1 files changed, 117 insertions, 0 deletions
diff --git a/toolkit/components/telemetry/other/TelemetryIOInterposeObserver.h b/toolkit/components/telemetry/other/TelemetryIOInterposeObserver.h
new file mode 100644
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+++ b/toolkit/components/telemetry/other/TelemetryIOInterposeObserver.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * IOInterposeObserver recording statistics of main-thread I/O during execution,
+ * aimed at consumption by TelemetryImpl
+ */
+
+#ifndef TelemetryIOInterposeObserver_h__
+#define TelemetryIOInterposeObserver_h__
+
+#include "core/TelemetryCommon.h"
+#include "jsapi.h"
+#include "mozilla/IOInterposer.h"
+#include "nsBaseHashtable.h"
+#include "nsClassHashtable.h"
+#include "nsHashKeys.h"
+#include "nsTArray.h"
+#include "nsTHashtable.h"
+
+namespace mozilla {
+namespace Telemetry {
+
+class TelemetryIOInterposeObserver : public IOInterposeObserver {
+  /** File-level statistics structure */
+  struct FileStats {
+    FileStats()
+        : creates(0), reads(0), writes(0), fsyncs(0), stats(0), totalTime(0) {}
+    uint32_t creates; /** Number of create/open operations */
+    uint32_t reads;   /** Number of read operations */
+    uint32_t writes;  /** Number of write operations */
+    uint32_t fsyncs;  /** Number of fsync operations */
+    uint32_t stats;   /** Number of stat operations */
+    double totalTime; /** Accumulated duration of all operations */
+  };
+
+  struct SafeDir {
+    SafeDir(const nsAString& aPath, const nsAString& aSubstName)
+        : mPath(aPath), mSubstName(aSubstName) {}
+    size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
+      return mPath.SizeOfExcludingThisIfUnshared(aMallocSizeOf) +
+             mSubstName.SizeOfExcludingThisIfUnshared(aMallocSizeOf);
+    }
+    nsString mPath;      /** Path to the directory */
+    nsString mSubstName; /** Name to substitute with */
+  };
+
+ public:
+  explicit TelemetryIOInterposeObserver(nsIFile* aXreDir);
+
+  /**
+   * An implementation of Observe that records statistics of all
+   * file IO operations.
+   */
+  void Observe(Observation& aOb) override;
+
+  /**
+   * Reflect recorded file IO statistics into Javascript
+   */
+  bool ReflectIntoJS(JSContext* cx, JS::Handle<JSObject*> rootObj);
+
+  /**
+   * Adds a path for inclusion in main thread I/O report.
+   * @param aPath Directory path
+   * @param aSubstName Name to substitute for aPath for privacy reasons
+   */
+  void AddPath(const nsAString& aPath, const nsAString& aSubstName);
+
+  /**
+   * Get size of hash table with file stats
+   */
+  size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+
+  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+
+ private:
+  enum Stage { STAGE_STARTUP = 0, STAGE_NORMAL, STAGE_SHUTDOWN, NUM_STAGES };
+  static inline Stage NextStage(Stage aStage) {
+    switch (aStage) {
+      case STAGE_STARTUP:
+        return STAGE_NORMAL;
+      case STAGE_NORMAL:
+        return STAGE_SHUTDOWN;
+      case STAGE_SHUTDOWN:
+        return STAGE_SHUTDOWN;
+      default:
+        return NUM_STAGES;
+    }
+  }
+
+  struct FileStatsByStage {
+    FileStats mStats[NUM_STAGES];
+  };
+  typedef nsBaseHashtableET<nsStringHashKey, FileStatsByStage> FileIOEntryType;
+
+  // Statistics for each filename
+  Common::AutoHashtable<FileIOEntryType> mFileStats;
+  // Container for allowed directories
+  nsTArray<SafeDir> mSafeDirs;
+  Stage mCurStage;
+
+  /**
+   * Reflect a FileIOEntryType object to a Javascript property on obj with
+   * filename as key containing array:
+   * [totalTime, creates, reads, writes, fsyncs, stats]
+   */
+  static bool ReflectFileStats(FileIOEntryType* entry, JSContext* cx,
+                               JS::Handle<JSObject*> obj);
+};
+
+}  // namespace Telemetry
+}  // namespace mozilla
+
+#endif  // TelemetryIOInterposeObserver_h__