gecko-dev/gfx/thebes/gfxXlibSurface.cpp

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * 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/. */

#include "gfxXlibSurface.h"

#include "cairo.h"
#include "cairo-xlib.h"
#include <X11/Xlibint.h> /* For XESetCloseDisplay */
#undef max               // Xlibint.h defines this and it breaks std::max
#undef min               // Xlibint.h defines this and it breaks std::min
#undef Data

#include "nsTArray.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/Preferences.h"
#include <algorithm>
#include "mozilla/CheckedInt.h"

using namespace mozilla;
using namespace mozilla::gfx;

gfxXlibSurface::gfxXlibSurface(Display* dpy, Drawable drawable, Visual* visual)
    : mPixmapTaken(false),
      mDisplay(XlibDisplay::Borrow(dpy)),
      mDrawable(drawable) {
  const gfx::IntSize size = DoSizeQuery();
  cairo_surface_t* surf =
      cairo_xlib_surface_create(dpy, drawable, visual, size.width, size.height);
  Init(surf);
}

gfxXlibSurface::gfxXlibSurface(Display* dpy, Drawable drawable, Visual* visual,
                               const gfx::IntSize& size)
    : gfxXlibSurface(XlibDisplay::Borrow(dpy), drawable, visual, size) {}

gfxXlibSurface::gfxXlibSurface(const std::shared_ptr<XlibDisplay>& dpy,
                               Drawable drawable, Visual* visual,
                               const gfx::IntSize& size)
    : mPixmapTaken(false), mDisplay(dpy), mDrawable(drawable) {
  NS_ASSERTION(Factory::CheckSurfaceSize(size, XLIB_IMAGE_SIDE_SIZE_LIMIT),
               "Bad size");

  cairo_surface_t* surf = cairo_xlib_surface_create(*dpy, drawable, visual,
                                                    size.width, size.height);
  Init(surf);
}

gfxXlibSurface::gfxXlibSurface(cairo_surface_t* csurf) : mPixmapTaken(false) {
  MOZ_ASSERT(cairo_surface_status(csurf) == 0,
             "Not expecting an error surface");

  mDrawable = cairo_xlib_surface_get_drawable(csurf);
  mDisplay = XlibDisplay::Borrow(cairo_xlib_surface_get_display(csurf));

  Init(csurf, true);
}

gfxXlibSurface::~gfxXlibSurface() {
  // gfxASurface's destructor calls RecordMemoryFreed().
  if (mPixmapTaken) {
    XFreePixmap(*mDisplay, mDrawable);
  }
}

static Drawable CreatePixmap(Screen* screen, const gfx::IntSize& size,
                             unsigned int depth, Drawable relatedDrawable) {
  if (!Factory::CheckSurfaceSize(size, XLIB_IMAGE_SIDE_SIZE_LIMIT))
    return X11None;

  if (relatedDrawable == X11None) {
    relatedDrawable = RootWindowOfScreen(screen);
  }
  Display* dpy = DisplayOfScreen(screen);
  // X gives us a fatal error if we try to create a pixmap of width
  // or height 0
  return XCreatePixmap(dpy, relatedDrawable, std::max(1, size.width),
                       std::max(1, size.height), depth);
}

void gfxXlibSurface::TakePixmap() {
  NS_ASSERTION(!mPixmapTaken, "I already own the Pixmap!");
  mPixmapTaken = true;

  // The bit depth returned from Cairo is technically int, but this is
  // the last place we'd be worried about that scenario.
  unsigned int bitDepth = cairo_xlib_surface_get_depth(CairoSurface());
  MOZ_ASSERT((bitDepth % 8) == 0, "Memory used not recorded correctly");

  // Divide by 8 because surface_get_depth gives us the number of *bits* per
  // pixel.
  gfx::IntSize size = GetSize();
  CheckedInt32 totalBytes =
      CheckedInt32(size.width) * CheckedInt32(size.height) * (bitDepth / 8);

  // Don't do anything in the "else" case.  We could add INT32_MAX, but that
  // would overflow the memory used counter.  It would also mean we tried for
  // a 2G image.  For now, we'll just assert,
  MOZ_ASSERT(totalBytes.isValid(), "Did not expect to exceed 2Gb image");
  if (totalBytes.isValid()) {
    RecordMemoryUsed(totalBytes.value());
  }
}

Drawable gfxXlibSurface::ReleasePixmap() {
  NS_ASSERTION(mPixmapTaken, "I don't own the Pixmap!");
  mPixmapTaken = false;
  RecordMemoryFreed();
  return mDrawable;
}

static cairo_user_data_key_t gDestroyPixmapKey;

struct DestroyPixmapClosure {
  DestroyPixmapClosure(Drawable d, Screen* s) : mPixmap(d), mScreen(s) {}
  Drawable mPixmap;
  Screen* mScreen;
};

static void DestroyPixmap(void* data) {
  DestroyPixmapClosure* closure = static_cast<DestroyPixmapClosure*>(data);
  XFreePixmap(DisplayOfScreen(closure->mScreen), closure->mPixmap);
  delete closure;
}

/* static */
cairo_surface_t* gfxXlibSurface::CreateCairoSurface(Screen* screen,
                                                    Visual* visual,
                                                    const gfx::IntSize& size,
                                                    Drawable relatedDrawable) {
  Drawable drawable = CreatePixmap(screen, size, DepthOfVisual(screen, visual),
                                   relatedDrawable);
  if (!drawable) return nullptr;

  cairo_surface_t* surface = cairo_xlib_surface_create(
      DisplayOfScreen(screen), drawable, visual, size.width, size.height);
  if (cairo_surface_status(surface)) {
    cairo_surface_destroy(surface);
    XFreePixmap(DisplayOfScreen(screen), drawable);
    return nullptr;
  }

  DestroyPixmapClosure* closure = new DestroyPixmapClosure(drawable, screen);
  cairo_surface_set_user_data(surface, &gDestroyPixmapKey, closure,
                              DestroyPixmap);
  return surface;
}

/* static */
already_AddRefed<gfxXlibSurface> gfxXlibSurface::Create(
    Screen* screen, Visual* visual, const gfx::IntSize& size,
    Drawable relatedDrawable) {
  return Create(XlibDisplay::Borrow(DisplayOfScreen(screen)), screen, visual,
                size, relatedDrawable);
};

/* static */
already_AddRefed<gfxXlibSurface> gfxXlibSurface::Create(
    const std::shared_ptr<XlibDisplay>& display, Screen* screen, Visual* visual,
    const gfx::IntSize& size, Drawable relatedDrawable) {
  MOZ_ASSERT(*display == DisplayOfScreen(screen));

  Drawable drawable = CreatePixmap(screen, size, DepthOfVisual(screen, visual),
                                   relatedDrawable);
  if (!drawable) return nullptr;

  RefPtr<gfxXlibSurface> result =
      new gfxXlibSurface(display, drawable, visual, size);
  result->TakePixmap();

  if (result->CairoStatus() != 0) return nullptr;

  return result.forget();
}

void gfxXlibSurface::Finish() { gfxASurface::Finish(); }

const gfx::IntSize gfxXlibSurface::GetSize() const {
  if (!mSurfaceValid) return gfx::IntSize(0, 0);

  return gfx::IntSize(cairo_xlib_surface_get_width(mSurface),
                      cairo_xlib_surface_get_height(mSurface));
}

const gfx::IntSize gfxXlibSurface::DoSizeQuery() {
  // figure out width/height/depth
  Window root_ignore;
  int x_ignore, y_ignore;
  unsigned int bwidth_ignore, width, height, depth;

  XGetGeometry(*mDisplay, mDrawable, &root_ignore, &x_ignore, &y_ignore, &width,
               &height, &bwidth_ignore, &depth);

  return gfx::IntSize(width, height);
}

class DisplayTable {
 public:
  static bool GetColormapAndVisual(Screen* screen, Visual* visual,
                                   Colormap* colormap,
                                   Visual** visualForColormap);

 private:
  struct ColormapEntry {
    // The Screen is needed here because colormaps (and their visuals) may
    // only be used on one Screen
    Screen* mScreen;
    Visual* mVisual;
    Colormap mColormap;
  };

  class DisplayInfo {
   public:
    explicit DisplayInfo(Display* display) : mDisplay(display) {}
    Display* mDisplay;
    nsTArray<ColormapEntry> mColormapEntries;
  };

  // Comparator for finding the DisplayInfo
  class FindDisplay {
   public:
    bool Equals(const DisplayInfo& info, const Display* display) const {
      return info.mDisplay == display;
    }
  };

  static int DisplayClosing(Display* display, XExtCodes* codes);

  nsTArray<DisplayInfo> mDisplays;
  static DisplayTable* sDisplayTable;
};

DisplayTable* DisplayTable::sDisplayTable;

// Pixmaps don't have a particular associated visual but the pixel values are
// interpreted according to a visual/colormap pairs.
//
// cairo is designed for surfaces with either TrueColor visuals or the
// default visual (which may not be true color).  TrueColor visuals don't
// really need a colormap because the visual indicates the pixel format,
// and cairo uses the default visual with the default colormap, so cairo
// surfaces don't need an explicit colormap.
//
// However, some toolkits (e.g. GDK) need a colormap even with TrueColor
// visuals.  We can create a colormap for these visuals, but it will use about
// 20kB of memory in the server, so we use the default colormap when
// suitable and share colormaps between surfaces.  Another reason for
// minimizing colormap turnover is that the plugin process must leak resources
// for each new colormap id when using older GDK libraries (bug 569775).
//
// Only the format of the pixels is important for rendering to Pixmaps, so if
// the format of a visual matches that of the surface, then that visual can be
// used for rendering to the surface.  Multiple visuals can match the same
// format (but have different GLX properties), so the visual returned may
// differ from the visual passed in.  Colormaps are tied to a visual, so
// should only be used with their visual.

/* static */
bool DisplayTable::GetColormapAndVisual(Screen* aScreen, Visual* aVisual,
                                        Colormap* aColormap,
                                        Visual** aVisualForColormap)

{
  Display* display = DisplayOfScreen(aScreen);

  // Use the default colormap if the default visual matches.
  Visual* defaultVisual = DefaultVisualOfScreen(aScreen);
  if (aVisual == defaultVisual) {
    *aColormap = DefaultColormapOfScreen(aScreen);
    *aVisualForColormap = defaultVisual;
    return true;
  }

  // Only supporting TrueColor non-default visuals
  if (!aVisual || aVisual->c_class != TrueColor) return false;

  if (!sDisplayTable) {
    sDisplayTable = new DisplayTable();
  }

  nsTArray<DisplayInfo>* displays = &sDisplayTable->mDisplays;
  size_t d = displays->IndexOf(display, 0, FindDisplay());

  if (d == displays->NoIndex) {
    d = displays->Length();
    // Register for notification of display closing, when this info
    // becomes invalid.
    XExtCodes* codes = XAddExtension(display);
    if (!codes) return false;

    XESetCloseDisplay(display, codes->extension, DisplayClosing);
    // Add a new DisplayInfo.
    displays->AppendElement(display);
  }

  nsTArray<ColormapEntry>* entries = &displays->ElementAt(d).mColormapEntries;

  // Only a small number of formats are expected to be used, so just do a
  // simple linear search.
  for (uint32_t i = 0; i < entries->Length(); ++i) {
    const ColormapEntry& entry = entries->ElementAt(i);
    if (aVisual == entry.mVisual) {
      *aColormap = entry.mColormap;
      *aVisualForColormap = entry.mVisual;
      return true;
    }
  }

  // No existing entry.  Create a colormap and add an entry.
  Colormap colormap =
      XCreateColormap(display, RootWindowOfScreen(aScreen), aVisual, AllocNone);
  ColormapEntry* newEntry = entries->AppendElement();
  newEntry->mScreen = aScreen;
  newEntry->mVisual = aVisual;
  newEntry->mColormap = colormap;

  *aColormap = colormap;
  *aVisualForColormap = aVisual;
  return true;
}

/* static */
int DisplayTable::DisplayClosing(Display* display, XExtCodes* codes) {
  // No need to free the colormaps explicitly as they will be released when
  // the connection is closed.
  sDisplayTable->mDisplays.RemoveElement(display, FindDisplay());
  if (sDisplayTable->mDisplays.Length() == 0) {
    delete sDisplayTable;
    sDisplayTable = nullptr;
  }
  return 0;
}

/* static */
bool gfxXlibSurface::GetColormapAndVisual(cairo_surface_t* aXlibSurface,
                                          Colormap* aColormap,
                                          Visual** aVisual) {
  Screen* screen = cairo_xlib_surface_get_screen(aXlibSurface);
  Visual* visual = cairo_xlib_surface_get_visual(aXlibSurface);

  return DisplayTable::GetColormapAndVisual(screen, visual, aColormap, aVisual);
}

bool gfxXlibSurface::GetColormapAndVisual(Colormap* aColormap,
                                          Visual** aVisual) {
  if (!mSurfaceValid) return false;

  return GetColormapAndVisual(CairoSurface(), aColormap, aVisual);
}

/* static */
int gfxXlibSurface::DepthOfVisual(const Screen* screen, const Visual* visual) {
  for (int d = 0; d < screen->ndepths; d++) {
    const Depth& d_info = screen->depths[d];
    if (visual >= &d_info.visuals[0] &&
        visual < &d_info.visuals[d_info.nvisuals])
      return d_info.depth;
  }

  NS_ERROR("Visual not on Screen.");
  return 0;
}

/* static */
Visual* gfxXlibSurface::FindVisual(Screen* screen, gfxImageFormat format) {
  int depth;
  unsigned long red_mask, green_mask, blue_mask;
  switch (format) {
    case gfx::SurfaceFormat::A8R8G8B8_UINT32:
      depth = 32;
      red_mask = 0xff0000;
      green_mask = 0xff00;
      blue_mask = 0xff;
      break;
    case gfx::SurfaceFormat::X8R8G8B8_UINT32:
      depth = 24;
      red_mask = 0xff0000;
      green_mask = 0xff00;
      blue_mask = 0xff;
      break;
    case gfx::SurfaceFormat::R5G6B5_UINT16:
      depth = 16;
      red_mask = 0xf800;
      green_mask = 0x7e0;
      blue_mask = 0x1f;
      break;
    case gfx::SurfaceFormat::A8:
    default:
      return nullptr;
  }

  for (int d = 0; d < screen->ndepths; d++) {
    const Depth& d_info = screen->depths[d];
    if (d_info.depth != depth) continue;

    for (int v = 0; v < d_info.nvisuals; v++) {
      Visual* visual = &d_info.visuals[v];

      if (visual->c_class == TrueColor && visual->red_mask == red_mask &&
          visual->green_mask == green_mask && visual->blue_mask == blue_mask)
        return visual;
    }
  }

  return nullptr;
}

Screen* gfxXlibSurface::XScreen() {
  return cairo_xlib_surface_get_screen(CairoSurface());
}