PATCH: Re: Btw.: glob-qualifier

[Sven Wischnowsky <wischnow@informatik.hu-berlin.de>]

Bart Schaefer wrote:

> Oof.  If you're going to make it usable, then REALLY make it usable.
> At the risk of further abusing the already over-used parentheses, how
> about (o(ug=w,o+r)) for "user and group must have exactly the write
> bit set, and other must have at least r" and (o(u+x,go-w)) for "user
> must have at least the execute bit set, and group and other must not
> have write" and so on.

The patch below implements this (with a few extras). The patch
contains a hunk for the docs and I dont' want to write it again here,
at least, Bart's examples work (with a different separator than the
parenthese, of course).

Of course, many of the things you can specify with this can also be
achieved by using the already existing qualifiers. Because of this,
I'm not sure, if this is important enough to be included. However,
some of the things you can do with `(o...)' can not be achieved with
the existing modifiers and for others it may be easier to remember.

Bye
 Sven

--- os/glob.c	Fri Jan 29 10:04:57 1999
+++ Src/glob.c	Fri Jan 29 14:11:56 1999
@@ -1006,21 +1006,96 @@
     return v;
 }
 
-/* get octal number after qualifier */
+/* get mode spec after qualifier */
 
 /**/
 static long
-qgetoctnum(char **s)
+qgetmodespec(char **s)
 {
-    long v = 0;
+    long yes = 0, no = 0, val, mask, t;
+    char *p = *s, c, how, end;
 
-    if (!idigit(**s)) {
-	zerr("octal number expected", NULL, 0);
-	return 0;
-    }
-    while (**s >= '0' && **s <= '7')
-	v = v * 010 + *(*s)++ - '0';
-    return v;
+    if ((c = *p) == '=' || c == Equals || c == '+' || c == '-' ||
+	c == '?' || c == Quest || (c >= '0' && c <= '7')) {
+	end = 0;
+	c = 0;
+    } else {
+	end = (c == '<' ? '>' :
+	       (c == '[' ? ']' :
+		(c == '{' ? '}' :
+		 (c == Inang ? Outang :
+		  (c == Inbrack ? Outbrack :
+		   (c == Inbrace ? Outbrace : c))))));
+	p++;
+    }
+    do {
+	mask = 0;
+	while (((c = *p) == 'u' || c == 'g' || c == 'o' || c == 'a') && end) {
+	    switch (c) {
+	    case 'o': mask |= 01007; break;
+	    case 'g': mask |= 02070; break;
+	    case 'u': mask |= 04700; break;
+	    case 'a': mask |= 07777; break;
+	    }
+	    p++;
+	}
+	how = ((c == '+' || c == '-') ? c : '=');
+	if (c == '+' || c == '-' || c == '=' || c == Equals)
+	    p++;
+	val = 0;
+	if (mask) {
+	    while ((c = *p++) != ',' && c != end) {
+		switch (c) {
+		case 'x': val |= 00111; break;
+		case 'w': val |= 00222; break;
+		case 'r': val |= 00444; break;
+		case 's': val |= 06000; break;
+		case 't': val |= 01000; break;
+		case '0': case '1': case '2': case '3':
+		case '4': case '5': case '6': case '7':
+		    t = ((long) c - '0');
+		    val |= t | (t << 3) | (t << 6);
+		    break;
+		default:
+		    zerr("invalid mode specification", NULL, 0);
+		    return 0;
+		}
+	    }
+	    if (how == '=' || how == '+') {
+		yes |= val & mask;
+		val = ~val;
+	    }
+	    if (how == '=' || how == '-')
+		no |= val & mask;
+	} else {
+	    t = 07777;
+	    while ((c = *p) == '?' || c == Quest ||
+		   (c >= '0' && c <= '7')) {
+		if (c == '?' || c == Quest) {
+		    t = (t << 3) | 7;
+		    val <<= 3;
+		} else {
+		    t <<= 3;
+		    val = (val << 3) | ((long) c - '0');
+		}
+		p++;
+	    }
+	    if (end && c != end && c != ',') {
+		zerr("invalid mode specification", NULL, 0);
+		return 0;
+	    }
+	    if (how == '=') {
+		yes = (yes & ~t) | val;
+		no = (no & ~t) | (~val & ~t);
+	    } else if (how == '+')
+		yes |= val;
+	    else
+		no |= val;
+	}
+    } while (end && c != end);
+
+    *s = p;
+    return ((yes & 07777) | ((no & 07777) << 12));
 }
 
 static int
@@ -1358,10 +1433,9 @@
 			}
 			break;
 		    case 'o':
-			/* Match octal mode of file exactly. *
-			 * Currently undocumented.           */
-			func = qualeqflags;
-			data = qgetoctnum(&s);
+			/* Match modes with chmod-spec. */
+			func = qualmodeflags;
+			data = qgetmodespec(&s);
 			break;
 		    case 'M':
 			/* Mark directories with a / */
@@ -3093,13 +3167,15 @@
     return mode_to_octal(buf->st_mode) & mod;
 }
 
-/* mode matches number supplied exactly  */
+/* mode matches specification */
 
 /**/
 static int
-qualeqflags(struct stat *buf, long mod)
+qualmodeflags(struct stat *buf, long mod)
 {
-    return mode_to_octal(buf->st_mode) == mod;
+    long v = mode_to_octal(buf->st_mode), y = mod & 07777, n = mod >> 12;
+
+    return ((v & y) == y && !(v & n));
 }
 
 /* regular executable file? */
--- od/Zsh/expn.yo	Fri Jan 29 10:05:09 1999
+++ Doc/Zsh/expn.yo	Fri Jan 29 14:28:21 1999
@@ -1088,6 +1088,49 @@
 item(tt(t))(
 files with the sticky bit (01000)
 )
+item(tt(o)var(spec))(
+files with access rights matching var(spec). This var(spec) may be a
+octal number optionally preceded by a `tt(=)', a `tt(PLUS())', or a
+`tt(-)'. If none of these characters is given, the behavior is the
+same as for `tt(=)'. The octal number decribes the mode bits to be
+expected, if combined with a `tt(=)', the value given must match the
+file-modes exactly, with a `tt(PLUS())', at least the bits in the
+given number must be set in the file-modes, and with a `tt(-)', the
+bits in the number must not be set. Giving a `tt(?)' instead of a
+octal digit anywhere in the number ensures that the corresponding bits 
+inthe file-modes are not checked, this is only useful in combination
+with `tt(=)'.
+
+If the qualifier `tt(o)' is followed by any other character anything
+up to the next matching character (`tt([)', `tt({)', and `tt(<)' match 
+`tt(])', `tt(})', and `tt(>)' respectively, any other character
+matches itself) is taken as a list of comma-separated
+var(sub-spec)s. Each var(sub-spec) may be either a octal number as
+described above or a list of any of the characters `tt(u)', `tt(g)',
+`tt(o)', and `tt(a)', followed by a `tt(=)', a `tt(PLUS())', or a
+`tt(-)', followed by a list of any of the characters `tt(r)', `tt(w)', 
+`tt(x)', `tt(s)', and `tt(t)', or a octal digit. The first list of
+characters specify which acess rights are to be checked. If a `tt(u)'
+is given, those for the owner of the file are used, if a `tt(g)' is
+given, those of the group are checked, a `tt(o)' means to test those
+of other users, and the `tt(a)' says to test all three groups. The
+`tt(=)', `tt(PLUS())', and `tt(-)' again says how the modes are to be
+checked and have the same meaning as described for the first form
+above. The second list of characters finally says which access rights
+are to be expected: `tt(r)' for read access, `tt(w)' for write access, 
+`tt(x)' for the right to execute the file (or to search a directory),
+`tt(s)' for the setuid and setgid bits, and `tt(t)' for the sticky
+bit.
+
+Thus, `tt(*(o70?))' gives the files for which the owner has read,
+write, and execute permission, and for which other group members have
+no rights, independent of the permissions for other user. The pattern
+`tt(*(o-100))' gives all files for which the owner does not have
+execute permission, and `tt(*(o:gu+w,o-rx))' gives the files for which 
+the owner and the other members of the group have at least write
+permission, and fo which other users don't have read or execute
+permission.
+)
 item(tt(d)var(dev))(
 files on the device var(dev)
 )

--
Sven Wischnowsky                         wischnow@informatik.hu-berlin.de