Fixed possible segfault by reverting to the key struct (again).

[st.git] / st.c

/* See LICENSE for licence details. */
#define _XOPEN_SOURCE 600
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <locale.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <sys/select.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <X11/Xlib.h>
#include <X11/keysym.h>
#include <X11/Xutil.h>

#define TNAME "st"

/* Arbitrary sizes */
#define ESCSIZ 256
#define ESCARG 16

#define SERRNO strerror(errno)
#define MIN(a, b)  ((a) < (b) ? (a) : (b))
#define MAX(a, b)  ((a) < (b) ? (b) : (a))
#define LEN(a)     (sizeof(a) / sizeof(a[0]))
#define DEFAULT(a, b)     (a) = (a) ? (a) : (b)    
#define BETWEEN(x, a, b)  ((a) <= (x) && (x) <= (b))
#define LIMIT(x, a, b)    (x) = (x) < (a) ? (a) : (x) > (b) ? (b) : (x)

/* Attribute, Cursor, Character state, Terminal mode, Screen draw mode */
enum { ATnone=0 , ATreverse=1 , ATunderline=2, ATbold=4 };
enum { CSup, CSdown, CSright, CSleft, CShide, CSdraw, CSwrap, CSsave, CSload };
enum { CRset=1, CRupdate=2 };
enum { TMwrap=1, TMinsert=2 };
enum { SCupdate, SCredraw };

typedef int Color;

typedef struct {
        char c;     /* character code  */
        char mode;  /* attribute flags */
        Color fg;   /* foreground      */
        Color bg;   /* background      */
        char state; /* state flag      */
} Glyph;

typedef Glyph* Line;

typedef struct {
        Glyph attr;  /* current char attributes */
        char hidden;
        int x;
        int y;
} TCursor;

/* Escape sequence structs */
/* ESC <pre> [[ [<priv>] <arg> [;]] <mode>] */
typedef struct {
        char buf[ESCSIZ+1]; /* raw string */
        int len;            /* raw string length */
        char pre;           
        char priv;
        int arg[ESCARG+1];
        int narg;           /* nb of args */
        char mode;
} Escseq;

/* Internal representation of the screen */
typedef struct {
        int row;    /* nb row */  
        int col;    /* nb col */
        Line* line; /* screen */
        TCursor c;  /* cursor */
        int top;    /* top    scroll limit */
        int bot;    /* bottom scroll limit */
        int mode;   /* terminal mode */
} Term;

/* Purely graphic info */
typedef struct {
        Display* dis;
        Window win;
        int scr;
        int w;  /* window width  */
        int h;  /* window height */
        int ch; /* char height */
        int cw; /* char width  */
} XWindow; 

typedef struct {
        KeySym k;
        char s[ESCSIZ];
} Key;

#include "config.h"

/* Drawing Context */
typedef struct {
        unsigned long col[LEN(colorname)];
        XFontStruct* font;
        GC gc;
} DC;

static void die(const char *errstr, ...);
static void draw(int);
static void execsh(void);
static void sigchld(int);
static void run(void);

static int escaddc(char);
static int escfinal(char);
static void escdump(void);
static void eschandle(void);
static void escparse(void);
static void escreset(void);

static void tclearregion(int, int, int, int);
static void tcpos(int);
static void tcursor(int);
static void tdeletechar(int);
static void tdeleteline(int);
static void tinsertblank(int);
static void tinsertblankline(int);
static void tmoveto(int, int);
static void tnew(int, int);
static void tnewline(void);
static void tputc(char);
static void tputs(char*, int);
static void tresize(int, int);
static void tscroll(void);
static void tsetattr(int*, int);
static void tsetchar(char);
static void tsetscroll(int, int);

static void ttynew(void);
static void ttyread(void);
static void ttyresize(int, int);
static void ttywrite(const char *, size_t);

static unsigned long xgetcol(const char *);
static void xclear(int, int, int, int);
static void xcursor(int);
static void xdrawc(int, int, Glyph);
static void xinit(void);
static void xscroll(void);

static void expose(XEvent *);
static char * kmap(KeySym);
static void kpress(XEvent *);
static void resize(XEvent *);

static void (*handler[LASTEvent])(XEvent *) = {
        [KeyPress] = kpress,
        [Expose] = expose,
        [ConfigureNotify] = resize
};

/* Globals */
static DC dc;
static XWindow xw;
static Term term;
static Escseq escseq;
static int cmdfd;
static pid_t pid;
static int running;

#ifdef DEBUG
void
tdump(void) {
        int row, col;
        Glyph c;

        for(row = 0; row < term.row; row++) {
                for(col = 0; col < term.col; col++) {
                        if(col == term.c.x && row == term.c.y)
                                putchar('#');
                        else {
                                c = term.line[row][col];
                                putchar(c.state & CRset ? c.c : '.');
                        }
                }
                putchar('\n');
        }
}
#endif

void
die(const char *errstr, ...) {
        va_list ap;

        va_start(ap, errstr);
        vfprintf(stderr, errstr, ap);
        va_end(ap);
        exit(EXIT_FAILURE);
}

void
execsh(void) {
        char *args[3] = {SHELL, "-i", NULL};
        putenv("TERM=" TNAME);
        execvp(SHELL, args);
}

void
xbell(void) { /* visual bell */
        XRectangle r = { 0, 0, xw.w, xw.h };
        XSetForeground(xw.dis, dc.gc, dc.col[BellCol]);
        XFillRectangles(xw.dis, xw.win, dc.gc, &r, 1);
        /* usleep(30000); */
        draw(SCredraw);
}

void 
sigchld(int a) {
        int stat = 0;
        if(waitpid(pid, &stat, 0) < 0)
                die("Waiting for pid %hd failed: %s\n", pid, SERRNO);
        if(WIFEXITED(stat))
                exit(WEXITSTATUS(stat));
        else
                exit(EXIT_FAILURE);
}

void
ttynew(void) {
        int m, s;
        char *pts;

        if((m = posix_openpt(O_RDWR | O_NOCTTY)) < 0)
                die("openpt failed: %s\n", SERRNO);
        if(grantpt(m) < 0)
                die("grandpt failed: %s\n", SERRNO);
        if(unlockpt(m) < 0)
                die("unlockpt failed: %s\n", SERRNO);
        if(!(pts = ptsname(m)))
                die("ptsname failed: %s\n", SERRNO);
        if((s = open(pts, O_RDWR | O_NOCTTY)) < 0)
                die("Couldn't open slave: %s\n", SERRNO);
        fcntl(s, F_SETFL, O_NDELAY);
        switch(pid = fork()) {
        case -1:
                die("fork failed\n");
                break;
        case 0:
                setsid(); /* create a new process group */
                dup2(s, STDIN_FILENO);
                dup2(s, STDOUT_FILENO);
                dup2(s, STDERR_FILENO);
                if(ioctl(s, TIOCSCTTY, NULL) < 0)
                        die("ioctl TTIOCSTTY failed: %s\n", SERRNO);
                execsh();
                break;
        default:
                close(s);
                cmdfd = m;
                signal(SIGCHLD, sigchld);
        }
}

void
dump(char c) {
        static int col;
        fprintf(stderr, " %02x %c ", c, isprint(c)?c:'.');
        if(++col % 10 == 0)
                fprintf(stderr, "\n");
}

void
ttyread(void) {
        char buf[BUFSIZ] = {0};
        int ret;

        switch(ret = read(cmdfd, buf, BUFSIZ)) {
        case -1: 
                die("Couldn't read from shell: %s\n", SERRNO);
                break;
        default:
                tputs(buf, ret);
        }
}

void
ttywrite(const char *s, size_t n) {
        if(write(cmdfd, s, n) == -1)
                die("write error on tty: %s\n", SERRNO);
}

void
ttyresize(int x, int y) {
        struct winsize w;

        w.ws_row = term.row;
        w.ws_col = term.col;
        w.ws_xpixel = w.ws_ypixel = 0;
        if(ioctl(cmdfd, TIOCSWINSZ, &w) < 0)
                fprintf(stderr, "Couldn't set window size: %s\n", SERRNO);
}

int
escfinal(char c) {
        if(escseq.len == 1)
                switch(c) {
                case '[':
                case ']':
                case '(':
                        return 0;
                case '=':
                case '>':
                default:
                        return 1;
                }
        else if(BETWEEN(c, 0x40, 0x7E))
                return 1;
        return 0;         
}

void
tcpos(int mode) {
        static int x = 0;
        static int y = 0;

        if(mode == CSsave)
                x = term.c.x, y = term.c.y;
        else if(mode == CSload)
                tmoveto(x, y);
}

void
tnew(int col, int row) {   /* screen size */
        term.row = row, term.col = col;
        term.top = 0, term.bot = term.row - 1;
        /* mode */
        term.mode = TMwrap;
        /* cursor */
        term.c.attr.mode = ATnone;
        term.c.attr.fg = DefaultFG;
        term.c.attr.bg = DefaultBG;
        term.c.x = term.c.y = 0;
        term.c.hidden = 0;
        /* allocate screen */
        term.line = calloc(term.row, sizeof(Line));
        for(row = 0 ; row < term.row; row++)
                term.line[row] = calloc(term.col, sizeof(Glyph));
}

void
tscroll(void) {
        Line temp = term.line[term.top];
        int i;
        /* X stuff _before_ the line swapping (results in wrong line index) */
        xscroll();
        for(i = term.top; i < term.bot; i++)
                term.line[i] = term.line[i+1];
        memset(temp, 0, sizeof(Glyph) * term.col);
        term.line[term.bot] = temp;
}

void
tnewline(void) {
        int y = term.c.y + 1;
        if(y > term.bot)
                tscroll(), y = term.bot;
        tmoveto(0, y);
}

int
escaddc(char c) {
        escseq.buf[escseq.len++] = c;
        if(escfinal(c) || escseq.len >= ESCSIZ) {
                escparse(), eschandle();
                return 0;
        }
        return 1;
}

void
escparse(void) {
        /* int noarg = 1; */
        char *p = escseq.buf;

        escseq.narg = 0;
        switch(escseq.pre = *p++) {
        case '[': /* CSI */
                if(*p == '?')
                        escseq.priv = 1, p++;

                while(p < escseq.buf+escseq.len) {
                        while(isdigit(*p)) {
                                escseq.arg[escseq.narg] *= 10;
                                escseq.arg[escseq.narg] += *(p++) - '0'/*, noarg = 0 */;
                        }
                        if(*p == ';')
                                escseq.narg++, p++;
                        else {
                                escseq.mode = *p;
                                escseq.narg++;
                                return;
                        }
                }
                break;
        case '(':
                /* XXX: graphic character set */
                break;
        }
}

void
tmoveto(int x, int y) {
        term.c.x = x < 0 ? 0 : x >= term.col ? term.col-1 : x;
        term.c.y = y < 0 ? 0 : y >= term.row ? term.row-1 : y;
}

void
tcursor(int dir) {
        int xf = term.c.x, yf = term.c.y;

        switch(dir) {
        case CSup:
                yf--;
                break;
        case CSdown:
                yf++;
                break;
        case CSleft:
                xf--;
                if(xf < 0) {
                        xf = term.col-1, yf--;
                        if(yf < term.top)
                                yf = term.top, xf = 0;
                }
                break;
        case CSright:
                xf++;
                if(xf >= term.col) {
                        xf = 0, yf++;
                        if(yf > term.bot)
                                yf = term.bot, tscroll();
                }
                break;
        }
        tmoveto(xf, yf);
}

void
tsetchar(char c) {
        term.line[term.c.y][term.c.x] = term.c.attr;
        term.line[term.c.y][term.c.x].c = c;
        term.line[term.c.y][term.c.x].state |= CRset | CRupdate;
}

void
tclearregion(int x1, int y1, int x2, int y2) {
        int x, y;

        LIMIT(x1, 0, term.col-1);
        LIMIT(x2, 0, term.col-1);
        LIMIT(y1, 0, term.row-1);
        LIMIT(y2, 0, term.row-1);

        /* XXX: could be optimized */
        for(x = x1; x <= x2; x++)
                for(y = y1; y <= y2; y++)
                        memset(&term.line[y][x], 0, sizeof(Glyph));

        xclear(x1, y1, x2, y2);
}

void
tdeletechar(int n) {
        int src = term.c.x + n;
        int dst = term.c.x;
        int size = term.col - src;

        if(src >= term.col) {
                tclearregion(term.c.x, term.c.y, term.col-1, term.c.y);
                return;
        }
        memmove(&term.line[term.c.y][dst], &term.line[term.c.y][src], size * sizeof(Glyph));
        tclearregion(term.col-size, term.c.y, term.col-1, term.c.y);
}

void
tinsertblank(int n) {
        int src = term.c.x;
        int dst = src + n;
        int size = term.col - n - src;

        if(dst >= term.col) {
                tclearregion(term.c.x, term.c.y, term.col-1, term.c.y);
                return;
        }
        memmove(&term.line[term.c.y][dst], &term.line[term.c.y][src], size * sizeof(Glyph));
        tclearregion(src, term.c.y, dst, term.c.y);
}

void
tsetlinestate(int n, int state) {
        int i;
        for(i = 0; i < term.col; i++)
                term.line[n][i].state |= state;
}

void
tinsertblankline (int n) {
        int i;
        Line blank;
        int bot = term.bot;

        if(term.c.y > term.bot)
                bot = term.row - 1;
        else if(term.c.y < term.top)
                bot = term.top - 1;
        if(term.c.y + n >= bot) {
                tclearregion(0, term.c.y, term.col-1, bot);
                return;
        }
        for(i = bot; i >= term.c.y+n; i--) {
                /* swap deleted line <-> blanked line */
                blank = term.line[i];
                term.line[i] = term.line[i-n];
                term.line[i-n] = blank;
                /* blank it */
                memset(blank, 0, term.col * sizeof(Glyph));
                tsetlinestate(i, CRupdate);
                tsetlinestate(i-n, CRupdate);
        }
}

void
tdeleteline(int n) {
        int i;
        Line blank;
        int bot = term.bot;

        if(term.c.y > term.bot)
                bot = term.row - 1;
        else if(term.c.y < term.top)
                bot = term.top - 1;
        if(term.c.y + n >= bot) {
                tclearregion(0, term.c.y, term.col-1, bot);
                return;
        }
        for(i = term.c.y; i <= bot-n; i++) {
                /* swap deleted line <-> blanked line */
                blank = term.line[i];
                term.line[i] = term.line[i+n];
                term.line[i+n] = blank;
                /* blank it */
                memset(blank, 0, term.col * sizeof(Glyph));
                tsetlinestate(i, CRupdate);
                tsetlinestate(i-n, CRupdate);
        }
}

void
tsetattr(int *attr, int l) {
        int i;

        for(i = 0; i < l; i++) {
                switch(attr[i]) {
                case 0:
                        memset(&term.c.attr, 0, sizeof(term.c.attr));
                        term.c.attr.fg = DefaultFG;
                        term.c.attr.bg = DefaultBG;
                        break;
                case 1:
                        term.c.attr.mode |= ATbold;      
                        break;
                case 4: 
                        term.c.attr.mode |= ATunderline;
                        break;
                case 7: 
                        term.c.attr.mode |= ATreverse;  
                        break;
                case 8:
                        term.c.hidden = CShide;
                        break;
                case 22: 
                        term.c.attr.mode &= ~ATbold;  
                        break;
                case 24: 
                        term.c.attr.mode &= ~ATunderline;
                        break;
                case 27: 
                        term.c.attr.mode &= ~ATreverse;  
                        break;
                case 39:
                        term.c.attr.fg = DefaultFG;
                        break;
                case 49:
                        term.c.attr.fg = DefaultBG;
                        break;
                default:
                        if(BETWEEN(attr[i], 30, 37))
                                term.c.attr.fg = attr[i] - 30;
                        else if(BETWEEN(attr[i], 40, 47))
                                term.c.attr.bg = attr[i] - 40;
                        break;
                }
        }
}

void
tsetscroll(int t, int b) {
        int temp;

        LIMIT(t, 0, term.row-1);
        LIMIT(b, 0, term.row-1);
        if(t > b) {
                temp = t;
                t = b;
                b = temp;
        }
        term.top = t;
        term.bot = b;    
}

void
eschandle(void) {
        switch(escseq.pre) {
        default:
                goto unknown_seq;
        case '[':
                switch(escseq.mode) {
                default:
                unknown_seq:
                        fprintf(stderr, "erresc: unknown sequence\n");
                        escdump();
                        break;
                case '@': /* Insert <n> blank char */
                        DEFAULT(escseq.arg[0], 1);
                        tinsertblank(escseq.arg[0]);
                        break;
                case 'A': /* Cursor <n> Up */
                case 'e':
                        DEFAULT(escseq.arg[0], 1);
                        tmoveto(term.c.x, term.c.y-escseq.arg[0]);
                        break;
                case 'B': /* Cursor <n> Down */
                        DEFAULT(escseq.arg[0], 1);
                        tmoveto(term.c.x, term.c.y+escseq.arg[0]);
                        break;
                case 'C': /* Cursor <n> Forward */
                case 'a':
                        DEFAULT(escseq.arg[0], 1);
                        tmoveto(term.c.x+escseq.arg[0], term.c.y);
                        break;
                case 'D': /* Cursor <n> Backward */
                        DEFAULT(escseq.arg[0], 1);
                        tmoveto(term.c.x-escseq.arg[0], term.c.y);
                        break;
                case 'E': /* Cursor <n> Down and first col */
                        DEFAULT(escseq.arg[0], 1);
                        tmoveto(0, term.c.y+escseq.arg[0]);
                        break;
                case 'F': /* Cursor <n> Up and first col */
                        DEFAULT(escseq.arg[0], 1);
                        tmoveto(0, term.c.y-escseq.arg[0]);
                        break;
                case 'G': /* Move to <col> */
                case '`':
                        DEFAULT(escseq.arg[0], 1);
                        tmoveto(escseq.arg[0]-1, term.c.y);
                        break;
                case 'H': /* Move to <row> <col> */
                case 'f':
                        DEFAULT(escseq.arg[0], 1);
                        DEFAULT(escseq.arg[1], 1);
                        tmoveto(escseq.arg[1]-1, escseq.arg[0]-1);
                        break;
                case 'J': /* Clear screen */
                        switch(escseq.arg[0]) {
                        case 0: /* below */
                                tclearregion(term.c.x, term.c.y, term.col-1, term.row-1);
                                break;
                        case 1: /* above */
                                tclearregion(0, 0, term.c.x, term.c.y);
                                break;
                        case 2: /* all */
                                tclearregion(0, 0, term.col-1, term.row-1);
                                break;                            
                        }
                        break;
                case 'K': /* Clear line */
                        switch(escseq.arg[0]) {
                        case 0: /* right */
                                tclearregion(term.c.x, term.c.y, term.col-1, term.c.y);
                                break;
                        case 1: /* left */
                                tclearregion(0, term.c.y, term.c.x, term.c.y);
                                break;
                        case 2: /* all */
                                tclearregion(0, term.c.y, term.col-1, term.c.y);
                                break;
                        }
                        break;
                case 'L': /* Insert <n> blank lines */
                        DEFAULT(escseq.arg[0], 1);
                        tinsertblankline(escseq.arg[0]);
                        break;
                case 'l':
                        if(escseq.priv && escseq.arg[0] == 25)
                                term.c.hidden = 1;
                        break;
                case 'M': /* Delete <n> lines */
                        DEFAULT(escseq.arg[0], 1);
                        tdeleteline(escseq.arg[0]);
                        break;
                case 'P': /* Delete <n> char */
                        DEFAULT(escseq.arg[0], 1);
                        tdeletechar(escseq.arg[0]);
                        break;
                case 'd': /* Move to <row> */
                        DEFAULT(escseq.arg[0], 1);
                        tmoveto(term.c.x, escseq.arg[0]-1);
                        break;
                case 'h': /* Set terminal mode */
                        if(escseq.priv && escseq.arg[0] == 25)
                                term.c.hidden = 0;
                        break;
                case 'm': /* Terminal attribute (color) */
                        tsetattr(escseq.arg, escseq.narg);
                        break;
                case 'r':
                        if(escseq.priv)
                                ;
                        else {
                                DEFAULT(escseq.arg[0], 1);
                                DEFAULT(escseq.arg[1], term.row);
                                tsetscroll(escseq.arg[0]-1, escseq.arg[1]-1);
                        }
                        break;
                case 's': /* Save cursor position */
                        tcpos(CSsave);
                        break;
                case 'u': /* Load cursor position */
                        tcpos(CSload);
                        break;
                }
                break;
        }
}

void
escdump(void) { 
        int i;
        printf("rawbuf  : %s\n", escseq.buf);
        printf("prechar : %c\n", escseq.pre);
        printf("private : %c\n", escseq.priv ? '?' : ' ');
        printf("narg    : %d\n", escseq.narg);
        if(escseq.narg)
                for(i = 0; i < escseq.narg; i++)
                        printf("\targ %d = %d\n", i, escseq.arg[i]);
        printf("mode    : %c\n", escseq.mode);
}

void
escreset(void) {
        memset(&escseq, 0, sizeof(escseq));
}

void
tputtab(void) {
        int space = TAB - term.c.x % TAB;
        
        if(term.c.x + space >= term.col)
                space--;
        
        for(; space > 0; space--)
                tcursor(CSright);
}

void
tputc(char c) {
        static int inesc = 0;
#if 0
        dump(c);
#endif  
        /* start of escseq */
        if(c == '\033')
                escreset(), inesc = 1;
        else if(inesc) {
                inesc = escaddc(c);
        } /* normal char */ 
        else switch(c) { 
                default:
                        tsetchar(c);
                        tcursor(CSright);
                        break;
                case '\t':
                        tputtab();
                        break;
                case '\b':
                        tcursor(CSleft);
                        break;
                case '\r':
                        tmoveto(0, term.c.y);
                        break;
                case '\n':
                        tnewline();
                        break;
                case '\a':
                        xbell();
                        break;
        }
}

void
tputs(char *s, int len) { 
        for(; len > 0; len--)
                tputc(*s++);
}

void
tresize(int col, int row) {
        int i;
        Line *line;
        int minrow = MIN(row, term.row);
        int mincol = MIN(col, term.col);

        if(col < 1 || row < 1)
                return;
        /* alloc */
        line = calloc(row, sizeof(Line));
        for(i = 0 ; i < row; i++)
                line[i] = calloc(col, sizeof(Glyph));
        /* copy */
        for(i = 0 ; i < minrow; i++)
                memcpy(line[i], term.line[i], mincol * sizeof(Glyph));
        /* free */
        for(i = 0; i < term.row; i++)
                free(term.line[i]);
        free(term.line);
        
        LIMIT(term.c.x, 0, col-1);
        LIMIT(term.c.y, 0, row-1);
        LIMIT(term.top, 0, row-1);
        LIMIT(term.bot, 0, row-1);
        
        term.bot = row-1;
        term.line = line;
        term.col = col, term.row = row;
}

unsigned long
xgetcol(const char *s) {
        XColor color;
        Colormap cmap = DefaultColormap(xw.dis, xw.scr);

        if(!XAllocNamedColor(xw.dis, cmap, s, &color, &color)) {
                color.pixel = WhitePixel(xw.dis, xw.scr);
                fprintf(stderr, "Could not allocate color '%s'\n", s);
        }
        return color.pixel;
}

void
xclear(int x1, int y1, int x2, int y2) {
        XClearArea(xw.dis, xw.win, 
                        x1 * xw.cw, y1 * xw.ch, 
                        (x2-x1+1) * xw.cw, (y2-y1+1) * xw.ch, 
                        False);
}

void
xscroll(void) {
        int srcy = (term.top+1) * xw.ch;
        int dsty = term.top * xw.ch;
        int height = (term.bot-term.top) * xw.ch;

        xcursor(CShide);
        XCopyArea(xw.dis, xw.win, xw.win, dc.gc, 0, srcy, xw.w, height, 0, dsty);
        xclear(0, term.bot, term.col-1, term.bot);
}

void
xinit(void) {
        XGCValues values;
        unsigned long valuemask;
        XClassHint chint;
        XWMHints wmhint;
        XSizeHints shint;
        char *args[] = {NULL};
        int i;

        xw.dis = XOpenDisplay(NULL);
        xw.scr = XDefaultScreen(xw.dis);
        if(!xw.dis)
                die("Can't open display\n");
        
        /* font */
        if(!(dc.font = XLoadQueryFont(xw.dis, FONT)))
                die("Can't load font %s\n", FONT);

        xw.cw = dc.font->max_bounds.rbearing - dc.font->min_bounds.lbearing;
        xw.ch = dc.font->ascent + dc.font->descent + LINESPACE;

        /* colors */
        for(i = 0; i < LEN(colorname); i++)
                dc.col[i] = xgetcol(colorname[i]);

        term.c.attr.fg = DefaultFG;
        term.c.attr.bg = DefaultBG;
        term.c.attr.mode = ATnone;
        /* windows */
        xw.h = term.row * xw.ch;
        xw.w = term.col * xw.cw;
        /* XXX: this BORDER is useless after the first resize, handle it in xdraws() */
        xw.win = XCreateSimpleWindow(xw.dis, XRootWindow(xw.dis, xw.scr), 0, 0,
                        xw.w, xw.h, BORDER, 
                        dc.col[DefaultBG],
                        dc.col[DefaultBG]);
        /* gc */
        values.foreground = XWhitePixel(xw.dis, xw.scr);
        values.font = dc.font->fid;
        valuemask = GCForeground | GCFont;
        dc.gc = XCreateGC(xw.dis, xw.win, valuemask, &values);
        XMapWindow(xw.dis, xw.win);
        /* wm stuff */
        chint.res_name = TNAME, chint.res_class = TNAME;
        wmhint.input = 1, wmhint.flags = InputHint;
        shint.height_inc = xw.ch, shint.width_inc = xw.cw;
        shint.height = xw.h, shint.width = xw.w;
        shint.flags = PSize | PResizeInc;
        XSetWMProperties(xw.dis, xw.win, NULL, NULL, &args[0], 0, &shint, &wmhint, &chint);
        XStoreName(xw.dis, xw.win, TNAME);
        XSync(xw.dis, 0);
}

void
xdrawc(int x, int y, Glyph g) {
        XRectangle r = { x * xw.cw, y * xw.ch, xw.cw, xw.ch };
        unsigned long xfg, xbg;

        /* reverse video */
        if(g.mode & ATreverse)
                xfg = dc.col[g.bg], xbg = dc.col[g.fg];
        else
                xfg = dc.col[g.fg], xbg = dc.col[g.bg];
        /* background */
        XSetForeground(xw.dis, dc.gc, xbg);
        XFillRectangles(xw.dis, xw.win, dc.gc, &r, 1);
        /* string */
        XSetForeground(xw.dis, dc.gc, xfg);
        XDrawString(xw.dis, xw.win, dc.gc, r.x, r.y+dc.font->ascent, &(g.c), 1);
        if(g.mode & ATbold)      /* XXX: bold hack (draw again at x+1) */
                XDrawString(xw.dis, xw.win, dc.gc, r.x+1, r.y+dc.font->ascent, &(g.c), 1);
        /* underline */
        if(g.mode & ATunderline) {
                r.y += dc.font->ascent + 1;
                XDrawLine(xw.dis, xw.win, dc.gc, r.x, r.y, r.x+r.width-1, r.y);
        }
}

void
xcursor(int mode) {
        static int oldx = 0;
        static int oldy = 0;
        Glyph g = {' ', ATnone, DefaultBG, DefaultCS, 0};
        
        LIMIT(oldx, 0, term.col-1);
        LIMIT(oldy, 0, term.row-1);
        
        if(term.line[term.c.y][term.c.x].state & CRset)
                g.c = term.line[term.c.y][term.c.x].c;
        /* remove the old cursor */
        if(term.line[oldy][oldx].state & CRset)
                xdrawc(oldx, oldy, term.line[oldy][oldx]);
        else 
                xclear(oldx, oldy, oldx, oldy);
        /* draw the new one */
        if(mode == CSdraw) {
                xdrawc(term.c.x, term.c.y, g);
                oldx = term.c.x, oldy = term.c.y;
        }
}

void
draw(int redraw_all) {
        int x, y;
        int changed, set;

        if(redraw_all)
                XClearWindow(xw.dis, xw.win);

        /* XXX: drawing could be optimised */
        for(y = 0; y < term.row; y++) {
                for(x = 0; x < term.col; x++) {
                        changed = term.line[y][x].state & CRupdate;
                        set = term.line[y][x].state & CRset;
                        if(redraw_all || changed) {
                                term.line[y][x].state &= ~CRupdate;
                                if(set)
                                        xdrawc(x, y, term.line[y][x]);
                                else
                                        xclear(x, y, x, y);
                        }
                }
        }
        xcursor(CSdraw);
}

void
expose(XEvent *ev) {
        draw(SCredraw);
}

char *
kmap(KeySym k) {
        int i;
        for(i = 0; i < LEN(key); i++)
                if(key[i].k == k)
                        return (char*)key[i].s;
        return NULL;
}

void
kpress(XEvent *ev) {
        XKeyEvent *e = &ev->xkey;
        KeySym ksym;
        char buf[32];
        char *customkey;
        int len;
        int meta;
        int shift;

        meta  = e->state & Mod1Mask;
        shift = e->state & ShiftMask;
        len = XLookupString(e, buf, sizeof(buf), &ksym, NULL);

        if(customkey = kmap(ksym))
                ttywrite(customkey, strlen(customkey));
        else if(len > 0) {
                buf[sizeof(buf)-1] = '\0';
                if(meta && len == 1)
                        ttywrite("\033", 1);
                ttywrite(buf, len);
        } else
                switch(ksym) {
                case XK_Insert:
                        if(shift)
                                /* XXX: paste X clipboard */;
                        break;
                default:
                        fprintf(stderr, "errkey: %d\n", (int)ksym);
                        break;
                }
}

void
resize(XEvent *e) {
        int col, row;
        col = e->xconfigure.width / xw.cw;
        row = e->xconfigure.height / xw.ch;
        
        if(term.col != col || term.row != row) {
                tresize(col, row);
                ttyresize(col, row);
                xw.w = e->xconfigure.width;
                xw.h = e->xconfigure.height;
                draw(SCredraw);
        }
}

void
run(void) {
        XEvent ev;
        fd_set rfd;
        int xfd = XConnectionNumber(xw.dis);

        running = 1;
        XSelectInput(xw.dis, xw.win, ExposureMask | KeyPressMask | StructureNotifyMask);
        XResizeWindow(xw.dis, xw.win, xw.w , xw.h); /* fix resize bug in wmii (?) */

        while(running) {
                FD_ZERO(&rfd);
                FD_SET(cmdfd, &rfd);
                FD_SET(xfd, &rfd);
                if(select(MAX(xfd, cmdfd)+1, &rfd, NULL, NULL, NULL) == -1) {
                        if(errno == EINTR)
                                continue;
                        die("select failed: %s\n", SERRNO);
                }
                if(FD_ISSET(cmdfd, &rfd)) {
                        ttyread();
                        draw(SCupdate);
                }
                while(XPending(xw.dis)) {
                        XNextEvent(xw.dis, &ev);
                        if(handler[ev.type])
                                (handler[ev.type])(&ev);
                }
        }
}

int
main(int argc, char *argv[]) {
        if(argc == 2 && !strncmp("-v", argv[1], 3))
                die("st-" VERSION ", © 2009 st engineers\n");
        else if(argc != 1)
                die("usage: st [-v]\n");
        setlocale(LC_CTYPE, "");
        tnew(80, 24);
        ttynew();
        xinit();
        run();
        return 0;
}