newt 0.7.2

Rust bindings for the Newt console UI library
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//
// Copyright (C) 2019 Robert Gill <rtgill82@gmail.com>
//
// This file is a part of newt-rs.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License version 2.1 as published by the Free Software Foundation.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//

use crate::component::Component;
use crate::widgets::Entry;

use newt_sys::newtComponent;
use crate::private::funcs::newt_entry_set_filter;

///
/// A callback used to filter text entered into an `Entry` component.
///
/// The function or closure associated with the callback should be
/// defined as follows:
///
/// `fn(entry: &Entry, data: Option<&T>, ch: char, cursor_pos: i32) -> char`
///
/// * `entry` - The `Entry` being filtered.
/// * `data` - The optional user data provided.
/// * `ch` - The character entered into the `Entry`.
/// * `cursor_pos` - The current cursor position in the `Entry`.
///
/// The function should return the character to be entered into the
/// `Entry` field or `'\0'` to ignore the entered character.
///
/// See the example under [Entry][entry_example].
///
/// [entry_example]: crate::widgets::Entry#example
///
pub struct EntryFilter<'a, F: 'a, T: 'a>
where F: FnMut(&Entry, Option<&T>, char, i32) -> char
{
    function: F,
    entries: Vec<(&'a Entry, Option<T>)>
}

impl<'a, F: 'a, T: 'a> EntryFilter<'a, F, T>
where F: FnMut(&Entry, Option<&T>, char, i32) -> char
{
    ///
    /// Create a new `EntryFilter`.
    ///
    /// Creates a new `EntryFilter` associated with the `Entry` `entry`.
    /// The function `function` will be called for each character entered.
    ///
    /// * `entry` - The `Entry` to associate with the callback.
    /// * `data` - The optonal user data to pass to the function.
    /// * `function` - The function or closure to be called when a character
    ///   is entered.
    ///
    pub fn new(entry: &'a Entry, data: Option<T>, function: F)
      -> Box<EntryFilter<'a, F, T>>
    {
        unsafe {
            let co: newtComponent = entry.co();
            let filter = Box::new(EntryFilter {
                function,
                entries: vec![(entry, data)]
            });
            newt_entry_set_filter(co, filter.as_ref());
            filter
        }
    }

    ///
    /// Associate another `Entry` with the `EntryFilter`.
    ///
    /// * `entry` - The `Entry` to associate with the callback.
    /// * `data` - The optonal user data to pass to the function.
    ///
    pub fn add_entry(&mut self, entry: &'a Entry, data: Option<T>) {
        unsafe {
            let co: newtComponent = entry.co();
            self.entries.push((entry, data));
            newt_entry_set_filter(co, self);
        }
    }

    pub(crate) fn call(&mut self, co: newtComponent, ch: char, cursor: i32)
        -> char
    {
        for (entry, data) in self.entries.iter() {
            if entry.co() == co {
                return (self.function)(entry, data.as_ref(), ch, cursor);
            }
        }
        '\0'
    }
}