vi: add fileformats option

Add a limited version of the 'fileformats' option.  Only the
'dos,unix' and 'unix,dos' settings are allowed with the former
as default.

When a file is read for editing its format is detected.  If it
only has LF line endings it's treated as being of type 'unix'
otherwise its type is 'dos'.

When an empty edit buffer is created it's given the first file
type listed in 'fileformats'.

The file type is stored in the read-only option 'fileformat'
and is used to select the appropriate line endings when the
file is written.

See GitHub issue #220.  Adds 168 bytes to the binary.

3 files changed, 119 insertions, 17 deletions

diff --git a/configs/mingw32_defconfig b/configs/mingw32_defconfig
index d9466af1d..179af2f67 100644
--- a/configs/mingw32_defconfig
+++ b/configs/mingw32_defconfig
@@ -1,7 +1,7 @@
 #
 # Automatically generated make config: don't edit
-# Busybox version: 1.34.0.git
-# Sat Jul 24 10:37:11 2021
+# Busybox version: 1.35.0.git
+# Mon Aug 30 08:54:18 2021
 #
 CONFIG_HAVE_DOT_CONFIG=y
 # CONFIG_PLATFORM_POSIX is not set
@@ -226,11 +226,13 @@ CONFIG_CHMOD=y
 # CONFIG_FEATURE_CHOWN_LONG_OPTIONS is not set
 # CONFIG_CHROOT is not set
 CONFIG_CKSUM=y
+CONFIG_CRC32=y
 CONFIG_COMM=y
 CONFIG_CP=y
 CONFIG_FEATURE_CP_LONG_OPTIONS=y
 # CONFIG_FEATURE_CP_REFLINK is not set
 CONFIG_CUT=y
+CONFIG_FEATURE_CUT_REGEX=y
 CONFIG_DATE=y
 CONFIG_FEATURE_DATE_ISOFMT=y
 # CONFIG_FEATURE_DATE_NANO is not set
@@ -354,10 +356,10 @@ CONFIG_BASE64=y
 CONFIG_UUENCODE=y
 CONFIG_WC=y
 CONFIG_FEATURE_WC_LARGE=y
-CONFIG_WHOAMI=y
 # CONFIG_WHO is not set
 # CONFIG_W is not set
 # CONFIG_USERS is not set
+CONFIG_WHOAMI=y
 CONFIG_YES=y
 
 #
@@ -446,6 +448,7 @@ CONFIG_FEATURE_VI_REGEX_SEARCH=y
 CONFIG_FEATURE_VI_DOT_CMD=y
 CONFIG_FEATURE_VI_READONLY=y
 CONFIG_FEATURE_VI_SETOPTS=y
+CONFIG_FEATURE_VI_FILE_FORMAT=y
 CONFIG_FEATURE_VI_SET=y
 CONFIG_FEATURE_VI_WIN_RESIZE=y
 # CONFIG_FEATURE_VI_ASK_TERMINAL is not set
@@ -530,10 +533,10 @@ CONFIG_INIT_TERMINAL_TYPE=""
 # CONFIG_USE_BB_SHADOW is not set
 # CONFIG_USE_BB_CRYPT is not set
 # CONFIG_USE_BB_CRYPT_SHA is not set
-# CONFIG_ADDGROUP is not set
-# CONFIG_FEATURE_ADDUSER_TO_GROUP is not set
 # CONFIG_ADD_SHELL is not set
 # CONFIG_REMOVE_SHELL is not set
+# CONFIG_ADDGROUP is not set
+# CONFIG_FEATURE_ADDUSER_TO_GROUP is not set
 # CONFIG_ADDUSER is not set
 # CONFIG_FEATURE_CHECK_NAMES is not set
 CONFIG_LAST_ID=0
@@ -752,6 +755,7 @@ CONFIG_REV=y
 # Miscellaneous Utilities
 #
 # CONFIG_ADJTIMEX is not set
+CONFIG_ASCII=y
 # CONFIG_BBCONFIG is not set
 # CONFIG_FEATURE_COMPRESS_BBCONFIG is not set
 CONFIG_BC=y
@@ -785,10 +789,10 @@ CONFIG_FEATURE_CROND_DIR=""
 # CONFIG_FEATURE_DEVFS is not set
 # CONFIG_DEVMEM is not set
 # CONFIG_FBSPLASH is not set
-# CONFIG_FLASHCP is not set
 # CONFIG_FLASH_ERASEALL is not set
 # CONFIG_FLASH_LOCK is not set
 # CONFIG_FLASH_UNLOCK is not set
+# CONFIG_FLASHCP is not set
 # CONFIG_HDPARM is not set
 # CONFIG_FEATURE_HDPARM_GET_IDENTITY is not set
 # CONFIG_FEATURE_HDPARM_HDIO_SCAN_HWIF is not set
@@ -839,13 +843,13 @@ CONFIG_STRINGS=y
 CONFIG_TIME=y
 CONFIG_TS=y
 CONFIG_TTYSIZE=y
-# CONFIG_UBIRENAME is not set
 # CONFIG_UBIATTACH is not set
 # CONFIG_UBIDETACH is not set
 # CONFIG_UBIMKVOL is not set
 # CONFIG_UBIRMVOL is not set
 # CONFIG_UBIRSVOL is not set
 # CONFIG_UBIUPDATEVOL is not set
+# CONFIG_UBIRENAME is not set
 # CONFIG_VOLNAME is not set
 # CONFIG_WATCHDOG is not set
 # CONFIG_FEATURE_WATCHDOG_OPEN_TWICE is not set
diff --git a/configs/mingw64_defconfig b/configs/mingw64_defconfig
index ef1ba4e22..f9be9aab2 100644
--- a/configs/mingw64_defconfig
+++ b/configs/mingw64_defconfig
@@ -1,7 +1,7 @@
 #
 # Automatically generated make config: don't edit
-# Busybox version: 1.34.0.git
-# Sat Jul 24 10:37:11 2021
+# Busybox version: 1.35.0.git
+# Mon Aug 30 08:54:18 2021
 #
 CONFIG_HAVE_DOT_CONFIG=y
 # CONFIG_PLATFORM_POSIX is not set
@@ -226,11 +226,13 @@ CONFIG_CHMOD=y
 # CONFIG_FEATURE_CHOWN_LONG_OPTIONS is not set
 # CONFIG_CHROOT is not set
 CONFIG_CKSUM=y
+CONFIG_CRC32=y
 CONFIG_COMM=y
 CONFIG_CP=y
 CONFIG_FEATURE_CP_LONG_OPTIONS=y
 # CONFIG_FEATURE_CP_REFLINK is not set
 CONFIG_CUT=y
+CONFIG_FEATURE_CUT_REGEX=y
 CONFIG_DATE=y
 CONFIG_FEATURE_DATE_ISOFMT=y
 # CONFIG_FEATURE_DATE_NANO is not set
@@ -354,10 +356,10 @@ CONFIG_BASE64=y
 CONFIG_UUENCODE=y
 CONFIG_WC=y
 CONFIG_FEATURE_WC_LARGE=y
-CONFIG_WHOAMI=y
 # CONFIG_WHO is not set
 # CONFIG_W is not set
 # CONFIG_USERS is not set
+CONFIG_WHOAMI=y
 CONFIG_YES=y
 
 #
@@ -446,6 +448,7 @@ CONFIG_FEATURE_VI_REGEX_SEARCH=y
 CONFIG_FEATURE_VI_DOT_CMD=y
 CONFIG_FEATURE_VI_READONLY=y
 CONFIG_FEATURE_VI_SETOPTS=y
+CONFIG_FEATURE_VI_FILE_FORMAT=y
 CONFIG_FEATURE_VI_SET=y
 CONFIG_FEATURE_VI_WIN_RESIZE=y
 # CONFIG_FEATURE_VI_ASK_TERMINAL is not set
@@ -530,10 +533,10 @@ CONFIG_INIT_TERMINAL_TYPE=""
 # CONFIG_USE_BB_SHADOW is not set
 # CONFIG_USE_BB_CRYPT is not set
 # CONFIG_USE_BB_CRYPT_SHA is not set
-# CONFIG_ADDGROUP is not set
-# CONFIG_FEATURE_ADDUSER_TO_GROUP is not set
 # CONFIG_ADD_SHELL is not set
 # CONFIG_REMOVE_SHELL is not set
+# CONFIG_ADDGROUP is not set
+# CONFIG_FEATURE_ADDUSER_TO_GROUP is not set
 # CONFIG_ADDUSER is not set
 # CONFIG_FEATURE_CHECK_NAMES is not set
 CONFIG_LAST_ID=0
@@ -752,6 +755,7 @@ CONFIG_REV=y
 # Miscellaneous Utilities
 #
 # CONFIG_ADJTIMEX is not set
+CONFIG_ASCII=y
 # CONFIG_BBCONFIG is not set
 # CONFIG_FEATURE_COMPRESS_BBCONFIG is not set
 CONFIG_BC=y
@@ -785,10 +789,10 @@ CONFIG_FEATURE_CROND_DIR=""
 # CONFIG_FEATURE_DEVFS is not set
 # CONFIG_DEVMEM is not set
 # CONFIG_FBSPLASH is not set
-# CONFIG_FLASHCP is not set
 # CONFIG_FLASH_ERASEALL is not set
 # CONFIG_FLASH_LOCK is not set
 # CONFIG_FLASH_UNLOCK is not set
+# CONFIG_FLASHCP is not set
 # CONFIG_HDPARM is not set
 # CONFIG_FEATURE_HDPARM_GET_IDENTITY is not set
 # CONFIG_FEATURE_HDPARM_HDIO_SCAN_HWIF is not set
@@ -839,13 +843,13 @@ CONFIG_STRINGS=y
 CONFIG_TIME=y
 CONFIG_TS=y
 CONFIG_TTYSIZE=y
-# CONFIG_UBIRENAME is not set
 # CONFIG_UBIATTACH is not set
 # CONFIG_UBIDETACH is not set
 # CONFIG_UBIMKVOL is not set
 # CONFIG_UBIRMVOL is not set
 # CONFIG_UBIRSVOL is not set
 # CONFIG_UBIUPDATEVOL is not set
+# CONFIG_UBIRENAME is not set
 # CONFIG_VOLNAME is not set
 # CONFIG_WATCHDOG is not set
 # CONFIG_FEATURE_WATCHDOG_OPEN_TWICE is not set
diff --git a/editors/vi.c b/editors/vi.c
index 2c1048a4c..b973cc056 100644
--- a/editors/vi.c
+++ b/editors/vi.c
@@ -112,6 +112,15 @@
 //config:       help
 //config:       Enable the editor to set some (ai, ic, showmatch) options.
 //config:
+//config:config FEATURE_VI_FILE_FORMAT
+//config:       bool "Enable detection of file format"
+//config:       default y
+//config:       depends on VI && FEATURE_VI_SETOPTS && PLATFORM_MINGW32
+//config:       help
+//config:       Enable the editor to detect the format of files it reads
+//config:       so they can be written out with the appropriate line
+//config:       endings. Enable the 'fileformats' option.
+//config:
 //config:config FEATURE_VI_SET
 //config:       bool "Support :set"
 //config:       default y
@@ -297,6 +306,7 @@ struct globals {
 
         // the rest
 #if ENABLE_FEATURE_VI_SETOPTS
+#if !ENABLE_FEATURE_VI_FILE_FORMAT
         smallint vi_setops;     // set by setops()
 #define VI_AUTOINDENT (1 << 0)
 #define VI_EXPANDTAB  (1 << 1)
@@ -304,6 +314,17 @@ struct globals {
 #define VI_IGNORECASE (1 << 3)
 #define VI_SHOWMATCH  (1 << 4)
 #define VI_TABSTOP    (1 << 5)
+#else
+        smalluint vi_setops;     // set by setops()
+#define VI_AUTOINDENT (1 << 0)
+#define VI_EXPANDTAB  (1 << 1)
+#define VI_FILEFORMAT (1 << 2)
+#define VI_FILEFORMATS (1 << 3)
+#define VI_ERR_METHOD (1 << 4)
+#define VI_IGNORECASE (1 << 5)
+#define VI_SHOWMATCH  (1 << 6)
+#define VI_TABSTOP    (1 << 7)
+#endif
 #define autoindent (vi_setops & VI_AUTOINDENT)
 #define expandtab  (vi_setops & VI_EXPANDTAB )
 #define err_method (vi_setops & VI_ERR_METHOD) // indicate error with beep or flash
@@ -313,10 +334,18 @@ struct globals {
 #define OPTS_STR \
                 "ai\0""autoindent\0" \
                 "et\0""expandtab\0" \
+                IF_FEATURE_VI_FILE_FORMAT("ff\0""fileformat\0") \
+                IF_FEATURE_VI_FILE_FORMAT("ffs\0""fileformats\0") \
                 "fl\0""flash\0" \
                 "ic\0""ignorecase\0" \
                 "sm\0""showmatch\0" \
                 "ts\0""tabstop\0"
+
+#define FF_DOS_UNIX 0
+#define FF_UNIX_DOS 1
+#define FORMATS_STR \
+                "dos,unix\0" \
+                "unix,dos\0"
 #else
 #define autoindent (0)
 #define expandtab  (0)
@@ -380,6 +409,10 @@ struct globals {
 #if ENABLE_FEATURE_VI_SETOPTS
         int indentcol;          // column of recently autoindent, 0 or -1
 #endif
+#if ENABLE_FEATURE_VI_FILE_FORMAT
+        smallint fileformat;
+        smallint fileformats;
+#endif
         smallint cmd_error;
 
         // former statics
@@ -507,6 +540,8 @@ struct globals {
 #define dotcnt                  (G.dotcnt             )
 #define last_search_pattern     (G.last_search_pattern)
 #define indentcol               (G.indentcol          )
+#define fileformat              (G.fileformat         )
+#define fileformats             (G.fileformats        )
 #define cmd_error               (G.cmd_error          )
 
 #define edit_file__cur_line     (G.edit_file__cur_line)
@@ -2066,6 +2101,10 @@ static int file_insert(const char *fn, char *p, int initial)
                 undo_push_insert(p, size, ALLOW_UNDO);
         }
 # endif
+#if ENABLE_FEATURE_VI_FILE_FORMAT
+        if (initial && cnt > 0)
+                fileformat = cnt == size ? FF_UNIX_DOS : FF_DOS_UNIX;
+#endif
  fi:
         close(fd);
 
@@ -2342,6 +2381,9 @@ static int init_text_buffer(char *fn)
         free(text);
         text_size = 10240;
         screenbegin = dot = end = text = xzalloc(text_size);
+#if ENABLE_FEATURE_VI_FILE_FORMAT
+        fileformat = fileformats;
+#endif
 
         update_filename(fn);
         rc = file_insert(fn, text, 1);
@@ -2387,6 +2429,13 @@ static uintptr_t string_insert(char *p, const char *s, int undo) // insert the s
 static int file_write(char *fn, char *first, char *last)
 {
         int fd, cnt, charcnt;
+#if ENABLE_PLATFORM_MINGW32
+# if ENABLE_FEATURE_VI_FILE_FORMAT
+#  define dos (fileformat == FF_DOS_UNIX)
+# else
+#  define dos (1)
+# endif
+#endif
 
         if (fn == 0) {
                 status_line_bold("No current filename");
@@ -2398,7 +2447,7 @@ static int file_write(char *fn, char *first, char *last)
 #if !ENABLE_PLATFORM_MINGW32
         fd = open(fn, (O_WRONLY | O_CREAT), 0666);
 #else
-        fd = open(fn, (O_WRONLY | O_CREAT | _O_TEXT), 0666);
+        fd = open(fn, (O_WRONLY | O_CREAT | (dos ? _O_TEXT : 0)), 0666);
 #endif
         if (fd < 0)
                 return -1;
@@ -2407,9 +2456,9 @@ static int file_write(char *fn, char *first, char *last)
 #if !ENABLE_PLATFORM_MINGW32
         ftruncate(fd, charcnt);
 #else
-        // File was written in text mode; this makes it bigger so adjust
+        // If file was written in text mode it will be bigger so adjust
         // the truncation to match.
-        ftruncate(fd, charcnt + count_cr(first, cnt));
+        ftruncate(fd, charcnt + (dos ? count_cr(first, cnt) : 0));
 #endif
         if (charcnt == cnt) {
                 // good write
@@ -2699,6 +2748,7 @@ static void setops(char *args, int flg_no)
 
         index = 1 << (index >> 1); // convert to VI_bit
 
+#if !ENABLE_FEATURE_VI_FILE_FORMAT
         if (index & VI_TABSTOP) {
                 int t;
                 if (!eq || flg_no) // no "=NNN" or it is "notabstop"?
@@ -2709,6 +2759,27 @@ static void setops(char *args, int flg_no)
                 tabstop = t;
                 return;
         }
+#else
+        if (index & VI_FILEFORMAT)
+                goto bad;
+        if (index & (VI_TABSTOP | VI_FILEFORMATS)) {
+                if (!eq || flg_no) // no "=NNN" or it is "notabstop"?
+                        goto bad;
+                if (index & VI_TABSTOP) {
+                        int t = bb_strtou(eq + 1, NULL, 10);
+                        if (t <= 0 || t > MAX_TABSTOP)
+                                goto bad;
+                        tabstop = t;
+                        return;
+                } else { // VI_FILEFORMATS
+                        int t = index_in_strings(FORMATS_STR, eq + 1);
+                        if (t < 0)
+                                goto bad;
+                        fileformats = t;
+                        return;
+                }
+        }
+#endif
         if (eq) goto bad; // boolean option has "="?
         if (flg_no) {
                 vi_setops &= ~index;
@@ -3205,6 +3276,7 @@ static void colon(char *buf)
                 if (!args[0] || strcmp(args, "all") == 0) {
                         // print out values of all options
 #  if ENABLE_FEATURE_VI_SETOPTS
+#   if !ENABLE_FEATURE_VI_FILE_FORMAT
                         status_line_bold(
                                 "%sautoindent "
                                 "%sexpandtab "
@@ -3219,6 +3291,28 @@ static void colon(char *buf)
                                 showmatch ? "" : "no",
                                 tabstop
                         );
+#   else // ENABLE_FEATURE_VI_FILE_FORMAT
+                        unsigned int mask = 1, j = 0;
+                        go_bottom_and_clear_to_eol();
+                        for (;;) {
+                                const char *name = nth_string(OPTS_STR, 2 * j + 1);
+                                if (!name[0])
+                                        break;
+                                if (mask == VI_FILEFORMAT)
+                                        printf("%s=%s ", name, nth_string("dos\0unix\0", fileformat));
+                                else if (mask == VI_FILEFORMATS)
+                                        printf("%s=%s ", name, nth_string(FORMATS_STR, fileformats));
+                                else if (mask == VI_TABSTOP)
+                                        printf("%s=%u ", name, tabstop);
+                                else
+                                        printf("%s%s ", vi_setops & mask ? "" : "no", name);
+                                if (j++ == 4)
+                                        bb_putchar('\n');
+                                mask <<= 1;
+                        }
+                        bb_putchar('\n');
+                        Hit_Return();
+#   endif
 #  endif
                         goto ret;
                 }