/**************************************************************************
* help.c -- This file is part of GNU nano. *
* *
* Copyright (C) 2000-2011, 2013-2017 Free Software Foundation, Inc. *
* Copyright (C) 2017 Rishabh Dave *
* Copyright (C) 2014-2017 Benno Schulenberg *
* *
* GNU nano is free software: you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published *
* by the Free Software Foundation, either version 3 of the License, *
* or (at your option) any later version. *
* *
* GNU nano 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 General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program. If not, see http://www.gnu.org/licenses/. *
* *
**************************************************************************/
#include "proto.h"
#include <errno.h>
#include <string.h>
#ifdef ENABLE_HELP
static char *help_text = NULL;
/* The text displayed in the help window. */
static const char *start_of_body = NULL;
/* The point in the help text just after the title. */
static char *end_of_intro = NULL;
/* The point in the help text where the shortcut descriptions begin. */
static size_t location;
/* The offset (in bytes) of the topleft of the shown help text. */
char *tempfilename = NULL;
/* Name of the temporary file used for wrapping the help text. */
/* Hard-wrap the help text, write it to the existing temporary file, and
* read that file into a new buffer. */
void wrap_the_help_text(bool redisplaying)
{
int sum = 0;
const char *ptr = start_of_body;
FILE *tempfile = fopen(tempfilename, "w+b");
/* If re-opening the temporary file failed, give up. */
if (tempfile == NULL) {
statusline(ALERT, _("Error writing temp file: %s"), strerror(errno));
return;
}
/* Write the body of the help_text into the temporary file. */
while (*ptr != '\0') {
int length = help_line_len(ptr);
fwrite(ptr, sizeof(char), length, tempfile);
ptr += length;
/* Hard-wrap the lines in the help text. */
if (*ptr != '\n')
fwrite("\n", sizeof(char), 1, tempfile);
else while (*ptr == '\n')
fwrite(ptr++, sizeof(char), 1, tempfile);
}
fclose(tempfile);
if (redisplaying)
close_buffer();
open_buffer(tempfilename, FALSE);
remove_magicline();
prepare_for_display();
/* Move to the position in the file where we were before. */
while (TRUE) {
sum += strlen(openfile->current->data);
if (sum > location)
break;
openfile->current = openfile->current->next;
}
openfile->edittop = openfile->current;
}
/* Our main help-viewer function. */
void do_help(void)
{
int kbinput = ERR;
functionptrtype func;
/* The function of the key the user typed in. */
int oldmenu = currmenu;
/* The menu we were called from. */
#ifdef ENABLE_LINENUMBERS
int was_margin = margin;
#endif
ssize_t was_tabsize = tabsize;
#ifndef DISABLE_COLOR
char *was_syntax = syntaxstr;
#endif
char *saved_answer = (answer != NULL) ? strdup(answer) : NULL;
/* The current answer when the user invokes help at the prompt. */
unsigned stash[sizeof(flags) / sizeof(flags[0])];
/* A storage place for the current flag settings. */
filestruct *line;
int length;
FILE *fp;
blank_statusbar();
/* Get a temporary file for the help text. If it fails, give up. */
tempfilename = safe_tempfile(&fp);
if (tempfilename == NULL) {
statusline(ALERT, _("Error writing temp file: %s"), strerror(errno));
free(saved_answer);
return;
}
fclose(fp);
/* Save the settings of all flags. */
memcpy(stash, flags, sizeof(flags));
/* Ensure that the help screen's shortcut list can be displayed. */
if (ISSET(NO_HELP) && LINES > 4) {
UNSET(NO_HELP);
window_init();
}
/* When searching, do it forward, case insensitive, and without regexes. */
UNSET(BACKWARDS_SEARCH);
UNSET(CASE_SENSITIVE);
UNSET(USE_REGEXP);
UNSET(WHITESPACE_DISPLAY);
UNSET(NOREAD_MODE);
SET(MULTIBUFFER);
#ifdef ENABLE_LINENUMBERS
UNSET(LINE_NUMBERS);
margin = 0;
#endif
tabsize = 8;
#ifndef DISABLE_COLOR
syntaxstr = "nanohelp";
#endif
curs_set(0);
/* Compose the help text from all the pieces. */
help_init();
inhelp = TRUE;
location = 0;
didfind = 0;
bottombars(MHELP);
wnoutrefresh(bottomwin);
/* Extract the title from the head of the help text. */
length = break_line(help_text, MAX_BUF_SIZE, TRUE);
title = charalloc(length * sizeof(char) + 1);
strncpy(title, help_text, length);
title[length] = '\0';
titlebar(title);
/* Skip over the title to point at the start of the body text. */
start_of_body = help_text + length;
while (*start_of_body == '\n')
start_of_body++;
wrap_the_help_text(FALSE);
edit_refresh();
while (TRUE) {
lastmessage = HUSH;
focusing = TRUE;
/* Show the cursor when we searched and found something. */
kbinput = get_kbinput(edit, didfind == 1);
didfind = 0;
func = parse_help_input(&kbinput);
if (func == total_refresh) {
total_redraw();
} else if (func == do_up_void) {
do_up(TRUE);
} else if (func == do_down_void) {
if (openfile->edittop->lineno + editwinrows - 1 <
openfile->filebot->lineno)
do_down(TRUE);
} else if (func == do_page_up) {
do_page_up();
} else if (func == do_page_down) {
do_page_down();
} else if (func == do_first_line) {
do_first_line();
} else if (func == do_last_line) {
do_last_line();
} else if (func == do_search) {
do_search();
bottombars(MHELP);
} else if (func == do_research) {
do_research();
#ifndef NANO_TINY
} else if (func == do_findprevious) {
do_findprevious();
} else if (func == do_findnext) {
do_findnext();
} else if (kbinput == KEY_WINCH) {
; /* Nothing to do. */
#endif
#ifdef ENABLE_MOUSE
} else if (kbinput == KEY_MOUSE) {
int dummy_x, dummy_y;
get_mouseinput(&dummy_x, &dummy_y, TRUE);
#endif
} else if (func == do_exit) {
/* Exit from the help viewer. */
close_buffer();
curs_set(0);
break;
} else
unbound_key(kbinput);
currmenu = MHELP;
edit_refresh();
location = 0;
line = openfile->fileage;
/* Count how far (in bytes) edittop is into the file. */
while (line != openfile->edittop) {
location += strlen(line->data);
line = line->next;
}
}
/* Restore the settings of all flags. */
memcpy(flags, stash, sizeof(flags));
#ifdef ENABLE_LINENUMBERS
margin = was_margin;
#endif
tabsize = was_tabsize;
#ifndef DISABLE_COLOR
syntaxstr = was_syntax;
#endif
/* Switch back to the buffer we were invoked from. */
switch_to_prev_buffer();
if (ISSET(NO_HELP)) {
currmenu = oldmenu;
window_init();
} else
bottombars(oldmenu);
free(title);
title = NULL;
inhelp = FALSE;
#ifdef ENABLE_BROWSER
if (oldmenu == MBROWSER || oldmenu == MWHEREISFILE || oldmenu == MGOTODIR)
browser_refresh();
else
#endif
total_refresh();
free(answer);
answer = saved_answer;
remove(tempfilename);
free(tempfilename);
free(help_text);
}
/* Allocate space for the help text for the current menu, and concatenate
* the different pieces of text into it. */
void help_init(void)
{
size_t allocsize = 0;
/* Space needed for help_text. */
const char *htx[3];
/* Untranslated help introduction. We break it up into three chunks
* in case the full string is too long for the compiler to handle. */
char *ptr;
const subnfunc *f;
const sc *s;
/* First, set up the initial help text for the current function. */
if (currmenu == MWHEREIS || currmenu == MREPLACE || currmenu == MREPLACEWITH) {
htx[0] = N_("Search Command Help Text\n\n "
"Enter the words or characters you would like to "
"search for, and then press Enter. If there is a "
"match for the text you entered, the screen will be "
"updated to the location of the nearest match for the "
"search string.\n\n The previous search string will be "
"shown in brackets after the search prompt. Hitting "
"Enter without entering any text will perform the "
"previous search. ");
htx[1] = N_("If you have selected text with the mark and then "
"search to replace, only matches in the selected text "
"will be replaced.\n\n The following function keys are "
"available in Search mode:\n\n");
htx[2] = NULL;
} else if (currmenu == MGOTOLINE) {
htx[0] = N_("Go To Line Help Text\n\n "
"Enter the line number that you wish to go to and hit "
"Enter. If there are fewer lines of text than the "
"number you entered, you will be brought to the last "
"line of the file.\n\n The following function keys are "
"available in Go To Line mode:\n\n");
htx[1] = NULL;
htx[2] = NULL;
} else if (currmenu == MINSERTFILE) {
htx[0] = N_("Insert File Help Text\n\n "
"Type in the name of a file to be inserted into the "
"current file buffer at the current cursor "
"location.\n\n If you have compiled nano with multiple "
"file buffer support, and enable multiple file buffers "
"with the -F or --multibuffer command line flags, the "
"Meta-F toggle, or a nanorc file, inserting a file "
"will cause it to be loaded into a separate buffer "
"(use Meta-< and > to switch between file buffers). ");
htx[1] = N_("If you need another blank buffer, do not enter "
"any filename, or type in a nonexistent filename at "
"the prompt and press Enter.\n\n The following "
"function keys are available in Insert File mode:\n\n");
htx[2] = NULL;
} else if (currmenu == MWRITEFILE) {
htx[0] = N_("Write File Help Text\n\n "
"Type the name that you wish to save the current file "
"as and press Enter to save the file.\n\n If you have "
"selected text with the mark, you will be prompted to "
"save only the selected portion to a separate file. To "
"reduce the chance of overwriting the current file with "
"just a portion of it, the current filename is not the "
"default in this mode.\n\n The following function keys "
"are available in Write File mode:\n\n");
htx[1] = NULL;
htx[2] = NULL;
}
#ifdef ENABLE_BROWSER
else if (currmenu == MBROWSER) {
htx[0] = N_("File Browser Help Text\n\n "
"The file browser is used to visually browse the "
"directory structure to select a file for reading "
"or writing. You may use the arrow keys or Page Up/"
"Down to browse through the files, and S or Enter to "
"choose the selected file or enter the selected "
"directory. To move up one level, select the "
"directory called \"..\" at the top of the file "
"list.\n\n The following function keys are available "
"in the file browser:\n\n");
htx[1] = NULL;
htx[2] = NULL;
} else if (currmenu == MWHEREISFILE) {
htx[0] = N_("Browser Search Command Help Text\n\n "
"Enter the words or characters you would like to "
"search for, and then press Enter. If there is a "
"match for the text you entered, the screen will be "
"updated to the location of the nearest match for the "
"search string.\n\n The previous search string will be "
"shown in brackets after the search prompt. Hitting "
"Enter without entering any text will perform the "
"previous search.\n\n");
htx[1] = N_(" The following function keys are available in "
"Browser Search mode:\n\n");
htx[2] = NULL;
} else if (currmenu == MGOTODIR) {
htx[0] = N_("Browser Go To Directory Help Text\n\n "
"Enter the name of the directory you would like to "
"browse to.\n\n If tab completion has not been "
"disabled, you can use the Tab key to (attempt to) "
"automatically complete the directory name.\n\n The "
"following function keys are available in Browser Go "
"To Directory mode:\n\n");
htx[1] = NULL;
htx[2] = NULL;
}
#endif /* ENABLE_BROWSER */
#ifndef DISABLE_SPELLER
else if (currmenu == MSPELL) {
htx[0] = N_("Spell Check Help Text\n\n "
"The spell checker checks the spelling of all text in "
"the current file. When an unknown word is "
"encountered, it is highlighted and a replacement can "
"be edited. It will then prompt to replace every "
"instance of the given misspelled word in the current "
"file, or, if you have selected text with the mark, in "
"the selected text.\n\n The following function keys "
"are available in Spell Check mode:\n\n");
htx[1] = NULL;
htx[2] = NULL;
}
#endif /* !DISABLE_SPELLER */
#ifndef NANO_TINY
else if (currmenu == MEXTCMD) {
htx[0] = N_("Execute Command Help Text\n\n "
"This mode allows you to insert the output of a "
"command run by the shell into the current buffer (or "
"a new buffer in multiple file buffer mode). If you "
"need another blank buffer, do not enter any "
"command.\n\n The following function keys are "
"available in Execute Command mode:\n\n");
htx[1] = NULL;
htx[2] = NULL;
}
#endif /* !NANO_TINY */
else {
/* Default to the main help list. */
htx[0] = N_("Main nano help text\n\n "
"The nano editor is designed to emulate the "
"functionality and ease-of-use of the UW Pico text "
"editor. There are four main sections of the editor. "
"The top line shows the program version, the current "
"filename being edited, and whether or not the file "
"has been modified. Next is the main editor window "
"showing the file being edited. The status line is "
"the third line from the bottom and shows important "
"messages. ");
htx[1] = N_("The bottom two lines show the most commonly used "
"shortcuts in the editor.\n\n Shortcuts are written as "
"follows: Control-key sequences are notated with a '^' "
"and can be entered either by using the Ctrl key or "
"pressing the Esc key twice. Meta-key sequences are "
"notated with 'M-' and can be entered using either the "
"Alt, Cmd, or Esc key, depending on your keyboard setup. ");
htx[2] = N_("Also, pressing Esc twice and then typing a "
"three-digit decimal number from 000 to 255 will enter "
"the character with the corresponding value. The "
"following keystrokes are available in the main editor "
"window. Alternative keys are shown in "
"parentheses:\n\n");
}
htx[0] = _(htx[0]);
if (htx[1] != NULL)
htx[1] = _(htx[1]);
if (htx[2] != NULL)
htx[2] = _(htx[2]);
allocsize += strlen(htx[0]);
if (htx[1] != NULL)
allocsize += strlen(htx[1]);
if (htx[2] != NULL)
allocsize += strlen(htx[2]);
/* Calculate the length of the shortcut help text. Each entry has
* one or two keys, which fill 16 columns, plus translated text,
* plus one or two \n's. */
for (f = allfuncs; f != NULL; f = f->next)
if (f->menus & currmenu)
allocsize += (16 * MAXCHARLEN) + strlen(_(f->help)) + 2;
#ifndef NANO_TINY
/* If we're on the main list, we also count the toggle help text.
* Each entry has "M-%c\t\t", five chars which fill 16 columns,
* plus a space, plus translated text, plus one or two '\n's. */
if (currmenu == MMAIN) {
size_t endis_len = strlen(_("enable/disable"));
for (s = sclist; s != NULL; s = s->next)
if (s->scfunc == do_toggle_void)
allocsize += strlen(_(flagtostr(s->toggle))) + endis_len + 8;
}
#endif
/* Allocate memory for the help text. */
help_text = charalloc(allocsize + 1);
/* Now add the text we want. */
strcpy(help_text, htx[0]);
if (htx[1] != NULL)
strcat(help_text, htx[1]);
if (htx[2] != NULL)
strcat(help_text, htx[2]);
ptr = help_text + strlen(help_text);
/* Remember this end-of-introduction, start-of-shortcuts. */
end_of_intro = ptr;
/* Now add our shortcut info. */
for (f = allfuncs; f != NULL; f = f->next) {
int scsfound = 0;
if ((f->menus & currmenu) == 0)
continue;
/* Let's simply show the first two shortcuts from the list. */
for (s = sclist; s != NULL; s = s->next) {
if ((s->menus & currmenu) == 0)
continue;
if (s->scfunc == f->scfunc) {
scsfound++;
/* Make the first column narrower (6) than the second (10),
* but allow it to spill into the second, for "M-Space". */
if (scsfound == 1) {
sprintf(ptr, "%s ", s->keystr);
/* Unicode arrows take three bytes instead of one. */
if (strstr(s->keystr, "\xE2") != NULL)
ptr += 8;
else
ptr += 6;
} else {
ptr += sprintf(ptr, "(%s)\t", s->keystr);
break;
}
}
}
if (scsfound == 0)
ptr += sprintf(ptr, "\t\t");
else if (scsfound == 1)
ptr += 10;
/* The shortcut's help text. */
ptr += sprintf(ptr, "%s\n", _(f->help));
if (f->blank_after)
ptr += sprintf(ptr, "\n");
}
#ifndef NANO_TINY
/* And the toggles... */
if (currmenu == MMAIN) {
int maximum = 0, counter = 0;
/* First see how many toggles there are. */
for (s = sclist; s != NULL; s = s->next)
maximum = (s->toggle && s->ordinal > maximum) ? s->ordinal : maximum;
/* Now show them in the original order. */
while (counter < maximum) {
counter++;
for (s = sclist; s != NULL; s = s->next)
if (s->toggle && s->ordinal == counter) {
ptr += sprintf(ptr, "%s\t\t%s %s\n", (s->menus == MMAIN ? s->keystr : ""),
_(flagtostr(s->toggle)), _("enable/disable"));
if (s->toggle == NO_COLOR_SYNTAX || s->toggle == TABS_TO_SPACES)
ptr += sprintf(ptr, "\n");
break;
}
}
}
#endif /* !NANO_TINY */
if (strlen(help_text) > allocsize)
statusline(ALERT, "Help text spilled over -- please report a bug");
}
/* Return the function that is bound to the given key, accepting certain
* plain characters too, for consistency with the file browser. */
functionptrtype parse_help_input(int *kbinput)
{
if (!meta_key) {
switch (*kbinput) {
case ' ':
return do_page_down;
case '-':
return do_page_up;
case 'W':
case 'w':
case '/':
return do_search;
case 'N':
#ifndef NANO_TINY
return do_findprevious;
#endif
case 'n':
return do_research;
case 'E':
case 'e':
case 'Q':
case 'q':
case 'X':
case 'x':
return do_exit;
}
}
return func_from_key(kbinput);
}
/* Calculate the displayable length of the help-text line starting at ptr. */
size_t help_line_len(const char *ptr)
{
size_t wrapping_point = (COLS > 24) ? COLS - 1 : 24;
/* The target width for wrapping long lines. */
ssize_t wrap_location;
/* Actual position where the line can be wrapped. */
size_t length = 0;
/* Full length of the line, until the first newline. */
/* Avoid overwide paragraphs in the introductory text. */
if (ptr < end_of_intro && COLS > 74)
wrapping_point = 74;
wrap_location = break_line(ptr, wrapping_point, TRUE);
/* Get the length of the entire line up to a null or a newline. */
while (*(ptr + length) != '\0' && *(ptr + length) != '\n')
length = move_mbright(ptr, length);
/* If the entire line will just fit the screen, don't wrap it. */
if (strnlenpt(ptr, length) <= wrapping_point + 1)
return length;
else if (wrap_location > 0)
return wrap_location;
else
return 0;
}
#endif /* ENABLE_HELP */
/* Start the help viewer. */
void do_help_void(void)
{
#ifdef ENABLE_HELP
do_help();
#else
if (currmenu == MMAIN)
say_there_is_no_help();
else
beep();
#endif
}