ui/base/x/x11_util.h

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_BASE_X_X11_UTIL_H_
#define UI_BASE_X_X11_UTIL_H_

// This file declares utility functions for X11 (Linux only).
//
// These functions do not require the Xlib headers to be included (which is why
// we use a void* for Visual*). The Xlib headers are highly polluting so we try
// hard to limit their spread into the rest of the code.

#include <string>
#include <vector>

#include "base/basictypes.h"
#include "base/event_types.h"
#include "base/memory/ref_counted_memory.h"
#include "ui/base/ui_export.h"
#include "ui/events/event_constants.h"
#include "ui/events/keycodes/keyboard_codes.h"
#include "ui/gfx/point.h"
#include "ui/gfx/x/x11_types.h"

typedef unsigned long Atom;
typedef unsigned long XSharedMemoryId;  // ShmSeg in the X headers.
typedef unsigned long Cursor;
typedef struct _XcursorImage XcursorImage;
typedef union _XEvent XEvent;

#if defined(TOOLKIT_GTK)
typedef struct _GdkDrawable GdkWindow;
typedef struct _GtkWidget GtkWidget;
typedef struct _GtkWindow GtkWindow;
#endif

namespace gfx {
class Canvas;
class Point;
class Rect;
}
class SkBitmap;

namespace ui {

// These functions use the default display and this /must/ be called from
// the UI thread. Thus, they don't support multiple displays.

// These functions cache their results ---------------------------------

// Check if there's an open connection to an X server.
UI_EXPORT bool XDisplayExists();
// Return an X11 connection for the current, primary display.

// X shared memory comes in three flavors:
// 1) No SHM support,
// 2) SHM putimage,
// 3) SHM pixmaps + putimage.
enum SharedMemorySupport {
  SHARED_MEMORY_NONE,
  SHARED_MEMORY_PUTIMAGE,
  SHARED_MEMORY_PIXMAP
};
// Return the shared memory type of our X connection.
UI_EXPORT SharedMemorySupport QuerySharedMemorySupport(XDisplay* dpy);

// Return true iff the display supports Xrender
UI_EXPORT bool QueryRenderSupport(XDisplay* dpy);

// Return the default screen number for the display
int GetDefaultScreen(XDisplay* display);

// Returns an X11 Cursor, sharable across the process.
// |cursor_shape| is an X font cursor shape, see XCreateFontCursor().
UI_EXPORT ::Cursor GetXCursor(int cursor_shape);

// Resets the cache used by GetXCursor(). Only useful for tests that may delete
// the display.
UI_EXPORT void ResetXCursorCache();

#if defined(USE_AURA)
// Creates a custom X cursor from the image. This takes ownership of image. The
// caller must not free/modify the image. The refcount of the newly created
// cursor is set to 1.
UI_EXPORT ::Cursor CreateReffedCustomXCursor(XcursorImage* image);

// Increases the refcount of the custom cursor.
UI_EXPORT void RefCustomXCursor(::Cursor cursor);

// Decreases the refcount of the custom cursor, and destroys it if it reaches 0.
UI_EXPORT void UnrefCustomXCursor(::Cursor cursor);

// Creates a XcursorImage and copies the SkBitmap |bitmap| on it. |bitmap|
// should be non-null. Caller owns the returned object.
UI_EXPORT XcursorImage* SkBitmapToXcursorImage(const SkBitmap* bitmap,
                                               const gfx::Point& hotspot);

// Coalesce all pending motion events (touch or mouse) that are at the top of
// the queue, and return the number eliminated, storing the last one in
// |last_event|.
UI_EXPORT int CoalescePendingMotionEvents(const XEvent* xev,
                                          XEvent* last_event);
#endif

// Hides the host cursor.
UI_EXPORT void HideHostCursor();

// Returns an invisible cursor.
UI_EXPORT ::Cursor CreateInvisibleCursor();

// These functions do not cache their results --------------------------

// Get the X window id for the default root window
UI_EXPORT XID GetX11RootWindow();

// Returns the user's current desktop.
bool GetCurrentDesktop(int* desktop);

#if defined(TOOLKIT_GTK)
// Get the X window id for the given GTK widget.
UI_EXPORT XID GetX11WindowFromGtkWidget(GtkWidget* widget);
XID GetX11WindowFromGdkWindow(GdkWindow* window);

// Get the GtkWindow* wrapping a given XID, if any.
// Returns NULL if there isn't already a GtkWindow* wrapping this XID;
// see gdk_window_foreign_new() etc. to wrap arbitrary XIDs.
UI_EXPORT GtkWindow* GetGtkWindowFromX11Window(XID xid);

// Get a Visual from the given widget. Since we don't include the Xlib
// headers, this is returned as a void*.
UI_EXPORT void* GetVisualFromGtkWidget(GtkWidget* widget);
#endif  // defined(TOOLKIT_GTK)

enum HideTitlebarWhenMaximized {
  SHOW_TITLEBAR_WHEN_MAXIMIZED = 0,
  HIDE_TITLEBAR_WHEN_MAXIMIZED = 1,
};
// Sets _GTK_HIDE_TITLEBAR_WHEN_MAXIMIZED on |window|.
UI_EXPORT void SetHideTitlebarWhenMaximizedProperty(
    XID window,
    HideTitlebarWhenMaximized property);

// Clears all regions of X11's default root window by filling black pixels.
UI_EXPORT void ClearX11DefaultRootWindow();

// Returns true if |window| is visible.
UI_EXPORT bool IsWindowVisible(XID window);

// Returns the bounds of |window|.
UI_EXPORT bool GetWindowRect(XID window, gfx::Rect* rect);

// Returns true if |window| contains the point |screen_loc|.
UI_EXPORT bool WindowContainsPoint(XID window, gfx::Point screen_loc);

// Return true if |window| has any property with |property_name|.
UI_EXPORT bool PropertyExists(XID window, const std::string& property_name);

// Returns the raw bytes from a property with minimal
// interpretation. |out_data| should be freed by XFree() after use.
UI_EXPORT bool GetRawBytesOfProperty(
    XID window,
    Atom property,
    scoped_refptr<base::RefCountedMemory>* out_data,
    size_t* out_data_bytes,
    size_t* out_data_items,
    Atom* out_type);

// Get the value of an int, int array, atom array or string property.  On
// success, true is returned and the value is stored in |value|.
//
// TODO(erg): Once we remove the gtk port and are 100% aura, all of these
// should accept an Atom instead of a string.
UI_EXPORT bool GetIntProperty(XID window, const std::string& property_name,
                              int* value);
UI_EXPORT bool GetXIDProperty(XID window, const std::string& property_name,
                              XID* value);
UI_EXPORT bool GetIntArrayProperty(XID window, const std::string& property_name,
                                   std::vector<int>* value);
UI_EXPORT bool GetAtomArrayProperty(XID window,
                                    const std::string& property_name,
                                    std::vector<Atom>* value);
UI_EXPORT bool GetStringProperty(
    XID window, const std::string& property_name, std::string* value);

// These setters all make round trips.
UI_EXPORT bool SetIntProperty(XID window,
                              const std::string& name,
                              const std::string& type,
                              int value);
UI_EXPORT bool SetIntArrayProperty(XID window,
                                   const std::string& name,
                                   const std::string& type,
                                   const std::vector<int>& value);
UI_EXPORT bool SetAtomArrayProperty(XID window,
                                    const std::string& name,
                                    const std::string& type,
                                    const std::vector<Atom>& value);

// Gets the X atom for default display corresponding to atom_name.
Atom GetAtom(const char* atom_name);

// Sets the WM_CLASS attribute for a given X11 window.
UI_EXPORT void SetWindowClassHint(XDisplay* display,
                                  XID window,
                                  std::string res_name,
                                  std::string res_class);

// Get |window|'s parent window, or None if |window| is the root window.
UI_EXPORT XID GetParentWindow(XID window);

// Walk up |window|'s hierarchy until we find a direct child of |root|.
XID GetHighestAncestorWindow(XID window, XID root);

static const int kAllDesktops = -1;
// Queries the desktop |window| is on, kAllDesktops if sticky. Returns false if
// property not found.
bool GetWindowDesktop(XID window, int* desktop);

// Translates an X11 error code into a printable string.
UI_EXPORT std::string GetX11ErrorString(XDisplay* display, int err);

// Implementers of this interface receive a notification for every X window of
// the main display.
class EnumerateWindowsDelegate {
 public:
  // |xid| is the X Window ID of the enumerated window.  Return true to stop
  // further iteration.
  virtual bool ShouldStopIterating(XID xid) = 0;

 protected:
  virtual ~EnumerateWindowsDelegate() {}
};

// Enumerates all windows in the current display.  Will recurse into child
// windows up to a depth of |max_depth|.
UI_EXPORT bool EnumerateAllWindows(EnumerateWindowsDelegate* delegate,
                                   int max_depth);

// Enumerates the top-level windows of the current display.
UI_EXPORT void EnumerateTopLevelWindows(ui::EnumerateWindowsDelegate* delegate);

// Returns all children windows of a given window in top-to-bottom stacking
// order.
UI_EXPORT bool GetXWindowStack(XID window, std::vector<XID>* windows);

// Restack a window in relation to one of its siblings.  If |above| is true,
// |window| will be stacked directly above |sibling|; otherwise it will stacked
// directly below it.  Both windows must be immediate children of the same
// window.
void RestackWindow(XID window, XID sibling, bool above);

// Return a handle to a X ShmSeg. |shared_memory_key| is a SysV
// IPC key. The shared memory region must contain 32-bit pixels.
UI_EXPORT XSharedMemoryId AttachSharedMemory(XDisplay* display,
                                             int shared_memory_support);
UI_EXPORT void DetachSharedMemory(XDisplay* display, XSharedMemoryId shmseg);

// Copies |source_bounds| from |drawable| to |canvas| at offset |dest_offset|.
// |source_bounds| is in physical pixels, while |dest_offset| is relative to
// the canvas's scale. Note that this function is slow since it uses
// XGetImage() to copy the data from the X server to this process before
// copying it to |canvas|.
UI_EXPORT bool CopyAreaToCanvas(XID drawable,
                                gfx::Rect source_bounds,
                                gfx::Point dest_offset,
                                gfx::Canvas* canvas);

// Return a handle to an XRender picture where |pixmap| is a handle to a
// pixmap containing Skia ARGB data.
UI_EXPORT XID CreatePictureFromSkiaPixmap(XDisplay* display, XID pixmap);

void FreePicture(XDisplay* display, XID picture);
void FreePixmap(XDisplay* display, XID pixmap);

enum WindowManagerName {
  WM_UNKNOWN,
  WM_BLACKBOX,
  WM_CHROME_OS,
  WM_COMPIZ,
  WM_ENLIGHTENMENT,
  WM_ICE_WM,
  WM_KWIN,
  WM_METACITY,
  WM_MUFFIN,
  WM_MUTTER,
  WM_OPENBOX,
  WM_XFWM4,
};
// Attempts to guess the window maager. Returns WM_UNKNOWN if we can't
// determine it for one reason or another.
UI_EXPORT WindowManagerName GuessWindowManager();

// Change desktop for |window| to the desktop of |destination| window.
UI_EXPORT bool ChangeWindowDesktop(XID window, XID destination);

// Enable the default X error handlers. These will log the error and abort
// the process if called. Use SetX11ErrorHandlers() from x11_util_internal.h
// to set your own error handlers.
UI_EXPORT void SetDefaultX11ErrorHandlers();

// Return true if a given window is in full-screen mode.
UI_EXPORT bool IsX11WindowFullScreen(XID window);

// Manages a piece of X11 allocated memory as a RefCountedMemory segment. This
// object takes ownership over the passed in memory and will free it with the
// X11 allocator when done.
class UI_EXPORT XRefcountedMemory : public base::RefCountedMemory {
 public:
  XRefcountedMemory(unsigned char* x11_data, size_t length)
      : x11_data_(length ? x11_data : NULL),
        length_(length) {
  }

  // Overridden from RefCountedMemory:
  virtual const unsigned char* front() const OVERRIDE;
  virtual size_t size() const OVERRIDE;

 private:
  virtual ~XRefcountedMemory();

  unsigned char* x11_data_;
  size_t length_;

  DISALLOW_COPY_AND_ASSIGN(XRefcountedMemory);
};

// Keeps track of a string returned by an X function (e.g. XGetAtomName) and
// makes sure it's XFree'd.
class UI_EXPORT XScopedString {
 public:
  explicit XScopedString(char* str) : string_(str) {}
  ~XScopedString();

  const char* string() const { return string_; }

 private:
  char* string_;

  DISALLOW_COPY_AND_ASSIGN(XScopedString);
};

// Keeps track of an image returned by an X function (e.g. XGetImage) and
// makes sure it's XDestroyImage'd.
class UI_EXPORT XScopedImage {
 public:
  explicit XScopedImage(XImage* image) : image_(image) {}
  ~XScopedImage();

  XImage* get() const {
    return image_;
  }

  XImage* operator->() const {
    return image_;
  }

  void reset(XImage* image);

 private:
  XImage* image_;

  DISALLOW_COPY_AND_ASSIGN(XScopedImage);
};

// Keeps track of a cursor returned by an X function and makes sure it's
// XFreeCursor'd.
class UI_EXPORT XScopedCursor {
 public:
  // Keeps track of |cursor| created with |display|.
  XScopedCursor(::Cursor cursor, XDisplay* display);
  ~XScopedCursor();

  ::Cursor get() const;
  void reset(::Cursor cursor);

 private:
  ::Cursor cursor_;
  XDisplay* display_;

  DISALLOW_COPY_AND_ASSIGN(XScopedCursor);
};

}  // namespace ui

#endif  // UI_BASE_X_X11_UTIL_H_