From 8de09846d1fb62e1bb6105199881a1262005f303 Mon Sep 17 00:00:00 2001
From: Lev Dragunov <l.dragunov@corp.mail.ru>
Date: Mon, 24 Aug 2015 14:08:55 +0300
Subject: [PATCH] [search] History corruption handling.

---
 search/query_saver.cpp                    | 49 +++++++++++++++++++----
 search/query_saver.hpp                    |  4 +-
 search/search_tests/query_saver_tests.cpp | 15 ++++++-
 3 files changed, 58 insertions(+), 10 deletions(-)

diff --git a/search/query_saver.cpp b/search/query_saver.cpp
index c5a4acce7c..a67b785c66 100644
--- a/search/query_saver.cpp
+++ b/search/query_saver.cpp
@@ -6,6 +6,8 @@
 #include "coding/reader.hpp"
 #include "coding/writer.hpp"
 
+#include "base/logging.hpp"
+
 namespace
 {
 size_t constexpr kMaxSuggestCount = 10;
@@ -44,10 +46,10 @@ void QuerySaver::Clear()
   Settings::Delete(kSettingsKey);
 }
 
-void QuerySaver::Serialize(vector<uint8_t> & data) const
+void QuerySaver::Serialize(string & data) const
 {
-  data.clear();
-  MemWriter<vector<uint8_t>> writer(data);
+  vector<uint8_t> rawData;
+  MemWriter<vector<uint8_t>> writer(rawData);
   TLength size = m_topQueries.size();
   writer.Write(&size, kLengthTypeSize);
   for (auto const & query : m_topQueries)
@@ -56,20 +58,53 @@ void QuerySaver::Serialize(vector<uint8_t> & data) const
     writer.Write(&size, kLengthTypeSize);
     writer.Write(query.c_str(), size);
   }
+  data = ToHex(&rawData[0], rawData.size());
+}
+
+void QuerySaver::EmergencyReset()
+{
+  Clear();
+  LOG(LWARNING, ("Search history data corrupted! Creating new one."));
 }
 
 void QuerySaver::Deserialize(string const & data)
 {
-  MemReader rawReader(data.c_str(), data.size());
+  string decodedData;
+  try
+  {
+   decodedData = FromHex(data);
+  }
+  catch (RootException const & ex)
+  {
+    EmergencyReset();
+    return;
+  }
+  MemReader rawReader(decodedData.c_str(), decodedData.size());
   ReaderSource<MemReader> reader(rawReader);
 
   TLength queriesCount;
   reader.Read(&queriesCount, kLengthTypeSize);
 
+  if (queriesCount > kMaxSuggestCount)
+  {
+    EmergencyReset();
+    return;
+  }
+
   for (TLength i = 0; i < queriesCount; ++i)
   {
     TLength stringLength;
+    if (reader.Size() < kLengthTypeSize)
+    {
+      EmergencyReset();
+      return;
+    }
     reader.Read(&stringLength, kLengthTypeSize);
+    if (reader.Size() < stringLength)
+    {
+      EmergencyReset();
+      return;
+    }
     vector<char> str(stringLength);
     reader.Read(&str[0], stringLength);
     m_topQueries.emplace_back(&str[0], stringLength);
@@ -78,9 +113,9 @@ void QuerySaver::Deserialize(string const & data)
 
 void QuerySaver::Save()
 {
-  vector<uint8_t> data;
+  string data;
   Serialize(data);
-  Settings::Set(kSettingsKey, ToHex(&data[0], data.size()));
+  Settings::Set(kSettingsKey, data);
 }
 
 void QuerySaver::Load()
@@ -89,6 +124,6 @@ void QuerySaver::Load()
   Settings::Get(kSettingsKey, hexData);
   if (hexData.empty())
     return;
-  Deserialize(FromHex(hexData));
+  Deserialize(hexData);
 }
 }  // namesapce search
diff --git a/search/query_saver.hpp b/search/query_saver.hpp
index 78d858c113..ccc603f796 100644
--- a/search/query_saver.hpp
+++ b/search/query_saver.hpp
@@ -18,12 +18,14 @@ public:
 
 private:
   friend void UnitTest_QuerySaverSerializerTest();
-  void Serialize(vector<uint8_t> & data) const;
+  friend void UnitTest_QuerySaverCorruptedStringTest();
+  void Serialize(string & data) const;
   void Deserialize(string const & data);
 
   void Save();
   void Load();
 
+  void EmergencyReset();
   list<string> m_topQueries;
 };
 }  // namespace search
diff --git a/search/search_tests/query_saver_tests.cpp b/search/search_tests/query_saver_tests.cpp
index 169cd5df54..7d8216fc3d 100644
--- a/search/search_tests/query_saver_tests.cpp
+++ b/search/search_tests/query_saver_tests.cpp
@@ -62,12 +62,12 @@ UNIT_TEST(QuerySaverSerializerTest)
   saver.Clear();
   saver.Add(record1);
   saver.Add(record2);
-  vector<uint8_t> data;
+  string data;
   saver.Serialize(data);
   TEST_GREATER(data.size(), 0, ());
   saver.Clear();
   TEST_EQUAL(saver.Get().size(), 0, ());
-  saver.Deserialize(string(data.begin(), data.end()));
+  saver.Deserialize(data);
 
   list<string> const & result = saver.Get();
   TEST_EQUAL(result.size(), 2, ());
@@ -75,6 +75,17 @@ UNIT_TEST(QuerySaverSerializerTest)
   TEST_EQUAL(result.front(), record2, ());
 }
 
+UNIT_TEST(QuerySaverCorruptedStringTest)
+{
+  // We can't catch the ASEERT exception on the DEBUG build.
+  // So we check only valid HEX string case.
+  QuerySaver saver;
+  string corrupted("DEADBEEF");
+  saver.Deserialize(corrupted);
+  list<string> const & result = saver.Get();
+  TEST_EQUAL(result.size(), 0, ());
+}
+
 UNIT_TEST(QuerySaverPersistanceStore)
 {
   {