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List:       kde-commits
Subject:    KDE/kdelibs/kjs
From:       Germain Garand <germain () ebooksfrance ! org>
Date:       2009-03-26 1:07:17
Message-ID: 1238029637.841746.15741.nullmailer () svn ! kde ! org
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SVN commit 944737 by ggarand:

Having the most standard compliant regular expression library thanks
to the kindness of the PCRE library author, we are now in the position of
having to add hacks for compatibility with other engines that only fixed
what's explicitely tested by the acid 3 test ;-(

Closing brackets that aren't part of a character class should be rejected
if they aren't escaped, but other engines accept that.

So upon R.E. compilation failure, we will detect such patterns, and attempt
another compilation after escaping any such brackets.

OK'ed by Maksim

CCBUG: 172383


 M  +78 -9     regexp.cpp  


--- trunk/KDE/kdelibs/kjs/regexp.cpp #944736:944737
@@ -127,6 +127,59 @@
   }
 }
 
+// For now, the only 'extension' to standard we are willing to deal with is
+// a non-escaped closing bracket, outside of a character class. e.g. /.*]/
+static bool sanitizePatternExtensions(UString &p)
+{
+  UString newPattern;
+
+  static const int StateNominal = 0, StateOpenBracket = 1;
+  WTF::Vector<int> v;
+  bool escape = false;
+
+  int state = StateNominal;
+  for (int i = 0; i < p.size(); ++i) {
+      UChar c = p[i];
+      if (escape) {
+        escape = false;
+      } else {
+        if (c == '\\') {
+          escape = true;
+        } else if (c == ']') {
+            if (state == StateOpenBracket) {
+                state = StateNominal;
+            } else if (state == StateNominal) {
+                v.append(i);
+            }
+        } else if (c == '[') {
+            if (state == StateOpenBracket) {
+                v.append(i);
+            } else if (state == StateNominal) {
+                state = StateOpenBracket;
+            }
+        }
+    }
+  }
+  if (state == StateOpenBracket) {
+      // this is not recoverable.
+      return false;
+  }
+  if (v.size()) {
+      int pos=0;
+      Vector<int>::const_iterator end = v.end();
+      for (Vector<int>::const_iterator it = v.begin(); it != end; ++it) {
+          newPattern += p.substr(pos, *it-pos);
+          pos = *it;
+          newPattern += UString('\\');
+      }
+      newPattern += p.substr(pos);
+      p = newPattern;
+      return true;
+  } else {
+    return false;
+  }
+}
+
 RegExp::RegExp(const UString &p, char flags)
   : _pat(p), _flags(flags), _valid(true), _numSubPatterns(0), _buffer(0), \
_originalPos(0)  {
@@ -161,18 +214,34 @@
 
   const char *errorMessage;
   int errorOffset;
+  bool secondTry = false;
 
-  // Fill our buffer with an encoded version, whether utf-8, or,
-  // if PCRE is incapable, truncated.
-  prepareMatch(intern);
-  _regex = pcre_compile(_buffer, options, &errorMessage, &errorOffset, NULL);
-  doneMatch(); //Cleanup buffers
-  if (!_regex) {
+  while (1) {
+    // Fill our buffer with an encoded version, whether utf-8, or,
+    // if PCRE is incapable, truncated.
+    prepareMatch(intern);
+    _regex = pcre_compile(_buffer, options, &errorMessage, &errorOffset, NULL);
+    doneMatch(); //Cleanup buffers
+    if (!_regex) {
+#ifdef PCRE_JAVASCRIPT_COMPAT
+      // The compilation failed. It is likely the pattern contains non-standard \
extensions. +      // We may try to tolerate some of those extensions.
+      bool doRecompile = !secondTry && sanitizePatternExtensions(intern);
+      if (doRecompile) {
+        secondTry = true;
 #ifndef NDEBUG
-    fprintf(stderr, "KJS: pcre_compile() failed with '%s'\n", errorMessage);
+        fprintf(stderr, "KJS: pcre_compile() failed with '%s' - non-standard \
extensions detected in pattern, trying second compile after correction.\n", \
errorMessage);  #endif
-    _valid = false;
-    return;
+        continue;
+      }
+#endif
+#ifndef NDEBUG
+      fprintf(stderr, "KJS: pcre_compile() failed with '%s'\n", errorMessage);
+#endif
+      _valid = false;
+      return;
+    }
+    break;
   }
 
 #ifdef PCRE_INFO_CAPTURECOUNT


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