Move damage tracking to separate file

src/damage.c

@@ -0,0 +1,70 @@
+#include "../include/damage.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <X11/extensions/Xdamage.h>
+
+bool gsr_damage_init(gsr_damage *self, Display *display) {
+    memset(self, 0, sizeof(*self));
+    self->display = display;
+
+    if(!XDamageQueryExtension(self->display, &self->damage_event, &self->damage_error)) {
+        fprintf(stderr, "gsr warning: gsr_damage_init: XDamage is not supported by your X11 server\n");
+        self->damage_event = 0;
+        self->damage_error = 0;
+        return false;
+    }
+
+    self->damaged = true;
+    return true;
+}
+
+void gsr_damage_deinit(gsr_damage *self) {
+    if(self->damage) {
+        XDamageDestroy(self->display, self->damage);
+        self->damage = None;
+    }
+}
+
+bool gsr_damage_set_target_window(gsr_damage *self, uint64_t window) {
+    if(self->damage_event == 0)
+        return false;
+
+    if(self->damage) {
+        XDamageDestroy(self->display, self->damage);
+        self->damage = None;
+    }
+
+    self->damage = XDamageCreate(self->display, window, XDamageReportNonEmpty);
+    if(self->damage) {
+        XDamageSubtract(self->display, self->damage, None, None);
+        self->damaged = true;
+        return true;
+    } else {
+        fprintf(stderr, "gsr warning: gsr_damage_set_target_window: XDamageCreate failed\n");
+        return false;
+    }
+}
+
+void gsr_damage_update(gsr_damage *self, XEvent *xev) {
+    if(self->damage_event == 0 || !self->damage)
+        return;
+
+    if(self->damage_event && xev->type == self->damage_event + XDamageNotify) {
+        XDamageNotifyEvent *de = (XDamageNotifyEvent*)xev;
+        XserverRegion region = XFixesCreateRegion(self->display, NULL, 0);
+        /* Subtract all the damage, repairing the window */
+        XDamageSubtract(self->display, de->damage, None, region);
+        XFixesDestroyRegion(self->display, region);
+        XFlush(self->display);
+        self->damaged = true;
+    }
+}
+
+bool gsr_damage_is_damaged(gsr_damage *self) {
+    return self->damage_event == 0 || !self->damage || self->damaged;
+}
+
+void gsr_damage_clear(gsr_damage *self) {
+    self->damaged = false;
+}