Replace FTS in the history_service with a brute force text search.

chrome/browser/history/query_parser.cc

Index: chrome/browser/history/query_parser.cc
diff --git a/chrome/browser/history/query_parser.cc b/chrome/browser/history/query_parser.cc
index 9fafc9bf1b29c3a189a2719e362ea38917ff58e5..6a436c24e224d60fc363527bb2dd8167e9946e7d 100644
--- a/chrome/browser/history/query_parser.cc
+++ b/chrome/browser/history/query_parser.cc
@@ -11,9 +11,14 @@
 #include "base/i18n/case_conversion.h"
 #include "base/logging.h"
 #include "base/stl_util.h"
+#include "base/strings/utf_string_conversions.h"
 
 namespace {
 
+// Chinese/Japanese/Thai languages do not use spaces between words, so we
+// allow any Chinese/Japanese/Thai character to match as a word boundary.
+char kSafeRegexWordBoundary[] = "(\\b|[\\u0E00-\\u0E7F]|[\\u4E00-\\u9FFF])";
+
 // Returns true if |mp1.first| is less than |mp2.first|. This is used to
 // sort match positions.
 int CompareMatchPosition(const Snippet::MatchPosition& mp1,
@@ -83,6 +88,8 @@ class QueryNodeWord : public QueryNode {
 
   // QueryNode:
   virtual int AppendToSQLiteQuery(string16* query) const OVERRIDE;
+  virtual void AppendSQLiteRegexpQueries(
+      std::vector<string16>* queries) const OVERRIDE;
   virtual bool IsWord() const OVERRIDE;
   virtual bool Matches(const string16& word, bool exact) const OVERRIDE;
   virtual bool HasMatchIn(
@@ -112,6 +119,19 @@ int QueryNodeWord::AppendToSQLiteQuery(string16* query) const {
   return 1;
 }
 
+void QueryNodeWord::AppendSQLiteRegexpQueries(
+      std::vector<string16>* queries) const {
+  string16 query = ASCIIToUTF16("(?i).*");
+  query.append(ASCIIToUTF16(kSafeRegexWordBoundary));
+  query.append(word_);
+  if (!literal_ && QueryParser::IsWordLongEnoughForPrefixSearch(word_))
+    query.append(ASCIIToUTF16("\\w*"));
+  query.append(ASCIIToUTF16(kSafeRegexWordBoundary));
+  query.append(ASCIIToUTF16(".*"));
+
+  queries->push_back(query);
+}
+
 bool QueryNodeWord::IsWord() const {
   return true;
 }
@@ -159,6 +179,8 @@ class QueryNodeList : public QueryNode {
 
   // QueryNode:
   virtual int AppendToSQLiteQuery(string16* query) const OVERRIDE;
+  virtual void AppendSQLiteRegexpQueries(
+      std::vector<string16>* queries) const OVERRIDE;
   virtual bool IsWord() const OVERRIDE;
   virtual bool Matches(const string16& word, bool exact) const OVERRIDE;
   virtual bool HasMatchIn(
@@ -204,6 +226,14 @@ int QueryNodeList::AppendToSQLiteQuery(string16* query) const {
   return AppendChildrenToString(query);
 }
 
+void QueryNodeList::AppendSQLiteRegexpQueries(
+      std::vector<string16>* queries) const {
+  for (QueryNodeVector::const_iterator node = children_.begin();
+       node != children_.end(); ++node) {
+    (*node)->AppendSQLiteRegexpQueries(queries);
+  }
+}
+
 bool QueryNodeList::IsWord() const {
   return false;
 }
@@ -243,6 +273,8 @@ class QueryNodePhrase : public QueryNodeList {
 
   // QueryNodeList:
   virtual int AppendToSQLiteQuery(string16* query) const OVERRIDE;
+  virtual void AppendSQLiteRegexpQueries(
+      std::vector<string16>* queries) const OVERRIDE;
   virtual bool HasMatchIn(
       const std::vector<QueryWord>& words,
       Snippet::MatchPositions* match_positions) const OVERRIDE;
@@ -262,6 +294,23 @@ int QueryNodePhrase::AppendToSQLiteQuery(string16* query) const {
   return num_words;
 }
 
+void QueryNodePhrase::AppendSQLiteRegexpQueries(
+      std::vector<string16>* queries) const {
+  string16 query = ASCIIToUTF16("(?i).*");
+  query.append(ASCIIToUTF16(kSafeRegexWordBoundary));
+  for (QueryNodeVector::const_iterator node = children_.begin();
+       node != children_.end(); ++node) {
+    (*node)->AppendToSQLiteQuery(&query);
+    if (node + 1 != children_.end()) {
+      // Match any non-word characters within phrase (enables url matching).
+      query.append(ASCIIToUTF16("\\W+"));
+    }
+  }
+  query.append(ASCIIToUTF16(kSafeRegexWordBoundary));
+  query.append(ASCIIToUTF16(".*"));
+  queries->push_back(query);
+}
+
 bool QueryNodePhrase::HasMatchIn(
     const std::vector<QueryWord>& words,
     Snippet::MatchPositions* match_positions) const {
@@ -308,6 +357,14 @@ int QueryParser::ParseQuery(const string16& query, string16* sqlite_query) {
   return root.AppendToSQLiteQuery(sqlite_query);
 }
 
+void QueryParser::ParseQueryAsRegexps(const string16& query,
+                                      std::vector<string16>* sqlite_queries) {
+  QueryNodeList root;
+  if (!ParseQueryImpl(query, &root))
+    return;
+  return root.AppendSQLiteRegexpQueries(sqlite_queries);
+}
+
 void QueryParser::ParseQueryWords(const string16& query,
                                   std::vector<string16>* words) {
   QueryNodeList root;