toolkit/components/telemetry/other/TelemetryIOInterposeObserver.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /**
   8  * IOInterposeObserver recording statistics of main-thread I/O during execution,
   9  * aimed at consumption by TelemetryImpl
  10  */
  11
  12 #ifndef TelemetryIOInterposeObserver_h__
  13 #define TelemetryIOInterposeObserver_h__
  14
  15 #include "core/TelemetryCommon.h"
  16 #include "js/RootingAPI.h"
  17 #include "js/TypeDecls.h"
  18 #include "mozilla/IOInterposer.h"
  19 #include "nsBaseHashtable.h"
  20 #include "nsHashKeys.h"
  21 #include "nsTArray.h"
  22
  23 namespace mozilla {
  24 namespace Telemetry {
  25
  26 class TelemetryIOInterposeObserver : public IOInterposeObserver {
  27   /** File-level statistics structure */
  28   struct FileStats {
  29     FileStats()
  30         : creates(0), reads(0), writes(0), fsyncs(0), stats(0), totalTime(0) {}
  31     uint32_t creates; /** Number of create/open operations */
  32     uint32_t reads;   /** Number of read operations */
  33     uint32_t writes;  /** Number of write operations */
  34     uint32_t fsyncs;  /** Number of fsync operations */
  35     uint32_t stats;   /** Number of stat operations */
  36     double totalTime; /** Accumulated duration of all operations */
  37   };
  38
  39   struct SafeDir {
  40     SafeDir(const nsAString& aPath, const nsAString& aSubstName)
  41         : mPath(aPath), mSubstName(aSubstName) {}
  42     size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
  43       return mPath.SizeOfExcludingThisIfUnshared(aMallocSizeOf) +
  44              mSubstName.SizeOfExcludingThisIfUnshared(aMallocSizeOf);
  45     }
  46     nsString mPath;      /** Path to the directory */
  47     nsString mSubstName; /** Name to substitute with */
  48   };
  49
  50  public:
  51   explicit TelemetryIOInterposeObserver(nsIFile* aXreDir);
  52
  53   /**
  54    * An implementation of Observe that records statistics of all
  55    * file IO operations.
  56    */
  57   void Observe(Observation& aOb) override;
  58
  59   /**
  60    * Reflect recorded file IO statistics into Javascript
  61    */
  62   bool ReflectIntoJS(JSContext* cx, JS::Handle<JSObject*> rootObj);
  63
  64   /**
  65    * Adds a path for inclusion in main thread I/O report.
  66    * @param aPath Directory path
  67    * @param aSubstName Name to substitute for aPath for privacy reasons
  68    */
  69   void AddPath(const nsAString& aPath, const nsAString& aSubstName);
  70
  71   /**
  72    * Get size of hash table with file stats
  73    */
  74   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
  75
  76   size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
  77
  78  private:
  79   enum Stage { STAGE_STARTUP = 0, STAGE_NORMAL, STAGE_SHUTDOWN, NUM_STAGES };
  80   static inline Stage NextStage(Stage aStage) {
  81     switch (aStage) {
  82       case STAGE_STARTUP:
  83         return STAGE_NORMAL;
  84       case STAGE_NORMAL:
  85         return STAGE_SHUTDOWN;
  86       case STAGE_SHUTDOWN:
  87         return STAGE_SHUTDOWN;
  88       default:
  89         return NUM_STAGES;
  90     }
  91   }
  92
  93   struct FileStatsByStage {
  94     FileStats mStats[NUM_STAGES];
  95   };
  96   typedef nsBaseHashtableET<nsStringHashKey, FileStatsByStage> FileIOEntryType;
  97
  98   // Statistics for each filename
  99   Common::AutoHashtable<FileIOEntryType> mFileStats;
 100   // Container for allowed directories
 101   nsTArray<SafeDir> mSafeDirs;
 102   Stage mCurStage;
 103
 104   /**
 105    * Reflect a FileIOEntryType object to a Javascript property on obj with
 106    * filename as key containing array:
 107    * [totalTime, creates, reads, writes, fsyncs, stats]
 108    */
 109   static bool ReflectFileStats(FileIOEntryType* entry, JSContext* cx,
 110                                JS::Handle<JSObject*> obj);
 111 };
 112
 113 }  // namespace Telemetry
 114 }  // namespace mozilla
 115
 116 #endif  // TelemetryIOInterposeObserver_h__