vi: rearrange functions, no logic changes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
c319310404
commit
24bd350aaa
532
editors/vi.c
532
editors/vi.c
@ -483,7 +483,6 @@ struct globals {
|
||||
} while (0)
|
||||
|
||||
|
||||
static void edit_file(char *); // edit one file
|
||||
static void do_cmd(int); // execute a command
|
||||
static int next_tabstop(int);
|
||||
static void sync_cursor(char *, int *, int *); // synchronize the screen cursor to dot
|
||||
@ -527,7 +526,6 @@ static uintptr_t text_hole_make(char *, int); // at "p", make a 'size' byte hole
|
||||
#define yank_delete(a,b,c,d,e) yank_delete(a,b,c,d)
|
||||
#endif
|
||||
static char *yank_delete(char *, char *, int, int, int); // yank text[] into register then delete
|
||||
static void show_help(void); // display some help info
|
||||
static void rawmode(void); // set "raw" mode on tty
|
||||
static void cookmode(void); // return to "cooked" mode on tty
|
||||
// sleep for 'h' 1/100 seconds, return 1/0 if stdin is (ready for read)/(not ready)
|
||||
@ -610,96 +608,44 @@ static void crash_test();
|
||||
static int crashme = 0;
|
||||
#endif
|
||||
|
||||
static void show_help(void)
|
||||
{
|
||||
puts("These features are available:"
|
||||
#if ENABLE_FEATURE_VI_SEARCH
|
||||
"\n\tPattern searches with / and ?"
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_DOT_CMD
|
||||
"\n\tLast command repeat with ."
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_YANKMARK
|
||||
"\n\tLine marking with 'x"
|
||||
"\n\tNamed buffers with \"x"
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_READONLY
|
||||
//not implemented: "\n\tReadonly if vi is called as \"view\""
|
||||
//redundant: usage text says this too: "\n\tReadonly with -R command line arg"
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_SET
|
||||
"\n\tSome colon mode commands with :"
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_SETOPTS
|
||||
"\n\tSettable options with \":set\""
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_USE_SIGNALS
|
||||
"\n\tSignal catching- ^C"
|
||||
"\n\tJob suspend and resume with ^Z"
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_WIN_RESIZE
|
||||
"\n\tAdapt to window re-sizes"
|
||||
#endif
|
||||
);
|
||||
}
|
||||
|
||||
static void write1(const char *out)
|
||||
{
|
||||
fputs(out, stdout);
|
||||
}
|
||||
|
||||
int vi_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
||||
int vi_main(int argc, char **argv)
|
||||
{
|
||||
int c;
|
||||
|
||||
INIT_G();
|
||||
|
||||
#if ENABLE_FEATURE_VI_UNDO
|
||||
/* undo_stack_tail = NULL; - already is */
|
||||
#if ENABLE_FEATURE_VI_UNDO_QUEUE
|
||||
undo_queue_state = UNDO_EMPTY;
|
||||
/* undo_q = 0; - already is */
|
||||
#endif
|
||||
#endif
|
||||
|
||||
#if ENABLE_FEATURE_VI_CRASHME
|
||||
srand((long) getpid());
|
||||
#endif
|
||||
#ifdef NO_SUCH_APPLET_YET
|
||||
// if we aren't "vi", we are "view"
|
||||
if (ENABLE_FEATURE_VI_READONLY && applet_name[2]) {
|
||||
SET_READONLY_MODE(readonly_mode);
|
||||
}
|
||||
#endif
|
||||
|
||||
// autoindent is not default in vim 7.3
|
||||
vi_setops = /*VI_AUTOINDENT |*/ VI_SHOWMATCH | VI_IGNORECASE;
|
||||
// 1- process $HOME/.exrc file (not inplemented yet)
|
||||
// 2- process EXINIT variable from environment
|
||||
// 3- process command line args
|
||||
#if ENABLE_FEATURE_VI_COLON
|
||||
{
|
||||
char *p = getenv("EXINIT");
|
||||
if (p && *p)
|
||||
initial_cmds[0] = xstrndup(p, MAX_INPUT_LEN);
|
||||
}
|
||||
#endif
|
||||
while ((c = getopt(argc, argv, "hCRH" IF_FEATURE_VI_COLON("c:"))) != -1) {
|
||||
switch (c) {
|
||||
#if ENABLE_FEATURE_VI_CRASHME
|
||||
case 'C':
|
||||
crashme = 1;
|
||||
break;
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_READONLY
|
||||
case 'R': // Read-only flag
|
||||
SET_READONLY_MODE(readonly_mode);
|
||||
break;
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_COLON
|
||||
case 'c': // cmd line vi command
|
||||
if (*optarg)
|
||||
initial_cmds[initial_cmds[0] != NULL] = xstrndup(optarg, MAX_INPUT_LEN);
|
||||
break;
|
||||
#endif
|
||||
case 'H':
|
||||
show_help();
|
||||
// fall through
|
||||
default:
|
||||
bb_show_usage();
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
|
||||
// The argv array can be used by the ":next" and ":rewind" commands
|
||||
argv += optind;
|
||||
argc -= optind;
|
||||
|
||||
//----- This is the main file handling loop --------------
|
||||
save_argc = argc;
|
||||
optind = 0;
|
||||
// "Save cursor, use alternate screen buffer, clear screen"
|
||||
write1(ESC"[?1049h");
|
||||
while (1) {
|
||||
edit_file(argv[optind]); // param might be NULL
|
||||
if (++optind >= argc)
|
||||
break;
|
||||
}
|
||||
// "Use normal screen buffer, restore cursor"
|
||||
write1(ESC"[?1049l");
|
||||
//-----------------------------------------------------------
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* read text from file or create an empty buf */
|
||||
/* will also update current_filename */
|
||||
static int init_text_buffer(char *fn)
|
||||
@ -748,153 +694,6 @@ static ALWAYS_INLINE int query_screen_dimensions(void)
|
||||
}
|
||||
#endif
|
||||
|
||||
static void edit_file(char *fn)
|
||||
{
|
||||
#if ENABLE_FEATURE_VI_YANKMARK
|
||||
#define cur_line edit_file__cur_line
|
||||
#endif
|
||||
int c;
|
||||
#if ENABLE_FEATURE_VI_USE_SIGNALS
|
||||
int sig;
|
||||
#endif
|
||||
|
||||
editing = 1; // 0 = exit, 1 = one file, 2 = multiple files
|
||||
rawmode();
|
||||
rows = 24;
|
||||
columns = 80;
|
||||
IF_FEATURE_VI_ASK_TERMINAL(G.get_rowcol_error =) query_screen_dimensions();
|
||||
#if ENABLE_FEATURE_VI_ASK_TERMINAL
|
||||
if (G.get_rowcol_error /* TODO? && no input on stdin */) {
|
||||
uint64_t k;
|
||||
write1(ESC"[999;999H" ESC"[6n");
|
||||
fflush_all();
|
||||
k = read_key(STDIN_FILENO, readbuffer, /*timeout_ms:*/ 100);
|
||||
if ((int32_t)k == KEYCODE_CURSOR_POS) {
|
||||
uint32_t rc = (k >> 32);
|
||||
columns = (rc & 0x7fff);
|
||||
if (columns > MAX_SCR_COLS)
|
||||
columns = MAX_SCR_COLS;
|
||||
rows = ((rc >> 16) & 0x7fff);
|
||||
if (rows > MAX_SCR_ROWS)
|
||||
rows = MAX_SCR_ROWS;
|
||||
}
|
||||
}
|
||||
#endif
|
||||
new_screen(rows, columns); // get memory for virtual screen
|
||||
init_text_buffer(fn);
|
||||
|
||||
#if ENABLE_FEATURE_VI_YANKMARK
|
||||
YDreg = 26; // default Yank/Delete reg
|
||||
// Ureg = 27; - const // hold orig line for "U" cmd
|
||||
mark[26] = mark[27] = text; // init "previous context"
|
||||
#endif
|
||||
|
||||
last_forward_char = last_input_char = '\0';
|
||||
crow = 0;
|
||||
ccol = 0;
|
||||
|
||||
#if ENABLE_FEATURE_VI_USE_SIGNALS
|
||||
signal(SIGWINCH, winch_handler);
|
||||
signal(SIGTSTP, tstp_handler);
|
||||
sig = sigsetjmp(restart, 1);
|
||||
if (sig != 0) {
|
||||
screenbegin = dot = text;
|
||||
}
|
||||
// int_handler() can jump to "restart",
|
||||
// must install handler *after* initializing "restart"
|
||||
signal(SIGINT, int_handler);
|
||||
#endif
|
||||
|
||||
cmd_mode = 0; // 0=command 1=insert 2='R'eplace
|
||||
cmdcnt = 0;
|
||||
tabstop = 8;
|
||||
offset = 0; // no horizontal offset
|
||||
c = '\0';
|
||||
#if ENABLE_FEATURE_VI_DOT_CMD
|
||||
free(ioq_start);
|
||||
ioq = ioq_start = NULL;
|
||||
lmc_len = 0;
|
||||
adding2q = 0;
|
||||
#endif
|
||||
|
||||
#if ENABLE_FEATURE_VI_COLON
|
||||
{
|
||||
char *p, *q;
|
||||
int n = 0;
|
||||
|
||||
while ((p = initial_cmds[n]) != NULL) {
|
||||
do {
|
||||
q = p;
|
||||
p = strchr(q, '\n');
|
||||
if (p)
|
||||
while (*p == '\n')
|
||||
*p++ = '\0';
|
||||
if (*q)
|
||||
colon(q);
|
||||
} while (p);
|
||||
free(initial_cmds[n]);
|
||||
initial_cmds[n] = NULL;
|
||||
n++;
|
||||
}
|
||||
}
|
||||
#endif
|
||||
redraw(FALSE); // dont force every col re-draw
|
||||
//------This is the main Vi cmd handling loop -----------------------
|
||||
while (editing > 0) {
|
||||
#if ENABLE_FEATURE_VI_CRASHME
|
||||
if (crashme > 0) {
|
||||
if ((end - text) > 1) {
|
||||
crash_dummy(); // generate a random command
|
||||
} else {
|
||||
crashme = 0;
|
||||
string_insert(text, "\n\n##### Ran out of text to work on. #####\n\n", NO_UNDO); // insert the string
|
||||
dot = text;
|
||||
refresh(FALSE);
|
||||
}
|
||||
}
|
||||
#endif
|
||||
last_input_char = c = get_one_char(); // get a cmd from user
|
||||
#if ENABLE_FEATURE_VI_YANKMARK
|
||||
// save a copy of the current line- for the 'U" command
|
||||
if (begin_line(dot) != cur_line) {
|
||||
cur_line = begin_line(dot);
|
||||
text_yank(begin_line(dot), end_line(dot), Ureg);
|
||||
}
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_DOT_CMD
|
||||
// These are commands that change text[].
|
||||
// Remember the input for the "." command
|
||||
if (!adding2q && ioq_start == NULL
|
||||
&& cmd_mode == 0 // command mode
|
||||
&& c > '\0' // exclude NUL and non-ASCII chars
|
||||
&& c < 0x7f // (Unicode and such)
|
||||
&& strchr(modifying_cmds, c)
|
||||
) {
|
||||
start_new_cmd_q(c);
|
||||
}
|
||||
#endif
|
||||
do_cmd(c); // execute the user command
|
||||
|
||||
// poll to see if there is input already waiting. if we are
|
||||
// not able to display output fast enough to keep up, skip
|
||||
// the display update until we catch up with input.
|
||||
if (!readbuffer[0] && mysleep(0) == 0) {
|
||||
// no input pending - so update output
|
||||
refresh(FALSE);
|
||||
show_status_line();
|
||||
}
|
||||
#if ENABLE_FEATURE_VI_CRASHME
|
||||
if (crashme > 0)
|
||||
crash_test(); // test editor variables
|
||||
#endif
|
||||
}
|
||||
//-------------------------------------------------------------------
|
||||
|
||||
go_bottom_and_clear_to_eol();
|
||||
cookmode();
|
||||
#undef cur_line
|
||||
}
|
||||
|
||||
//----- The Colon commands -------------------------------------
|
||||
#if ENABLE_FEATURE_VI_COLON
|
||||
static char *get_one_address(char *p, int *addr) // get colon addr, if present
|
||||
@ -2589,39 +2388,6 @@ static char *yank_delete(char *start, char *stop, int dist, int yf, int undo)
|
||||
return p;
|
||||
}
|
||||
|
||||
static void show_help(void)
|
||||
{
|
||||
puts("These features are available:"
|
||||
#if ENABLE_FEATURE_VI_SEARCH
|
||||
"\n\tPattern searches with / and ?"
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_DOT_CMD
|
||||
"\n\tLast command repeat with ."
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_YANKMARK
|
||||
"\n\tLine marking with 'x"
|
||||
"\n\tNamed buffers with \"x"
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_READONLY
|
||||
//not implemented: "\n\tReadonly if vi is called as \"view\""
|
||||
//redundant: usage text says this too: "\n\tReadonly with -R command line arg"
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_SET
|
||||
"\n\tSome colon mode commands with :"
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_SETOPTS
|
||||
"\n\tSettable options with \":set\""
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_USE_SIGNALS
|
||||
"\n\tSignal catching- ^C"
|
||||
"\n\tJob suspend and resume with ^Z"
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_WIN_RESIZE
|
||||
"\n\tAdapt to window re-sizes"
|
||||
#endif
|
||||
);
|
||||
}
|
||||
|
||||
#if ENABLE_FEATURE_VI_DOT_CMD
|
||||
static void start_new_cmd_q(char c)
|
||||
{
|
||||
@ -4495,3 +4261,235 @@ static void crash_test()
|
||||
}
|
||||
}
|
||||
#endif
|
||||
|
||||
static void edit_file(char *fn)
|
||||
{
|
||||
#if ENABLE_FEATURE_VI_YANKMARK
|
||||
#define cur_line edit_file__cur_line
|
||||
#endif
|
||||
int c;
|
||||
#if ENABLE_FEATURE_VI_USE_SIGNALS
|
||||
int sig;
|
||||
#endif
|
||||
|
||||
editing = 1; // 0 = exit, 1 = one file, 2 = multiple files
|
||||
rawmode();
|
||||
rows = 24;
|
||||
columns = 80;
|
||||
IF_FEATURE_VI_ASK_TERMINAL(G.get_rowcol_error =) query_screen_dimensions();
|
||||
#if ENABLE_FEATURE_VI_ASK_TERMINAL
|
||||
if (G.get_rowcol_error /* TODO? && no input on stdin */) {
|
||||
uint64_t k;
|
||||
write1(ESC"[999;999H" ESC"[6n");
|
||||
fflush_all();
|
||||
k = read_key(STDIN_FILENO, readbuffer, /*timeout_ms:*/ 100);
|
||||
if ((int32_t)k == KEYCODE_CURSOR_POS) {
|
||||
uint32_t rc = (k >> 32);
|
||||
columns = (rc & 0x7fff);
|
||||
if (columns > MAX_SCR_COLS)
|
||||
columns = MAX_SCR_COLS;
|
||||
rows = ((rc >> 16) & 0x7fff);
|
||||
if (rows > MAX_SCR_ROWS)
|
||||
rows = MAX_SCR_ROWS;
|
||||
}
|
||||
}
|
||||
#endif
|
||||
new_screen(rows, columns); // get memory for virtual screen
|
||||
init_text_buffer(fn);
|
||||
|
||||
#if ENABLE_FEATURE_VI_YANKMARK
|
||||
YDreg = 26; // default Yank/Delete reg
|
||||
// Ureg = 27; - const // hold orig line for "U" cmd
|
||||
mark[26] = mark[27] = text; // init "previous context"
|
||||
#endif
|
||||
|
||||
last_forward_char = last_input_char = '\0';
|
||||
crow = 0;
|
||||
ccol = 0;
|
||||
|
||||
#if ENABLE_FEATURE_VI_USE_SIGNALS
|
||||
signal(SIGWINCH, winch_handler);
|
||||
signal(SIGTSTP, tstp_handler);
|
||||
sig = sigsetjmp(restart, 1);
|
||||
if (sig != 0) {
|
||||
screenbegin = dot = text;
|
||||
}
|
||||
// int_handler() can jump to "restart",
|
||||
// must install handler *after* initializing "restart"
|
||||
signal(SIGINT, int_handler);
|
||||
#endif
|
||||
|
||||
cmd_mode = 0; // 0=command 1=insert 2='R'eplace
|
||||
cmdcnt = 0;
|
||||
tabstop = 8;
|
||||
offset = 0; // no horizontal offset
|
||||
c = '\0';
|
||||
#if ENABLE_FEATURE_VI_DOT_CMD
|
||||
free(ioq_start);
|
||||
ioq = ioq_start = NULL;
|
||||
lmc_len = 0;
|
||||
adding2q = 0;
|
||||
#endif
|
||||
|
||||
#if ENABLE_FEATURE_VI_COLON
|
||||
{
|
||||
char *p, *q;
|
||||
int n = 0;
|
||||
|
||||
while ((p = initial_cmds[n]) != NULL) {
|
||||
do {
|
||||
q = p;
|
||||
p = strchr(q, '\n');
|
||||
if (p)
|
||||
while (*p == '\n')
|
||||
*p++ = '\0';
|
||||
if (*q)
|
||||
colon(q);
|
||||
} while (p);
|
||||
free(initial_cmds[n]);
|
||||
initial_cmds[n] = NULL;
|
||||
n++;
|
||||
}
|
||||
}
|
||||
#endif
|
||||
redraw(FALSE); // dont force every col re-draw
|
||||
//------This is the main Vi cmd handling loop -----------------------
|
||||
while (editing > 0) {
|
||||
#if ENABLE_FEATURE_VI_CRASHME
|
||||
if (crashme > 0) {
|
||||
if ((end - text) > 1) {
|
||||
crash_dummy(); // generate a random command
|
||||
} else {
|
||||
crashme = 0;
|
||||
string_insert(text, "\n\n##### Ran out of text to work on. #####\n\n", NO_UNDO); // insert the string
|
||||
dot = text;
|
||||
refresh(FALSE);
|
||||
}
|
||||
}
|
||||
#endif
|
||||
last_input_char = c = get_one_char(); // get a cmd from user
|
||||
#if ENABLE_FEATURE_VI_YANKMARK
|
||||
// save a copy of the current line- for the 'U" command
|
||||
if (begin_line(dot) != cur_line) {
|
||||
cur_line = begin_line(dot);
|
||||
text_yank(begin_line(dot), end_line(dot), Ureg);
|
||||
}
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_DOT_CMD
|
||||
// These are commands that change text[].
|
||||
// Remember the input for the "." command
|
||||
if (!adding2q && ioq_start == NULL
|
||||
&& cmd_mode == 0 // command mode
|
||||
&& c > '\0' // exclude NUL and non-ASCII chars
|
||||
&& c < 0x7f // (Unicode and such)
|
||||
&& strchr(modifying_cmds, c)
|
||||
) {
|
||||
start_new_cmd_q(c);
|
||||
}
|
||||
#endif
|
||||
do_cmd(c); // execute the user command
|
||||
|
||||
// poll to see if there is input already waiting. if we are
|
||||
// not able to display output fast enough to keep up, skip
|
||||
// the display update until we catch up with input.
|
||||
if (!readbuffer[0] && mysleep(0) == 0) {
|
||||
// no input pending - so update output
|
||||
refresh(FALSE);
|
||||
show_status_line();
|
||||
}
|
||||
#if ENABLE_FEATURE_VI_CRASHME
|
||||
if (crashme > 0)
|
||||
crash_test(); // test editor variables
|
||||
#endif
|
||||
}
|
||||
//-------------------------------------------------------------------
|
||||
|
||||
go_bottom_and_clear_to_eol();
|
||||
cookmode();
|
||||
#undef cur_line
|
||||
}
|
||||
|
||||
int vi_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
||||
int vi_main(int argc, char **argv)
|
||||
{
|
||||
int c;
|
||||
|
||||
INIT_G();
|
||||
|
||||
#if ENABLE_FEATURE_VI_UNDO
|
||||
/* undo_stack_tail = NULL; - already is */
|
||||
#if ENABLE_FEATURE_VI_UNDO_QUEUE
|
||||
undo_queue_state = UNDO_EMPTY;
|
||||
/* undo_q = 0; - already is */
|
||||
#endif
|
||||
#endif
|
||||
|
||||
#if ENABLE_FEATURE_VI_CRASHME
|
||||
srand((long) getpid());
|
||||
#endif
|
||||
#ifdef NO_SUCH_APPLET_YET
|
||||
// if we aren't "vi", we are "view"
|
||||
if (ENABLE_FEATURE_VI_READONLY && applet_name[2]) {
|
||||
SET_READONLY_MODE(readonly_mode);
|
||||
}
|
||||
#endif
|
||||
|
||||
// autoindent is not default in vim 7.3
|
||||
vi_setops = /*VI_AUTOINDENT |*/ VI_SHOWMATCH | VI_IGNORECASE;
|
||||
// 1- process $HOME/.exrc file (not inplemented yet)
|
||||
// 2- process EXINIT variable from environment
|
||||
// 3- process command line args
|
||||
#if ENABLE_FEATURE_VI_COLON
|
||||
{
|
||||
char *p = getenv("EXINIT");
|
||||
if (p && *p)
|
||||
initial_cmds[0] = xstrndup(p, MAX_INPUT_LEN);
|
||||
}
|
||||
#endif
|
||||
while ((c = getopt(argc, argv, "hCRH" IF_FEATURE_VI_COLON("c:"))) != -1) {
|
||||
switch (c) {
|
||||
#if ENABLE_FEATURE_VI_CRASHME
|
||||
case 'C':
|
||||
crashme = 1;
|
||||
break;
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_READONLY
|
||||
case 'R': // Read-only flag
|
||||
SET_READONLY_MODE(readonly_mode);
|
||||
break;
|
||||
#endif
|
||||
#if ENABLE_FEATURE_VI_COLON
|
||||
case 'c': // cmd line vi command
|
||||
if (*optarg)
|
||||
initial_cmds[initial_cmds[0] != NULL] = xstrndup(optarg, MAX_INPUT_LEN);
|
||||
break;
|
||||
#endif
|
||||
case 'H':
|
||||
show_help();
|
||||
// fall through
|
||||
default:
|
||||
bb_show_usage();
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
|
||||
// The argv array can be used by the ":next" and ":rewind" commands
|
||||
argv += optind;
|
||||
argc -= optind;
|
||||
|
||||
//----- This is the main file handling loop --------------
|
||||
save_argc = argc;
|
||||
optind = 0;
|
||||
// "Save cursor, use alternate screen buffer, clear screen"
|
||||
write1(ESC"[?1049h");
|
||||
while (1) {
|
||||
edit_file(argv[optind]); // param might be NULL
|
||||
if (++optind >= argc)
|
||||
break;
|
||||
}
|
||||
// "Use normal screen buffer, restore cursor"
|
||||
write1(ESC"[?1049l");
|
||||
//-----------------------------------------------------------
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user