text: /*
   * 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 PageScaleConstraintsSet_h
  #define PageScaleConstraintsSet_h
  
  #include "core/CoreExport.h"
  #include "core/dom/ViewportDescription.h"
  #include "core/frame/PageScaleConstraints.h"
  #include "platform/Length.h"
  #include "platform/geometry/IntSize.h"
  #include "wtf/PassOwnPtr.h"
  
  namespace blink {
  
  // This class harmonizes the viewport (particularly page scale) constraints from
  // the meta viewport tag and other sources.
  class CORE_EXPORT PageScaleConstraintsSet {
  public:
      static PassOwnPtr<PageScaleConstraintsSet> create()
      {
          return adoptPtr(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 m_pageDefinedConstraints; }
      void updatePageDefinedConstraints(const ViewportDescription&, Length legacyFallbackWidth);
      void adjustForAndroidWebViewQuirks(const ViewportDescription&, int layoutFallbackWidth, float deviceScaleFactor, bool supportTargetDensityDPI, bool wideViewportQuirkEnabled, bool useWideViewport, bool loadWithOverviewMode, bool nonUserScalableQuirkEnabled);
      void clearPageDefinedConstraints();
  
      // Constraints may also be set from Chromium -- this overrides any
      // page-defined values.
      const PageScaleConstraints& userAgentConstraints() const { return m_userAgentConstraints; }
      void setUserAgentConstraints(const PageScaleConstraints&);
  
      const PageScaleConstraints& fullscreenConstraints() const { return m_fullscreenConstraints; }
      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 m_finalConstraints; }
      void computeFinalConstraints();
      void adjustFinalConstraintsToContentsSize(IntSize contentsSize, int nonOverlayScrollbarWidth, bool shrinksViewportContentToFit);
  
      void didChangeContentsSize(IntSize contentsSize, float pageScaleFactor);
  
      // 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 m_needsReset; }
  
      // This is set when one of the inputs to finalConstraints changes.
      bool constraintsDirty() const { return m_constraintsDirty; }
  
      void didChangeViewSize(const IntSize&);
  
      IntSize mainFrameSize() const;
  
      IntSize layoutSize() const;
  
  private:
      PageScaleConstraintsSet();
  
      PageScaleConstraints computeConstraintsStack() const;
  
      PageScaleConstraints m_defaultConstraints;
      PageScaleConstraints m_pageDefinedConstraints;
      PageScaleConstraints m_userAgentConstraints;
      PageScaleConstraints m_fullscreenConstraints;
      PageScaleConstraints m_finalConstraints;
  
      int m_lastContentsWidth;
      IntSize m_viewSize;
  
      bool m_needsReset;
      bool m_constraintsDirty;
  };
  
  } // namespace blink
  
  #endif // PageScaleConstraintsSet_h
  