Add Streams API support to XMLHttpRequest

Source/core/xml/XMLHttpRequest.cpp

Index: Source/core/xml/XMLHttpRequest.cpp
diff --git a/Source/core/xml/XMLHttpRequest.cpp b/Source/core/xml/XMLHttpRequest.cpp
index cc6d559f71327a67760ae612ff3a9361b804d8c8..243b8d8849c4db6a33ee826c40cfcd91247657c3 100644
--- a/Source/core/xml/XMLHttpRequest.cpp
+++ b/Source/core/xml/XMLHttpRequest.cpp
@@ -23,12 +23,7 @@
 #include "config.h"
 #include "core/xml/XMLHttpRequest.h"
 
-#include <wtf/ArrayBuffer.h>
-#include <wtf/ArrayBufferView.h>
-#include <wtf/RefCountedLeakCounter.h>
-#include <wtf/StdLibExtras.h>
-#include <wtf/text/CString.h>
-#include <wtf/UnusedParam.h>
+#include "RuntimeEnabledFeatures.h"
 #include "core/dom/ContextFeatures.h"
 #include "core/dom/DOMImplementation.h"
 #include "core/dom/Event.h"
@@ -39,6 +34,7 @@
 #include "core/editing/markup.h"
 #include "core/fileapi/Blob.h"
 #include "core/fileapi/File.h"
+#include "core/fileapi/Stream.h"
 #include "core/html/DOMFormData.h"
 #include "core/html/HTMLDocument.h"
 #include "core/inspector/InspectorInstrumentation.h"
@@ -58,6 +54,12 @@
 #include "core/xml/XMLHttpRequestProgressEvent.h"
 #include "core/xml/XMLHttpRequestUpload.h"
 #include "weborigin/SecurityOrigin.h"
+#include "wtf/ArrayBuffer.h"
+#include "wtf/ArrayBufferView.h"
+#include "wtf/RefCountedLeakCounter.h"
+#include "wtf/StdLibExtras.h"
+#include "wtf/UnusedParam.h"
+#include "wtf/text/CString.h"
 
 namespace WebCore {
 
@@ -313,6 +315,19 @@ ArrayBuffer* XMLHttpRequest::responseArrayBuffer(ExceptionCode& ec)
     return m_responseArrayBuffer.get();
 }
 
+Stream* XMLHttpRequest::responseStream(ExceptionCode& ec)
+{
+    if (m_responseTypeCode != ResponseTypeStream) {
+        ec = InvalidStateError;
+        return 0;
+    }
+
+    if (m_error || (m_state != LOADING && m_state != DONE))
+        return 0;
+
+    return m_responseStream.get();
+}
+
 void XMLHttpRequest::setTimeout(unsigned long timeout, ExceptionCode& ec)
 {
     // FIXME: Need to trigger or update the timeout Timer here, if needed. http://webkit.org/b/98156
@@ -342,35 +357,43 @@ void XMLHttpRequest::setResponseType(const String& responseType, ExceptionCode&
         return;
     }
 
-    if (responseType == "")
+    if (responseType == "") {
         m_responseTypeCode = ResponseTypeDefault;
-    else if (responseType == "text")
+    } else if (responseType == "text") {
         m_responseTypeCode = ResponseTypeText;
-    else if (responseType == "document")
+    } else if (responseType == "document") {
         m_responseTypeCode = ResponseTypeDocument;
-    else if (responseType == "blob")
+    } else if (responseType == "blob") {
         m_responseTypeCode = ResponseTypeBlob;
-    else if (responseType == "arraybuffer")
+    } else if (responseType == "arraybuffer") {
         m_responseTypeCode = ResponseTypeArrayBuffer;
-    else
+    } else if (responseType == "stream") {
+        if (RuntimeEnabledFeatures::streamEnabled())
+            m_responseTypeCode = ResponseTypeStream;
+        else
+            return;
+    } else {
         ASSERT_NOT_REACHED();
+    }
 }
 
 String XMLHttpRequest::responseType()
 {
     switch (m_responseTypeCode) {
     case ResponseTypeDefault:
-        return "";
+        return ASCIILiteral("");
     case ResponseTypeText:
-        return "text";
+        return ASCIILiteral("text");
     case ResponseTypeDocument:
-        return "document";
+        return ASCIILiteral("document");
     case ResponseTypeBlob:
-        return "blob";
+        return ASCIILiteral("blob");
     case ResponseTypeArrayBuffer:
-        return "arraybuffer";
+        return ASCIILiteral("arraybuffer");
+    case ResponseTypeStream:
+        return ASCIILiteral("stream");
     }
-    return "";
+    return ASCIILiteral("");
 }
 
 XMLHttpRequestUpload* XMLHttpRequest::upload()
@@ -938,7 +961,7 @@ String XMLHttpRequest::getAllResponseHeaders(ExceptionCode& ec) const
 {
     if (m_state < HEADERS_RECEIVED) {
         ec = InvalidStateError;
-        return "";
+        return ASCIILiteral("");
     }
 
     StringBuilder stringBuilder;
@@ -1086,6 +1109,9 @@ void XMLHttpRequest::didFinishLoading(unsigned long identifier, double)
 
     InspectorInstrumentation::didFinishXHRLoading(scriptExecutionContext(), this, identifier, m_responseText, m_url, m_lastSendURL, m_lastSendLineNumber);
 
+    if (m_responseStream)
+        m_responseStream->finalize();
+
     bool hadLoader = m_loader;
     m_loader = 0;
 
@@ -1162,6 +1188,10 @@ void XMLHttpRequest::didReceiveData(const char* data, int len)
         if (!m_binaryResponseBuilder)
             m_binaryResponseBuilder = SharedBuffer::create();
         m_binaryResponseBuilder->append(data, len);
+    } else if (m_responseTypeCode == ResponseTypeStream) {
+        if (!m_responseStream)
+            m_responseStream = Stream::create(responseMIMEType());
+        m_responseStream->addData(data, len);

[michaeln, 2013/07/24 03:57:22]

Also, it it a desired characteristic of this implementation that the network be
gated such that it run too far ahead of the stream consumer? And if so, is that
flow control an important characteristic? If that is the behavior we want, I
think this approach (stuffing data into the stream at this callsite) makes that
more challenging to achieve then some alternatives (that would stuff data into
the stream in the browser process).

     }
 
     if (!m_error) {