third_party/WebKit/Source/core/frame/FrameHost.h

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
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 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
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 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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#ifndef FrameHost_h
#define FrameHost_h

#include "core/CoreExport.h"
#include "core/frame/PageScaleConstraintsSet.h"
#include "core/frame/TopControls.h"
#include "core/frame/VisualViewport.h"
#include "platform/heap/Handle.h"
#include "wtf/Allocator.h"
#include "wtf/Noncopyable.h"
#include "wtf/OwnPtr.h"
#include "wtf/PassOwnPtr.h"

namespace blink {

class ChromeClient;
class ConsoleMessageStorage;
class Deprecation;
class EventHandlerRegistry;
class Page;
class PageScaleConstraintsSet;
class Settings;
class UseCounter;
class Visitor;

// FrameHost is the set of global data shared between multiple frames
// and is provided by the embedder to each frame when created.
// FrameHost currently corresponds to the Page object in core/page
// however the concept of a Page is moving up out of Blink.
// In an out-of-process iframe world, a single Page may have
// multiple frames in different process, thus Page becomes a
// browser-level concept and Blink core/ only knows about its LocalFrame (and FrameHost).
// Separating Page from the rest of core/ through this indirection
// allows us to slowly refactor Page without breaking the rest of core.
class CORE_EXPORT FrameHost final : public NoBaseWillBeGarbageCollectedFinalized<FrameHost> {
    WTF_MAKE_NONCOPYABLE(FrameHost); USING_FAST_MALLOC_WILL_BE_REMOVED(FrameHost);
public:
    static PassOwnPtrWillBeRawPtr<FrameHost> create(Page&);
    ~FrameHost();

    // Careful: This function will eventually be removed.
    Page& page() const { return *m_page; }
    Settings& settings() const;
    ChromeClient& chromeClient() const;
    UseCounter& useCounter() const;
    Deprecation& deprecation() const;

    // Corresponds to pixel density of the device where this Page is
    // being displayed. In multi-monitor setups this can vary between pages.
    // This value does not account for Page zoom, use LocalFrame::devicePixelRatio instead.
    float deviceScaleFactor() const;

    TopControls& topControls() const;
    VisualViewport& visualViewport() const;
    PageScaleConstraintsSet& pageScaleConstraintsSet() const;
    EventHandlerRegistry& eventHandlerRegistry() const;

    const AtomicString& overrideEncoding() const { return m_overrideEncoding; }
    void setOverrideEncoding(const AtomicString& encoding) { m_overrideEncoding = encoding; }

    ConsoleMessageStorage& consoleMessageStorage() const;

    DECLARE_TRACE();

    // Don't allow more than a certain number of frames in a page.
    // This seems like a reasonable upper bound, and otherwise mutually
    // recursive frameset pages can quickly bring the program to its knees
    // with exponential growth in the number of frames.
    static const int maxNumberOfFrames = 1000;
    void incrementSubframeCount() { ++m_subframeCount; }
    void decrementSubframeCount() { ASSERT(m_subframeCount); --m_subframeCount; }
    int subframeCount() const;

    void setDefaultPageScaleLimits(float minScale, float maxScale);
    void setUserAgentPageScaleConstraints(PageScaleConstraints newConstraints);

private:
    explicit FrameHost(Page&);

    RawPtrWillBeMember<Page> m_page;
    const OwnPtrWillBeMember<TopControls> m_topControls;
    const OwnPtr<PageScaleConstraintsSet> m_pageScaleConstraintsSet;
    const OwnPtrWillBeMember<VisualViewport> m_visualViewport;
    const OwnPtrWillBeMember<EventHandlerRegistry> m_eventHandlerRegistry;
    const OwnPtrWillBeMember<ConsoleMessageStorage> m_consoleMessageStorage;

    AtomicString m_overrideEncoding;
    int m_subframeCount;
};

} // namespace blink

#endif // FrameHost_h