {
+        *buffer = nullptr;
+        *available = 0;
+        if (m_formData) {
+            m_formData->flatten(m_flattenFormData);
+            m_formData = nullptr;
+            DCHECK_EQ(m_flattenFormDataOffset, 0u);
+        }
+        if (m_flattenFormDataOffset == m_flattenFormData.size())
+            return Result::Done;
+        *buffer = m_flattenFormData.data() + m_flattenFormDataOffset;
+        *available = m_flattenFormData.size() - m_flattenFormDataOffset;
+        return Result::Ok;
+    }
+    Result endRead(size_t readSize) override
+    {
+        DCHECK(!m_formData);
+        DCHECK_LE(m_flattenFormDataOffset + readSize, m_flattenFormData.size());
+        m_flattenFormDataOffset += readSize;
+        return Result::Ok;
+    }
+    PassRefPtr<BlobDataHandle> drainAsBlobDataHandle(BlobSizePolicy policy) override
+    {
+        if (!m_formData)
+            return nullptr;
+
+        Vector<char> data;
+        m_formData->flatten(data);
+        m_formData = nullptr;
+        std::unique_ptr<BlobData> blobData = BlobData::create();
+        blobData->appendBytes(data.data(), data.size());
+        auto length = blobData->length();
+        return BlobDataHandle::create(std::move(blobData), length);
+    }
+    PassRefPtr<EncodedFormData> drainAsFormData() override
+    {
+        return m_formData.release();
+    }
+    void setClient(BytesConsumer::Client* client) override
+    {
+        DCHECK(client);
+    }
+    void clearClient() override
+    {
+    }
+    void cancel() override
+    {
+        m_state = PublicState::Closed;
+        m_formData = nullptr;
+        m_flattenFormData.clear();
+        m_flattenFormDataOffset = 0;
+    }
+    PublicState getPublicState() const override
+    {
+        return m_state;
+    }
+    Error getError() const override
+    {
+        NOTREACHED();
+        return Error();
+    }
+    String debugName() const override
+    {
+        return "SimpleFormDataBytesConsumer";
+    }
+
+private:
+    // either one of |m_formData| and |m_flattenFormData| is usable at a time.
+    RefPtr<EncodedFormData> m_formData;
+    Vector<char> m_flattenFormData;
+    size_t m_flattenFormDataOffset = 0;
+    PublicState m_state = PublicState::ReadableOrWaiting;
+};
+
+class ComplexFormDataBytesConsumer final : public BytesConsumer {
+public:
+    ComplexFormDataBytesConsumer(ExecutionContext* executionContext, PassRefPtr<EncodedFormData> formData, BytesConsumer* consumer)
+        : m_formData(formData)
+    {
+        if (consumer) {
+            // For testing.
+            m_blobBytesConsumer = consumer;
+            return;
+        }
+
+        std::unique_ptr<BlobData> blobData = BlobData::create();
+        for (const auto& element : m_formData->elements()) {
+            switch (element.m_type) {
+            case FormDataElement::data:
+                blobData->appendBytes(element.m_data.data(), element.m_data.size());
+                break;
+            case FormDataElement::encodedFile:
+                blobData->appendFile(element.m_filename, element.m_fileStart, element.m_fileLength, element.m_expectedFileModificationTime);
+                break;
+            case FormDataElement::encodedBlob:
+                if (element.m_optionalBlobDataHandle)
+                    blobData->appendBlob(element.m_optionalBlobDataHandle, 0, element.m_optionalBlobDataHandle->size());
+                break;
+            case FormDataElement::encodedFileSystemURL:
+                blobData->appendFileSystemURL(element.m_fileSystemURL, element.m_fileStart, element.m_fileLength, element.m_expectedFileModificationTime);
+                break;
+            }
+        }
+        // Here we handle m_formData->boundary() as a C-style string. See
+        // FormDataEncoder::generateUniqueBoundaryString.
+        blobData->setContentType(AtomicString("multipart/form-data; boundary=") + m_formData->boundary().data());
+        auto size = blobData->length();
+        m_blobBytesConsumer = new BlobBytesConsumer(executionContext, BlobDataHandle::create(std::move(blobData), size));
+    }
+
+    // BytesConsumer implementation
+    Result beginRead(const char** buffer, size_t* available) override
+    {
+        m_formData = nullptr;
+        return m_blobBytesConsumer->beginRead(buffer, available);

[hiroshige, 2016/09/15 09:47:33]

IIUC this code returns Done after drainAsFormData() returns non-null, because
|m_blobBytesConsumer| is cancelled. Leaving a short comment might be helpful to
understand the behavior.

[yhirano, 2016/09/16 03:10:32]

Done.

+    }
+    Result endRead(size_t readSize) override
+    {
+        return m_blobBytesConsumer->endRead(readSize);
+    }
+    PassRefPtr<BlobDataHandle> drainAsBlobDataHandle(BlobSizePolicy policy) override
+    {
+        RefPtr<BlobDataHandle> handle = m_blobBytesConsumer->drainAsBlobDataHandle(policy);
+        if (handle)
+            m_formData = nullptr;
+        return handle.release();
+    }
+    PassRefPtr<EncodedFormData> drainAsFormData() override
+    {
+        if (!m_formData)
+            return nullptr;
+        m_blobBytesConsumer->cancel();
+        return m_formData.release();
+    }
+    void setClient(BytesConsumer::Client* client) override
+    {
+        m_blobBytesConsumer->setClient(client);
+    }
+    void clearClient() override
+    {
+        m_blobBytesConsumer->clearClient();
+    }
+    void cancel() override
+    {
+        m_formData = nullptr;
+        m_blobBytesConsumer->cancel();
+    }
+    PublicState getPublicState() const override
+    {
+        return m_blobBytesConsumer->getPublicState();
+    }
+    Error getError() const override
+    {
+        return m_blobBytesConsumer->getError();
+    }
+    String debugName() const override
+    {
+        return "ComplexFormDataBytesConsumer";
+    }
+
+    DEFINE_INLINE_TRACE()
+    {
+        visitor->trace(m_blobBytesConsumer);
+        BytesConsumer::trace(visitor);
+    }
+
+private:
+    RefPtr<EncodedFormData> m_formData;
+    Member<BytesConsumer> m_blobBytesConsumer;
+};
+
+} // namespace
+
+FormDataBytesConsumer::FormDataBytesConsumer(const String& string)
+    : m_impl(new SimpleFormDataBytesConsumer(EncodedFormData::create(UTF8Encoding().encode(string, WTF::EntitiesForUnencodables))))
+{
+}
+
+FormDataBytesConsumer::FormDataBytesConsumer(DOMArrayBuffer* buffer)
+    : m_impl(new SimpleFormDataBytesConsumer(EncodedFormData::create(buffer->data(), buffer->byteLength())))
+{
+}
+
+FormDataBytesConsumer::FormDataBytesConsumer(DOMArrayBufferView* view)
+    : m_impl(new SimpleFormDataBytesConsumer(EncodedFormData::create(view->baseAddress(), view->byteLength())))
+{
+}
+
+FormDataBytesConsumer::FormDataBytesConsumer(ExecutionContext* executionContext, PassRefPtr<EncodedFormData> formData)
+    : FormDataBytesConsumer(executionContext, formData, nullptr)
+{
+}
+
+FormDataBytesConsumer::FormDataBytesConsumer(ExecutionContext* executionContext, PassRefPtr<EncodedFormData> formData, BytesConsumer* consumer)
+    : m_impl(isSimple(formData.get()) ?
+        static_cast<BytesConsumer*>(new SimpleFormDataBytesConsumer(formData)) :
+        static_cast<BytesConsumer*>(new ComplexFormDataBytesConsumer(executionContext, formData, consumer)))
+{
+}
+
+} // namespace blink