link.c

一个很有名的浏览器

	assert(doc_view && doc_view->vs);
	if_assert_failed return 0;

	link = get_current_link(doc_view);
	return (link && link_in_view(doc_view, link));
}

/* Look for the first and the last link currently visible in our
 * viewport. */
static void
get_visible_links_range(struct document_view *doc_view, int *first, int *last)
{
	struct document *document = doc_view->document;
	int height = int_min(doc_view->vs->y + doc_view->box.height,
	                     document->height);
	int y;

	*first = document->nlinks - 1;
	*last = 0;

	for (y = int_max(0, doc_view->vs->y); y < height; y++) {
		if (document->lines1[y])
			int_upper_bound(first, document->lines1[y]
					       - document->links);

		if (document->lines2[y])
			int_lower_bound(last, document->lines2[y]
					      - document->links);
	}
}

int
next_link_in_view(struct document_view *doc_view, int current, int direction,
	          int (*fn)(struct document_view *, struct link *),
	          void (*cntr)(struct document_view *, struct link *))
{
	struct document *document;
	struct view_state *vs;
	int start, end;

	assert(doc_view && doc_view->document && doc_view->vs && fn);
	if_assert_failed return 0;

	document = doc_view->document;
	vs = doc_view->vs;

	get_visible_links_range(doc_view, &start, &end);

	current_link_blur(doc_view);

	/* Go from the @current link in @direction until either
	 * fn() is happy or we would leave the current viewport. */
	while (current >= start && current <= end) {
		if (fn(doc_view, &document->links[current])) {
			vs->current_link = current;
			if (cntr) cntr(doc_view, &document->links[current]);
			current_link_hover(doc_view);
			return 1;
		}
		current += direction;
	}

	vs->current_link = -1;
	return 0;
}

/* Get the bounding columns of @link at line @y (or all lines if @y == -1). */
static void
get_link_x_bounds(struct link *link, int y, int *min_x, int *max_x)
{
	int point;

	if (min_x) *min_x = INT_MAX;
	if (max_x) *max_x = 0;

	for (point = 0; point < link->npoints; point++) {
		if (y >= 0 && link->points[point].y != y)
			continue;
		if (min_x) int_upper_bound(min_x, link->points[point].x);
		if (max_x) int_lower_bound(max_x, link->points[point].x);
	}
}

/* Check whether there is any point between @min_x and @max_x at the line @y
 * in link @link. */
static int
get_link_x_intersect(struct link *link, int y, int min_x, int max_x)
{
	int point;

	for (point = 0; point < link->npoints; point++) {
		if (link->points[point].y != y)
			continue;
		if (link->points[point].x >= min_x
		    && link->points[point].x <= max_x)
			return link->points[point].x + 1;
	}

	return 0;
}

/* Check whether there is any point between @min_y and @max_y in the column @x
 * in link @link. */
static int
get_link_y_intersect(struct link *link, int x, int min_y, int max_y)
{
	int point;

	for (point = 0; point < link->npoints; point++) {
		if (link->points[point].x != x)
			continue;
		if (link->points[point].y >= min_y
		    && link->points[point].y <= max_y)
			return link->points[point].y + 1;
	}

	return 0;
}

int
next_link_in_dir(struct document_view *doc_view, int dir_x, int dir_y)
{
	struct document *document;
	struct view_state *vs;
	struct link *link;
	int min_x = INT_MAX, max_x = 0;
	int min_y, max_y;

	assert(doc_view && doc_view->document && doc_view->vs);
	if_assert_failed return 0;
	assert(dir_x || dir_y);
	if_assert_failed return 0;

	document = doc_view->document;
	vs = doc_view->vs;

	link = get_current_link(doc_view);
	if (!link) return 0;

	/* Find the link's "bounding box" coordinates. */

	get_link_x_bounds(link, -1, &min_x, &max_x);

	min_y = link->points[0].y;
	max_y = link->points[link->npoints - 1].y;

	/* Now go from the bounding box edge in the appropriate
	 * direction and find the nearest link. */

	if (dir_y) {
		/* Vertical movement */

		/* The current line number */
		int y = (dir_y > 0 ? max_y : min_y) + dir_y;
		/* The bounding line numbers */
		int top = int_max(0, doc_view->vs->y);
		int bottom = int_min(doc_view->vs->y + doc_view->box.height,
				     document->height);

		for (; dir_y > 0 ? y < bottom : y >= top; y += dir_y) {
			/* @backup points to the nearest link from the left
			 * to the desired position. */
			struct link *backup = NULL;

			link = document->lines1[y];
			if (!link) continue;

			/* Go through all the links on line. */
			for (; link <= document->lines2[y]; link++) {
				int l_min_x, l_max_x;

				/* Some links can be totally out of order here,
				 * ie. in tables or when using tabindex. */
				if (y < link->points[0].y
				    || y > link->points[link->npoints - 1].y)
					continue;

				get_link_x_bounds(link, y, &l_min_x, &l_max_x);
				if (l_min_x > max_x) {
					/* This link is too at the right. */
					if (!backup)
						backup = link;
					continue;
				}
				if (l_max_x < min_x) {
					/* This link is too at the left. */
					backup = link;
					continue;
				}
				/* This link is aligned with the current one. */
				goto chose_link;
			}

			if (backup) {
				link = backup;
				goto chose_link;
			}
		}

		if (!y || y == document->height) {
			/* We just stay at the same place, do not invalidate
			 * the link number. */
			return 0;
		}

	} else {
		/* Horizontal movement */

		/* The current column number */
		int x = (dir_x > 0 ? max_x : min_x) + dir_x;
		/* How many lines are already past their last link */
		int last = 0;

		while ((last < max_y - min_y + 1) && (x += dir_x) >= 0) {
			int y;

			last = 0;

			/* Go through all the lines */
			for (y = min_y; y <= max_y; y++) {
				link = document->lines1[y];
				if (!link) continue;

				/* Go through all the links on line. */
				while (link <= document->lines2[y]) {
					if (get_link_y_intersect(link, x,
					                         min_y,
					                         max_y))
						goto chose_link;
					link++;
				}

				/* Check if we already aren't past the last
				 * link on this line. */
				if (!get_link_x_intersect(document->lines2[y],
				                          y, x, INT_MAX))
					last++;
			}
		}

		/* We just stay  */
		return 0;
	}

	current_link_blur(doc_view);
	vs->current_link = -1;
	return 0;

chose_link:
	/* The link is in bounds, take it. */
	current_link_blur(doc_view);
	vs->current_link = get_link_index(document, link);
	set_pos_x(doc_view, link);
	current_link_hover(doc_view);
	return 1;
}

void
set_pos_x(struct document_view *doc_view, struct link *link)
{
	int xm = 0;
	int xl = INT_MAX;
	int i;

	assert(doc_view && link);
	if_assert_failed return;

	for (i = 0; i < link->npoints; i++) {
		int y = link->points[i].y - doc_view->vs->y;

		if (y >= 0 && y < doc_view->box.height) {
			int_lower_bound(&xm, link->points[i].x + 1);
			int_upper_bound(&xl, link->points[i].x);
		}
	}

	if (xl != INT_MAX)
		int_bounds(&doc_view->vs->x, xm - doc_view->box.width, xl);
}

void
set_pos_y(struct document_view *doc_view, struct link *link)
{
	int ym = 0;
	int height;
	int i;

	assert(doc_view && doc_view->document && doc_view->vs && link);
	if_assert_failed return;

	height = doc_view->document->height;
	for (i = 0; i < link->npoints; i++) {
		int_lower_bound(&ym, link->points[i].y + 1);
		int_upper_bound(&height, link->points[i].y);
	}
	doc_view->vs->y = (ym + height - doc_view->box.height) / 2;
	int_bounds(&doc_view->vs->y, 0,
		   doc_view->document->height - doc_view->box.height);
}

/* direction == 1 -> DOWN
 * direction == -1 -> UP */
static void
find_link(struct document_view *doc_view, int direction, int page_mode)
{
	struct link **line;
	struct link *link = NULL;
	int link_pos;
	int y, ymin, ymax;

	assert(doc_view && doc_view->document && doc_view->vs);
	if_assert_failed return;

	if (direction == -1) {
		/* UP */
		line = doc_view->document->lines2;
		if (!line) goto nolink;
		y = doc_view->vs->y + doc_view->box.height - 1;
		int_upper_bound(&y, doc_view->document->height - 1);
		if (y < 0) goto nolink;
	} else {
		/* DOWN */
		line = doc_view->document->lines1;
		if (!line) goto nolink;
		y = doc_view->vs->y;
		int_lower_bound(&y, 0);
		if (y >= doc_view->document->height) goto nolink;
	}

	ymin = int_max(0, doc_view->vs->y);
	ymax = int_min(doc_view->document->height,
		       doc_view->vs->y + doc_view->box.height);

	if (direction == -1) {
		/* UP */
		do {
			struct link *cur = line[y--];

			if (cur && (!link || cur > link))
				link = cur;
		} while (y >= ymin && y < ymax);

	} else {
		/* DOWN */
		do {
			struct link *cur = line[y++];

			if (cur && (!link || cur < link))
				link = cur;
		} while (y >= ymin && y < ymax);
	}

	if (!link) goto nolink;

	link_pos = link - doc_view->document->links;
	if (page_mode) {
		/* PAGE */
		next_link_in_view(doc_view, link_pos, direction, link_in_view, NULL);
		return;
	}
	current_link_blur(doc_view);
	doc_view->vs->current_link = link_pos;
	set_pos_x(doc_view, link);
	current_link_hover(doc_view);
	return;

nolink:
	current_link_blur(doc_view);
	doc_view->vs->current_link = -1;
}

void
find_link_up(struct document_view *doc_view)
{
	find_link(doc_view, -1, 0);
}

void
find_link_page_up(struct document_view *doc_view)
{
	find_link(doc_view, -1, 1);
}

void
find_link_down(struct document_view *doc_view)
{
	find_link(doc_view, 1, 0);
}

void
find_link_page_down(struct document_view *doc_view)
{
	find_link(doc_view, 1, 1);
}

struct uri *
get_link_uri(struct session *ses, struct document_view *doc_view,
	     struct link *link)
{
	assert(ses && doc_view && link);
	if_assert_failed return NULL;

	switch (link->type) {
		case LINK_HYPERTEXT:
		case LINK_MAP:
			if (link->where) return get_uri(link->where, 0);
			return get_uri(link->where_img, 0);

		case LINK_BUTTON:
		case LINK_FIELD:
			return get_form_uri(ses, doc_view,
					    get_link_form_control(link));

		default:
			return NULL;
	}
}

struct link *
goto_current_link(struct session *ses, struct document_view *doc_view, int do_reload)
{
	struct link *link;
	struct uri *uri;

	assert(doc_view && ses);
	if_assert_failed return NULL;

	link = get_current_link(doc_view);
	if (!link) return NULL;

	if (link_is_form(link))
		uri = get_form_uri(ses, doc_view, get_link_form_control(link));
	else