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

/*
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 * in the documentation and/or other materials provided with the
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#ifndef PageScaleConstraintsSet_h
#define PageScaleConstraintsSet_h

#include <memory>
#include "core/CoreExport.h"
#include "core/dom/ViewportDescription.h"
#include "core/frame/PageScaleConstraints.h"
#include "platform/Length.h"
#include "platform/geometry/IntSize.h"
#include "platform/wtf/Allocator.h"
#include "platform/wtf/PtrUtil.h"

namespace blink {

// This class harmonizes the viewport (particularly page scale) constraints from
// the meta viewport tag and other sources.
class CORE_EXPORT PageScaleConstraintsSet {
  USING_FAST_MALLOC(PageScaleConstraintsSet);

 public:
  static std::unique_ptr<PageScaleConstraintsSet> Create() {
    return WTF::WrapUnique(new PageScaleConstraintsSet);
  }

  void SetDefaultConstraints(const PageScaleConstraints&);
  const PageScaleConstraints& DefaultConstraints() const;

  // Settings defined in the website's viewport tag, if viewport tag support
  // is enabled.
  const PageScaleConstraints& PageDefinedConstraints() const {
    return page_defined_constraints_;
  }
  void UpdatePageDefinedConstraints(const ViewportDescription&,
                                    Length legacy_fallback_width);
  void AdjustForAndroidWebViewQuirks(const ViewportDescription&,
                                     int layout_fallback_width,
                                     float device_scale_factor,
                                     bool support_target_density_dpi,
                                     bool wide_viewport_quirk_enabled,
                                     bool use_wide_viewport,
                                     bool load_with_overview_mode,
                                     bool non_user_scalable_quirk_enabled);
  void ClearPageDefinedConstraints();

  // Constraints may also be set from Chromium -- this overrides any
  // page-defined values.
  const PageScaleConstraints& UserAgentConstraints() const {
    return user_agent_constraints_;
  }
  void SetUserAgentConstraints(const PageScaleConstraints&);

  const PageScaleConstraints& FullscreenConstraints() const {
    return fullscreen_constraints_;
  }
  void SetFullscreenConstraints(const PageScaleConstraints&);

  // Actual computed values, taking into account the above plus the current
  // viewport size and document width.
  const PageScaleConstraints& FinalConstraints() const {
    return final_constraints_;
  }
  void ComputeFinalConstraints();
  void AdjustFinalConstraintsToContentsSize(
      IntSize contents_size,
      int non_overlay_scrollbar_width,
      bool shrinks_viewport_content_to_fit);

  void DidChangeContentsSize(IntSize contents_size, float page_scale_factor);

  // This should be set to true on each page load to note that the page scale
  // factor needs to be reset to its initial value.
  void SetNeedsReset(bool);
  bool NeedsReset() const { return needs_reset_; }

  // This is set when one of the inputs to finalConstraints changes.
  bool ConstraintsDirty() const { return constraints_dirty_; }

  void DidChangeInitialContainingBlockSize(const IntSize&);

  IntSize GetLayoutSize() const;
  IntSize InitialViewportSize() const { return icb_size_; }

 private:
  PageScaleConstraintsSet();

  PageScaleConstraints ComputeConstraintsStack() const;

  PageScaleConstraints default_constraints_;
  PageScaleConstraints page_defined_constraints_;
  PageScaleConstraints user_agent_constraints_;
  PageScaleConstraints fullscreen_constraints_;
  PageScaleConstraints final_constraints_;

  int last_contents_width_;
  IntSize icb_size_;

  bool needs_reset_;
  bool constraints_dirty_;
};

}  // namespace blink

#endif  // PageScaleConstraintsSet_h