gecko-dev/image/ImageCacheKey.cpp
2016-04-11 11:00:03 +02:00

162 lines
4.4 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "ImageCacheKey.h"
#include "mozilla/Move.h"
#include "File.h"
#include "ImageURL.h"
#include "nsHostObjectProtocolHandler.h"
#include "nsString.h"
#include "mozilla/dom/workers/ServiceWorkerManager.h"
#include "nsIDocument.h"
#include "nsPrintfCString.h"
namespace mozilla {
using namespace dom;
namespace image {
bool
URISchemeIs(ImageURL* aURI, const char* aScheme)
{
bool schemeMatches = false;
if (NS_WARN_IF(NS_FAILED(aURI->SchemeIs(aScheme, &schemeMatches)))) {
return false;
}
return schemeMatches;
}
static Maybe<uint64_t>
BlobSerial(ImageURL* aURI)
{
nsAutoCString spec;
aURI->GetSpec(spec);
RefPtr<BlobImpl> blob;
if (NS_SUCCEEDED(NS_GetBlobForBlobURISpec(spec, getter_AddRefs(blob))) &&
blob) {
return Some(blob->GetSerialNumber());
}
return Nothing();
}
ImageCacheKey::ImageCacheKey(nsIURI* aURI, nsIDocument* aDocument)
: mURI(new ImageURL(aURI))
, mControlledDocument(GetControlledDocumentToken(aDocument))
, mIsChrome(URISchemeIs(mURI, "chrome"))
{
MOZ_ASSERT(NS_IsMainThread());
if (URISchemeIs(mURI, "blob")) {
mBlobSerial = BlobSerial(mURI);
}
mHash = ComputeHash(mURI, mBlobSerial, mControlledDocument);
}
ImageCacheKey::ImageCacheKey(ImageURL* aURI, nsIDocument* aDocument)
: mURI(aURI)
, mControlledDocument(GetControlledDocumentToken(aDocument))
, mIsChrome(URISchemeIs(mURI, "chrome"))
{
MOZ_ASSERT(aURI);
if (URISchemeIs(mURI, "blob")) {
mBlobSerial = BlobSerial(mURI);
}
mHash = ComputeHash(mURI, mBlobSerial, mControlledDocument);
}
ImageCacheKey::ImageCacheKey(const ImageCacheKey& aOther)
: mURI(aOther.mURI)
, mBlobSerial(aOther.mBlobSerial)
, mControlledDocument(aOther.mControlledDocument)
, mHash(aOther.mHash)
, mIsChrome(aOther.mIsChrome)
{ }
ImageCacheKey::ImageCacheKey(ImageCacheKey&& aOther)
: mURI(Move(aOther.mURI))
, mBlobSerial(Move(aOther.mBlobSerial))
, mControlledDocument(aOther.mControlledDocument)
, mHash(aOther.mHash)
, mIsChrome(aOther.mIsChrome)
{ }
bool
ImageCacheKey::operator==(const ImageCacheKey& aOther) const
{
// Don't share the image cache between a controlled document and anything else.
if (mControlledDocument != aOther.mControlledDocument) {
return false;
}
if (mBlobSerial || aOther.mBlobSerial) {
// If at least one of us has a blob serial, just compare the blob serial and
// the ref portion of the URIs.
return mBlobSerial == aOther.mBlobSerial &&
mURI->HasSameRef(*aOther.mURI);
}
// For non-blob URIs, compare the URIs.
return *mURI == *aOther.mURI;
}
const char*
ImageCacheKey::Spec() const
{
return mURI->Spec();
}
/* static */ uint32_t
ImageCacheKey::ComputeHash(ImageURL* aURI,
const Maybe<uint64_t>& aBlobSerial,
void* aControlledDocument)
{
// Since we frequently call Hash() several times in a row on the same
// ImageCacheKey, as an optimization we compute our hash once and store it.
nsPrintfCString ptr("%p", aControlledDocument);
if (aBlobSerial) {
// For blob URIs, we hash the serial number of the underlying blob, so that
// different blob URIs which point to the same blob share a cache entry. We
// also include the ref portion of the URI to support -moz-samplesize, which
// requires us to create different Image objects even if the source data is
// the same.
nsAutoCString ref;
aURI->GetRef(ref);
return HashGeneric(*aBlobSerial, HashString(ref + ptr));
}
// For non-blob URIs, we hash the URI spec.
nsAutoCString spec;
aURI->GetSpec(spec);
return HashString(spec + ptr);
}
/* static */ void*
ImageCacheKey::GetControlledDocumentToken(nsIDocument* aDocument)
{
// For non-controlled documents, we just return null. For controlled
// documents, we cast the pointer into a void* to avoid dereferencing
// it (since we only use it for comparisons), and return it.
void* pointer = nullptr;
using dom::workers::ServiceWorkerManager;
RefPtr<ServiceWorkerManager> swm = ServiceWorkerManager::GetInstance();
if (aDocument && swm) {
ErrorResult rv;
if (swm->IsControlled(aDocument, rv)) {
pointer = aDocument;
}
}
return pointer;
}
} // namespace image
} // namespace mozilla