The Tor Browser: gfx/cairo/win32-ddb-dib.patch@97036ab72558 (annotated)

gfx/cairo/win32-ddb-dib.patch@97036ab72558 (annotated)

gfx/cairo/win32-ddb-dib.patch

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.

 b=455513; add optional flag to allow converting a DDB to a DIB internally, if the surface is every used as a source; r=jmuizelaar
 If a DDB is used as a source for an operation that can't be handled
 natively by GDI, we end up needing to take a really slow path (creating a
 temporary surface for acquire_source) for each operation.  If we convert
 the DDB to a DIB, we then end up having a real image buffer and can hand
 things off to pixman directly.
 This isn't the default mode because I'm not sure if there are cases where a
 DDB is explicitly needed (e.g. for printing), and it would change
 current cairo behaviour.  It might become the default at some point in the
 future.
 diff --git a/gfx/cairo/cairo/src/cairo-win32-private.h b/gfx/cairo/cairo/src/cairo-win32-private.h
 --- a/gfx/cairo/cairo/src/cairo-win32-private.h
 +++ b/gfx/cairo/cairo/src/cairo-win32-private.h
@@ -117,6 +117,9 @@
      /* Whether we can use the CHECKJPEGFORMAT escape function */
      CAIRO_WIN32_SURFACE_CAN_CHECK_PNG = (1<<8),
 +
 +    /* if this DDB surface can be converted to a DIB if necessary */
 +    CAIRO_WIN32_SURFACE_CAN_CONVERT_TO_DIB = (1<<9),
  };
  cairo_status_t
 diff --git a/gfx/cairo/cairo/src/cairo-win32-surface.c b/gfx/cairo/cairo/src/cairo-win32-surface.c
 --- a/gfx/cairo/cairo/src/cairo-win32-surface.c
 +++ b/gfx/cairo/cairo/src/cairo-win32-surface.c
@@ -560,6 +560,56 @@
      return CAIRO_STATUS_SUCCESS;
  }
 +static void
 +_cairo_win32_convert_ddb_to_dib (cairo_win32_surface_t *surface)
 +{
 +    cairo_win32_surface_t *new_surface;
 +    int width = surface->extents.width;
 +    int height = surface->extents.height;
 +
 +    BOOL ok;
 +    HBITMAP oldbitmap;
 +
 +    new_surface = (cairo_win32_surface_t*)
 +	_cairo_win32_surface_create_for_dc (surface->dc,
 +					    surface->format,
 +					    width,
 +					    height);
 +
 +    if (new_surface->base.status)
 +	return;
 +
 +    /* DDB can't be 32bpp, so BitBlt is safe */
 +    ok = BitBlt (new_surface->dc,
 +		 0, 0, width, height,
 +		 surface->dc,
 +		 0, 0, SRCCOPY);
 +
 +    if (!ok)
 +	goto out;
 +
 +    /* Now swap around new_surface and surface's internal bitmap
 +     * pointers. */
 +    DeleteDC (new_surface->dc);
 +    new_surface->dc = NULL;
 +
 +    oldbitmap = SelectObject (surface->dc, new_surface->bitmap);
 +    DeleteObject (oldbitmap);
 +
 +    surface->image = new_surface->image;
 +    surface->is_dib = new_surface->is_dib;
 +    surface->bitmap = new_surface->bitmap;
 +
 +    new_surface->bitmap = NULL;
 +    new_surface->image = NULL;
 +
 +    /* Finally update flags */
 +    surface->flags = _cairo_win32_flags_for_dc (surface->dc);
 +
 +  out:
 +    cairo_surface_destroy ((cairo_surface_t*)new_surface);
 +}
 +
  static cairo_status_t
  _cairo_win32_surface_acquire_source_image (void                    *abstract_surface,
  					   cairo_image_surface_t  **image_out,
@@ -568,6 +618,17 @@
      cairo_win32_surface_t *surface = abstract_surface;
      cairo_win32_surface_t *local = NULL;
      cairo_status_t status;
 +
 +    if (!surface->image && !surface->is_dib && surface->bitmap &&
 +	(surface->flags & CAIRO_WIN32_SURFACE_CAN_CONVERT_TO_DIB) != 0)
 +    {
 +	/* This is a DDB, and we're being asked to use it as a source for
 +	 * something that we couldn't support natively.  So turn it into
 +	 * a DIB, so that we have an equivalent image surface, as long
 +	 * as we're allowed to via flags.
 +	 */
 +	_cairo_win32_convert_ddb_to_dib (surface);
 +    }
      if (surface->image) {
  	*image_out = (cairo_image_surface_t *)surface->image;
@@ -2133,3 +2194,61 @@
      free(rd);
      fflush (stderr);
  }
 +
 +/**
 + * cairo_win32_surface_set_can_convert_to_dib
 + * @surface: a #cairo_surface_t
 + * @can_convert: a #cairo_bool_t indicating whether this surface can
 + *               be coverted to a DIB if necessary
 + *
 + * A DDB surface with this flag set can be converted to a DIB if it's
 + * used as a source in a way that GDI can't natively handle; for
 + * example, drawing a RGB24 DDB onto an ARGB32 DIB.  Doing this
 + * conversion results in a significant speed optimization, because we
 + * can call on pixman to perform the operation natively, instead of
 + * reading the data from the DC each time.
 + *
 + * Return value: %CAIRO_STATUS_SUCCESS if the flag was successfully
 + * changed, or an error otherwise.
 + *
 + */
 +cairo_status_t
 +cairo_win32_surface_set_can_convert_to_dib (cairo_surface_t *asurface, cairo_bool_t can_convert)
 +{
 +    cairo_win32_surface_t *surface = (cairo_win32_surface_t*) asurface;
 +    if (surface->base.type != CAIRO_SURFACE_TYPE_WIN32)
 +	return CAIRO_STATUS_SURFACE_TYPE_MISMATCH;
 +
 +    if (surface->bitmap) {
 +	if (can_convert)
 +	    surface->flags |= CAIRO_WIN32_SURFACE_CAN_CONVERT_TO_DIB;
 +	else
 +	    surface->flags &= ~CAIRO_WIN32_SURFACE_CAN_CONVERT_TO_DIB;
 +    }
 +
 +    return CAIRO_STATUS_SUCCESS;
 +}
 +
 +/**
 + * cairo_win32_surface_get_can_convert_to_dib
 + * @surface: a #cairo_surface_t
 + * @can_convert: a #cairo_bool_t* that receives the return value
 + *
 + * Returns the value of the flag indicating whether the surface can be
 + * converted to a DIB if necessary, as set by
 + * cairo_win32_surface_set_can_convert_to_dib.
 + *
 + * Return value: %CAIRO_STATUS_SUCCESS if the flag was successfully
 + * retreived, or an error otherwise.
 + *
 + */
 +cairo_status_t
 +cairo_win32_surface_get_can_convert_to_dib (cairo_surface_t *asurface, cairo_bool_t *can_convert)
 +{
 +    cairo_win32_surface_t *surface = (cairo_win32_surface_t*) asurface;
 +    if (surface->base.type != CAIRO_SURFACE_TYPE_WIN32)
 +	return CAIRO_STATUS_SURFACE_TYPE_MISMATCH;
 +
 +    *can_convert = ((surface->flags & CAIRO_WIN32_SURFACE_CAN_CONVERT_TO_DIB) != 0);
 +    return CAIRO_STATUS_SUCCESS;
 +}
 diff --git a/gfx/cairo/cairo/src/cairo-win32.h b/gfx/cairo/cairo/src/cairo-win32.h
 --- a/gfx/cairo/cairo/src/cairo-win32.h
 +++ b/gfx/cairo/cairo/src/cairo-win32.h
@@ -68,6 +68,12 @@ cairo_win32_surface_get_dc (cairo_surface_t *surface);
  cairo_public cairo_surface_t *
  cairo_win32_surface_get_image (cairo_surface_t *surface);
 +cairo_public cairo_status_t
 +cairo_win32_surface_set_can_convert_to_dib (cairo_surface_t *surface, cairo_bool_t can_convert);
 +
 +cairo_public cairo_status_t
 +cairo_win32_surface_get_can_convert_to_dib (cairo_surface_t *surface, cairo_bool_t *can_convert);
 +
  #if CAIRO_HAS_WIN32_FONT

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gfx/cairo/win32-ddb-dib.patch@97036ab72558 (annotated)

gfx/cairo/win32-ddb-dib.patch