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eda-tools/eeshow/gui/aoi.c
Werner Almesberger 0d2b024d9c eeshow/gui/ (aoi_click): also protect from access after free
Unlike aoi_hover, aoi_click was not observed to actually run into this
problem. But better safe than sorry.
2016-08-20 20:42:34 -03:00

150 lines
2.8 KiB
C

/*
* gui/aoi.c - GUI: areas of interest
*
* Written 2016 by Werner Almesberger
* Copyright 2016 by Werner Almesberger
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
/*
* Resources:
*
* http://zetcode.com/gfx/cairo/cairobackends/
* https://developer.gnome.org/gtk3/stable/gtk-migrating-2-to-3.html
*/
#include <stddef.h>
#include <math.h>
#include <assert.h>
#include "misc/util.h"
#include "gui/aoi.h"
static const struct aoi *hovering = NULL;
struct aoi *aoi_add(struct aoi **aois, const struct aoi *cfg)
{
struct aoi *new;
new = alloc_type(struct aoi);
*new = *cfg;
new->next = *aois;
*aois = new;
return new;
}
void aoi_update(struct aoi *aoi, const struct aoi *cfg)
{
struct aoi *next = aoi->next;
*aoi = *cfg;
aoi->next = next;
}
static bool in_aoi(const struct aoi *aoi, int x, int y)
{
return x >= aoi->x && x < aoi->x + aoi->w &&
y >= aoi->y && y < aoi->y + aoi->h;
}
/*
* We need a pointer to the anchor of the AoI list here because dehovering may
* delete the AoI *aois points to.
*
* We could just check if hovering == *aois, but that seems risky, because
* hover(..., 0) may destroy more than just the AoI being dehovered.
*/
bool aoi_hover(struct aoi *const *aois, int x, int y)
{
const struct aoi *aoi;
if (hovering) {
if (in_aoi(hovering, x, y))
return 1;
hovering->hover(hovering->user, 0);
hovering = NULL;
}
for (aoi = *aois; aoi; aoi = aoi->next)
if (aoi->hover && in_aoi(aoi, x, y) &&
aoi->hover(aoi->user, 1)) {
hovering = aoi;
return 1;
}
return 0;
}
static bool need_dehover(const struct aoi *aois, int x, int y)
{
const struct aoi *aoi;
if (!hovering)
return 0;
if (hovering->click)
return 0;
for (aoi = aois; aoi; aoi = aoi->next)
if (aoi->related == hovering && aoi->click && in_aoi(aoi, x, y))
return 0;
return 1;
}
/* Pointer to the anchor needed for the same reason as in aoi_hover. */
bool aoi_click(struct aoi *const *aois, int x, int y)
{
const struct aoi *aoi;
if (need_dehover(*aois, x, y))
aoi_dehover();
for (aoi = *aois; aoi; aoi = aoi->next)
if (aoi->click && in_aoi(aoi, x, y)) {
aoi->click(aoi->user);
return 1;
}
return 0;
}
void aoi_set_related(struct aoi *aoi, const struct aoi *related)
{
assert(!aoi->related);
aoi->related = related;
}
void aoi_remove(struct aoi **aois, const struct aoi *aoi)
{
assert(aoi);
if (hovering == aoi) {
aoi->hover(aoi->user, 0);
hovering = NULL;
}
while (*aois && *aois != aoi)
aois = &(*aois)->next;
assert(*aois);
*aois = aoi->next;
free((void *) aoi);
}
void aoi_dehover(void)
{
if (hovering)
hovering->hover(hovering->user, 0);
hovering = NULL;
}