patterns: Add base class for regular expression matching

2 files changed, 51 insertions, 0 deletions

diff --git a/apt-pkg/cachefilter-patterns.cc b/apt-pkg/cachefilter-patterns.cc
index bf6166ee4..42bc2babb 100644
--- a/apt-pkg/cachefilter-patterns.cc
+++ b/apt-pkg/cachefilter-patterns.cc
@@ -6,8 +6,12 @@
  * SPDX-License-Identifier: GPL-2.0+
  */
 
+#include <config.h>
+
 #include <apt-pkg/cachefilter-patterns.h>
 
+#include <apti18n.h>
+
 namespace APT
 {
 namespace Internal
@@ -272,6 +276,38 @@ std::string PatternParser::aWord(std::unique_ptr<PatternTreeParser::Node> &nodeP
    return node->word.to_string();
 }
 
+namespace Patterns
+{
+
+BaseRegexMatcher::BaseRegexMatcher(std::string const &Pattern)
+{
+   pattern = new regex_t;
+   int const Res = regcomp(pattern, Pattern.c_str(), REG_EXTENDED | REG_ICASE | REG_NOSUB);
+   if (Res == 0)
+      return;
+
+   delete pattern;
+   pattern = NULL;
+   char Error[300];
+   regerror(Res, pattern, Error, sizeof(Error));
+   _error->Error(_("Regex compilation error - %s"), Error);
+}
+bool BaseRegexMatcher::operator()(const char *string)
+{
+   if (unlikely(pattern == NULL))
+      return false;
+   else
+      return regexec(pattern, string, 0, 0, 0) == 0;
+}
+BaseRegexMatcher::~BaseRegexMatcher()
+{
+   if (pattern == NULL)
+      return;
+   regfree(pattern);
+   delete pattern;
+}
+} // namespace Patterns
+
 } // namespace Internal
 
 // The bridge into the public world
diff --git a/apt-pkg/cachefilter-patterns.h b/apt-pkg/cachefilter-patterns.h
index d37da815f..f13edbbc2 100644
--- a/apt-pkg/cachefilter-patterns.h
+++ b/apt-pkg/cachefilter-patterns.h
@@ -117,6 +117,21 @@ namespace Patterns
 {
 using namespace APT::CacheFilter;
 
+/** \brief Basic helper class for matching regex */
+class BaseRegexMatcher
+{
+   regex_t *pattern;
+
+   public:
+   BaseRegexMatcher(std::string const &string);
+   ~BaseRegexMatcher();
+   bool operator()(const char *cstring);
+   bool operator()(std::string const &string)
+   {
+      return (*this)(string.c_str());
+   }
+};
+
 struct PackageIsAutomatic : public PackageMatcher
 {
    pkgCacheFile *Cache;