rename: replace "compton" in the codebase

leftovers:

1) config file path. Has to implement compatibility functionalities before
  we can change it.

2) links in man pages. Has to migrate the repo first.

3) _COMPTON_SHADOW, it has become a defacto standard, so we have to keep
   supporting it.

4) dbus names, undecided whether we should/could change it.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/picom.h

@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c)
+
+// Throw everything in here.
+// !!! DON'T !!!
+
+// === Includes ===
+
+#include <locale.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <xcb/xproto.h>
+
+#include <X11/Xutil.h>
+#include "backend/backend.h"
+#include "c2.h"
+#include "common.h"
+#include "compiler.h"
+#include "config.h"
+#include "log.h"        // XXX clean up
+#include "region.h"
+#include "render.h"
+#include "types.h"
+#include "utils.h"
+#include "win.h"
+#include "x.h"
+
+enum root_flags { ROOT_FLAGS_SCREEN_CHANGE = 1 };
+
+// == Functions ==
+// TODO move static inline functions that are only used in picom.c, into
+//      picom.c
+
+// inline functions must be made static to compile correctly under clang:
+// http://clang.llvm.org/compatibility.html#inline
+
+void add_damage(session_t *ps, const region_t *damage);
+
+uint32_t determine_evmask(session_t *ps, xcb_window_t wid, win_evmode_t mode);
+
+xcb_window_t find_client_win(session_t *ps, xcb_window_t w);
+
+/// Handle configure event of a root window
+void configure_root(session_t *ps, int width, int height);
+
+void circulate_win(session_t *ps, xcb_circulate_notify_event_t *ce);
+
+void update_refresh_rate(session_t *ps);
+
+void root_damaged(session_t *ps);
+
+void cxinerama_upd_scrs(session_t *ps);
+
+void queue_redraw(session_t *ps);
+
+void discard_ignore(session_t *ps, unsigned long sequence);
+
+void set_root_flags(session_t *ps, uint64_t flags);
+
+void quit(session_t *ps);
+
+xcb_window_t session_get_target_window(session_t *);
+
+/**
+ * Set a <code>switch_t</code> array of all unset wintypes to true.
+ */
+static inline void wintype_arr_enable_unset(switch_t arr[]) {
+	wintype_t i;
+
+	for (i = 0; i < NUM_WINTYPES; ++i)
+		if (UNSET == arr[i])
+			arr[i] = ON;
+}
+
+/**
+ * Check if a window ID exists in an array of window IDs.
+ *
+ * @param arr the array of window IDs
+ * @param count amount of elements in the array
+ * @param wid window ID to search for
+ */
+static inline bool array_wid_exists(const xcb_window_t *arr, int count, xcb_window_t wid) {
+	while (count--) {
+		if (arr[count] == wid) {
+			return true;
+		}
+	}
+
+	return false;
+}
+
+/**
+ * Destroy a condition list.
+ */
+static inline void free_wincondlst(c2_lptr_t **pcondlst) {
+	while ((*pcondlst = c2_free_lptr(*pcondlst)))
+		continue;
+}
+
+#ifndef CONFIG_OPENGL
+static inline void free_paint_glx(session_t *ps attr_unused, paint_t *p attr_unused) {
+}
+static inline void
+free_win_res_glx(session_t *ps attr_unused, struct managed_win *w attr_unused) {
+}
+#endif
+
+/**
+ * Create a XTextProperty of a single string.
+ */
+static inline XTextProperty *make_text_prop(session_t *ps, char *str) {
+	XTextProperty *pprop = ccalloc(1, XTextProperty);
+
+	if (XmbTextListToTextProperty(ps->dpy, &str, 1, XStringStyle, pprop)) {
+		XFree(pprop->value);
+		free(pprop);
+		pprop = NULL;
+	}
+
+	return pprop;
+}
+
+/**
+ * Set a single-string text property on a window.
+ */
+static inline bool
+wid_set_text_prop(session_t *ps, xcb_window_t wid, xcb_atom_t prop_atom, char *str) {
+	XTextProperty *pprop = make_text_prop(ps, str);
+	if (!pprop) {
+		log_error("Failed to make text property: %s.", str);
+		return false;
+	}
+
+	XSetTextProperty(ps->dpy, wid, pprop, prop_atom);
+	XFree(pprop->value);
+	XFree(pprop);
+
+	return true;
+}
+
+/**
+ * Dump an drawable's info.
+ */
+static inline void dump_drawable(session_t *ps, xcb_drawable_t drawable) {
+	auto r = xcb_get_geometry_reply(ps->c, xcb_get_geometry(ps->c, drawable), NULL);
+	if (!r) {
+		log_trace("Drawable %#010x: Failed", drawable);
+		return;
+	}
+	log_trace("Drawable %#010x: x = %u, y = %u, wid = %u, hei = %d, b = %u, d = %u",
+	          drawable, r->x, r->y, r->width, r->height, r->border_width, r->depth);
+	free(r);
+}