source: mainline/uspace/app/nav/panel.c@ 97c3c59

/*
 * Copyright (c) 2021 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup nav
 * @{
 */
/** @file Navigator panel.
 *
 * Displays a file listing.
 */

#include <dirent.h>
#include <errno.h>
#include <gfx/render.h>
#include <gfx/text.h>
#include <stdlib.h>
#include <str.h>
#include <task.h>
#include <ui/control.h>
#include <ui/paint.h>
#include <ui/resource.h>
#include <vfs/vfs.h>
#include <qsort.h>
#include "panel.h"
#include "nav.h"

static void panel_ctl_destroy(void *);
static errno_t panel_ctl_paint(void *);
static ui_evclaim_t panel_ctl_kbd_event(void *, kbd_event_t *);
static ui_evclaim_t panel_ctl_pos_event(void *, pos_event_t *);

/** Panel control ops */
ui_control_ops_t panel_ctl_ops = {
        .destroy = panel_ctl_destroy,
        .paint = panel_ctl_paint,
        .kbd_event = panel_ctl_kbd_event,
        .pos_event = panel_ctl_pos_event
};

/** Create panel.
 *
 * @param window Containing window
 * @param active @c true iff panel should be active
 * @param rpanel Place to store pointer to new panel
 * @return EOK on success or an error code
 */
errno_t panel_create(ui_window_t *window, bool active, panel_t **rpanel)
{
        panel_t *panel;
        errno_t rc;

        panel = calloc(1, sizeof(panel_t));
        if (panel == NULL)
                return ENOMEM;

        rc = ui_control_new(&panel_ctl_ops, (void *)panel,
            &panel->control);
        if (rc != EOK) {
                free(panel);
                return rc;
        }

        rc = gfx_color_new_ega(0x07, &panel->color);
        if (rc != EOK)
                goto error;

        rc = gfx_color_new_ega(0x30, &panel->curs_color);
        if (rc != EOK)
                goto error;

        rc = gfx_color_new_ega(0x0f, &panel->act_border_color);
        if (rc != EOK)
                goto error;

        rc = gfx_color_new_ega(0x0f, &panel->dir_color);
        if (rc != EOK)
                goto error;

        rc = gfx_color_new_ega(0x0a, &panel->svc_color);
        if (rc != EOK)
                goto error;

        panel->window = window;
        list_initialize(&panel->entries);
        panel->entries_cnt = 0;
        panel->active = active;
        *rpanel = panel;
        return EOK;
error:
        if (panel->color != NULL)
                gfx_color_delete(panel->color);
        if (panel->curs_color != NULL)
                gfx_color_delete(panel->curs_color);
        if (panel->act_border_color != NULL)
                gfx_color_delete(panel->act_border_color);
        if (panel->dir_color != NULL)
                gfx_color_delete(panel->dir_color);
        if (panel->svc_color != NULL)
                gfx_color_delete(panel->svc_color);
        ui_control_delete(panel->control);
        free(panel);
        return rc;
}

/** Destroy panel.
 *
 * @param panel Panel
 */
void panel_destroy(panel_t *panel)
{
        gfx_color_delete(panel->color);
        gfx_color_delete(panel->curs_color);
        gfx_color_delete(panel->act_border_color);
        gfx_color_delete(panel->dir_color);
        gfx_color_delete(panel->svc_color);
        panel_clear_entries(panel);
        ui_control_delete(panel->control);
        free(panel);
}

/** Paint panel entry.
 *
 * @param entry Panel entry
 * @param entry_idx Entry index (within list of entries)
 * @return EOK on success or an error code
 */
errno_t panel_entry_paint(panel_entry_t *entry, size_t entry_idx)
{
        panel_t *panel = entry->panel;
        gfx_context_t *gc = ui_window_get_gc(panel->window);
        ui_resource_t *res = ui_window_get_res(panel->window);
        gfx_font_t *font = ui_resource_get_font(res);
        gfx_text_fmt_t fmt;
        gfx_coord2_t pos;
        gfx_rect_t rect;
        size_t rows;
        errno_t rc;

        gfx_text_fmt_init(&fmt);
        rows = panel_page_size(panel);

        /* Do not display entry outside of current page */
        if (entry_idx < panel->page_idx ||
            entry_idx >= panel->page_idx + rows)
                return EOK;

        pos.x = panel->rect.p0.x + 1;
        pos.y = panel->rect.p0.y + 1 + entry_idx - panel->page_idx;

        if (entry == panel->cursor && panel->active)
                fmt.color = panel->curs_color;
        else if (entry->isdir)
                fmt.color = panel->dir_color;
        else if (entry->svc != 0)
                fmt.color = panel->svc_color;
        else
                fmt.color = panel->color;

        /* Draw entry background */
        rect.p0 = pos;
        rect.p1.x = panel->rect.p1.x - 1;
        rect.p1.y = rect.p0.y + 1;

        rc = gfx_set_color(gc, fmt.color);
        if (rc != EOK)
                return rc;

        rc = gfx_fill_rect(gc, &rect);
        if (rc != EOK)
                return rc;

        rc = gfx_puttext(font, &pos, &fmt, entry->name);
        if (rc != EOK)
                return rc;

        return EOK;
}

/** Paint panel.
 *
 * @param panel Panel
 */
errno_t panel_paint(panel_t *panel)
{
        gfx_context_t *gc = ui_window_get_gc(panel->window);
        ui_resource_t *res = ui_window_get_res(panel->window);
        gfx_text_fmt_t fmt;
        panel_entry_t *entry;
        ui_box_style_t bstyle;
        gfx_color_t *bcolor;
        int i, lines;
        errno_t rc;

        gfx_text_fmt_init(&fmt);

        rc = gfx_set_color(gc, panel->color);
        if (rc != EOK)
                return rc;

        rc = gfx_fill_rect(gc, &panel->rect);
        if (rc != EOK)
                return rc;

        if (panel->active) {
                bstyle = ui_box_double;
                bcolor = panel->act_border_color;
        } else {
                bstyle = ui_box_single;
                bcolor = panel->color;
        }

        rc = ui_paint_text_box(res, &panel->rect, bstyle, bcolor);
        if (rc != EOK)
                return rc;

        lines = panel_page_size(panel);
        i = 0;

        entry = panel->page;
        while (entry != NULL && i < lines) {
                rc = panel_entry_paint(entry, panel->page_idx + i);
                if (rc != EOK)
                        return rc;

                ++i;
                entry = panel_next(entry);
        }

        rc = gfx_update(gc);
        if (rc != EOK)
                return rc;

        return EOK;
}

/** Handle panel keyboard event.
 *
 * @param panel Panel
 * @param event Keyboard event
 * @return ui_claimed iff event was claimed
 */
ui_evclaim_t panel_kbd_event(panel_t *panel, kbd_event_t *event)
{
        if (!panel->active)
                return ui_unclaimed;

        if (event->type == KEY_PRESS) {
                if ((event->mods & (KM_CTRL | KM_ALT | KM_SHIFT)) == 0) {
                        switch (event->key) {
                        case KC_UP:
                                panel_cursor_up(panel);
                                break;
                        case KC_DOWN:
                                panel_cursor_down(panel);
                                break;
                        case KC_HOME:
                                panel_cursor_top(panel);
                                break;
                        case KC_END:
                                panel_cursor_bottom(panel);
                                break;
                        case KC_PAGE_UP:
                                panel_page_up(panel);
                                break;
                        case KC_PAGE_DOWN:
                                panel_page_down(panel);
                                break;
                        case KC_ENTER:
                                panel_open(panel, panel->cursor);
                                break;
                        default:
                                break;
                        }
                }
        }

        return ui_claimed;
}

/** Handle panel position event.
 *
 * @param panel Panel
 * @param event Position event
 * @return ui_claimed iff event was claimed
 */
ui_evclaim_t panel_pos_event(panel_t *panel, pos_event_t *event)
{
        return ui_unclaimed;
}

/** Get base control for panel.
 *
 * @param panel Panel
 * @return Base UI control
 */
ui_control_t *panel_ctl(panel_t *panel)
{
        return panel->control;
}

/** Set panel rectangle.
 *
 * @param panel Panel
 * @param rect Rectangle
 */
void panel_set_rect(panel_t *panel, gfx_rect_t *rect)
{
        panel->rect = *rect;
}

/** Get panel page size.
 *
 * @param panel Panel
 * @return Number of entries that fit in panel at the same time.
 */
unsigned panel_page_size(panel_t *panel)
{
        return panel->rect.p1.y - panel->rect.p0.y - 2;
}

/** Determine if panel is active.
 *
 * @param panel Panel
 * @return @c true iff panel is active
 */
bool panel_is_active(panel_t *panel)
{
        return panel->active;
}

/** Activate panel.
 *
 * @param panel Panel
 *
 * @return EOK on success or an error code
 */
errno_t panel_activate(panel_t *panel)
{
        errno_t rc;

        if (panel->dir != NULL) {
                rc = vfs_cwd_set(panel->dir);
                if (rc != EOK)
                        return rc;
        }

        panel->active = true;
        (void) panel_paint(panel);
        return EOK;
}

/** Deactivate panel.
 *
 * @param panel Panel
 */
void panel_deactivate(panel_t *panel)
{
        panel->active = false;
        (void) panel_paint(panel);
}

/** Initialize panel entry attributes.
 *
 * @param attr Attributes
 */
void panel_entry_attr_init(panel_entry_attr_t *attr)
{
        memset(attr, 0, sizeof(*attr));
}

/** Destroy panel control.
 *
 * @param arg Argument (panel_t *)
 */
void panel_ctl_destroy(void *arg)
{
        panel_t *panel = (panel_t *) arg;

        panel_destroy(panel);
}

/** Paint panel control.
 *
 * @param arg Argument (panel_t *)
 * @return EOK on success or an error code
 */
errno_t panel_ctl_paint(void *arg)
{
        panel_t *panel = (panel_t *) arg;

        return panel_paint(panel);
}

/** Handle panel control keyboard event.
 *
 * @param arg Argument (panel_t *)
 * @param kbd_event Keyboard event
 * @return @c ui_claimed iff the event is claimed
 */
ui_evclaim_t panel_ctl_kbd_event(void *arg, kbd_event_t *event)
{
        panel_t *panel = (panel_t *) arg;

        return panel_kbd_event(panel, event);
}

/** Handle panel control position event.
 *
 * @param arg Argument (panel_t *)
 * @param pos_event Position event
 * @return @c ui_claimed iff the event is claimed
 */
ui_evclaim_t panel_ctl_pos_event(void *arg, pos_event_t *event)
{
        panel_t *panel = (panel_t *) arg;

        return panel_pos_event(panel, event);
}

/** Append new panel entry.
 *
 * @param panel Panel
 * @param attr Entry attributes
 * @return EOK on success or an error code
 */
errno_t panel_entry_append(panel_t *panel, panel_entry_attr_t *attr)
{
        panel_entry_t *entry;

        entry = calloc(1, sizeof(panel_entry_t));
        if (entry == NULL)
                return ENOMEM;

        entry->panel = panel;
        entry->name = str_dup(attr->name);
        if (entry->name == NULL) {
                free(entry);
                return ENOMEM;
        }

        entry->size = attr->size;
        entry->isdir = attr->isdir;
        entry->svc = attr->svc;
        link_initialize(&entry->lentries);
        list_append(&entry->lentries, &panel->entries);
        ++panel->entries_cnt;
        return EOK;
}

/** Delete panel entry.
 *
 * @param entry Panel entry
 */
void panel_entry_delete(panel_entry_t *entry)
{
        if (entry->panel->cursor == entry)
                entry->panel->cursor = NULL;
        if (entry->panel->page == entry)
                entry->panel->page = NULL;

        list_remove(&entry->lentries);
        --entry->panel->entries_cnt;
        free((char *) entry->name);
        free(entry);
}

/** Clear panel entry list.
 *
 * @param panel Panel
 */
void panel_clear_entries(panel_t *panel)
{
        panel_entry_t *entry;

        entry = panel_first(panel);
        while (entry != NULL) {
                panel_entry_delete(entry);
                entry = panel_first(panel);
        }
}

/** Read directory into panel entry list.
 *
 * @param panel Panel
 * @param dirname Directory path
 * @return EOK on success or an error code
 */
errno_t panel_read_dir(panel_t *panel, const char *dirname)
{
        DIR *dir;
        struct dirent *dirent;
        vfs_stat_t finfo;
        char newdir[256];
        char *ndir = NULL;
        panel_entry_attr_t attr;
        panel_entry_t *next;
        panel_entry_t *prev;
        char *olddn;
        size_t pg_size;
        size_t i;
        errno_t rc;

        rc = vfs_cwd_set(dirname);
        if (rc != EOK)
                return rc;

        rc = vfs_cwd_get(newdir, sizeof(newdir));
        if (rc != EOK)
                return rc;

        ndir = str_dup(newdir);
        if (ndir == NULL)
                return ENOMEM;

        dir = opendir(".");
        if (dir == NULL) {
                rc = errno;
                goto error;
        }

        if (str_cmp(ndir, "/") != 0) {
                /* Need to add a synthetic up-dir entry */
                panel_entry_attr_init(&attr);
                attr.name = "..";
                attr.isdir = true;

                rc = panel_entry_append(panel, &attr);
                if (rc != EOK)
                        goto error;
        }

        dirent = readdir(dir);
        while (dirent != NULL) {
                rc = vfs_stat_path(dirent->d_name, &finfo);
                if (rc != EOK) {
                        /* Possibly a stale entry */
                        dirent = readdir(dir);
                        continue;
                }

                panel_entry_attr_init(&attr);
                attr.name = dirent->d_name;
                attr.size = finfo.size;
                attr.isdir = finfo.is_directory;
                attr.svc = finfo.service;

                rc = panel_entry_append(panel, &attr);
                if (rc != EOK)
                        goto error;

                dirent = readdir(dir);
        }

        closedir(dir);

        rc = panel_sort(panel);
        if (rc != EOK)
                goto error;

        panel->cursor = panel_first(panel);
        panel->cursor_idx = 0;
        panel->page = panel_first(panel);
        panel->page_idx = 0;

        /* Moving up? */
        if (str_cmp(dirname, "..") == 0) {
                /* Get the last component of old path */
                olddn = str_rchr(panel->dir, '/');
                if (olddn != NULL && *olddn != '\0') {
                        /* Find corresponding entry */
                        ++olddn;
                        next = panel_next(panel->cursor);
                        while (next != NULL && str_cmp(next->name, olddn) <= 0 &&
                            next->isdir) {
                                panel->cursor = next;
                                ++panel->cursor_idx;
                                next = panel_next(panel->cursor);
                        }

                        /* Move page so that cursor is in the center */
                        panel->page = panel->cursor;
                        panel->page_idx = panel->cursor_idx;

                        pg_size = panel_page_size(panel);

                        for (i = 0; i < pg_size / 2; i++) {
                                prev = panel_prev(panel->page);
                                if (prev == NULL)
                                        break;

                                panel->page = prev;
                                --panel->page_idx;
                        }
                }
        }

        free(panel->dir);
        panel->dir = ndir;

        return EOK;
error:
        (void) vfs_cwd_set(panel->dir);
        if (ndir != NULL)
                free(ndir);
        if (dir != NULL)
                closedir(dir);
        return rc;
}

/** Sort panel entries.
 *
 * @param panel Panel
 * @return EOK on success, ENOMEM if out of memory
 */
errno_t panel_sort(panel_t *panel)
{
        panel_entry_t **emap;
        panel_entry_t *entry;
        size_t i;

        /* Create an array to hold pointer to each entry */
        emap = calloc(panel->entries_cnt, sizeof(panel_entry_t *));
        if (emap == NULL)
                return ENOMEM;

        /* Write entry pointers to array */
        entry = panel_first(panel);
        i = 0;
        while (entry != NULL) {
                assert(i < panel->entries_cnt);
                emap[i++] = entry;
                entry = panel_next(entry);
        }

        /* Sort the array of pointers */
        qsort(emap, panel->entries_cnt, sizeof(panel_entry_t *),
            panel_entry_ptr_cmp);

        /* Unlink entries from entry list */
        entry = panel_first(panel);
        while (entry != NULL) {
                list_remove(&entry->lentries);
                entry = panel_first(panel);
        }

        /* Add entries back to entry list sorted */
        for (i = 0; i < panel->entries_cnt; i++)
                list_append(&emap[i]->lentries, &panel->entries);

        free(emap);
        return EOK;
}

/** Compare two panel entries indirectly referenced by pointers.
 *
 * @param pa Pointer to pointer to first entry
 * @param pb Pointer to pointer to second entry
 * @return <0, =0, >=0 if pa < b, pa == pb, pa > pb, resp.
 */
int panel_entry_ptr_cmp(const void *pa, const void *pb)
{
        panel_entry_t *a = *(panel_entry_t **)pa;
        panel_entry_t *b = *(panel_entry_t **)pb;
        int dcmp;

        /* Sort directories first */
        dcmp = b->isdir - a->isdir;
        if (dcmp != 0)
                return dcmp;

        return str_cmp(a->name, b->name);
}

/** Return first panel entry.
 *
 * @panel Panel
 * @return First panel entry or @c NULL if there are no entries
 */
panel_entry_t *panel_first(panel_t *panel)
{
        link_t *link;

        link = list_first(&panel->entries);
        if (link == NULL)
                return NULL;

        return list_get_instance(link, panel_entry_t, lentries);
}

/** Return last panel entry.
 *
 * @panel Panel
 * @return Last panel entry or @c NULL if there are no entries
 */
panel_entry_t *panel_last(panel_t *panel)
{
        link_t *link;

        link = list_last(&panel->entries);
        if (link == NULL)
                return NULL;

        return list_get_instance(link, panel_entry_t, lentries);
}

/** Return next panel entry.
 *
 * @param cur Current entry
 * @return Next entry or @c NULL if @a cur is the last entry
 */
panel_entry_t *panel_next(panel_entry_t *cur)
{
        link_t *link;

        link = list_next(&cur->lentries, &cur->panel->entries);
        if (link == NULL)
                return NULL;

        return list_get_instance(link, panel_entry_t, lentries);
}

/** Return previous panel entry.
 *
 * @param cur Current entry
 * @return Previous entry or @c NULL if @a cur is the first entry
 */
panel_entry_t *panel_prev(panel_entry_t *cur)
{
        link_t *link;

        link = list_prev(&cur->lentries, &cur->panel->entries);
        if (link == NULL)
                return NULL;

        return list_get_instance(link, panel_entry_t, lentries);
}

/** Move cursor to a new position, possibly scrolling.
 *
 * @param panel Panel
 * @param entry New entry under cursor
 * @param entry_idx Index of new entry under cursor
 */
void panel_cursor_move(panel_t *panel, panel_entry_t *entry, size_t entry_idx)
{
        gfx_context_t *gc = ui_window_get_gc(panel->window);
        panel_entry_t *old_cursor;
        size_t old_idx;
        size_t rows;
        panel_entry_t *e;
        size_t i;

        rows = panel_page_size(panel);

        old_cursor = panel->cursor;
        old_idx = panel->cursor_idx;

        panel->cursor = entry;
        panel->cursor_idx = entry_idx;

        if (entry_idx >= panel->page_idx &&
            entry_idx < panel->page_idx + rows) {
                /*
                 * If cursor is still on the current page, we're not
                 * scrolling. Just unpaint old cursor and paint new
                 * cursor.
                 */
                panel_entry_paint(old_cursor, old_idx);
                panel_entry_paint(panel->cursor, panel->cursor_idx);

                (void) gfx_update(gc);
        } else {
                /*
                 * Need to scroll and update all rows.
                 */

                /* Scrolling up */
                if (entry_idx < panel->page_idx) {
                        panel->page = entry;
                        panel->page_idx = entry_idx;
                }

                /* Scrolling down */
                if (entry_idx >= panel->page_idx + rows) {
                        if (entry_idx >= rows) {
                                panel->page_idx = entry_idx - rows + 1;
                                /* Find first page entry (go back rows - 1) */
                                e = entry;
                                for (i = 0; i < rows - 1; i++) {
                                        e = panel_prev(e);
                                }

                                /* Should be valid */
                                assert(e != NULL);
                                panel->page = e;
                        } else {
                                panel->page = panel_first(panel);
                                panel->page_idx = 0;
                        }
                }

                (void) panel_paint(panel);
        }
}

/** Move cursor one entry up.
 *
 * @param panel Panel
 */
void panel_cursor_up(panel_t *panel)
{
        panel_entry_t *prev;
        size_t prev_idx;

        prev = panel_prev(panel->cursor);
        prev_idx = panel->cursor_idx - 1;
        if (prev != NULL)
                panel_cursor_move(panel, prev, prev_idx);
}

/** Move cursor one entry down.
 *
 * @param panel Panel
 */
void panel_cursor_down(panel_t *panel)
{
        panel_entry_t *next;
        size_t next_idx;

        next = panel_next(panel->cursor);
        next_idx = panel->cursor_idx + 1;
        if (next != NULL)
                panel_cursor_move(panel, next, next_idx);
}

/** Move cursor to top.
 *
 * @param panel Panel
 */
void panel_cursor_top(panel_t *panel)
{
        panel_cursor_move(panel, panel_first(panel), 0);
}

/** Move cursor to bottom.
 *
 * @param panel Panel
 */
void panel_cursor_bottom(panel_t *panel)
{
        panel_cursor_move(panel, panel_last(panel), panel->entries_cnt - 1);
}

/** Move one page up.
 *
 * @param panel Panel
 */
void panel_page_up(panel_t *panel)
{
        gfx_context_t *gc = ui_window_get_gc(panel->window);
        panel_entry_t *old_page;
        panel_entry_t *old_cursor;
        size_t old_idx;
        size_t rows;
        panel_entry_t *entry;
        size_t i;

        rows = panel_page_size(panel);

        old_page = panel->page;
        old_cursor = panel->cursor;
        old_idx = panel->cursor_idx;

        /* Move page by rows entries up (if possible) */
        for (i = 0; i < rows; i++) {
                entry = panel_prev(panel->page);
                if (entry != NULL) {
                        panel->page = entry;
                        --panel->page_idx;
                }
        }

        /* Move cursor by rows entries up (if possible) */

        for (i = 0; i < rows; i++) {
                entry = panel_prev(panel->cursor);
                if (entry != NULL) {
                        panel->cursor = entry;
                        --panel->cursor_idx;
                }
        }

        if (panel->page != old_page) {
                /* We have scrolled. Need to repaint all entries */
                (void) panel_paint(panel);
        } else if (panel->cursor != old_cursor) {
                /* No scrolling, but cursor has moved */
                panel_entry_paint(old_cursor, old_idx);
                panel_entry_paint(panel->cursor, panel->cursor_idx);

                (void) gfx_update(gc);
        }
}

/** Move one page down.
 *
 * @param panel Panel
 */
void panel_page_down(panel_t *panel)
{
        gfx_context_t *gc = ui_window_get_gc(panel->window);
        panel_entry_t *old_page;
        panel_entry_t *old_cursor;
        size_t old_idx;
        size_t max_idx;
        size_t rows;
        panel_entry_t *entry;
        size_t i;

        rows = panel_page_size(panel);

        old_page = panel->page;
        old_cursor = panel->cursor;
        old_idx = panel->cursor_idx;
        max_idx = panel->entries_cnt - rows;

        /* Move page by rows entries down (if possible) */
        for (i = 0; i < rows; i++) {
                entry = panel_next(panel->page);
                /* Do not scroll that results in a short page */
                if (entry != NULL && panel->page_idx < max_idx) {
                        panel->page = entry;
                        ++panel->page_idx;
                }
        }

        /* Move cursor by rows entries down (if possible) */

        for (i = 0; i < rows; i++) {
                entry = panel_next(panel->cursor);
                if (entry != NULL) {
                        panel->cursor = entry;
                        ++panel->cursor_idx;
                }
        }

        if (panel->page != old_page) {
                /* We have scrolled. Need to repaint all entries */
                (void) panel_paint(panel);
        } else if (panel->cursor != old_cursor) {
                /* No scrolling, but cursor has moved */
                panel_entry_paint(old_cursor, old_idx);
                panel_entry_paint(panel->cursor, panel->cursor_idx);

                (void) gfx_update(gc);
        }
}

/** Open panel entry.
 *
 * Perform Open action on a panel entry (e.g. switch to a subdirectory).
 *
 * @param panel Panel
 * @param entry Panel entry
 *
 * @return EOK on success or an error code
 */
errno_t panel_open(panel_t *panel, panel_entry_t *entry)
{
        if (entry->isdir)
                return panel_open_dir(panel, entry);
        else if (entry->svc == 0)
                return panel_open_file(panel, entry);
        else
                return EOK;
}

/** Open panel directory entry.
 *
 * Perform Open action on a directory entry (i.e. switch to the directory).
 *
 * @param panel Panel
 * @param entry Panel entry (which is a directory)
 *
 * @return EOK on success or an error code
 */
errno_t panel_open_dir(panel_t *panel, panel_entry_t *entry)
{
        gfx_context_t *gc = ui_window_get_gc(panel->window);
        char *dirname;
        errno_t rc;

        assert(entry->isdir);

        /*
         * Need to copy out name before we free the entry below
         * via panel_clear_entries().
         */
        dirname = str_dup(entry->name);
        if (dirname == NULL)
                return ENOMEM;

        panel_clear_entries(panel);

        rc = panel_read_dir(panel, dirname);
        if (rc != EOK) {
                free(dirname);
                return rc;
        }

        free(dirname);

        rc = panel_paint(panel);
        if (rc != EOK)
                return rc;

        return gfx_update(gc);
}

/** Open panel file entry.
 *
 * Perform Open action on a file entry (i.e. try running it).
 *
 * @param panel Panel
 * @param entry Panel entry (which is a file)
 *
 * @return EOK on success or an error code
 */
errno_t panel_open_file(panel_t *panel, panel_entry_t *entry)
{
        task_id_t id;
        task_wait_t wait;
        task_exit_t texit;
        int retval;
        errno_t rc;

        /* It's not a directory */
        assert(!entry->isdir);
        /* It's not a service-special file */
        assert(entry->svc == 0);

        rc = task_spawnl(&id, &wait, entry->name, entry->name, NULL);
        if (rc != EOK)
                return rc;

        rc = task_wait(&wait, &texit, &retval);
        if ((rc != EOK) || (texit != TASK_EXIT_NORMAL))
                return rc;

        (void) ui_paint(ui_window_get_ui(panel->window));
        return EOK;
}

/** @}
 */