Feature #80: D-Bus support

- Add D-Bus support. Currently 7 methods are available: "reset" (same as
  SIGUSR1), "list_win" (list the windows compton manages), "win_get"
  (get a property of the window), "win_set" (set a property of the
  window), "find_win" (find window based on client window / focus),
  "opts_get" (get the value of a compton option), and "opts_set" (set
  the value of a compton option), together with 4 signals: "win_added",
  "win_destroyed", "win_mapped", "win_unmapped".

- D-Bus support depends on libdbus.

- As there are many items and my time is tight, no much tests are done.
  Bugs to be expected.

- Create a new header file `common.h` that contains shared content.

- Fix some bugs in timeout handling.

- Update file headers in all source files.

- Re-enable --unredir-if-possible on multi-screen set-ups, as the user
  could turn if off manually anyway.

- Check if the window is mapped in `repair_win()`.

- Add ps->track_atom_lst and its handlers, to prepare for the new
  condition format.

- Known issue 1: "win_get", "win_set", "opts_get", "opts_set" support a
  very limited number of targets only. New ones will be added gradually.

- Known issue 2: Accidental drop of D-Bus connection is not handled.

- Known issue 3: Introspection does not reveal all available methods,
  because some methods have unpredictable prototypes. Still hesitating
  about what to do...

- Known issue 4: Error handling is not finished yet. Compton does not
  always reply with the correct error message (but it does print out the
  correct error message, usually).

1 files changed, 1370 insertions, 0 deletions

diff --git a/common.h b/common.h
new file mode 100644
index 000000000..31c9c2002
--- /dev/null
+++ b/common.h
@@ -0,0 +1,1370 @@
+/*
+ * Compton - a compositor for X11
+ *
+ * Based on `xcompmgr` - Copyright (c) 2003, Keith Packard
+ *
+ * Copyright (c) 2011-2013, Christopher Jeffrey
+ * See LICENSE for more information.
+ *
+ */
+
+// === Options ===
+
+// Debug options, enable them using -D in CFLAGS
+// #define DEBUG_REPAINT    1
+// #define DEBUG_EVENTS     1
+// #define DEBUG_RESTACK    1
+// #define DEBUG_WINTYPE    1
+// #define DEBUG_CLIENTWIN  1
+// #define DEBUG_WINDATA    1
+// #define DEBUG_WINMATCH   1
+// #define DEBUG_REDIR      1
+// #define DEBUG_ALLOC_REG  1
+// #define DEBUG_FRAME      1
+// #define DEBUG_LEADER     1
+// #define MONITOR_REPAINT  1
+
+// Whether to enable PCRE regular expression support in blacklists, enabled
+// by default
+// #define CONFIG_REGEX_PCRE 1
+// Whether to enable JIT support of libpcre. This may cause problems on PaX
+// kernels.
+// #define CONFIG_REGEX_PCRE_JIT 1
+// Whether to enable parsing of configuration files using libconfig.
+// #define CONFIG_LIBCONFIG 1
+// Whether we are using a legacy version of libconfig (1.3.x).
+// #define CONFIG_LIBCONFIG_LEGACY 1
+// Whether to enable DRM VSync support
+// #define CONFIG_VSYNC_DRM 1
+// Whether to enable OpenGL VSync support
+// #define CONFIG_VSYNC_OPENGL 1
+// Whether to enable DBus support with libdbus.
+// #define CONFIG_DBUS 1
+
+// === Includes ===
+
+// For some special functions
+#define _GNU_SOURCE
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+#include <sys/poll.h>
+#include <assert.h>
+#include <time.h>
+#include <sys/time.h>
+
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/Xatom.h>
+#include <X11/extensions/Xcomposite.h>
+#include <X11/extensions/Xdamage.h>
+#include <X11/extensions/Xrender.h>
+#include <X11/extensions/shape.h>
+#include <X11/extensions/Xrandr.h>
+#include <X11/extensions/Xdbe.h>
+
+// libpcre
+#ifdef CONFIG_REGEX_PCRE
+#include <pcre.h>
+
+// For compatiblity with <libpcre-8.20
+#ifndef PCRE_STUDY_JIT_COMPILE
+#define PCRE_STUDY_JIT_COMPILE    0
+#define LPCRE_FREE_STUDY(extra)   pcre_free(extra)
+#else
+#define LPCRE_FREE_STUDY(extra)   pcre_free_study(extra)
+#endif
+
+#endif
+
+// libconfig
+#ifdef CONFIG_LIBCONFIG
+#include <libgen.h>
+#include <libconfig.h>
+#endif
+
+// libdbus
+#ifdef CONFIG_DBUS
+#include <dbus/dbus.h>
+#endif
+
+// libGL
+#ifdef CONFIG_VSYNC_OPENGL
+#include <GL/glx.h>
+#endif
+
+// === Macros ===
+
+#define MSTR_(s)        #s
+#define MSTR(s)         MSTR_(s)
+
+/// Print out an error message.
+#define printf_err(format, ...) \
+  fprintf(stderr, format "\n", ## __VA_ARGS__)
+
+/// Print out an error message with function name.
+#define printf_errf(format, ...) \
+  printf_err("%s" format,  __func__, ## __VA_ARGS__)
+
+/// Print out an error message with function name, and quit with a
+/// specific exit code.
+#define printf_errfq(code, format, ...) { \
+  printf_err("%s" format,  __func__, ## __VA_ARGS__); \
+  exit(code); \
+}
+
+/// Print out a debug message.
+#define printf_dbg(format, ...) \
+  printf(format, ## __VA_ARGS__); \
+  fflush(stdout)
+
+/// Print out a debug message with function name.
+#define printf_dbgf(format, ...) \
+  printf_dbg("%s" format, __func__, ## __VA_ARGS__)
+
+// Use #s here to prevent macro expansion
+/// Macro used for shortening some debugging code.
+#define CASESTRRET(s)   case s: return #s
+
+// === Constants ===
+#if !(COMPOSITE_MAJOR > 0 || COMPOSITE_MINOR >= 2)
+#error libXcomposite version unsupported
+#endif
+
+#define ROUNDED_PERCENT 0.05
+#define ROUNDED_PIXELS  10
+
+#define OPAQUE 0xffffffff
+#define REGISTER_PROP "_NET_WM_CM_S"
+
+#define TIME_MS_MAX LONG_MAX
+#define FADE_DELTA_TOLERANCE 0.2
+#define SWOPTI_TOLERANCE 3000
+#define TIMEOUT_RUN_TOLERANCE 0.05
+#define WIN_GET_LEADER_MAX_RECURSION 20
+
+#define SEC_WRAP (15L * 24L * 60L * 60L)
+
+#define NS_PER_SEC 1000000000L
+#define US_PER_SEC 1000000L
+#define MS_PER_SEC 1000
+
+#define XRFILTER_CONVOLUTION  "convolution"
+#define XRFILTER_GUASSIAN     "gaussian"
+#define XRFILTER_BINOMIAL     "binomial"
+
+// Window flags
+
+// Window size is changed
+#define WFLAG_SIZE_CHANGE   0x0001
+// Window size/position is changed
+#define WFLAG_POS_CHANGE    0x0002
+// Window opacity / dim state changed
+#define WFLAG_OPCT_CHANGE   0x0004
+
+// === Types ===
+
+typedef uint32_t opacity_t;
+typedef long time_ms_t;
+
+typedef enum {
+  WINTYPE_UNKNOWN,
+  WINTYPE_DESKTOP,
+  WINTYPE_DOCK,
+  WINTYPE_TOOLBAR,
+  WINTYPE_MENU,
+  WINTYPE_UTILITY,
+  WINTYPE_SPLASH,
+  WINTYPE_DIALOG,
+  WINTYPE_NORMAL,
+  WINTYPE_DROPDOWN_MENU,
+  WINTYPE_POPUP_MENU,
+  WINTYPE_TOOLTIP,
+  WINTYPE_NOTIFY,
+  WINTYPE_COMBO,
+  WINTYPE_DND,
+  NUM_WINTYPES
+} wintype_t;
+
+/// Enumeration type to represent switches.
+typedef enum {
+  OFF,    // false
+  ON,     // true
+  UNSET
+} switch_t;
+
+/// Enumeration type of window painting mode.
+typedef enum {
+  WMODE_TRANS,
+  WMODE_SOLID,
+  WMODE_ARGB
+} winmode_t;
+
+/// Structure representing needed window updates.
+typedef struct {
+  bool shadow       : 1;
+  bool fade         : 1;
+  bool focus        : 1;
+  bool invert_color : 1;
+} win_upd_t;
+
+/// Structure representing Window property value.
+typedef struct {
+  // All pointers have the same length, right?
+  // I wanted to use anonymous union but it's a GNU extension...
+  union {
+    unsigned char *p8;
+    short *p16;
+    long *p32;
+  } data;
+  unsigned long nitems;
+  Atom type;
+  int format;
+} winprop_t;
+
+typedef struct _ignore {
+  struct _ignore *next;
+  unsigned long sequence;
+} ignore_t;
+
+enum wincond_target {
+  CONDTGT_NAME,
+  CONDTGT_CLASSI,
+  CONDTGT_CLASSG,
+  CONDTGT_ROLE,
+};
+
+enum wincond_type {
+  CONDTP_EXACT,
+  CONDTP_ANYWHERE,
+  CONDTP_FROMSTART,
+  CONDTP_WILDCARD,
+  CONDTP_REGEX_PCRE,
+};
+
+#define CONDF_IGNORECASE 0x0001
+
+typedef struct _wincond {
+  enum wincond_target target;
+  enum wincond_type type;
+  char *pattern;
+#ifdef CONFIG_REGEX_PCRE
+  pcre *regex_pcre;
+  pcre_extra *regex_pcre_extra;
+#endif
+  int16_t flags;
+  struct _wincond *next;
+} wincond_t;
+
+/// VSync modes.
+typedef enum {
+  VSYNC_NONE,
+  VSYNC_DRM,
+  VSYNC_OPENGL,
+} vsync_t;
+
+#ifdef CONFIG_VSYNC_OPENGL
+typedef int (*f_WaitVideoSync) (int, int, unsigned *);
+typedef int (*f_GetVideoSync) (unsigned *);
+#endif
+
+typedef struct {
+  int size;
+  double *data;
+} conv;
+
+/// Linked list type of atoms.
+typedef struct _latom {
+  Atom atom;
+  struct _latom *next;
+} latom_t;
+
+struct _timeout_t;
+
+struct _win;
+
+/// Structure representing all options.
+typedef struct {
+  // === General ===
+  char *display;
+  /// Whether to try to detect WM windows and mark them as focused.
+  bool mark_wmwin_focused;
+  /// Whether to mark override-redirect windows as focused.
+  bool mark_ovredir_focused;
+  /// Whether to fork to background.
+  bool fork_after_register;
+  /// Whether to detect rounded corners.
+  bool detect_rounded_corners;
+  /// Whether to paint on X Composite overlay window instead of root
+  /// window.
+  bool paint_on_overlay;
+  /// Whether to unredirect all windows if a full-screen opaque window
+  /// is detected.
+  bool unredir_if_possible;
+  /// Whether to enable D-Bus support.
+  bool dbus;
+  /// Path to log file.
+  char *logpath;
+  /// Whether to work under synchronized mode for debugging.
+  bool synchronize;
+
+  // === VSync & software optimization ===
+  /// User-specified refresh rate.
+  int refresh_rate;
+  /// Whether to enable refresh-rate-based software optimization.
+  bool sw_opti;
+  /// VSync method to use;
+  vsync_t vsync;
+  /// Whether to enable double buffer.
+  bool dbe;
+  /// Whether to do VSync aggressively.
+  bool vsync_aggressive;
+
+  // === Shadow ===
+  /// Enable/disable shadow for specific window types.
+  bool wintype_shadow[NUM_WINTYPES];
+  /// Red, green and blue tone of the shadow.
+  double shadow_red, shadow_green, shadow_blue;
+  int shadow_radius;
+  int shadow_offset_x, shadow_offset_y;
+  double shadow_opacity;
+  bool clear_shadow;
+  /// Shadow blacklist. A linked list of conditions.
+  wincond_t *shadow_blacklist;
+  /// Whether bounding-shaped window should be ignored.
+  bool shadow_ignore_shaped;
+  /// Whether to respect _COMPTON_SHADOW.
+  bool respect_prop_shadow;
+
+  // === Fading ===
+  /// Enable/disable fading for specific window types.
+  bool wintype_fade[NUM_WINTYPES];
+  /// How much to fade in in a single fading step.
+  opacity_t fade_in_step;
+  /// How much to fade out in a single fading step.
+  opacity_t fade_out_step;
+  /// Fading time delta. In milliseconds.
+  time_ms_t fade_delta;
+  /// Whether to disable fading on window open/close.
+  bool no_fading_openclose;
+  /// Fading blacklist. A linked list of conditions.
+  wincond_t *fade_blacklist;
+
+  // === Opacity ===
+  /// Default opacity for specific window types
+  double wintype_opacity[NUM_WINTYPES];
+  /// Default opacity for inactive windows.
+  /// 32-bit integer with the format of _NET_WM_OPACITY. 0 stands for
+  /// not enabled, default.
+  opacity_t inactive_opacity;
+  /// Whether inactive_opacity overrides the opacity set by window
+  /// attributes.
+  bool inactive_opacity_override;
+  /// Frame opacity. Relative to window opacity, also affects shadow
+  /// opacity.
+  double frame_opacity;
+  /// Whether to detect _NET_WM_OPACITY on client windows. Used on window
+  /// managers that don't pass _NET_WM_OPACITY to frame windows.
+  bool detect_client_opacity;
+  /// Step for pregenerating alpha pictures. 0.01 - 1.0.
+  double alpha_step;
+
+  // === Other window processing ===
+  /// Whether to blur background of semi-transparent / ARGB windows.
+  bool blur_background;
+  /// Whether to blur background when the window frame is not opaque.
+  /// Implies blur_background.
+  bool blur_background_frame;
+  /// Whether to use fixed blur strength instead of adjusting according
+  /// to window opacity.
+  bool blur_background_fixed;
+  /// How much to dim an inactive window. 0.0 - 1.0, 0 to disable.
+  double inactive_dim;
+  /// Whether to use fixed inactive dim opacity, instead of deciding
+  /// based on window opacity.
+  bool inactive_dim_fixed;
+  /// Conditions of windows to have inverted colors.
+  wincond_t *invert_color_list;
+
+  // === Focus related ===
+  /// Consider windows of specific types to be always focused.
+  bool wintype_focus[NUM_WINTYPES];
+  /// Whether to use EWMH _NET_ACTIVE_WINDOW to find active window.
+  bool use_ewmh_active_win;
+  /// A list of windows always to be considered focused.
+  wincond_t *focus_blacklist;
+  /// Whether to do window grouping with <code>WM_TRANSIENT_FOR</code>.
+  bool detect_transient;
+  /// Whether to do window grouping with <code>WM_CLIENT_LEADER</code>.
+  bool detect_client_leader;
+
+  // === Calculated ===
+  /// Whether compton needs to track focus changes.
+  bool track_focus;
+  /// Whether compton needs to track window name and class.
+  bool track_wdata;
+  /// Whether compton needs to track window leaders.
+  bool track_leader;
+} options_t;
+
+/// Structure containing all necessary data for a compton session.
+typedef struct {
+  // === Display related ===
+  /// Display in use.
+  Display *dpy;
+  /// Default screen.
+  int scr;
+  /// Default visual.
+  Visual *vis;
+  /// Default depth.
+  int depth;
+  /// Root window.
+  Window root;
+  /// Height of root window.
+  int root_height;
+  /// Width of root window.
+  int root_width;
+  // Damage of root window.
+  // Damage root_damage;
+  /// X Composite overlay window. Used if <code>--paint-on-overlay</code>.
+  Window overlay;
+  /// Picture of the root window background.
+  Picture root_tile;
+  /// A region of the size of the screen.
+  XserverRegion screen_reg;
+  /// Picture of root window. Destination of painting in no-DBE painting
+  /// mode.
+  Picture root_picture;
+  /// A Picture acting as the painting target.
+  Picture tgt_picture;
+  /// Temporary buffer to paint to before sending to display.
+  Picture tgt_buffer;
+  /// DBE back buffer for root window. Used in DBE painting mode.
+  XdbeBackBuffer root_dbe;
+  /// Window ID of the window we register as a symbol.
+  Window reg_win;
+
+  // === Operation related ===
+  /// Program options.
+  options_t o;
+  /// File descriptors to check for reading.
+  fd_set *pfds_read;
+  /// File descriptors to check for writing.
+  fd_set *pfds_write;
+  /// File descriptors to check for exceptions.
+  fd_set *pfds_except;
+  /// Largest file descriptor in fd_set-s above.
+  int nfds_max;
+  /// Linked list of all timeouts.
+  struct _timeout_t *tmout_lst;
+  /// Whether we have received an event in this cycle.
+  bool ev_received;
+  /// Whether the program is idling. I.e. no fading, no potential window
+  /// changes.
+  bool idling;
+  /// Program start time.
+  struct timeval time_start;
+  /// The region needs to painted on next paint.
+  XserverRegion all_damage;
+  /// Whether all windows are currently redirected.
+  bool redirected;
+  /// Whether there's a highest full-screen window, and all windows could
+  /// be unredirected.
+  bool unredir_possible;
+  /// Pre-generated alpha pictures.
+  Picture *alpha_picts;
+  /// Whether all reg_ignore of windows should expire in this paint.
+  bool reg_ignore_expire;
+  /// Time of last fading. In milliseconds.
+  time_ms_t fade_time;
+  /// Head pointer of the error ignore linked list.
+  ignore_t *ignore_head;
+  /// Pointer to the <code>next</code> member of tail element of the error
+  /// ignore linked list.
+  ignore_t **ignore_tail;
+  /// Reset program after next paint.
+  bool reset;
+
+  // === Expose event related ===
+  /// Pointer to an array of <code>XRectangle</code>-s of exposed region.
+  XRectangle *expose_rects;
+  /// Number of <code>XRectangle</code>-s in <code>expose_rects</code>.
+  int size_expose;
+  /// Index of the next free slot in <code>expose_rects</code>.
+  int n_expose;
+
+  // === Window related ===
+  /// Linked list of all windows.
+  struct _win *list;
+  /// Pointer to <code>win</code> of current active window. Used by
+  /// EWMH <code>_NET_ACTIVE_WINDOW</code> focus detection. In theory,
+  /// it's more reliable to store the window ID directly here, just in
+  /// case the WM does something extraordinary, but caching the pointer
+  /// means another layer of complexity.
+  struct _win *active_win;
+  /// Window ID of leader window of currently active window. Used for
+  /// subsidiary window detection.
+  Window active_leader;
+
+  // === Shadow/dimming related ===
+  /// 1x1 black Picture.
+  Picture black_picture;
+  /// 1x1 Picture of the shadow color.
+  Picture cshadow_picture;
+  /// 1x1 white Picture.
+  Picture white_picture;
+  /// Gaussian map of shadow.
+  conv *gaussian_map;
+  // for shadow precomputation
+  /// Shadow depth on one side.
+  int cgsize;
+  /// Pre-computed color table for corners of shadow.
+  unsigned char *shadow_corner;
+  /// Pre-computed color table for a side of shadow.
+  unsigned char *shadow_top;
+
+  // === Software-optimization-related ===
+  /// Currently used refresh rate.
+  short refresh_rate;
+  /// Interval between refresh in nanoseconds.
+  long refresh_intv;
+  /// Nanosecond offset of the first painting.
+  long paint_tm_offset;
+
+  #ifdef CONFIG_VSYNC_DRM
+  // === DRM VSync related ===
+  /// File descriptor of DRI device file. Used for DRM VSync.
+  int drm_fd;
+  #endif
+
+  #ifdef CONFIG_VSYNC_OPENGL
+  // === OpenGL VSync related ===
+  /// GLX context.
+  GLXContext glx_context;
+  /// Pointer to glXGetVideoSyncSGI function.
+  f_GetVideoSync glx_get_video_sync;
+  /// Pointer to glXWaitVideoSyncSGI function.
+  f_WaitVideoSync glx_wait_video_sync;
+  #endif
+
+  // === X extension related ===
+  /// Event base number for X Fixes extension.
+  int xfixes_event;
+  /// Error base number for X Fixes extension.
+  int xfixes_error;
+  /// Event base number for X Damage extension.
+  int damage_event;
+  /// Error base number for X Damage extension.
+  int damage_error;
+  /// Event base number for X Render extension.
+  int render_event;
+  /// Error base number for X Render extension.
+  int render_error;
+  /// Event base number for X Composite extension.
+  int composite_event;
+  /// Error base number for X Composite extension.
+  int composite_error;
+  /// Major opcode for X Composite extension.
+  int composite_opcode;
+  /// Whether X Composite NameWindowPixmap is available. Aka if X
+  /// Composite version >= 0.2.
+  bool has_name_pixmap;
+  /// Whether X Shape extension exists.
+  bool shape_exists;
+  /// Event base number for X Shape extension.
+  int shape_event;
+  /// Error base number for X Shape extension.
+  int shape_error;
+  /// Whether X RandR extension exists.
+  bool randr_exists;
+  /// Event base number for X RandR extension.
+  int randr_event;
+  /// Error base number for X RandR extension.
+  int randr_error;
+  #ifdef CONFIG_VSYNC_OPENGL
+  /// Whether X GLX extension exists.
+  bool glx_exists;
+  /// Event base number for X GLX extension.
+  int glx_event;
+  /// Error base number for X GLX extension.
+  int glx_error;
+  #endif
+  /// Whether X DBE extension exists.
+  bool dbe_exists;
+  /// Whether X Render convolution filter exists.
+  bool xrfilter_convolution_exists;
+
+  // === Atoms ===
+  /// Atom of property <code>_NET_WM_OPACITY</code>.
+  Atom atom_opacity;
+  /// Atom of <code>_NET_FRAME_EXTENTS</code>.
+  Atom atom_frame_extents;
+  /// Property atom to identify top-level frame window. Currently
+  /// <code>WM_STATE</code>.
+  Atom atom_client;
+  /// Atom of property <code>WM_NAME</code>.
+  Atom atom_name;
+  /// Atom of property <code>_NET_WM_NAME</code>.
+  Atom atom_name_ewmh;
+  /// Atom of property <code>WM_CLASS</code>.
+  Atom atom_class;
+  /// Atom of property <code>WM_WINDOW_ROLE</code>.
+  Atom atom_role;
+  /// Atom of property <code>WM_TRANSIENT_FOR</code>.
+  Atom atom_transient;
+  /// Atom of property <code>WM_CLIENT_LEADER</code>.
+  Atom atom_client_leader;
+  /// Atom of property <code>_NET_ACTIVE_WINDOW</code>.
+  Atom atom_ewmh_active_win;
+  /// Atom of property <code>_COMPTON_SHADOW</code>.
+  Atom atom_compton_shadow;
+  /// Atom of property <code>_NET_WM_WINDOW_TYPE</code>.
+  Atom atom_win_type;
+  /// Array of atoms of all possible window types.
+  Atom atoms_wintypes[NUM_WINTYPES];
+  /// Linked list of additional atoms to track.
+  latom_t *track_atom_lst;
+
+#ifdef CONFIG_DBUS
+  // === DBus related ===
+  // DBus connection.
+  DBusConnection *dbus_conn;
+  // DBus service name.
+  char *dbus_service;
+#endif
+} session_t;
+
+/// Structure representing a top-level window compton manages.
+typedef struct _win {
+  /// Pointer to the next structure in the linked list.
+  struct _win *next;
+  /// Pointer to the next higher window to paint.
+  struct _win *prev_trans;
+
+  // Core members
+  /// ID of the top-level frame window.
+  Window id;
+  /// Window attributes.
+  XWindowAttributes a;
+  /// Window painting mode.
+  winmode_t mode;
+  /// Whether the window has been damaged at least once.
+  bool damaged;
+  /// Damage of the window.
+  Damage damage;
+  /// NameWindowPixmap of the window.
+  Pixmap pixmap;
+  /// Picture of the window.
+  Picture picture;
+  /// Bounding shape of the window.
+  XserverRegion border_size;
+  /// Region of the whole window, shadow region included.
+  XserverRegion extents;
+  /// Window flags. Definitions above.
+  int_fast16_t flags;
+  /// Whether there's a pending <code>ConfigureNotify</code> happening
+  /// when the window is unmapped.
+  bool need_configure;
+  /// Queued <code>ConfigureNotify</code> when the window is unmapped.
+  XConfigureEvent queue_configure;
+  /// Region to be ignored when painting. Basically the region where
+  /// higher opaque windows will paint upon. Depends on window frame
+  /// opacity state, window geometry, window mapped/unmapped state,
+  /// window mode, of this and all higher windows.
+  XserverRegion reg_ignore;
+  /// Cached width/height of the window including border.
+  int widthb, heightb;
+  /// Whether the window has been destroyed.
+  bool destroyed;
+  /// Whether the window is bounding-shaped.
+  bool bounding_shaped;
+  /// Whether the window just have rounded corners.
+  bool rounded_corners;
+  /// Whether this window is to be painted.
+  bool to_paint;
+  /// Whether this window is in open/close state.
+  bool in_openclose;
+
+  // Client window related members
+  /// ID of the top-level client window of the window.
+  Window client_win;
+  /// Type of the window.
+  wintype_t window_type;
+  /// Whether it looks like a WM window. We consider a window WM window if
+  /// it does not have a decedent with WM_STATE and it is not override-
+  /// redirected itself.
+  bool wmwin;
+  /// Leader window ID of the window.
+  Window leader;
+  /// Cached topmost window ID of the window.
+  Window cache_leader;
+
+  // Focus-related members
+  /// Whether the window is to be considered focused.
+  bool focused;
+  /// Override value of window focus state. Set by D-Bus method calls.
+  switch_t focused_force;
+  /// Whether the window is actually focused.
+  bool focused_real;
+
+  // Blacklist related members
+  /// Name of the window.
+  char *name;
+  /// Window instance class of the window.
+  char *class_instance;
+  /// Window general class of the window.
+  char *class_general;
+  /// <code>WM_WINDOW_ROLE</code> value of the window.
+  char *role;
+  wincond_t *cache_sblst;
+  wincond_t *cache_fblst;
+  wincond_t *cache_fcblst;
+  wincond_t *cache_ivclst;
+
+  // Opacity-related members
+  /// Current window opacity.
+  opacity_t opacity;
+  /// Target window opacity.
+  opacity_t opacity_tgt;
+  /// Cached value of opacity window attribute.
+  opacity_t opacity_prop;
+  /// Cached value of opacity window attribute on client window. For
+  /// broken window managers not transferring client window's
+  /// _NET_WM_OPACITY value
+  opacity_t opacity_prop_client;
+  /// Alpha mask Picture to render window with opacity.
+  Picture alpha_pict;
+
+  // Fading-related members
+  /// Do not fade if it's false. Change on window type change.
+  /// Used by fading blacklist in the future.
+  bool fade;
+  /// Callback to be called after fading completed.
+  void (*fade_callback) (session_t *ps, struct _win *w);
+
+  // Frame-opacity-related members
+  /// Current window frame opacity. Affected by window opacity.
+  double frame_opacity;
+  /// Alpha mask Picture to render window frame with opacity.
+  Picture frame_alpha_pict;
+  /// Frame widths. Determined by client window attributes.
+  unsigned int left_width, right_width, top_width, bottom_width;
+
+  // Shadow-related members
+  /// Whether a window has shadow. Calculated.
+  bool shadow;
+  /// Override value of window shadow state. Set by D-Bus method calls.
+  switch_t shadow_force;
+  /// Opacity of the shadow. Affected by window opacity and frame opacity.
+  double shadow_opacity;
+  /// X offset of shadow. Affected by commandline argument.
+  int shadow_dx;
+  /// Y offset of shadow. Affected by commandline argument.
+  int shadow_dy;
+  /// Width of shadow. Affected by window size and commandline argument.
+  int shadow_width;
+  /// Height of shadow. Affected by window size and commandline argument.
+  int shadow_height;
+  /// Picture to render shadow. Affected by window size.
+  Picture shadow_pict;
+  /// Alpha mask Picture to render shadow. Affected by shadow opacity.
+  Picture shadow_alpha_pict;
+  /// The value of _COMPTON_SHADOW attribute of the window. Below 0 for
+  /// none.
+  long prop_shadow;
+
+  // Dim-related members
+  /// Whether the window is to be dimmed.
+  bool dim;
+  /// Picture for dimming. Affected by user-specified inactive dim
+  /// opacity and window opacity.
+  Picture dim_alpha_pict;
+
+  /// Whether to invert window color.
+  bool invert_color;
+  /// Override value of window color inversion state. Set by D-Bus method
+  /// calls.
+  switch_t invert_color_force;
+} win;
+
+/// Temporary structure used for communication between
+/// <code>get_cfg()</code> and <code>parse_config()</code>.
+struct options_tmp {
+  bool no_dock_shadow;
+  bool no_dnd_shadow;
+  double menu_opacity;
+};
+
+/// Structure for a recorded timeout.
+typedef struct _timeout_t {
+  bool enabled;
+  void *data;
+  bool (*callback)(session_t *ps, struct _timeout_t *ptmout);
+  time_ms_t interval;
+  time_ms_t firstrun;
+  time_ms_t lastrun;
+  struct _timeout_t *next;
+} timeout_t;
+
+/// Enumeration for window event hints.
+typedef enum {
+  WIN_EVMODE_UNKNOWN,
+  WIN_EVMODE_FRAME,
+  WIN_EVMODE_CLIENT
+} win_evmode_t;
+
+extern const char *WINTYPES[NUM_WINTYPES];
+extern session_t *ps_g;
+
+// == Debugging code ==
+static inline void
+print_timestamp(session_t *ps);
+
+#ifdef DEBUG_ALLOC_REG
+
+#include <execinfo.h>
+#define BACKTRACE_SIZE  5
+
+/**
+ * Print current backtrace, excluding the first two items.
+ *
+ * Stolen from glibc manual.
+ */
+static inline void
+print_backtrace(void) {
+  void *array[BACKTRACE_SIZE];
+  size_t size;
+  char **strings;
+
+  size = backtrace(array, BACKTRACE_SIZE);
+  strings = backtrace_symbols(array, size);
+
+  for (size_t i = 2; i < size; i++)
+     printf ("%s\n", strings[i]);
+
+  free(strings);
+}
+
+/**
+ * Wrapper of <code>XFixesCreateRegion</code>, for debugging.
+ */
+static inline XserverRegion
+XFixesCreateRegion_(Display *dpy, XRectangle *p, int n,
+    const char *func, int line) {
+  XserverRegion reg = XFixesCreateRegion(dpy, p, n);
+  print_timestamp(ps_g);
+  printf("%#010lx: XFixesCreateRegion() in %s():%d\n", reg, func, line);
+  print_backtrace();
+  fflush(stdout);
+  return reg;
+}
+
+/**
+ * Wrapper of <code>XFixesDestroyRegion</code>, for debugging.
+ */
+static inline void
+XFixesDestroyRegion_(Display *dpy, XserverRegion reg,
+    const char *func, int line) {
+  XFixesDestroyRegion(dpy, reg);
+  print_timestamp(ps_g);
+  printf("%#010lx: XFixesDestroyRegion() in %s():%d\n", reg, func, line);
+  fflush(stdout);
+}
+
+#define XFixesCreateRegion(dpy, p, n) XFixesCreateRegion_(dpy, p, n, __func__, __LINE__)
+#define XFixesDestroyRegion(dpy, reg) XFixesDestroyRegion_(dpy, reg, __func__, __LINE__)
+#endif
+
+// === Functions ===
+
+/**
+ * Return whether a struct timeval value is empty.
+ */
+static inline bool
+timeval_isempty(struct timeval *ptv) {
+  if (!ptv)
+    return false;
+
+  return ptv->tv_sec <= 0 && ptv->tv_usec <= 0;
+}
+
+/**
+ * Compare a struct timeval with a time in milliseconds.
+ *
+ * @return > 0 if ptv > ms, 0 if ptv == 0, -1 if ptv < ms
+ */
+static inline int
+timeval_ms_cmp(struct timeval *ptv, time_ms_t ms) {
+  assert(ptv);
+
+  // We use those if statement instead of a - expression because of possible
+  // truncation problem from long to int.
+  {
+    long sec = ms / MS_PER_SEC;
+    if (ptv->tv_sec > sec)
+      return 1;
+    if (ptv->tv_sec < sec)
+      return -1;
+  }
+
+  {
+    long usec = ms % MS_PER_SEC * (US_PER_SEC / MS_PER_SEC);
+    if (ptv->tv_usec > usec)
+      return 1;
+    if (ptv->tv_usec < usec)
+      return -1;
+  }
+
+  return 0;
+}
+
+/**
+ * Subtracting two struct timeval values.
+ *
+ * Taken from glibc manual.
+ *
+ * Subtract the `struct timeval' values X and Y,
+ * storing the result in RESULT.
+ * Return 1 if the difference is negative, otherwise 0.
+ */
+static inline int
+timeval_subtract(struct timeval *result,
+                 struct timeval *x,
+                 struct timeval *y) {
+  /* Perform the carry for the later subtraction by updating y. */
+  if (x->tv_usec < y->tv_usec) {
+    long nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
+    y->tv_usec -= 1000000 * nsec;
+    y->tv_sec += nsec;
+  }
+
+  if (x->tv_usec - y->tv_usec > 1000000) {
+    long nsec = (x->tv_usec - y->tv_usec) / 1000000;
+    y->tv_usec += 1000000 * nsec;
+    y->tv_sec -= nsec;
+  }
+
+  /* Compute the time remaining to wait.
+     tv_usec is certainly positive. */
+  result->tv_sec = x->tv_sec - y->tv_sec;
+  result->tv_usec = x->tv_usec - y->tv_usec;
+
+  /* Return 1 if result is negative. */
+  return x->tv_sec < y->tv_sec;
+}
+
+/**
+ * Subtracting two struct timespec values.
+ *
+ * Taken from glibc manual.
+ *
+ * Subtract the `struct timespec' values X and Y,
+ * storing the result in RESULT.
+ * Return 1 if the difference is negative, otherwise 0.
+ */
+static inline int
+timespec_subtract(struct timespec *result,
+                 struct timespec *x,
+                 struct timespec *y) {
+  /* Perform the carry for the later subtraction by updating y. */
+  if (x->tv_nsec < y->tv_nsec) {
+    long nsec = (y->tv_nsec - x->tv_nsec) / NS_PER_SEC + 1;
+    y->tv_nsec -= NS_PER_SEC * nsec;
+    y->tv_sec += nsec;
+  }
+
+  if (x->tv_nsec - y->tv_nsec > NS_PER_SEC) {
+    long nsec = (x->tv_nsec - y->tv_nsec) / NS_PER_SEC;
+    y->tv_nsec += NS_PER_SEC * nsec;
+    y->tv_sec -= nsec;
+  }
+
+  /* Compute the time remaining to wait.
+     tv_nsec is certainly positive. */
+  result->tv_sec = x->tv_sec - y->tv_sec;
+  result->tv_nsec = x->tv_nsec - y->tv_nsec;
+
+  /* Return 1 if result is negative. */
+  return x->tv_sec < y->tv_sec;
+}
+
+/**
+ * Get current time in struct timeval.
+ */
+static inline struct timeval __attribute__((const))
+get_time_timeval(void) {
+  struct timeval tv = { 0, 0 };
+
+  gettimeofday(&tv, NULL);
+
+  // Return a time of all 0 if the call fails
+  return tv;
+}
+
+/**
+ * Get current time in struct timespec.
+ *
+ * Note its starting time is unspecified.
+ */
+static inline struct timespec __attribute__((const))
+get_time_timespec(void) {
+  struct timespec tm = { 0, 0 };
+
+  clock_gettime(CLOCK_MONOTONIC, &tm);
+
+  // Return a time of all 0 if the call fails
+  return tm;
+}
+
+
+/**
+ * Print time passed since program starts execution.
+ *
+ * Used for debugging.
+ */
+static inline void
+print_timestamp(session_t *ps) {
+  struct timeval tm, diff;
+
+  if (gettimeofday(&tm, NULL)) return;
+
+  timeval_subtract(&diff, &tm, &ps->time_start);
+  printf("[ %5ld.%02ld ] ", diff.tv_sec, diff.tv_usec / 10000);
+}
+
+/**
+ * Allocate the space and copy a string.
+ */
+static inline char * __attribute__((const))
+mstrcpy(const char *src) {
+  char *str = malloc(sizeof(char) * (strlen(src) + 1));
+
+  strcpy(str, src);
+
+  return str;
+}
+
+/**
+ * Allocate the space and copy a string.
+ */
+static inline char * __attribute__((const))
+mstrncpy(const char *src, unsigned len) {
+  char *str = malloc(sizeof(char) * (len + 1));
+
+  strncpy(str, src, len);
+
+  return str;
+}
+
+/**
+ * Allocate the space and join two strings.
+ */
+static inline char * __attribute__((const))
+mstrjoin(const char *src1, const char *src2) {
+  char *str = malloc(sizeof(char) * (strlen(src1) + strlen(src2) + 1));
+
+  strcpy(str, src1);
+  strcat(str, src2);
+
+  return str;
+}
+
+/**
+ * Allocate the space and join two strings;
+ */
+static inline char * __attribute__((const))
+mstrjoin3(const char *src1, const char *src2, const char *src3) {
+  char *str = malloc(sizeof(char) * (strlen(src1) + strlen(src2)
+        + strlen(src3) + 1));
+
+  strcpy(str, src1);
+  strcat(str, src2);
+  strcat(str, src3);
+
+  return str;
+}
+
+/**
+ * Normalize an int value to a specific range.
+ *
+ * @param i int value to normalize
+ * @param min minimal value
+ * @param max maximum value
+ * @return normalized value
+ */
+static inline int __attribute__((const))
+normalize_i_range(int i, int min, int max) {
+  if (i > max) return max;
+  if (i < min) return min;
+  return i;
+}
+
+/**
+ * Select the larger integer of two.
+ */
+static inline int __attribute__((const))
+max_i(int a, int b) {
+  return (a > b ? a : b);
+}
+
+/**
+ * Select the smaller integer of two.
+ */
+static inline int __attribute__((const))
+min_i(int a, int b) {
+  return (a > b ? b : a);
+}
+
+/**
+ * Select the larger long integer of two.
+ */
+static inline long __attribute__((const))
+max_l(long a, long b) {
+  return (a > b ? a : b);
+}
+
+/**
+ * Select the smaller long integer of two.
+ */
+static inline long __attribute__((const))
+min_l(long a, long b) {
+  return (a > b ? b : a);
+}
+
+/**
+ * Normalize a double value to a specific range.
+ *
+ * @param d double value to normalize
+ * @param min minimal value
+ * @param max maximum value
+ * @return normalized value
+ */
+static inline double __attribute__((const))
+normalize_d_range(double d, double min, double max) {
+  if (d > max) return max;
+  if (d < min) return min;
+  return d;
+}
+
+/**
+ * Normalize a double value to 0.\ 0 - 1.\ 0.
+ *
+ * @param d double value to normalize
+ * @return normalized value
+ */
+static inline double __attribute__((const))
+normalize_d(double d) {
+  return normalize_d_range(d, 0.0, 1.0);
+}
+
+timeout_t *
+timeout_insert(session_t *ps, time_ms_t interval,
+    bool (*callback)(session_t *ps, timeout_t *ptmout), void *data);
+
+void
+timeout_invoke(session_t *ps, timeout_t *ptmout);
+
+bool
+timeout_drop(session_t *ps, timeout_t *prm);
+
+/**
+ * Add a file descriptor to a select() fd_set.
+ */
+static inline bool
+fds_insert_select(fd_set **ppfds, int fd) {
+  assert(fd <= FD_SETSIZE);
+
+  if (!*ppfds) {
+    if ((*ppfds = malloc(sizeof(fd_set)))) {
+      FD_ZERO(*ppfds);
+    }
+    else {
+      fprintf(stderr, "Failed to allocate memory for select() fdset.\n");
+      exit(1);
+    }
+  }
+
+  FD_SET(fd, *ppfds);
+
+  return true;
+}
+
+/**
+ * Add a new file descriptor to wait for.
+ */
+static inline bool
+fds_insert(session_t *ps, int fd, short events) {
+  bool result = true;
+
+  ps->nfds_max = max_i(fd + 1, ps->nfds_max);
+
+  if (POLLIN & events)
+    result = fds_insert_select(&ps->pfds_read, fd) && result;
+  if (POLLOUT & events)
+    result = fds_insert_select(&ps->pfds_write, fd) && result;
+  if (POLLPRI & events)
+    result = fds_insert_select(&ps->pfds_except, fd) && result;
+
+  return result;
+}
+
+/**
+ * Delete a file descriptor to wait for.
+ */
+static inline void
+fds_drop(session_t *ps, int fd, short events) {
+  // Drop fd from respective fd_set-s
+  if (POLLIN & events && ps->pfds_read)
+    FD_CLR(fd, ps->pfds_read);
+  if (POLLOUT & events && ps->pfds_write)
+    FD_CLR(fd, ps->pfds_write);
+  if (POLLPRI & events && ps->pfds_except)
+    FD_CLR(fd, ps->pfds_except);
+}
+
+#define CPY_FDS(key) \
+  fd_set * key = NULL; \
+  if (ps->key) { \
+    key = malloc(sizeof(fd_set)); \
+    memcpy(key, ps->key, sizeof(fd_set)); \
+    if (!key) { \
+      fprintf(stderr, "Failed to allocate memory for copying select() fdset.\n"); \
+      exit(1); \
+    } \
+  } \
+
+/**
+ * Poll for changes.
+ *
+ * poll() is much better than select(), but ppoll() does not exist on
+ * *BSD.
+ */
+static inline int
+fds_poll(session_t *ps, struct timeval *ptv) {
+  // Copy fds
+  CPY_FDS(pfds_read);
+  CPY_FDS(pfds_write);
+  CPY_FDS(pfds_except);
+
+  int ret = select(ps->nfds_max, pfds_read, pfds_write, pfds_except, ptv);
+
+  free(pfds_read);
+  free(pfds_write);
+  free(pfds_except);
+
+  return ret;
+}
+#undef CPY_FDS
+
+/**
+ * Find a window from window id in window linked list of the session.
+ */
+static inline win *
+find_win(session_t *ps, Window id) {
+  if (!id)
+    return NULL;
+
+  win *w;
+
+  for (w = ps->list; w; w = w->next) {
+    if (w->id == id && !w->destroyed)
+      return w;
+  }
+
+  return 0;
+}
+
+/**
+ * Find out the WM frame of a client window using existing data.
+ *
+ * @param id window ID
+ * @return struct _win object of the found window, NULL if not found
+ */
+static inline win *
+find_toplevel(session_t *ps, Window id) {
+  if (!id)
+    return NULL;
+
+  for (win *w = ps->list; w; w = w->next) {
+    if (w->client_win == id && !w->destroyed)
+      return w;
+  }
+
+  return NULL;
+}
+
+/**
+ * Find out the currently focused window.
+ *
+ * @return struct _win object of the found window, NULL if not found
+ */
+static inline win *
+find_focused(session_t *ps) {
+  if (!ps->o.track_focus)
+    return NULL;
+
+  for (win *w = ps->list; w; w = w->next) {
+    if (w->focused_real && !w->destroyed)
+      return w;
+  }
+
+  return NULL;
+}
+
+/**
+ * Copies a region
+ */
+static inline XserverRegion
+copy_region(const session_t *ps, XserverRegion oldregion) {
+  XserverRegion region = XFixesCreateRegion(ps->dpy, NULL, 0);
+
+  XFixesCopyRegion(ps->dpy, region, oldregion);
+
+  return region;
+}
+
+#ifdef CONFIG_DBUS
+/** @name DBus handling
+ */
+///@{
+bool
+cdbus_init(session_t *ps);
+
+void
+cdbus_destroy(session_t *ps);
+
+void
+cdbus_loop(session_t *ps);
+
+void
+cdbus_ev_win_added(session_t *ps, win *w);
+
+void
+cdbus_ev_win_destroyed(session_t *ps, win *w);
+
+void
+cdbus_ev_win_mapped(session_t *ps, win *w);
+
+void
+cdbus_ev_win_unmapped(session_t *ps, win *w);
+//!@}
+
+/** @name DBus hooks
+ */
+///@{
+void
+win_set_shadow_force(session_t *ps, win *w, switch_t val);
+
+void
+win_set_focused_force(session_t *ps, win *w, switch_t val);
+
+void
+win_set_invert_color_force(session_t *ps, win *w, switch_t val);
+
+void
+force_repaint(session_t *ps);
+//!@}
+#endif