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 enum MethodID {
  23   kSequentialFileRead,
  24   kSequentialFileSkip,
  25   kRandomAccessFileRead,
  26   kWritableFileAppend,
  27   kWritableFileClose,
  28   kWritableFileFlush,
  29   kWritableFileSync,
  30   kNewSequentialFile,
  31   kNewRandomAccessFile,
  32   kNewWritableFile,
  33   kDeleteFile,
  34   kCreateDir,
  35   kDeleteDir,
  36   kGetFileSize,
  37   kRenameFile,
  38   kLockFile,
  39   kUnlockFile,
  40   kGetTestDirectory,
  41   kNewLogger,
  42   kSyncParent,
  43   kGetChildren,
  44   kNumEntries
  45 };
  46
  47 const char* MethodIDToString(MethodID method);
  48
  49 leveldb::Status MakeIOError(leveldb::Slice filename,
  50                             const std::string& message,
  51                             MethodID method,
  52                             base::File::Error error);
  53 leveldb::Status MakeIOError(leveldb::Slice filename,
  54                             const std::string& message,
  55                             MethodID method);
  56
  57 enum ErrorParsingResult {
  58   METHOD_ONLY,
  59   METHOD_AND_PFE,
  60   METHOD_AND_ERRNO,
  61   NONE,
  62 };
  63
  64 ErrorParsingResult ParseMethodAndError(const char* string,
  65                                        MethodID* method,
  66                                        int* error);
  67 int GetCorruptionCode(const leveldb::Status& status);
  68 int GetNumCorruptionCodes();
  69 std::string GetCorruptionMessage(const leveldb::Status& status);
  70 bool IndicatesDiskFull(const leveldb::Status& status);
  71 bool IsIOError(const leveldb::Status& status);
  72
  73 class UMALogger {
  74  public:
  75   virtual void RecordErrorAt(MethodID method) const = 0;
  76   virtual void RecordOSError(MethodID method,
  77                              base::File::Error error) const = 0;
  78   virtual void RecordBackupResult(bool success) const = 0;
  79 };
  80
  81 class RetrierProvider {
  82  public:
  83   virtual int MaxRetryTimeMillis() const = 0;
  84   virtual base::HistogramBase* GetRetryTimeHistogram(MethodID method) const = 0;
  85   virtual base::HistogramBase* GetRecoveredFromErrorHistogram(
  86       MethodID method) const = 0;
  87 };
  88
  89 class WriteTracker {
  90  public:
  91   virtual void DidCreateNewFile(const std::string& fname) = 0;
  92   virtual bool DoesDirNeedSync(const std::string& fname) = 0;
  93   virtual void DidSyncDir(const std::string& fname) = 0;
  94 };
  95
  96 class ChromiumEnv : public leveldb::Env,
  97                     public UMALogger,
  98                     public RetrierProvider,
  99                     public WriteTracker {
 100  public:
 101   ChromiumEnv();
 102
 103   typedef void(ScheduleFunc)(void*);
 104
 105   static bool MakeBackup(const std::string& fname);
 106   static const char* FileErrorString(::base::File::Error error);
 107   static bool HasTableExtension(const base::FilePath& path);
 108   virtual ~ChromiumEnv();
 109
 110   virtual bool FileExists(const std::string& fname);
 111   virtual leveldb::Status GetChildren(const std::string& dir,
 112                                       std::vector<std::string>* result);
 113   virtual leveldb::Status DeleteFile(const std::string& fname);
 114   virtual leveldb::Status CreateDir(const std::string& name);
 115   virtual leveldb::Status DeleteDir(const std::string& name);
 116   virtual leveldb::Status GetFileSize(const std::string& fname, uint64_t* size);
 117   virtual leveldb::Status RenameFile(const std::string& src,
 118                                      const std::string& dst);
 119   virtual leveldb::Status LockFile(const std::string& fname,
 120                                    leveldb::FileLock** lock);
 121   virtual leveldb::Status UnlockFile(leveldb::FileLock* lock);
 122   virtual void Schedule(ScheduleFunc*, void* arg);
 123   virtual void StartThread(void (*function)(void* arg), void* arg);
 124   virtual leveldb::Status GetTestDirectory(std::string* path);
 125   virtual uint64_t NowMicros();
 126   virtual void SleepForMicroseconds(int micros);
 127   virtual leveldb::Status NewSequentialFile(const std::string& fname,
 128                                             leveldb::SequentialFile** result);
 129   virtual leveldb::Status NewRandomAccessFile(
 130       const std::string& fname,
 131       leveldb::RandomAccessFile** result);
 132   virtual leveldb::Status NewWritableFile(const std::string& fname,
 133                                           leveldb::WritableFile** result);
 134   virtual leveldb::Status NewLogger(const std::string& fname,
 135                                     leveldb::Logger** result);
 136
 137  protected:
 138   virtual void DidSyncDir(const std::string& fname);
 139
 140   std::string name_;
 141   bool make_backup_;
 142
 143  private:
 144   virtual void DidCreateNewFile(const std::string& fname);
 145   virtual bool DoesDirNeedSync(const std::string& fname);
 146   virtual void RecordErrorAt(MethodID method) const;
 147   virtual void RecordOSError(MethodID method,
 148                              base::File::Error error) const;
 149   void RecordOpenFilesLimit(const std::string& type);
 150   base::HistogramBase* GetMaxFDHistogram(const std::string& type) const;
 151   base::HistogramBase* GetOSErrorHistogram(MethodID method, int limit) const;
 152
 153   // File locks may not be exclusive within a process (e.g. on POSIX). Track
 154   // locks held by the ChromiumEnv to prevent access within the process.
 155   class LockTable {
 156    public:
 157     bool Insert(const std::string& fname) {
 158       leveldb::MutexLock l(&mu_);
 159       return locked_files_.insert(fname).second;
 160     }
 161     bool Remove(const std::string& fname) {
 162       leveldb::MutexLock l(&mu_);
 163       return locked_files_.erase(fname) == 1;
 164     }
 165    private:
 166     leveldb::port::Mutex mu_;
 167     std::set<std::string> locked_files_;
 168   };
 169
 170   std::set<std::string> directories_needing_sync_;
 171   base::Lock directory_sync_lock_;
 172
 173   const int kMaxRetryTimeMillis;
 174   // BGThread() is the body of the background thread
 175   void BGThread();
 176   static void BGThreadWrapper(void* arg) {
 177     reinterpret_cast<ChromiumEnv*>(arg)->BGThread();
 178   }
 179
 180   virtual void RecordBackupResult(bool result) const;
 181   void RestoreIfNecessary(const std::string& dir,
 182                           std::vector<std::string>* children);
 183   base::FilePath RestoreFromBackup(const base::FilePath& base_name);
 184   void RecordLockFileAncestors(int num_missing_ancestors) const;
 185   base::HistogramBase* GetMethodIOErrorHistogram() const;
 186   base::HistogramBase* GetLockFileAncestorHistogram() const;
 187
 188   // RetrierProvider implementation.
 189   virtual int MaxRetryTimeMillis() const { return kMaxRetryTimeMillis; }
 190   virtual base::HistogramBase* GetRetryTimeHistogram(MethodID method) const;
 191   virtual base::HistogramBase* GetRecoveredFromErrorHistogram(
 192       MethodID method) const;
 193
 194   base::FilePath test_directory_;
 195
 196   ::base::Lock mu_;
 197   ::base::ConditionVariable bgsignal_;
 198   bool started_bgthread_;
 199
 200   // Entry per Schedule() call
 201   struct BGItem {
 202     void* arg;
 203     void (*function)(void*);
 204   };
 205   typedef std::deque<BGItem> BGQueue;
 206   BGQueue queue_;
 207   LockTable locks_;
 208 };
 209
 210 }  // namespace leveldb_env
 211
 212 #endif  // THIRD_PARTY_LEVELDATABASE_ENV_CHROMIUM_H_