ls: make color-related code more readable. Fix a case when

 it was working non-deterministically.

function                                             old     new   delta
bold                                                   -      34     +34
showfiles                                           1508    1495     -13
fgcolor                                               50      34     -16
bgcolor                                               34       -     -34
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 0/2 up/down: 34/-63)            Total: -29 bytes

1 files changed, 43 insertions, 19 deletions

diff --git a/coreutils/ls.c b/coreutils/ls.c
index a461b154f..8007f2a2e 100644
--- a/coreutils/ls.c
+++ b/coreutils/ls.c
@@ -127,14 +127,6 @@ SPLIT_SUBDIR    = 2,
 
 };
 
-#define TYPEINDEX(mode) (((mode) >> 12) & 0x0f)
-#define TYPECHAR(mode)  ("0pcCd?bB-?l?s???" [TYPEINDEX(mode)])
-#define APPCHAR(mode)   ("\0|\0\0/\0\0\0\0\0@\0=\0\0\0" [TYPEINDEX(mode)])
-#define COLOR(mode)     ("\000\043\043\043\042\000\043\043"\
-                         "\000\000\044\000\043\000\000\040" [TYPEINDEX(mode)])
-#define ATTR(mode)      ("\00\00\01\00\01\00\01\00"\
-                         "\00\00\01\00\01\00\00\01" [TYPEINDEX(mode)])
-
 /* "[-]Cadil1", POSIX mandated options, busybox always supports */
 /* "[-]gnsx", POSIX non-mandated options, busybox always supports */
 /* "[-]Q" GNU option? busybox always supports */
@@ -344,18 +336,46 @@ static struct dnode *my_stat(const char *fullname, const char *name, int force_f
         return cur;
 }
 
+
+/* FYI type values: 1:fifo 2:char 4:dir 6:blk 8:file 10:link 12:socket
+ * (various wacky OSes: 13:Sun door 14:BSD whiteout 5:XENIX named file
+ *  3/7:multiplexed char/block device)
+ * and we use 0 for unknown and 15 for executables (see below) */
+#define TYPEINDEX(mode) (((mode) >> 12) & 0x0f)
+#define TYPECHAR(mode)  ("0pcCd?bB-?l?s???" [TYPEINDEX(mode)])
+#define APPCHAR(mode)   ("\0|\0\0/\0\0\0\0\0@\0=\0\0\0" [TYPEINDEX(mode)])
+/* 036 black foreground              050 black background
+   037 red foreground                051 red background
+   040 green foreground              052 green background
+   041 brown foreground              053 brown background
+   042 blue foreground               054 blue background
+   043 magenta (purple) foreground   055 magenta background
+   044 cyan (light blue) foreground  056 cyan background
+   045 gray foreground               057 white background
+*/
+#define COLOR(mode) ( \
+        /*un  fi  chr     dir     blk     file    link    sock        exe */ \
+        "\037\043\043\045\042\045\043\043\000\045\044\045\043\045\045\040" \
+        [TYPEINDEX(mode)])
+/* Select normal (0) [actually "reset all"] or bold (1)
+ * (other attributes are 2:dim 4:underline 5:blink 7:reverse,
+ *  let's use 7 for "impossible" types, just for fun)
+ * Note: coreutils 6.9 uses inverted red for setuid binaries.
+ */
+#define ATTR(mode) ( \
+        /*un fi chr   dir   blk   file  link  sock     exe */ \
+        "\01\00\01\07\01\07\01\07\00\07\01\07\01\07\07\01" \
+        [TYPEINDEX(mode)])
+
 #if ENABLE_FEATURE_LS_COLOR
+/* mode of zero is interpreted as "unknown" (stat failed) */
 static char fgcolor(mode_t mode)
 {
-        /* Check wheter the file is existing (if so, color it red!) */
-        if (errno == ENOENT)
-                return '\037';
         if (S_ISREG(mode) && (mode & (S_IXUSR | S_IXGRP | S_IXOTH)))
                 return COLOR(0xF000);   /* File is executable ... */
         return COLOR(mode);
 }
-
-static char bgcolor(mode_t mode)
+static char bold(mode_t mode)
 {
         if (S_ISREG(mode) && (mode & (S_IXUSR | S_IXGRP | S_IXOTH)))
                 return ATTR(0xF000);    /* File is executable ... */
@@ -378,6 +398,7 @@ static char append_char(mode_t mode)
 }
 #endif
 
+
 #define countdirs(A, B) count_dirs((A), (B), 1)
 #define countsubdirs(A, B) count_dirs((A), (B), 0)
 static int count_dirs(struct dnode **dn, int nfiles, int notsubdirs)
@@ -818,10 +839,11 @@ static int list_single(const struct dnode *dn)
                         break;
 #endif
                 case LIST_FILENAME:
-                        errno = 0;
 #if ENABLE_FEATURE_LS_COLOR
-                        if (show_color && !lstat(dn->fullname, &info)) {
-                                printf("\033[%u;%um", bgcolor(info.st_mode),
+                        if (show_color) {
+                                info.st_mode = 0; /* for fgcolor() */
+                                lstat(dn->fullname, &info);
+                                printf("\033[%u;%um", bold(info.st_mode),
                                                 fgcolor(info.st_mode));
                         }
 #endif
@@ -836,14 +858,16 @@ static int list_single(const struct dnode *dn)
                                 if (!lpath) break;
                                 printf(" -> ");
 #if ENABLE_FEATURE_LS_FILETYPES || ENABLE_FEATURE_LS_COLOR
-                                if (!stat(dn->fullname, &info)) {
+#if ENABLE_FEATURE_LS_COLOR
+                                info.st_mode = 0; /* for fgcolor() */
+#endif
+                                if (stat(dn->fullname, &info) == 0) {
                                         append = append_char(info.st_mode);
                                 }
 #endif
 #if ENABLE_FEATURE_LS_COLOR
                                 if (show_color) {
-                                        errno = 0;
-                                        printf("\033[%u;%um", bgcolor(info.st_mode),
+                                        printf("\033[%u;%um", bold(info.st_mode),
                                                    fgcolor(info.st_mode));
                                 }
 #endif