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 <map>
  10 #include <set>
  11 #include <string>
  12 #include <vector>
  13
  14 #include "base/files/file.h"
  15 #include "base/files/file_path.h"
  16 #include "base/metrics/histogram.h"
  17 #include "leveldb/env.h"
  18 #include "port/port_chromium.h"
  19 #include "util/mutexlock.h"
  20
  21 namespace leveldb_env {
  22
  23 enum MethodID {
  24   kSequentialFileRead,
  25   kSequentialFileSkip,
  26   kRandomAccessFileRead,
  27   kWritableFileAppend,
  28   kWritableFileClose,
  29   kWritableFileFlush,
  30   kWritableFileSync,
  31   kNewSequentialFile,
  32   kNewRandomAccessFile,
  33   kNewWritableFile,
  34   kDeleteFile,
  35   kCreateDir,
  36   kDeleteDir,
  37   kGetFileSize,
  38   kRenameFile,
  39   kLockFile,
  40   kUnlockFile,
  41   kGetTestDirectory,
  42   kNewLogger,
  43   kSyncParent,
  44   kGetChildren,
  45   kNumEntries
  46 };
  47
  48 const char* MethodIDToString(MethodID method);
  49
  50 leveldb::Status MakeIOError(leveldb::Slice filename,
  51                             const char* message,
  52                             MethodID method,
  53                             int saved_errno);
  54 leveldb::Status MakeIOError(leveldb::Slice filename,
  55                             const char* message,
  56                             MethodID method,
  57                             base::File::Error error);
  58 leveldb::Status MakeIOError(leveldb::Slice filename,
  59                             const char* message,
  60                             MethodID method);
  61
  62 enum ErrorParsingResult {
  63   METHOD_ONLY,
  64   METHOD_AND_PFE,
  65   METHOD_AND_ERRNO,
  66   NONE,
  67 };
  68
  69 ErrorParsingResult ParseMethodAndError(const char* string,
  70                                        MethodID* method,
  71                                        int* error);
  72 int GetCorruptionCode(const leveldb::Status& status);
  73 int GetNumCorruptionCodes();
  74 std::string GetCorruptionMessage(const leveldb::Status& status);
  75 bool IndicatesDiskFull(const leveldb::Status& status);
  76 bool IsIOError(const leveldb::Status& status);
  77 bool IsCorruption(const leveldb::Status& status);
  78 std::string FilePathToString(const base::FilePath& file_path);
  79
  80 class UMALogger {
  81  public:
  82   virtual void RecordErrorAt(MethodID method) const = 0;
  83   virtual void RecordOSError(MethodID method, int saved_errno) const = 0;
  84   virtual void RecordOSError(MethodID method,
  85                              base::File::Error error) const = 0;
  86   virtual void RecordBackupResult(bool success) const = 0;
  87 };
  88
  89 class RetrierProvider {
  90  public:
  91   virtual int MaxRetryTimeMillis() const = 0;
  92   virtual base::HistogramBase* GetRetryTimeHistogram(MethodID method) const = 0;
  93   virtual base::HistogramBase* GetRecoveredFromErrorHistogram(
  94       MethodID method) const = 0;
  95 };
  96
  97 class WriteTracker {
  98  public:
  99   virtual void DidCreateNewFile(const std::string& fname) = 0;
 100   virtual bool DoesDirNeedSync(const std::string& fname) = 0;
 101   virtual void DidSyncDir(const std::string& fname) = 0;
 102 };
 103
 104 class ChromiumEnv : public leveldb::Env,
 105                     public UMALogger,
 106                     public RetrierProvider,
 107                     public WriteTracker {
 108  public:
 109   typedef void(ScheduleFunc)(void*);
 110
 111   static bool MakeBackup(const std::string& fname);
 112   static base::FilePath CreateFilePath(const std::string& file_path);
 113   static const char* FileErrorString(::base::File::Error error);
 114   static bool HasTableExtension(const base::FilePath& path);
 115   virtual ~ChromiumEnv();
 116
 117   virtual bool FileExists(const std::string& fname);
 118   virtual leveldb::Status GetChildren(const std::string& dir,
 119                                       std::vector<std::string>* result);
 120   virtual leveldb::Status DeleteFile(const std::string& fname);
 121   virtual leveldb::Status CreateDir(const std::string& name);
 122   virtual leveldb::Status DeleteDir(const std::string& name);
 123   virtual leveldb::Status GetFileSize(const std::string& fname, uint64_t* size);
 124   virtual leveldb::Status RenameFile(const std::string& src,
 125                                      const std::string& dst);
 126   virtual leveldb::Status LockFile(const std::string& fname,
 127                                    leveldb::FileLock** lock);
 128   virtual leveldb::Status UnlockFile(leveldb::FileLock* lock);
 129   virtual void Schedule(ScheduleFunc*, void* arg);
 130   virtual void StartThread(void (*function)(void* arg), void* arg);
 131   virtual leveldb::Status GetTestDirectory(std::string* path);
 132   virtual uint64_t NowMicros();
 133   virtual void SleepForMicroseconds(int micros);
 134
 135  protected:
 136   ChromiumEnv();
 137
 138   virtual void DidCreateNewFile(const std::string& fname);
 139   virtual bool DoesDirNeedSync(const std::string& fname);
 140   virtual void DidSyncDir(const std::string& fname);
 141   virtual base::File::Error GetDirectoryEntries(
 142       const base::FilePath& dir_param,
 143       std::vector<base::FilePath>* result) const = 0;
 144   virtual void RecordErrorAt(MethodID method) const;
 145   virtual void RecordOSError(MethodID method, int saved_errno) const;
 146   virtual void RecordOSError(MethodID method,
 147                              base::File::Error error) const;
 148   base::HistogramBase* GetMaxFDHistogram(const std::string& type) const;
 149   base::HistogramBase* GetOSErrorHistogram(MethodID method, int limit) const;
 150
 151   std::string name_;
 152   bool make_backup_;
 153
 154  private:
 155   // File locks may not be exclusive within a process (e.g. on POSIX). Track
 156   // locks held by the ChromiumEnv to prevent access within the process.
 157   class LockTable {
 158    public:
 159     bool Insert(const std::string& fname) {
 160       leveldb::MutexLock l(&mu_);
 161       return locked_files_.insert(fname).second;
 162     }
 163     bool Remove(const std::string& fname) {
 164       leveldb::MutexLock l(&mu_);
 165       return locked_files_.erase(fname) == 1;
 166     }
 167    private:
 168     leveldb::port::Mutex mu_;
 169     std::set<std::string> locked_files_;
 170   };
 171
 172   std::map<std::string, bool> needs_sync_map_;
 173   base::Lock map_lock_;
 174
 175   const int kMaxRetryTimeMillis;
 176   // BGThread() is the body of the background thread
 177   void BGThread();
 178   static void BGThreadWrapper(void* arg) {
 179     reinterpret_cast<ChromiumEnv*>(arg)->BGThread();
 180   }
 181
 182   virtual void RecordBackupResult(bool result) const;
 183   void RestoreIfNecessary(const std::string& dir,
 184                           std::vector<std::string>* children);
 185   base::FilePath RestoreFromBackup(const base::FilePath& base_name);
 186   void RecordLockFileAncestors(int num_missing_ancestors) const;
 187   base::HistogramBase* GetMethodIOErrorHistogram() const;
 188   base::HistogramBase* GetLockFileAncestorHistogram() const;
 189
 190   // RetrierProvider implementation.
 191   virtual int MaxRetryTimeMillis() const { return kMaxRetryTimeMillis; }
 192   virtual base::HistogramBase* GetRetryTimeHistogram(MethodID method) const;
 193   virtual base::HistogramBase* GetRecoveredFromErrorHistogram(
 194       MethodID method) const;
 195
 196   base::FilePath test_directory_;
 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_