lnav/src/xterm_mouse.hh

/**
 * Copyright (c) 2007-2012, Timothy Stack
 *
 * 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.
 * * Neither the name of Timothy Stack nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''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 REGENTS OR CONTRIBUTORS 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.
 *
 * @file xterm_mouse.hh
 */

#ifndef __xterm_mouse_hh
#define __xterm_mouse_hh

#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <string>

#if defined HAVE_NCURSESW_CURSES_H
#  include <ncursesw/curses.h>
#elif defined HAVE_NCURSESW_H
#  include <ncursesw.h>
#elif defined HAVE_NCURSES_CURSES_H
#  include <ncurses/curses.h>
#elif defined HAVE_NCURSES_H
#  include <ncurses.h>
#elif defined HAVE_CURSES_H
#  include <curses.h>
#else
#  error "SysV or X/Open-compatible Curses header file required"
#endif

#include "lnav_log.hh"

/**
 * Base class for delegates of the xterm_mouse class.
 */
class mouse_behavior {
public:
    virtual ~mouse_behavior() { };

    /**
     * Callback used to process mouse events.
     *
     * @param button The button that was pressed or released.  This will
     *   be one of the XT_BUTTON or XT_SCROLL constants in the xterm_mouse
     *   class.
     * @param x      The X coordinate where the event occurred.
     * @param y      The Y coordinate where the event occurred.
     */
    virtual void mouse_event(int button, bool release, int x, int y) = 0;
};

/**
 * Class that handles xterm mouse events coming through the ncurses interface.
 */
class xterm_mouse {
public:
    static const int XT_BUTTON1        = 0;
    static const int XT_BUTTON2        = 1;
    static const int XT_BUTTON3        = 2;

    static const int XT_DRAG_FLAG = 32;
    static const int XT_SCROLL_WHEEL_FLAG = 64;
    static const int XT_SCROLL_UP         =
        XT_SCROLL_WHEEL_FLAG | XT_BUTTON1;
    static const int XT_SCROLL_DOWN =
        XT_SCROLL_WHEEL_FLAG | XT_BUTTON2;

    static const int XT_BUTTON__MASK =
        XT_SCROLL_WHEEL_FLAG |
        XT_BUTTON1 |
        XT_BUTTON2 |
        XT_BUTTON3;

    static const char *XT_TERMCAP;
    static const char *XT_TERMCAP_TRACKING;
    static const char *XT_TERMCAP_SGR;

    /**
     * @return True if the user's terminal supports xterm-mouse events.
     */
    static bool is_available()
    {
        const char *termname = getenv("TERM");
        bool retval = false;

        if (termname and strstr(termname, "xterm") != NULL) {
            retval = isatty(STDOUT_FILENO);
        }
        return retval;
    };

    xterm_mouse() : xm_enabled(false), xm_behavior(NULL) {};

    ~xterm_mouse()
    {
        if (this->is_enabled())
            set_enabled(false);
    };

    /**
     * @param enabled True if xterm mouse support should be enabled in the
     *   terminal.
     */
    void set_enabled(bool enabled)
    {
        if (is_available()) {
            putp(tparm((char *)XT_TERMCAP, enabled ? 1 : 0));
            putp(tparm((char *)XT_TERMCAP_TRACKING, enabled ? 1 : 0));
            putp(tparm((char *)XT_TERMCAP_SGR, enabled ? 1 : 0));
            fflush(stdout);
            this->xm_enabled = enabled;
        }
    };

    /**
     * @return True if xterm mouse support is enabled, false otherwise.
     */
    bool is_enabled() const
    {
        return this->xm_enabled;
    };

    /**
     * @param mb The delegate to send mouse events to.
     */
    void set_behavior(mouse_behavior *mb)
    {
        this->xm_behavior = mb;
    };

    mouse_behavior *get_behavior() { return this->xm_behavior; };

    /**
     * Handle a KEY_MOUSE character from ncurses.
     * @param ch unused
     */
    void handle_mouse(int ch_unused)
    {
        bool release = false;
        int ch;
        size_t index = 0;
        int bstate, x, y;
        char buffer[64];
        bool done = false;

        while (!done) {
            if (index >= sizeof(buffer) - 1) {
                break;
            }
            ch = getch();
            switch (ch) {
            case 'm':
                release = true;
                done = true;
                break;
            case 'M':
                done = true;
                break;
            default:
                buffer[index++] = (char)ch;
                break;
            }
        }
        buffer[index] = '\0';

        if (sscanf(buffer, "<%d;%d;%d", &bstate, &x, &y) == 3) {
            if (this->xm_behavior) {
                this->xm_behavior->mouse_event(bstate, release, x, y);
            }
        }
        else {
            log_error("bad mouse escape sequence: %s", buffer);
        }
    };

private:
    bool            xm_enabled;
    mouse_behavior *xm_behavior;
};
#endif