lineedit: do not hang on error, but return error indicator.
[oweals/busybox.git] / util-linux / more.c
index 65409999b09d8aba7f1813773cb1ba9d13b18b2f..1fd6f9ee82c975afe3b8821bc1792a1c9d05b5ba 100644 (file)
-#include "internal.h"
-#include <stdio.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/ioctl.h>
-#include <fcntl.h>
+/* vi: set sw=4 ts=4: */
+/*
+ * Mini more implementation for busybox
+ *
+ * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ *
+ * Latest version blended together by Erik Andersen <andersen@codepoet.org>,
+ * based on the original more implementation by Bruce, and code from the
+ * Debian boot-floppies team.
+ *
+ * Termios corrects by Vladimir Oleynik <dzo@simtreas.ru>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
 
-#define BB_MORE_TERM
+#include "libbb.h"
 
-#ifdef BB_MORE_TERM
-       #include <termios.h>
-       #include <signal.h>
+/* Support for FEATURE_USE_TERMIOS */
 
-       FILE *cin;
-       struct termios initial_settings, new_settings;
+struct globals {
+       int cin_fileno;
+       struct termios initial_settings;
+       struct termios new_settings;
+} FIX_ALIASING;
+#define G (*(struct globals*)bb_common_bufsiz1)
+#define INIT_G() ((void)0)
+#define initial_settings (G.initial_settings)
+#define new_settings     (G.new_settings    )
+#define cin_fileno       (G.cin_fileno      )
 
-       void gotsig(int sig) { 
-               tcsetattr(fileno(cin), TCSANOW, &initial_settings);
-               exit(0);
-       }
-#endif
+#define setTermSettings(fd, argp) do { \
+               if (ENABLE_FEATURE_USE_TERMIOS) tcsetattr(fd, TCSANOW, argp); \
+       } while (0)
+#define getTermSettings(fd, argp) tcgetattr(fd, argp)
+
+static void gotsig(int sig UNUSED_PARAM)
+{
+       bb_putchar('\n');
+       setTermSettings(cin_fileno, &initial_settings);
+       exit(EXIT_FAILURE);
+}
 
-const char     more_usage[] = "more [file]\n"
-"\n"
-"\tDisplays a file, one page at a time.\n"
-"\tIf there are no arguments, the standard input is displayed.\n";
+#define CONVERTED_TAB_SIZE 8
 
-extern int
-more_fn(const struct FileInfo * i)
+int more_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int more_main(int argc UNUSED_PARAM, char **argv)
 {
-       FILE *  f = stdin;
-       int     c;
-       int     lines = 0, tlines = 0;
-       int     next_page = 0;
-       int     rows = 24, cols = 79;
-#ifdef BB_MORE_TERM
-       long sizeb = 0;
-       struct stat st; 
-       struct winsize win;
-#endif
-       
-       if ( i ) {
-               if (! (f = fopen(i->source, "r") )) {
-                       name_and_error(i->source);
-                       return 1;
-               }
-               fstat(fileno(f), &st);
-               sizeb = st.st_size / 100;
+       int c = c; /* for compiler */
+       int lines;
+       int input = 0;
+       int spaces = 0;
+       int please_display_more_prompt;
+       struct stat st;
+       FILE *file;
+       FILE *cin;
+       int len;
+       unsigned terminal_width;
+       unsigned terminal_height;
+
+       INIT_G();
+
+       argv++;
+       /* Another popular pager, most, detects when stdout
+        * is not a tty and turns into cat. This makes sense. */
+       if (!isatty(STDOUT_FILENO))
+               return bb_cat(argv);
+       cin = fopen_for_read(CURRENT_TTY);
+       if (!cin)
+               return bb_cat(argv);
+
+       if (ENABLE_FEATURE_USE_TERMIOS) {
+               cin_fileno = fileno(cin);
+               getTermSettings(cin_fileno, &initial_settings);
+               new_settings = initial_settings;
+               new_settings.c_lflag &= ~ICANON;
+               new_settings.c_lflag &= ~ECHO;
+               new_settings.c_cc[VMIN] = 1;
+               new_settings.c_cc[VTIME] = 0;
+               setTermSettings(cin_fileno, &new_settings);
+               bb_signals(0
+                       + (1 << SIGINT)
+                       + (1 << SIGQUIT)
+                       + (1 << SIGTERM)
+                       , gotsig);
        }
-               
-#ifdef BB_MORE_TERM
-       cin = fopen("/dev/tty", "r");
-       tcgetattr(fileno(cin),&initial_settings);
-       new_settings = initial_settings;
-       new_settings.c_lflag &= ~ICANON;
-       new_settings.c_lflag &= ~ECHO;
-       tcsetattr(fileno(cin), TCSANOW, &new_settings);
-       
-       (void) signal(SIGINT, gotsig);
-
-       ioctl(STDOUT_FILENO, TIOCGWINSZ, &win);
-       if (win.ws_row > 4)     rows = win.ws_row - 2;
-       if (win.ws_col > 0)     cols = win.ws_col - 1;
-
-
-#endif
-
-       while ( (c = getc(f)) != EOF ) {
-               if ( next_page ) {
-                       char    garbage;
-                       int     len;
-                       tlines += lines;
-                       lines = 0;
-                       next_page = 0;          //Percentage is based on bytes, not lines.
-                       if ( i && i->source )   //It is not very acurate, but still useful.
-                               len = printf("%s - %%%2ld - line: %d", i->source, (ftell(f) - sizeb - sizeb) / sizeb, tlines);
-                       else
-                               len = printf("line: %d", tlines);
-                               
-                       fflush(stdout);
-#ifndef BB_MORE_TERM           
-                       read(2, &garbage, 1);
-#else                          
-                       do {
-                               fread(&garbage, 1, 1, cin);     
-                       } while ((garbage != ' ') && (garbage != '\n'));
-                       
-                       if (garbage == '\n') {
-                               lines = rows;
-                               tlines -= rows;
-                       }                                       
-                       garbage = 0;                            
-                       //clear line, since tabs don't overwrite.
-                       while(len-- > 0)        putchar('\b');
-                       while(len++ < cols)     putchar(' ');
-                       while(len-- > 0)        putchar('\b');
-                       fflush(stdout);
-#endif                                                         
+
+       do {
+               file = stdin;
+               if (*argv) {
+                       file = fopen_or_warn(*argv, "r");
+                       if (!file)
+                               continue;
                }
-               putchar(c);
-               if ( c == '\n' && ++lines == (rows + 1) )
-                       next_page = 1;
-       }
-       if ( f != stdin )
-               fclose(f);
-#ifdef BB_MORE_TERM
-       gotsig(0);
-#endif 
+               st.st_size = 0;
+               fstat(fileno(file), &st);
+
+               please_display_more_prompt = 0;
+               /* never returns w, h <= 1 */
+               get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height);
+               terminal_height -= 1;
+
+               len = 0;
+               lines = 0;
+               while (spaces || (c = getc(file)) != EOF) {
+                       int wrap;
+                       if (spaces)
+                               spaces--;
+ loop_top:
+                       if (input != 'r' && please_display_more_prompt) {
+                               len = printf("--More-- ");
+                               if (st.st_size > 0) {
+                                       len += printf("(%u%% of %"OFF_FMT"u bytes)",
+                                               (int) (ftello(file)*100 / st.st_size),
+                                               st.st_size);
+                               }
+                               fflush_all();
+
+                               /*
+                                * We've just displayed the "--More--" prompt, so now we need
+                                * to get input from the user.
+                                */
+                               for (;;) {
+                                       input = getc(cin);
+                                       input = tolower(input);
+                                       if (!ENABLE_FEATURE_USE_TERMIOS)
+                                               printf("\033[A"); /* cursor up */
+                                       /* Erase the last message */
+                                       printf("\r%*s\r", len, "");
+
+                                       /* Due to various multibyte escape
+                                        * sequences, it's not ok to accept
+                                        * any input as a command to scroll
+                                        * the screen. We only allow known
+                                        * commands, else we show help msg. */
+                                       if (input == ' ' || input == '\n' || input == 'q' || input == 'r')
+                                               break;
+                                       len = printf("(Enter:next line Space:next page Q:quit R:show the rest)");
+                               }
+                               len = 0;
+                               lines = 0;
+                               please_display_more_prompt = 0;
+
+                               if (input == 'q')
+                                       goto end;
+
+                               /* The user may have resized the terminal.
+                                * Re-read the dimensions. */
+                               if (ENABLE_FEATURE_USE_TERMIOS) {
+                                       get_terminal_width_height(cin_fileno, &terminal_width, &terminal_height);
+                                       terminal_height -= 1;
+                               }
+                       }
+
+                       /* Crudely convert tabs into spaces, which are
+                        * a bajillion times easier to deal with. */
+                       if (c == '\t') {
+                               spaces = CONVERTED_TAB_SIZE - 1;
+                               c = ' ';
+                       }
+
+                       /*
+                        * There are two input streams to worry about here:
+                        *
+                        * c    : the character we are reading from the file being "mored"
+                        * input: a character received from the keyboard
+                        *
+                        * If we hit a newline in the _file_ stream, we want to test and
+                        * see if any characters have been hit in the _input_ stream. This
+                        * allows the user to quit while in the middle of a file.
+                        */
+                       wrap = (++len > terminal_width);
+                       if (c == '\n' || wrap) {
+                               /* Then outputting this character
+                                * will move us to a new line. */
+                               if (++lines >= terminal_height || input == '\n')
+                                       please_display_more_prompt = 1;
+                               len = 0;
+                       }
+                       if (c != '\n' && wrap) {
+                               /* Then outputting this will also put a character on
+                                * the beginning of that new line. Thus we first want to
+                                * display the prompt (if any), so we skip the putchar()
+                                * and go back to the top of the loop, without reading
+                                * a new character. */
+                               goto loop_top;
+                       }
+                       /* My small mind cannot fathom backspaces and UTF-8 */
+                       putchar(c);
+               }
+               fclose(file);
+               fflush_all();
+       } while (*argv && *++argv);
+ end:
+       setTermSettings(cin_fileno, &initial_settings);
        return 0;
 }