getline.c

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                             /*  .teclarc configuration file, or NULL. */
  char *user_file;           /* The pathname of the user-specific */
                             /*  .teclarc configuration file, or NULL. */
  int configured;            /* True as soon as any teclarc configuration */
                             /*  file has been read. */
  int echo;                  /* True to display the line as it is being */
                             /*  entered. If 0, only the prompt will be */
                             /*  displayed, and the line will not be */
                             /*  archived in the history list. */
  int last_signal;           /* The last signal that was caught by */
                             /*  the last call to gl_get_line(), or -1 */
                             /*  if no signal has been caught yet. */
#ifdef HAVE_SELECT
  FreeList *fd_node_mem;     /* A freelist of GlFdNode structures */
  GlFdNode *fd_nodes;        /* The list of fd event descriptions */
  fd_set rfds;               /* The set of fds to watch for readability */
  fd_set wfds;               /* The set of fds to watch for writability */
  fd_set ufds;               /* The set of fds to watch for urgent data */
  int max_fd;                /* The maximum file-descriptor being watched */
#endif
};

/*
 * Define the max amount of space needed to store a termcap terminal
 * description. Unfortunately this has to be done by guesswork, so
 * there is the potential for buffer overflows if we guess too small.
 * Fortunately termcap has been replaced by terminfo on most
 * platforms, and with terminfo this isn't an issue. The value that I
 * am using here is the conventional value, as recommended by certain
 * web references.
 */
#ifdef USE_TERMCAP
#define TERMCAP_BUF_SIZE 2048
#endif

/*
 * Set the size of the string segments used to store terminal capability
 * strings.
 */
#define CAPMEM_SEGMENT_SIZE 512

/*
 * If no terminal size information is available, substitute the
 * following vt100 default sizes.
 */
#define GL_DEF_NLINE 24
#define GL_DEF_NCOLUMN 80

/*
 * List the signals that we need to catch. In general these are
 * those that by default terminate or suspend the process, since
 * in such cases we need to restore terminal settings.
 */
static const struct GlDefSignal {
  int signo;            /* The number of the signal */
  unsigned flags;       /* A bitwise union of GlSignalFlags enumerators */
  GlAfterSignal after;  /* What to do after the signal has been delivered */
  int errno_value;      /* What to set errno to */
} gl_signal_list[] = {
  {SIGABRT,   GLS_SUSPEND_INPUT, GLS_ABORT, EINTR},
  {SIGINT,    GLS_SUSPEND_INPUT, GLS_ABORT, EINTR},
  {SIGTERM,   GLS_SUSPEND_INPUT, GLS_ABORT, EINTR},
#if defined (SIGALRM)
  {SIGALRM,   GLS_RESTORE_ENV, GLS_CONTINUE, 0},
#endif
#if defined (SIGCONT)
  {SIGCONT,   GLS_RESTORE_ENV, GLS_CONTINUE, 0},
#endif
#if defined(SIGHUP)
#ifdef ENOTTY
  {SIGHUP,    GLS_SUSPEND_INPUT, GLS_ABORT, ENOTTY},
#else
  {SIGHUP,    GLS_SUSPEND_INPUT, GLS_ABORT, EINTR},
#endif
#endif
#if defined(SIGPIPE)
#ifdef EPIPE
  {SIGPIPE,   GLS_SUSPEND_INPUT, GLS_ABORT, EPIPE},
#else
  {SIGPIPE,   GLS_SUSPEND_INPUT, GLS_ABORT, EINTR},
#endif
#endif
#ifdef SIGPWR
  {SIGPWR,    GLS_RESTORE_ENV, GLS_CONTINUE, 0},
#endif
#ifdef SIGQUIT
  {SIGQUIT,   GLS_SUSPEND_INPUT, GLS_ABORT, EINTR},
#endif
#ifdef SIGTSTP
  {SIGTSTP,   GLS_SUSPEND_INPUT, GLS_CONTINUE, 0},
#endif
#ifdef SIGTTIN
  {SIGTTIN,   GLS_SUSPEND_INPUT, GLS_CONTINUE, 0},
#endif
#ifdef SIGTTOU
  {SIGTTOU,   GLS_SUSPEND_INPUT, GLS_CONTINUE, 0},
#endif
#ifdef SIGUSR1
  {SIGUSR1,   GLS_RESTORE_ENV, GLS_CONTINUE, 0},
#endif
#ifdef SIGUSR2
  {SIGUSR2,   GLS_RESTORE_ENV, GLS_CONTINUE, 0},
#endif
#ifdef SIGVTALRM
  {SIGVTALRM, GLS_RESTORE_ENV, GLS_CONTINUE, 0},
#endif
#ifdef SIGWINCH
  {SIGWINCH,  GLS_RESTORE_ENV, GLS_CONTINUE, 0},
#endif
#ifdef SIGXCPU
  {SIGXCPU,   GLS_RESTORE_ENV, GLS_CONTINUE, 0},
#endif
};

/*
 * Define file-scope variables for use in signal handlers.
 */
static volatile sig_atomic_t gl_pending_signal = -1;
static sigjmp_buf gl_setjmp_buffer;

static void gl_signal_handler(int signo);

static int gl_check_caught_signal(GetLine *gl);

/*
 * Unfortunately both terminfo and termcap require one to use the tputs()
 * function to output terminal control characters, and this function
 * doesn't allow one to specify a file stream. As a result, the following
 * file-scope variable is used to pass the current output file stream.
 * This is bad, but there doesn't seem to be any alternative.
 */
#if defined(USE_TERMINFO) || defined(USE_TERMCAP)
static FILE *tputs_fp = NULL;
#endif

/*
 * Define a tab to be a string of 8 spaces.
 */
#define TAB_WIDTH 8

/*
 * Does the system send us SIGWINCH signals when the terminal size
 * changes?
 */
#ifdef USE_SIGWINCH
static int gl_resize_terminal(GetLine *gl, int redisplay);
#endif

/*
 * Getline calls this to temporarily override certain signal handlers
 * of the calling program.
 */
static int gl_override_signal_handlers(GetLine *gl);

/*
 * Getline calls this to restore the signal handlers of the calling
 * program.
 */
static int gl_restore_signal_handlers(GetLine *gl);

/*
 * Put the terminal into raw input mode, after saving the original
 * terminal attributes in gl->oldattr.
 */
static int gl_raw_terminal_mode(GetLine *gl);

/*
 * Restore the terminal attributes from gl->oldattr.
 */
static int gl_restore_terminal_attributes(GetLine *gl);

/*
 * Read a line from the user in raw mode.
 */
static int gl_get_input_line(GetLine *gl, const char *start_line,
			     int start_pos, int val);

/*
 * Handle the receipt of the potential start of a new key-sequence from
 * the user.
 */
static int gl_interpret_char(GetLine *gl, char c);

/*
 * Bind a single control or meta character to an action.
 */
static int gl_bind_control_char(GetLine *gl, KtBinder binder,
				char c, const char *action);

/*
 * Set up terminal-specific key bindings.
 */
static int gl_bind_terminal_keys(GetLine *gl);

/*
 * Lookup terminal control string and size information.
 */
static int gl_control_strings(GetLine *gl, const char *term);

/*
 * Wrappers around the terminfo and termcap functions that lookup
 * strings in the terminal information databases.
 */
#ifdef USE_TERMINFO
static const char *gl_tigetstr(GetLine *gl, const char *name);
#elif defined(USE_TERMCAP)
static const char *gl_tgetstr(GetLine *gl, const char *name, char **bufptr);
#endif

/*
 * Output a binary string directly to the terminal.
 */
static int gl_output_raw_string(GetLine *gl, const char *string);

/*
 * Output a terminal control sequence.
 */
static int gl_output_control_sequence(GetLine *gl, int nline,
				      const char *string);

/*
 * Output a character or string to the terminal after converting tabs
 * to spaces and control characters to a caret followed by the modified
 * character.
 */
static int gl_output_char(GetLine *gl, char c, char pad);
static int gl_output_string(GetLine *gl, const char *string, char pad);

/*
 * Delete nc characters starting from the one under the cursor.
 * Optionally copy the deleted characters to the cut buffer.
 */
static int gl_delete_chars(GetLine *gl, int nc, int cut);

/*
 * Add a character to the line buffer at the current cursor position,
 * inserting or overwriting according the current mode.
 */
static int gl_add_char_to_line(GetLine *gl, char c);

/*
 * Insert/append a string to the line buffer and terminal at the current
 * cursor position.
 */
static int gl_add_string_to_line(GetLine *gl, const char *s);

/*
 * Read a single character from the terminal.
 */
static int gl_read_character(GetLine *gl, char *c, int val);


/*
 * Move the terminal cursor n positions to the left or right.
 */
static int gl_terminal_move_cursor(GetLine *gl, int n);

/*
 * Move the terminal cursor to a given position.
 */
static int gl_set_term_curpos(GetLine *gl, int term_curpos);

/*
 * Set the position of the cursor both in the line input buffer and on the
 * terminal.
 */
/* static int gl_place_cursor(GetLine *gl, int buff_curpos); */

/*
 * Return the terminal cursor position that corresponds to a given
 * line buffer cursor position.
 */
static int gl_buff_curpos_to_term_curpos(GetLine *gl, int buff_curpos);

/*
 * Return the number of terminal characters needed to display a
 * given raw character.
 */
static int gl_displayed_char_width(GetLine *gl, char c, int term_curpos);

/*
 * Return the number of terminal characters needed to display a
 * given substring.
 */
static int gl_displayed_string_width(GetLine *gl, const char *string, int nc,
				     int term_curpos);
/*
 * Return non-zero if 'c' is to be considered part of a word.
 */
static int gl_is_word_char(int c);

/*
 * Read a tecla configuration file.
 */
static int _gl_read_config_file(GetLine *gl, const char *filename, KtBinder who);

/*
 * Read a tecla configuration string.
 */
static int _gl_read_config_string(GetLine *gl, const char *buffer, KtBinder who);

/*
 * Define the callback function used by _gl_parse_config_line() to
 * read the next character of a configuration stream.
 */
#define GLC_GETC_FN(fn) int (fn)(void *stream)
typedef GLC_GETC_FN(GlcGetcFn);

static GLC_GETC_FN(glc_file_getc);  /* Read from a file */
static GLC_GETC_FN(glc_buff_getc);  /* Read from a string */

/*
 * Parse a single configuration command line.
 */
static int _gl_parse_config_line(GetLine *gl, void *stream, GlcGetcFn *getc_fn,
				 const char *origin, KtBinder who, int *lineno);

/*
 * Bind the actual arrow key bindings to match those of the symbolic
 * arrow-key bindings.
 */
static int _gl_bind_arrow_keys(GetLine *gl);

/*
 * Copy the binding of the specified symbolic arrow-key binding to
 * the terminal specific, and default arrow-key key-sequences. 
 */
static int _gl_rebind_arrow_key(KeyTab *bindings, const char *name,
				const char *term_seq,
				const char *def_seq1,
				const char *def_seq2);

/*
 * After the gl_read_from_file() action has been used to tell gl_get_line()
 * to temporarily read input from a file, gl_revert_input() arranges
 * for input to be reverted to the input stream last registered with
 * gl_change_terminal().
 */
static void gl_revert_input(GetLine *gl);

/*
 * Flush unwritten characters to the terminal.
 */
static int gl_flush_output(GetLine *gl);

/*
 * Change the editor style being emulated.
 */
static int gl_change_editor(GetLine *gl, GlEditor editor);

/*
 * Searching in a given direction, return the index of a given (or
 * read) character in the input line, or the character that precedes
 * it in the specified search direction. Return -1 if not found.
 */
static int gl_find_char(GetLine *gl, int count, int forward, int onto, char c);

/*
 * Return the buffer index of the nth word ending after the cursor.
 */
static int gl_nth_word_end_forward(GetLine *gl, int n);

/*
 * Return the buffer index of the nth word start after the cursor.
 */
static int gl_nth_word_start_forward(GetLine *gl, int n);

/*
 * Return the buffer index of the nth word start before the cursor.
 */
static int gl_nth_word_start_backward(GetLine *gl, int n);

/*
 * When called when vi command mode is enabled, this function saves the
 * current line and cursor position for potential restoration later
 * by the vi undo command.