st/st.c

/* See LICENSE for license details. */
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <pwd.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/types.h>
#include <sys/wait.h>
#include <termios.h>
#include <unistd.h>
#include <wchar.h>

#include "st.h"
#include "win.h"

#if   defined(__linux)
 #include <pty.h>
#elif defined(__OpenBSD__) || defined(__NetBSD__) || defined(__APPLE__)
 #include <util.h>
#elif defined(__FreeBSD__) || defined(__DragonFly__)
 #include <libutil.h>
#endif

/* Arbitrary sizes */
#define UTF_INVALID   0xFFFD
#define UTF_SIZ       4
#define ESC_BUF_SIZ   (128*UTF_SIZ)
#define ESC_ARG_SIZ   16
#define CAR_PER_ARG   4
#define STR_BUF_SIZ   ESC_BUF_SIZ
#define STR_ARG_SIZ   ESC_ARG_SIZ

/* macros */
#define IS_SET(flag)		((term.mode & (flag)) != 0)
#define ISCONTROLC0(c)		(BETWEEN(c, 0, 0x1f) || (c) == 0x7f)
#define ISCONTROLC1(c)		(BETWEEN(c, 0x80, 0x9f))
#define ISCONTROL(c)		(ISCONTROLC0(c) || ISCONTROLC1(c))
#define ISDELIM(u)		(u && wcschr(worddelimiters, u))

enum term_mode {
	MODE_WRAP        = 1 << 0,
	MODE_INSERT      = 1 << 1,
	MODE_ALTSCREEN   = 1 << 2,
	MODE_CRLF        = 1 << 3,
	MODE_ECHO        = 1 << 4,
	MODE_PRINT       = 1 << 5,
	MODE_UTF8        = 1 << 6,
};

enum cursor_movement {
	CURSOR_SAVE,
	CURSOR_LOAD
};

enum cursor_state {
	CURSOR_DEFAULT  = 0,
	CURSOR_WRAPNEXT = 1,
	CURSOR_ORIGIN   = 2
};

enum charset {
	CS_GRAPHIC0,
	CS_GRAPHIC1,
	CS_UK,
	CS_USA,
	CS_MULTI,
	CS_GER,
	CS_FIN
};

enum escape_state {
	ESC_START      = 1,
	ESC_CSI        = 2,
	ESC_STR        = 4,  /* DCS, OSC, PM, APC */
	ESC_ALTCHARSET = 8,
	ESC_STR_END    = 16, /* a final string was encountered */
	ESC_TEST       = 32, /* Enter in test mode */
	ESC_UTF8       = 64,
};

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

typedef struct {
	int mode;
	int type;
	int snap;
	/*
	 * Selection variables:
	 * nb – normalized coordinates of the beginning of the selection
	 * ne – normalized coordinates of the end of the selection
	 * ob – original coordinates of the beginning of the selection
	 * oe – original coordinates of the end of the selection
	 */
	struct {
		int x, y;
	} nb, ne, ob, oe;

	int alt;
} Selection;

/* Internal representation of the screen */
typedef struct {
	int row;      /* nb row */
	int col;      /* nb col */
	Line *line;   /* screen */
	Line *alt;    /* alternate screen */
	int *dirty;   /* dirtyness of lines */
	TCursor c;    /* cursor */
	int ocx;      /* old cursor col */
	int ocy;      /* old cursor row */
	int top;      /* top    scroll limit */
	int bot;      /* bottom scroll limit */
	int mode;     /* terminal mode flags */
	int esc;      /* escape state flags */
	char trantbl[4]; /* charset table translation */
	int charset;  /* current charset */
	int icharset; /* selected charset for sequence */
	int *tabs;
	Rune lastc;   /* last printed char outside of sequence, 0 if control */
} Term;

/* CSI Escape sequence structs */
/* ESC '[' [[ [<priv>] <arg> [;]] <mode> [<mode>]] */
typedef struct {
	char buf[ESC_BUF_SIZ]; /* raw string */
	size_t len;            /* raw string length */
	char priv;
	int arg[ESC_ARG_SIZ];
	int narg;              /* nb of args */
	char mode[2];
	int carg[ESC_ARG_SIZ][CAR_PER_ARG]; /* colon args */
} CSIEscape;

/* STR Escape sequence structs */
/* ESC type [[ [<priv>] <arg> [;]] <mode>] ESC '\' */
typedef struct {
	char type;             /* ESC type ... */
	char *buf;             /* allocated raw string */
	size_t siz;            /* allocation size */
	size_t len;            /* raw string length */
	char *args[STR_ARG_SIZ];
	int narg;              /* nb of args */
} STREscape;

static void execsh(char *, char **);
static void stty(char **);
static void sigchld(int);
static void ttywriteraw(const char *, size_t);

static void csidump(void);
static void csihandle(void);
static void readcolonargs(char **, int, int[][CAR_PER_ARG]);
static void csiparse(void);
static void csireset(void);
static void osc_color_response(int, int, int);
static int eschandle(uchar);
static void strdump(void);
static void strhandle(void);
static void strparse(void);
static void strreset(void);

static void tprinter(char *, size_t);
static void tdumpsel(void);
static void tdumpline(int);
static void tdump(void);
static void tclearregion(int, int, int, int);
static void tcursor(int);
static void tdeletechar(int);
static void tdeleteline(int);
static void tinsertblank(int);
static void tinsertblankline(int);
static int tlinelen(int);
static void tmoveto(int, int);
static void tmoveato(int, int);
static void tnewline(int);
static void tputtab(int);
static void tputc(Rune);
static void treset(void);
static void tscrollup(int, int);
static void tscrolldown(int, int);
static void tsetattr(const int *, int);
static void tsetchar(Rune, const Glyph *, int, int);
static void tsetdirt(int, int);
static void tsetscroll(int, int);
static void tswapscreen(void);
static void tsetmode(int, int, const int *, int);
static int twrite(const char *, int, int);
static void tfulldirt(void);
static void tcontrolcode(uchar );
static void tdectest(char );
static void tdefutf8(char);
static int32_t tdefcolor(const int *, int *, int);
static void tdeftran(char);
static void tstrsequence(uchar);

static void drawregion(int, int, int, int);

static void selnormalize(void);
static void selscroll(int, int);
static void selsnap(int *, int *, int);

static size_t utf8decode(const char *, Rune *, size_t);
static Rune utf8decodebyte(char, size_t *);
static char utf8encodebyte(Rune, size_t);
static size_t utf8validate(Rune *, size_t);

static char *base64dec(const char *);
static char base64dec_getc(const char **);

static ssize_t xwrite(int, const char *, size_t);

/* Globals */
static Term term;
static Selection sel;
static CSIEscape csiescseq;
static STREscape strescseq;
static int iofd = 1;
static int cmdfd;
static pid_t pid;

static const uchar utfbyte[UTF_SIZ + 1] = {0x80,    0, 0xC0, 0xE0, 0xF0};
static const uchar utfmask[UTF_SIZ + 1] = {0xC0, 0x80, 0xE0, 0xF0, 0xF8};
static const Rune utfmin[UTF_SIZ + 1] = {       0,    0,  0x80,  0x800,  0x10000};
static const Rune utfmax[UTF_SIZ + 1] = {0x10FFFF, 0x7F, 0x7FF, 0xFFFF, 0x10FFFF};

#include <time.h>
static int su = 0;
struct timespec sutv;

static void
tsync_begin()
{
	clock_gettime(CLOCK_MONOTONIC, &sutv);
	su = 1;
}

static void
tsync_end()
{
	su = 0;
}

int
tinsync(uint timeout)
{
	struct timespec now;
	if (su && !clock_gettime(CLOCK_MONOTONIC, &now)
	       && TIMEDIFF(now, sutv) >= timeout)
		su = 0;
	return su;
}

ssize_t
xwrite(int fd, const char *s, size_t len)
{
	size_t aux = len;
	ssize_t r;

	while (len > 0) {
		r = write(fd, s, len);
		if (r < 0)
			return r;
		len -= r;
		s += r;
	}

	return aux;
}

void *
xmalloc(size_t len)
{
	void *p;

	if (!(p = malloc(len)))
		die("malloc: %s\n", strerror(errno));

	return p;
}

void *
xrealloc(void *p, size_t len)
{
	if ((p = realloc(p, len)) == NULL)
		die("realloc: %s\n", strerror(errno));

	return p;
}

char *
xstrdup(const char *s)
{
	char *p;

	if ((p = strdup(s)) == NULL)
		die("strdup: %s\n", strerror(errno));

	return p;
}

size_t
utf8decode(const char *c, Rune *u, size_t clen)
{
	size_t i, j, len, type;
	Rune udecoded;

	*u = UTF_INVALID;
	if (!clen)
		return 0;
	udecoded = utf8decodebyte(c[0], &len);
	if (!BETWEEN(len, 1, UTF_SIZ))
		return 1;
	for (i = 1, j = 1; i < clen && j < len; ++i, ++j) {
		udecoded = (udecoded << 6) | utf8decodebyte(c[i], &type);
		if (type != 0)
			return j;
	}
	if (j < len)
		return 0;
	*u = udecoded;
	utf8validate(u, len);

	return len;
}

Rune
utf8decodebyte(char c, size_t *i)
{
	for (*i = 0; *i < LEN(utfmask); ++(*i))
		if (((uchar)c & utfmask[*i]) == utfbyte[*i])
			return (uchar)c & ~utfmask[*i];

	return 0;
}

size_t
utf8encode(Rune u, char *c)
{
	size_t len, i;

	len = utf8validate(&u, 0);
	if (len > UTF_SIZ)
		return 0;

	for (i = len - 1; i != 0; --i) {
		c[i] = utf8encodebyte(u, 0);
		u >>= 6;
	}
	c[0] = utf8encodebyte(u, len);

	return len;
}

char
utf8encodebyte(Rune u, size_t i)
{
	return utfbyte[i] | (u & ~utfmask[i]);
}

size_t
utf8validate(Rune *u, size_t i)
{
	if (!BETWEEN(*u, utfmin[i], utfmax[i]) || BETWEEN(*u, 0xD800, 0xDFFF))
		*u = UTF_INVALID;
	for (i = 1; *u > utfmax[i]; ++i)
		;

	return i;
}

char
base64dec_getc(const char **src)
{
	while (**src && !isprint((unsigned char)**src))
		(*src)++;
	return **src ? *((*src)++) : '=';  /* emulate padding if string ends */
}

char *
base64dec(const char *src)
{
	size_t in_len = strlen(src);
	char *result, *dst;
	static const char base64_digits[256] = {
		[43] = 62, 0, 0, 0, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
		0, 0, 0, -1, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
		13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 0, 0, 0, 0,
		0, 0, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
		40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
	};

	if (in_len % 4)
		in_len += 4 - (in_len % 4);
	result = dst = xmalloc(in_len / 4 * 3 + 1);
	while (*src) {
		int a = base64_digits[(unsigned char) base64dec_getc(&src)];
		int b = base64_digits[(unsigned char) base64dec_getc(&src)];
		int c = base64_digits[(unsigned char) base64dec_getc(&src)];
		int d = base64_digits[(unsigned char) base64dec_getc(&src)];

		/* invalid input. 'a' can be -1, e.g. if src is "\n" (c-str) */
		if (a == -1 || b == -1)
			break;

		*dst++ = (a << 2) | ((b & 0x30) >> 4);
		if (c == -1)
			break;
		*dst++ = ((b & 0x0f) << 4) | ((c & 0x3c) >> 2);
		if (d == -1)
			break;
		*dst++ = ((c & 0x03) << 6) | d;
	}
	*dst = '\0';
	return result;
}

void
selinit(void)
{
	sel.mode = SEL_IDLE;
	sel.snap = 0;
	sel.ob.x = -1;
}

int
tlinelen(int y)
{
	int i = term.col;

	if (term.line[y][i - 1].mode & ATTR_WRAP)
		return i;

	while (i > 0 && term.line[y][i - 1].u == ' ')
		--i;

	return i;
}

void
selstart(int col, int row, int snap)
{
	selclear();
	sel.mode = SEL_EMPTY;
	sel.type = SEL_REGULAR;
	sel.alt = IS_SET(MODE_ALTSCREEN);
	sel.snap = snap;
	sel.oe.x = sel.ob.x = col;
	sel.oe.y = sel.ob.y = row;
	selnormalize();

	if (sel.snap != 0)
		sel.mode = SEL_READY;
	tsetdirt(sel.nb.y, sel.ne.y);
}

void
selextend(int col, int row, int type, int done)
{
	int oldey, oldex, oldsby, oldsey, oldtype;

	if (sel.mode == SEL_IDLE)
		return;
	if (done && sel.mode == SEL_EMPTY) {
		selclear();
		return;
	}

	oldey = sel.oe.y;
	oldex = sel.oe.x;
	oldsby = sel.nb.y;
	oldsey = sel.ne.y;
	oldtype = sel.type;

	sel.oe.x = col;
	sel.oe.y = row;
	selnormalize();
	sel.type = type;

	if (oldey != sel.oe.y || oldex != sel.oe.x || oldtype != sel.type || sel.mode == SEL_EMPTY)
		tsetdirt(MIN(sel.nb.y, oldsby), MAX(sel.ne.y, oldsey));

	sel.mode = done ? SEL_IDLE : SEL_READY;
}

void
selnormalize(void)
{
	int i;

	if (sel.type == SEL_REGULAR && sel.ob.y != sel.oe.y) {
		sel.nb.x = sel.ob.y < sel.oe.y ? sel.ob.x : sel.oe.x;
		sel.ne.x = sel.ob.y < sel.oe.y ? sel.oe.x : sel.ob.x;
	} else {
		sel.nb.x = MIN(sel.ob.x, sel.oe.x);
		sel.ne.x = MAX(sel.ob.x, sel.oe.x);
	}
	sel.nb.y = MIN(sel.ob.y, sel.oe.y);
	sel.ne.y = MAX(sel.ob.y, sel.oe.y);

	selsnap(&sel.nb.x, &sel.nb.y, -1);
	selsnap(&sel.ne.x, &sel.ne.y, +1);

	/* expand selection over line breaks */
	if (sel.type == SEL_RECTANGULAR)
		return;
	i = tlinelen(sel.nb.y);
	if (i < sel.nb.x)
		sel.nb.x = i;
	if (tlinelen(sel.ne.y) <= sel.ne.x)
		sel.ne.x = term.col - 1;
}

int
selected(int x, int y)
{
	if (sel.mode == SEL_EMPTY || sel.ob.x == -1 ||
			sel.alt != IS_SET(MODE_ALTSCREEN))
		return 0;

	if (sel.type == SEL_RECTANGULAR)
		return BETWEEN(y, sel.nb.y, sel.ne.y)
		    && BETWEEN(x, sel.nb.x, sel.ne.x);

	return BETWEEN(y, sel.nb.y, sel.ne.y)
	    && (y != sel.nb.y || x >= sel.nb.x)
	    && (y != sel.ne.y || x <= sel.ne.x);
}

void
selsnap(int *x, int *y, int direction)
{
	int newx, newy, xt, yt;
	int delim, prevdelim;
	const Glyph *gp, *prevgp;