Event matching by regular expression matching on URLs.

chrome/common/extensions/matcher/regex_set_matcher.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/common/extensions/matcher/regex_set_matcher.h"
+
+#include "base/logging.h"
+#include "base/string_util.h"
+#include "base/stl_util.h"
+#include "chrome/common/extensions/matcher/substring_set_matcher.h"
+#include "third_party/re2/re2/filtered_re2.h"
+#include "third_party/re2/re2/re2.h"
+
+namespace extensions {
+
+RegexSetMatcher::RegexSetMatcher() {}
+
+RegexSetMatcher::~RegexSetMatcher() {
+  DeleteSubstringPatterns();
+}
+
+void RegexSetMatcher::AddPatterns(
+    const std::vector<const StringPattern*>& regex_list) {
+  if (regex_list.empty())
+    return;
+  for (size_t i = 0; i < regex_list.size(); ++i) {
+    regexes_[regex_list[i]->id()] = regex_list[i];
+  }
+
+  RebuildMatcher();
+}
+
+void RegexSetMatcher::ClearPatterns() {
+  regexes_.clear();
+  RebuildMatcher();
+}
+
+bool RegexSetMatcher::Match(const std::string& text,
+                            std::set<StringPattern::ID>* matches) const {
+  if (regexes_.empty())
+    return false;
+  if (!filtered_re2_.get()) {
+    LOG(ERROR) << "RegexSetMatcher was not initialized";
+    return false;
+  }
+
+  // FilteredRE2 expects lowercase for prefiltering (but we still
+  // match case-sensitively).
+  std::vector<int> atoms(FindSubstringMatches(
+      StringToLowerASCII(text)));
+
+  std::vector<int> re2_ids;
+  filtered_re2_->AllMatches(text, atoms, &re2_ids);
+
+  std::set<StringPattern::ID> matched_ids;
+  for (size_t i = 0; i < re2_ids.size(); ++i) {
+    StringPattern::ID id = re2_id_map_[re2_ids[i]];
+    matches->insert(id);
+  }
+  return !matched_ids.empty();
+}
+
+std::vector<int> RegexSetMatcher::FindSubstringMatches(
+    const std::string& text) const {
+  std::set<int> atoms_set;
+  substring_matcher_->Match(text, &atoms_set);
+  return std::vector<int>(atoms_set.begin(), atoms_set.end());
+}
+
+void RegexSetMatcher::RebuildMatcher() {
+  re2_id_map_.clear();
+  filtered_re2_.reset(new re2::FilteredRE2());
+  if (regexes_.empty())
+    return;
+
+  for (RegexMap::iterator it = regexes_.begin(); it != regexes_.end(); ++it) {
+    int re2_id;
+    RE2::ErrorCode error = filtered_re2_->Add(
+        it->second->pattern(), RE2::DefaultOptions, &re2_id);
+    if (error == RE2::NoError) {
+      DCHECK_EQ((int)re2_id_map_.size(), re2_id);
+      re2_id_map_.push_back(it->first);
+    } else {
+      // TODO(yoz): Return an unparseable regex error as soon as possible.
+      LOG(ERROR) << "Could not parse regex (id=" << it->first << ", "
+                 << it->second->pattern() << ")";
+    }
+  }
+
+  std::vector<std::string> strings_to_match;
+  filtered_re2_->Compile(&strings_to_match);
+  DeleteSubstringPatterns();
+
+  // Build SubstringSetMatcher from |strings_to_match|.
+  for (size_t i = 0; i < strings_to_match.size(); ++i) {
+    substring_patterns_.push_back(
+        new StringPattern(strings_to_match[i], i));
+  }
+  substring_matcher_.reset(new SubstringSetMatcher);
+  substring_matcher_->RegisterPatterns(substring_patterns_);
+}
+
+void RegexSetMatcher::DeleteSubstringPatterns() {
+  STLDeleteElements(&substring_patterns_);
+}
+
+}  // namespace extensions