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/*
* Copyright (C) 2013 Google 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:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of Google Inc. 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 THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
* OWNER OR 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.
*/
#ifndef HTMLImport_h
#define HTMLImport_h
#include "core/html/imports/HTMLImportState.h"
#include "platform/heap/Handle.h"
#include "wtf/TreeNode.h"
#include "wtf/Vector.h"
namespace WebCore {
class Document;
class LocalFrame;
class HTMLImportChild;
class HTMLImportLoader;
class HTMLImportsController;
class KURL;
//
// # Basic Data Structure and Algorithms of HTML Imports implemenation.
//
// ## The Import Tree
//
// HTML Imports form a tree:
//
// * The root of the tree is HTMLImportTreeRoot.
//
// * The HTMLImportTreeRoot is owned HTMLImportsController, which is owned by the master
// document as a DocumentSupplement.
//
// * The non-root nodes are HTMLImportChild. They are all owned by HTMLImporTreeRoot.
// LinkStyle is wired into HTMLImportChild by implementing HTMLImportChildClient interface
//
// * Both HTMLImportTreeRoot and HTMLImportChild are derived from HTMLImport superclass
// that models the tree data structure using WTF::TreeNode and provides a set of
// virtual functions.
//
// HTMLImportsController also owns all loaders in the tree and manages their lifetime through it.
// One assumption is that the tree is append-only and nodes are never inserted in the middle of the tree nor removed.
//
// Full diagram is here:
// https://docs.google.com/drawings/d/1jFQrO0IupWrlykTNzQ3Nv2SdiBiSz4UE9-V3-vDgBb0/
//
// # Import Sharing and HTMLImportLoader
//
// The HTML Imports spec calls for de-dup mechanism to share already loaded imports.
// To implement this, the actual loading machinery is split out from HTMLImportChild to
// HTMLImportLoader, and each loader shares HTMLImportLoader with other loader if the URL is same.
// Check around HTMLImportsController::findLink() for more detail.
//
// HTMLImportLoader can be shared by multiple imports.
//
// HTMLImportChild (1)-->(*) HTMLImportLoader
//
//
// # Script Blocking
//
// - An import blocks the HTML parser of its own imported document from running <script>
// until all of its children are loaded.
// Note that dynamically added import won't block the parser.
//
// - An import under loading also blocks imported documents that follow from being created.
// This is because an import can include another import that has same URLs of following ones.
// In such case, the preceding import should be loaded and following ones should be de-duped.
//
// The superclass of HTMLImportTreeRoot and HTMLImportChild
// This represents the import tree data structure.
class HTMLImport : public NoBaseWillBeGarbageCollectedFinalized<HTMLImport>, public TreeNode<HTMLImport> {
public:
enum SyncMode {
Sync = 0,
Async = 1
};
virtual ~HTMLImport() { }
// FIXME: Consider returning HTMLImportTreeRoot.
HTMLImport* root();
bool precedes(HTMLImport*);
bool isRoot() const { return !parent(); }
bool isSync() const { return SyncMode(m_sync) == Sync; }
bool formsCycle() const;
const HTMLImportState& state() const { return m_state; }
void appendImport(HTMLImport*);
virtual Document* document() const = 0;
virtual bool isDone() const = 0; // FIXME: Should be renamed to haveFinishedLoading()
virtual HTMLImportLoader* loader() const { return 0; }
virtual void stateWillChange() { }
virtual void stateDidChange();
virtual void trace(Visitor*) { }
protected:
// Stating from most conservative state.
// It will be corrected through state update flow.
explicit HTMLImport(SyncMode sync)
: m_sync(sync)
{ }
static void recalcTreeState(HTMLImport* root);
#if !defined(NDEBUG)
void show();
void showTree(HTMLImport* highlight, unsigned depth);
virtual void showThis();
#endif
private:
HTMLImportState m_state;
unsigned m_sync : 1;
};
} // namespace WebCore
#endif // HTMLImport_h
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