Introduce "navigate" mode in Requests

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

 // Copyright 2014 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 "config.h"
 #include "modules/fetch/RequestInit.h"
 
 #include "bindings/core/v8/Dictionary.h"
 #include "bindings/core/v8/V8ArrayBuffer.h"
 #include "bindings/core/v8/V8ArrayBufferView.h"
 #include "bindings/core/v8/V8Binding.h"
 #include "bindings/core/v8/V8Blob.h"
 #include "bindings/core/v8/V8FormData.h"
 #include "core/fileapi/Blob.h"
 #include "core/html/FormData.h"
 #include "modules/fetch/FetchBlobDataConsumerHandle.h"
 #include "modules/fetch/FetchFormDataConsumerHandle.h"
 #include "modules/fetch/Headers.h"
 #include "platform/blob/BlobData.h"
 #include "platform/network/EncodedFormData.h"
 #include "platform/weborigin/ReferrerPolicy.h"
 
 namespace blink {
 
 RequestInit::RequestInit(ExecutionContext* context, const Dictionary& options, ExceptionState& exceptionState)
-    : opaque(false), isReferrerSet(false)
+    : opaque(false), areAnyMembersSet(false)
 {
-    bool areAnyMembersSet = false;
-
     areAnyMembersSet = DictionaryHelper::get(options, "method", method) || areAnyMembersSet;

[Mike West, 2015/10/20 07:27:04]

Nit: here and elsewhere, `|=` would be clearer.

[shiva.jm, 2015/10/21 08:34:59]

only at these line(30), it holds good,
but for other lines, it might fail for cases
where more than 1 member is set, i.e 
if 'method' also true != 'headers' also true.
so we can only apply `|=` at line 30 only.

[hiroshige, 2015/10/30 12:31:30]

Anyway, if we want to do that change, I think it is better to do it in a
separate CL, so my comment below doesn't block this CL.

How it fails when both |method| and |headers| are set?

These two alternatives have pros and cons.
I slightly prefer 2. as mkwst@ suggested.

1. areAnyMembersSet = get() || areAnyMembersSet
get() is on the left-hand side to avoid short-circuit of || operator.
I.e. "areAnyMembersSet = areAnyMembersSet || get(options, "headers", headers)"
is a bug, because get() is not called and thus headers field is not set if
areAnyMembersSet is true.
This is somehow error-prone.

2. areAnyMembersSet |= get()
'|=' is bitwise OR (not ||) and thus does not short-circuit.
So get() is always called, avoiding the problem of 1.

A possible drawback is that we use logical computation using bitwise operators
-- reminds us of the ghost of the problem that (1 && 2) is true but (1 & 2) is
false.
In this case, it seems OK:
- areAnyMembersSet is bool, and bool has only 0 or 1.
- This is OR operator, so both (1 || 2) and (1 | 2) are true.

3. or should we write like the following?
if (get())
    areAnyMembersSet = true;

[shiva.jm, 2015/11/02 12:06:20]

Thanks for more detailed inputs, i misunderstand the
bitwise '|=' operator operation. agree with option 2 above,
so we can change as below:

1) areAnyMembersSet = DictionaryHelper::get() || areAnyMembersSet;
----> areAnyMembersSet |= get();
2) areAnyMembersSet = areAnyMembersSet || isReferrerStringSet;
----> areAnyMembersSet |= isReferrerStringSet;
3) areAnyMembersSet = areAnyMembersSet || isBodySet;
----> areAnyMembersSet |= isBodySet;

shall we change in these CL Or separate CL?

     areAnyMembersSet = DictionaryHelper::get(options, "headers", headers) || areAnyMembersSet;
     if (!headers) {
         Vector<Vector<String>> headersVector;
         if (DictionaryHelper::get(options, "headers", headersVector, exceptionState)) {
             headers = Headers::create(headersVector, exceptionState);
             areAnyMembersSet = true;
         } else {
             areAnyMembersSet = DictionaryHelper::get(options, "headers", headersDictionary) || areAnyMembersSet;
         }
     }
@@ skipping 13 matching lines @@
         // If any of init's members are present, unset request's
         // omit-Origin-header flag, set request's referrer to "client",
         // and request's referrer policy to the empty string.
         //
         // We need to use "about:client" instead of |clientReferrerString|,
         // because "about:client" => |clientReferrerString| conversion is done
         // in Request::createRequestWithRequestOrString.
         referrer = Referrer("about:client", ReferrerPolicyDefault);
         if (isReferrerStringSet)
             referrer.referrer = referrerString;
-        isReferrerSet = true;
     }
 
     if (!isBodySet || v8Body->IsUndefined() || v8Body->IsNull())
         return;
     v8::Isolate* isolate = toIsolate(context);
     if (v8Body->IsArrayBuffer()) {
         body = FetchFormDataConsumerHandle::create(V8ArrayBuffer::toImpl(v8::Local<v8::Object>::Cast(v8Body)));
     } else if (v8Body->IsArrayBufferView()) {
         body = FetchFormDataConsumerHandle::create(V8ArrayBufferView::toImpl(v8::Local<v8::Object>::Cast(v8Body)));
     } else if (V8Blob::hasInstance(v8Body, isolate)) {
         RefPtr<BlobDataHandle> blobDataHandle = V8Blob::toImpl(v8::Local<v8::Object>::Cast(v8Body))->blobDataHandle();
         contentType = blobDataHandle->type();
         body = FetchBlobDataConsumerHandle::create(context, blobDataHandle.release());
     } else if (V8FormData::hasInstance(v8Body, isolate)) {
         FormData* domFormData = V8FormData::toImpl(v8::Local<v8::Object>::Cast(v8Body));
         opaque = domFormData->opaque();
 
         RefPtr<EncodedFormData> formData = domFormData->encodeMultiPartFormData();
         // Here we handle formData->boundary() as a C-style string. See
         // FormDataEncoder::generateUniqueBoundaryString.
         contentType = AtomicString("multipart/form-data; boundary=", AtomicString::ConstructFromLiteral) + formData->boundary().data();
         body = FetchFormDataConsumerHandle::create(context, formData.release());
     } else if (v8Body->IsString()) {
         contentType = "text/plain;charset=UTF-8";
         body = FetchFormDataConsumerHandle::create(toUSVString(isolate, v8Body, exceptionState));
     }
 }
 
 }