The Tor Browser: gfx/src/nsDeviceContext.h@97036ab72558 (annotated)

gfx/src/nsDeviceContext.h@97036ab72558 (annotated)

gfx/src/nsDeviceContext.h

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* 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/. */
 #ifndef _NS_DEVICECONTEXT_H_
 #define _NS_DEVICECONTEXT_H_
 #include <stdint.h>                     // for uint32_t
 #include <sys/types.h>                  // for int32_t
 #include "gfxTypes.h"                   // for gfxFloat
 #include "mozilla/Assertions.h"         // for MOZ_ASSERT_HELPER2
 #include "nsAutoPtr.h"                  // for nsRefPtr
 #include "nsCOMPtr.h"                   // for nsCOMPtr
 #include "nsCoord.h"                    // for nscoord
 #include "nsError.h"                    // for nsresult
 #include "nsISupports.h"                // for NS_INLINE_DECL_REFCOUNTING
 #include "nsMathUtils.h"                // for NS_round
 #include "nscore.h"                     // for char16_t, nsAString
 #include "mozilla/AppUnits.h"           // for AppUnits
 class gfxASurface;
 class gfxTextPerfMetrics;
 class gfxUserFontSet;
 class nsFont;
 class nsFontCache;
 class nsFontMetrics;
 class nsIAtom;
 class nsIDeviceContextSpec;
 class nsIScreen;
 class nsIScreenManager;
 class nsIWidget;
 class nsRect;
 class nsRenderingContext;
 class nsDeviceContext MOZ_FINAL
 {
 public:
     nsDeviceContext();
     NS_INLINE_DECL_REFCOUNTING(nsDeviceContext)
     /**
      * Initialize the device context from a widget
      * @param aWidget a widget to initialize the device context from
      * @return error status
      */
     nsresult Init(nsIWidget *aWidget);
     /**
      * Initialize the device context from a device context spec
      * @param aDevSpec the specification of the printing device
      * @return error status
      */
     nsresult InitForPrinting(nsIDeviceContextSpec *aDevSpec);
     /**
      * Create a rendering context and initialize it.  Only call this
      * method on device contexts that were initialized for printing.
      *
      * @return the new rendering context (guaranteed to be non-null)
      */
     already_AddRefed<nsRenderingContext> CreateRenderingContext();
     /**
      * Gets the number of app units in one CSS pixel; this number is global,
      * not unique to each device context.
      */
     static int32_t AppUnitsPerCSSPixel() { return mozilla::AppUnitsPerCSSPixel(); }
     /**
      * Gets the number of app units in one device pixel; this number
      * is usually a factor of AppUnitsPerCSSPixel(), although that is
      * not guaranteed.
      */
     int32_t AppUnitsPerDevPixel() const { return mAppUnitsPerDevPixel; }
     /**
      * Convert device pixels which is used for gfx/thebes to nearest
      * (rounded) app units
      */
     nscoord GfxUnitsToAppUnits(gfxFloat aGfxUnits) const
     { return nscoord(NS_round(aGfxUnits * AppUnitsPerDevPixel())); }
     /**
      * Convert app units to device pixels which is used for gfx/thebes.
      */
     gfxFloat AppUnitsToGfxUnits(nscoord aAppUnits) const
     { return gfxFloat(aAppUnits) / AppUnitsPerDevPixel(); }
     /**
      * Gets the number of app units in one physical inch; this is the
      * device's DPI times AppUnitsPerDevPixel().
      */
     int32_t AppUnitsPerPhysicalInch() const
     { return mAppUnitsPerPhysicalInch; }
     /**
      * Gets the number of app units in one CSS inch; this is
      * 96 times AppUnitsPerCSSPixel.
      */
     static int32_t AppUnitsPerCSSInch() { return mozilla::AppUnitsPerCSSInch(); }
     /**
      * Get the unscaled ratio of app units to dev pixels; useful if something
      * needs to be converted from to unscaled pixels
      */
     int32_t UnscaledAppUnitsPerDevPixel() const
     { return mAppUnitsPerDevNotScaledPixel; }
     /**
      * Get the nsFontMetrics that describe the properties of
      * an nsFont.
      * @param aFont font description to obtain metrics for
      * @param aLanguage the language of the document
      * @param aMetrics out parameter for font metrics
      * @param aUserFontSet user font set
      * @return error status
      */
     nsresult GetMetricsFor(const nsFont& aFont, nsIAtom* aLanguage,
                            gfxUserFontSet* aUserFontSet,
                            gfxTextPerfMetrics* aTextPerf,
                            nsFontMetrics*& aMetrics);
     /**
      * Notification when a font metrics instance created for this device is
      * about to be deleted
      */
     nsresult FontMetricsDeleted(const nsFontMetrics* aFontMetrics);
     /**
      * Attempt to free up resources by flushing out any fonts no longer
      * referenced by anything other than the font cache itself.
      * @return error status
      */
     nsresult FlushFontCache();
     /**
      * Return the bit depth of the device.
      */
     nsresult GetDepth(uint32_t& aDepth);
     /**
      * Get the size of the displayable area of the output device
      * in app units.
      * @param aWidth out parameter for width
      * @param aHeight out parameter for height
      * @return error status
      */
     nsresult GetDeviceSurfaceDimensions(nscoord& aWidth, nscoord& aHeight);
     /**
      * Get the size of the content area of the output device in app
      * units.  This corresponds on a screen device, for instance, to
      * the entire screen.
      * @param aRect out parameter for full rect. Position (x,y) will
      *              be (0,0) or relative to the primary monitor if
      *              this is not the primary.
      * @return error status
      */
     nsresult GetRect(nsRect& aRect);
     /**
      * Get the size of the content area of the output device in app
      * units.  This corresponds on a screen device, for instance, to
      * the area reported by GetDeviceSurfaceDimensions, minus the
      * taskbar (Windows) or menubar (Macintosh).
      * @param aRect out parameter for client rect. Position (x,y) will
      *              be (0,0) adjusted for any upper/left non-client
      *              space if present or relative to the primary
      *              monitor if this is not the primary.
      * @return error status
      */
     nsresult GetClientRect(nsRect& aRect);
     /**
      * Inform the output device that output of a document is beginning
      * Used for print related device contexts. Must be matched 1:1 with
      * EndDocument() or AbortDocument().
      *
      * @param aTitle - title of Document
      * @param aPrintToFileName - name of file to print to, if nullptr
      * then don't print to file
      * @param aStartPage - starting page number (must be greater than zero)
      * @param aEndPage - ending page number (must be less than or
      * equal to number of pages)
      *
      * @return error status
      */
     nsresult BeginDocument(const nsAString& aTitle,
                            char16_t*       aPrintToFileName,
                            int32_t          aStartPage,
                            int32_t          aEndPage);
     /**
      * Inform the output device that output of a document is ending.
      * Used for print related device contexts. Must be matched 1:1 with
      * BeginDocument()
      * @return error status
      */
     nsresult EndDocument();
     /**
      * Inform the output device that output of a document is being aborted.
      * Must be matched 1:1 with BeginDocument()
      * @return error status
      */
     nsresult AbortDocument();
     /**
      * Inform the output device that output of a page is beginning
      * Used for print related device contexts. Must be matched 1:1 with
      * EndPage() and within a BeginDocument()/EndDocument() pair.
      * @return error status
      */
     nsresult BeginPage();
     /**
      * Inform the output device that output of a page is ending
      * Used for print related device contexts. Must be matched 1:1 with
      * BeginPage() and within a BeginDocument()/EndDocument() pair.
      * @return error status
      */
     nsresult EndPage();
     /**
      * Check to see if the DPI has changed
      * @return whether there was actually a change in the DPI (whether
      *         AppUnitsPerDevPixel() or AppUnitsPerPhysicalInch()
      *         changed)
      */
     bool CheckDPIChange();
     /**
      * Set the pixel scaling factor: all lengths are multiplied by this factor
      * when we convert them to device pixels. Returns whether the ratio of
      * app units to dev pixels changed because of the scale factor.
      */
     bool SetPixelScale(float aScale);
     /**
      * Returns the pixel scaling factor (page zoom factor) applied.
      */
     float GetPixelScale() const { return mPixelScale; }
     /**
      * True if this device context was created for printing.
      */
     bool IsPrinterSurface();
 private:
     // Private destructor, to discourage deletion outside of Release():
     ~nsDeviceContext();
     void SetDPI();
     void ComputeClientRectUsingScreen(nsRect *outRect);
     void ComputeFullAreaUsingScreen(nsRect *outRect);
     void FindScreen(nsIScreen **outScreen);
     void CalcPrintingSize();
     void UpdateScaledAppUnits();
     nscoord  mWidth;
     nscoord  mHeight;
     uint32_t mDepth;
     int32_t  mAppUnitsPerDevPixel;
     int32_t  mAppUnitsPerDevNotScaledPixel;
     int32_t  mAppUnitsPerPhysicalInch;
     float    mPixelScale;
     float    mPrintingScale;
     nsFontCache*                   mFontCache;
     nsCOMPtr<nsIWidget>            mWidget;
     nsCOMPtr<nsIScreenManager>     mScreenManager;
     nsCOMPtr<nsIDeviceContextSpec> mDeviceContextSpec;
     nsRefPtr<gfxASurface>          mPrintingSurface;
 #ifdef XP_MACOSX
     nsRefPtr<gfxASurface>          mCachedPrintingSurface;
 #endif
 };
 #endif /* _NS_DEVICECONTEXT_H_ */

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gfx/src/nsDeviceContext.h@97036ab72558 (annotated)

gfx/src/nsDeviceContext.h