// parse a component of the expanded set.
// At this point, no pattern may contain "/" in it
// so we're going to return a 2d array, where each entry is the full
// pattern, split on '/', and then turned into a regular expression.
// A regexp is made at the end which joins each array with an
// escaped /, and another full one which joins each regexp with |.
//
// Following the lead of Bash 4.1, note that "**" only has special meaning
// when it is the *only* thing in a path portion. Otherwise, any series
// of * is equivalent to a single *. Globstar behavior is enabled by
// default, and can be disabled by setting options.noglobstar.
private Tuple <ParseItem, bool> Parse(string pattern, bool isSub)
{
// shortcuts
if (!options.NoGlobStar && pattern == "**")
{
return(Tuple.Create(GlobStar.Instance, false));
}
if (pattern == "")
{
return(Tuple.Create(ParseItem.Empty, false));
}
string re = "";
bool hasMagic = options.NoCase, escaping = false, inClass = false;
// ? => one single character
var patternListStack = new Stack <PatternListEntry>();
char plType;
char?stateChar = null;
int reClassStart = -1, classStart = -1;
// . and .. never match anything that doesn't start with .,
// even when options.dot is set.
string patternStart = pattern[0] == '.' ? "" // anything
// not (start or / followed by . or .. followed by / or end)
: options.Dot ? "(?!(?:^|\\/)\\.{1,2}(?:$|\\/))"
: "(?!\\.)";
Action clearStateChar = () =>
{
if (stateChar != null)
{
// we had some state-tracking character
// that wasn't consumed by this pass.
switch (stateChar)
{
case '*':
re += star;
hasMagic = true;
break;
case '?':
re += qmark;
hasMagic = true;
break;
default:
re += "\\" + stateChar;
break;
}
stateChar = null;
}
};
for (var i = 0; i < pattern.Length; i++)
{
var c = pattern[i];
//if (options.debug) {
// console.error("%s\t%s %s %j", pattern, i, re, c)
//}
// skip over any that are escaped.
if (escaping && reSpecials.Contains(c))
{
re += "\\" + c;
escaping = false;
continue;
}
switch (c)
{
case '/':
// completely not allowed, even escaped.
// Should already be path-split by now.
return(null);
case '\\':
clearStateChar();
escaping = true;
continue;
// the various stateChar values
// for the 'extglob' stuff.
case '?':
case '*':
case '+':
case '@':
case '!':
//if (options.debug) {
// console.error("%s\t%s %s %j <-- stateChar", pattern, i, re, c)
//}
// all of those are literals inside a class, except that
// the glob [!a] means [^a] in regexp
if (inClass)
{
if (c == '!' && i == classStart + 1)
{
c = '^';
}
re += c;
continue;
}
// if we already have a stateChar, then it means
// that there was something like ** or +? in there.
// Handle the stateChar, then proceed with this one.
clearStateChar();
stateChar = c;
// if extglob is disabled, then +(asdf|foo) isn't a thing.
// just clear the statechar *now*, rather than even diving into
// the patternList stuff.
if (options.NoExt)
{
clearStateChar();
}
continue;
case '(':
if (inClass)
{
re += "(";
continue;
}
if (stateChar == null)
{
re += "\\(";
continue;
}
plType = stateChar.Value;
patternListStack.Push(new PatternListEntry {
Type = plType, Start = i - 1, ReStart = re.Length
});
// negation is (?:(?!js)[^/]*)
re += stateChar == '!' ? "(?:(?!" : "(?:";
stateChar = null;
continue;
case ')':
if (inClass || !patternListStack.Any())
{
re += "\\)";
continue;
}
hasMagic = true;
re += ')';
plType = patternListStack.Pop().Type;
// negation is (?:(?!js)[^/]*)
// The others are (?:<pattern>)<type>
switch (plType)
{
case '!':
re += "[^/]*?)";
break;
case '?':
case '+':
case '*': re += plType; break;
case '@': break; // the default anyway
}
continue;
case '|':
if (inClass || !patternListStack.Any() || escaping)
{
re += "\\|";
escaping = false;
continue;
}
re += "|";
continue;
// these are mostly the same in regexp and glob
case '[':
// swallow any state-tracking char before the [
clearStateChar();
if (inClass)
{
re += "\\" + c;
continue;
}
inClass = true;
classStart = i;
reClassStart = re.Length;
re += c;
continue;
case ']':
// a right bracket shall lose its special
// meaning and represent itself in
// a bracket expression if it occurs
// first in the list. -- POSIX.2 2.8.3.2
if (i == classStart + 1 || !inClass)
{
re += "\\" + c;
escaping = false;
continue;
}
// finish up the class.
hasMagic = true;
inClass = false;
re += c;
continue;
default:
// swallow any state char that wasn't consumed
clearStateChar();
if (escaping)
{
// no need
escaping = false;
}
else if (reSpecials.Contains(c) && !(c == '^' && inClass))
{
re += "\\";
}
re += c;
break;
} // switch
} // for
// handle the case where we left a class open.
// "[abc" is valid, equivalent to "\[abc"
if (inClass)
{
// split where the last [ was, and escape it
// this is a huge pita. We now have to re-walk
// the contents of the would-be class to re-translate
// any characters that were passed through as-is
string cs = pattern.Substring(classStart + 1);
var sp = this.Parse(cs, true);
re = re.Substring(0, reClassStart) + "\\[" + sp.Item1.Source;
hasMagic = hasMagic || sp.Item2;
}
// handle the case where we had a +( thing at the *end*
// of the pattern.
// each pattern list stack adds 3 chars, and we need to go through
// and escape any | chars that were passed through as-is for the regexp.
// Go through and escape them, taking care not to double-escape any
// | chars that were already escaped.
while (patternListStack.Any())
{
var pl = patternListStack.Pop();
var tail = re.Substring(pl.ReStart + 3);
// maybe some even number of \, then maybe 1 \, followed by a |
tail = escapeCheck.Replace(tail, m =>
{
string escape = m.Groups[2].Value;
// the | isn't already escaped, so escape it.
if (String.IsNullOrEmpty(escape))
{
escape = "\\";
}
// need to escape all those slashes *again*, without escaping the
// one that we need for escaping the | character. As it works out,
// escaping an even number of slashes can be done by simply repeating
// it exactly after itself. That's why this trick works.
//
// I am sorry that you have to see this.
return(m.Groups[1].Value + m.Groups[1].Value + escape + "|");
});
// console.error("tail=%j\n %s", tail, tail)
var t = pl.Type == '*' ? star
: pl.Type == '?' ? qmark
: "\\" + pl.Type;
hasMagic = true;
re = re.Remove(pl.ReStart)
+ t + "\\("
+ tail;
}
// handle trailing things that only matter at the very end.
clearStateChar();
if (escaping)
{
// trailing \\
re += "\\\\";
}
// only need to apply the nodot start if the re starts with
// something that could conceivably capture a dot
var addPatternStart = false;
switch (re[0])
{
case '.':
case '[':
case '(': addPatternStart = true; break;
}
// if the re is not "" at this point, then we need to make sure
// it doesn't match against an empty path part.
// Otherwise a/* will match a/, which it should not.
if (re != "" && hasMagic)
{
re = "(?=.)" + re;
}
if (addPatternStart)
{
re = patternStart + re;
}
// parsing just a piece of a larger pattern.
if (isSub)
{
return(Tuple.Create(ParseItem.Literal(re), hasMagic));
}
// skip the regexp for non-magical patterns
// unescape anything in it, though, so that it'll be
// an exact match against a file etc.
if (!hasMagic)
{
return(Tuple.Create(ParseItem.Literal(GlobUnescape(pattern)), false));
}
return(new Tuple <ParseItem, bool>(new MagicItem(re, options), false));
}
