third_party/leveldatabase/env_chromium.h

   1 // Copyright (c) 2013 The LevelDB Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file. See the AUTHORS file for names of contributors.
   4
   5 #ifndef THIRD_PARTY_LEVELDATABASE_ENV_CHROMIUM_H_
   6 #define THIRD_PARTY_LEVELDATABASE_ENV_CHROMIUM_H_
   7
   8 #include <deque>
   9 #include <set>
  10 #include <string>
  11 #include <vector>
  12
  13 #include "base/files/file.h"
  14 #include "base/files/file_path.h"
  15 #include "base/metrics/histogram.h"
  16 #include "leveldb/env.h"
  17 #include "port/port_chromium.h"
  18 #include "util/mutexlock.h"
  19
  20 namespace leveldb_env {
  21
  22 // These entries map to values in tools/metrics/histograms/histograms.xml. New
  23 // values should be appended at the end.
  24 enum MethodID {
  25   kSequentialFileRead,
  26   kSequentialFileSkip,
  27   kRandomAccessFileRead,
  28   kWritableFileAppend,
  29   kWritableFileClose,
  30   kWritableFileFlush,
  31   kWritableFileSync,
  32   kNewSequentialFile,
  33   kNewRandomAccessFile,
  34   kNewWritableFile,
  35   kDeleteFile,
  36   kCreateDir,
  37   kDeleteDir,
  38   kGetFileSize,
  39   kRenameFile,
  40   kLockFile,
  41   kUnlockFile,
  42   kGetTestDirectory,
  43   kNewLogger,
  44   kSyncParent,
  45   kGetChildren,
  46   kNewAppendableFile,
  47   kNumEntries
  48 };
  49
  50 // The default value for leveldb::Options::reuse_logs. Currently log reuse is an
  51 // experimental feature in leveldb. More info at:
  52 // https://github.com/google/leveldb/commit/251ebf5dc70129ad3
  53 #if defined(OS_CHROMEOS)
  54 // Reusing logs on Chrome OS resulted in an unacceptably high leveldb corruption
  55 // rate (at least for Indexed DB). More info at https://crbug.com/460568
  56 const bool kDefaultLogReuseOptionValue = false;
  57 #else
  58 const bool kDefaultLogReuseOptionValue = true;
  59 #endif
  60
  61 const char* MethodIDToString(MethodID method);
  62
  63 leveldb::Status MakeIOError(leveldb::Slice filename,
  64                             const std::string& message,
  65                             MethodID method,
  66                             base::File::Error error);
  67 leveldb::Status MakeIOError(leveldb::Slice filename,
  68                             const std::string& message,
  69                             MethodID method);
  70
  71 enum ErrorParsingResult {
  72   METHOD_ONLY,
  73   METHOD_AND_BFE,
  74   NONE,
  75 };
  76
  77 ErrorParsingResult ParseMethodAndError(const leveldb::Status& status,
  78                                        MethodID* method,
  79                                        base::File::Error* error);
  80 int GetCorruptionCode(const leveldb::Status& status);
  81 int GetNumCorruptionCodes();
  82 std::string GetCorruptionMessage(const leveldb::Status& status);
  83 bool IndicatesDiskFull(const leveldb::Status& status);
  84
  85 class UMALogger {
  86  public:
  87   virtual void RecordErrorAt(MethodID method) const = 0;
  88   virtual void RecordOSError(MethodID method,
  89                              base::File::Error error) const = 0;
  90   virtual void RecordBackupResult(bool success) const = 0;
  91 };
  92
  93 class RetrierProvider {
  94  public:
  95   virtual int MaxRetryTimeMillis() const = 0;
  96   virtual base::HistogramBase* GetRetryTimeHistogram(MethodID method) const = 0;
  97   virtual base::HistogramBase* GetRecoveredFromErrorHistogram(
  98       MethodID method) const = 0;
  99 };
 100
 101 class ChromiumEnv : public leveldb::Env,
 102                     public UMALogger,
 103                     public RetrierProvider {
 104  public:
 105   ChromiumEnv();
 106
 107   typedef void(ScheduleFunc)(void*);
 108
 109   static bool MakeBackup(const std::string& fname);
 110   virtual ~ChromiumEnv();
 111
 112   virtual bool FileExists(const std::string& fname);
 113   virtual leveldb::Status GetChildren(const std::string& dir,
 114                                       std::vector<std::string>* result);
 115   virtual leveldb::Status DeleteFile(const std::string& fname);
 116   virtual leveldb::Status CreateDir(const std::string& name);
 117   virtual leveldb::Status DeleteDir(const std::string& name);
 118   virtual leveldb::Status GetFileSize(const std::string& fname, uint64_t* size);
 119   virtual leveldb::Status RenameFile(const std::string& src,
 120                                      const std::string& dst);
 121   virtual leveldb::Status LockFile(const std::string& fname,
 122                                    leveldb::FileLock** lock);
 123   virtual leveldb::Status UnlockFile(leveldb::FileLock* lock);
 124   virtual void Schedule(ScheduleFunc*, void* arg);
 125   virtual void StartThread(void (*function)(void* arg), void* arg);
 126   virtual leveldb::Status GetTestDirectory(std::string* path);
 127   virtual uint64_t NowMicros();
 128   virtual void SleepForMicroseconds(int micros);
 129   virtual leveldb::Status NewSequentialFile(const std::string& fname,
 130                                             leveldb::SequentialFile** result);
 131   virtual leveldb::Status NewRandomAccessFile(
 132       const std::string& fname,
 133       leveldb::RandomAccessFile** result);
 134   virtual leveldb::Status NewWritableFile(const std::string& fname,
 135                                           leveldb::WritableFile** result);
 136   virtual leveldb::Status NewAppendableFile(const std::string& fname,
 137                                             leveldb::WritableFile** result);
 138   virtual leveldb::Status NewLogger(const std::string& fname,
 139                                     leveldb::Logger** result);
 140
 141  protected:
 142   ChromiumEnv(const std::string& name, bool make_backup);
 143
 144  private:
 145   static const char* FileErrorString(base::File::Error error);
 146
 147   virtual void RecordErrorAt(MethodID method) const;
 148   virtual void RecordOSError(MethodID method,
 149                              base::File::Error error) const;
 150   void RecordOpenFilesLimit(const std::string& type);
 151   base::HistogramBase* GetMaxFDHistogram(const std::string& type) const;
 152   base::HistogramBase* GetOSErrorHistogram(MethodID method, int limit) const;
 153
 154   // File locks may not be exclusive within a process (e.g. on POSIX). Track
 155   // locks held by the ChromiumEnv to prevent access within the process.
 156   class LockTable {
 157    public:
 158     bool Insert(const std::string& fname) {
 159       leveldb::MutexLock l(&mu_);
 160       return locked_files_.insert(fname).second;
 161     }
 162     bool Remove(const std::string& fname) {
 163       leveldb::MutexLock l(&mu_);
 164       return locked_files_.erase(fname) == 1;
 165     }
 166    private:
 167     leveldb::port::Mutex mu_;
 168     std::set<std::string> locked_files_;
 169   };
 170
 171   const int kMaxRetryTimeMillis;
 172   // BGThread() is the body of the background thread
 173   void BGThread();
 174   static void BGThreadWrapper(void* arg) {
 175     reinterpret_cast<ChromiumEnv*>(arg)->BGThread();
 176   }
 177
 178   virtual void RecordBackupResult(bool result) const;
 179   void RestoreIfNecessary(const std::string& dir,
 180                           std::vector<std::string>* children);
 181   base::FilePath RestoreFromBackup(const base::FilePath& base_name);
 182   void RecordLockFileAncestors(int num_missing_ancestors) const;
 183   base::HistogramBase* GetMethodIOErrorHistogram() const;
 184   base::HistogramBase* GetLockFileAncestorHistogram() const;
 185
 186   // RetrierProvider implementation.
 187   virtual int MaxRetryTimeMillis() const { return kMaxRetryTimeMillis; }
 188   virtual base::HistogramBase* GetRetryTimeHistogram(MethodID method) const;
 189   virtual base::HistogramBase* GetRecoveredFromErrorHistogram(
 190       MethodID method) const;
 191
 192   base::FilePath test_directory_;
 193
 194   std::string name_;
 195   std::string uma_ioerror_base_name_;
 196   bool make_backup_;
 197
 198   base::Lock mu_;
 199   base::ConditionVariable bgsignal_;
 200   bool started_bgthread_;
 201
 202   // Entry per Schedule() call
 203   struct BGItem {
 204     void* arg;
 205     void (*function)(void*);
 206   };
 207   typedef std::deque<BGItem> BGQueue;
 208   BGQueue queue_;
 209   LockTable locks_;
 210 };
 211
 212 }  // namespace leveldb_env
 213
 214 #endif  // THIRD_PARTY_LEVELDATABASE_ENV_CHROMIUM_H_