base/trace_event/memory_allocator_dump.h

   1 // Copyright 2015 The Chromium 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.
   4
   5 #ifndef BASE_TRACE_EVENT_MEMORY_ALLOCATOR_DUMP_H_
   6 #define BASE_TRACE_EVENT_MEMORY_ALLOCATOR_DUMP_H_
   7
   8 #include <string>
   9
  10 #include "base/base_export.h"
  11 #include "base/basictypes.h"
  12 #include "base/logging.h"
  13 #include "base/memory/ref_counted.h"
  14 #include "base/trace_event/memory_allocator_dump_guid.h"
  15 #include "base/values.h"
  16
  17 namespace base {
  18 namespace trace_event {
  19
  20 class MemoryDumpManager;
  21 class ProcessMemoryDump;
  22 class TracedValue;
  23
  24 // Data model for user-land memory allocator dumps.
  25 class BASE_EXPORT MemoryAllocatorDump {
  26  public:
  27   // MemoryAllocatorDump is owned by ProcessMemoryDump.
  28   MemoryAllocatorDump(const std::string& absolute_name,
  29                       ProcessMemoryDump* process_memory_dump,
  30                       const MemoryAllocatorDumpGuid& guid);
  31   MemoryAllocatorDump(const std::string& absolute_name,
  32                       ProcessMemoryDump* process_memory_dump);
  33   ~MemoryAllocatorDump();
  34
  35   // Standard attribute |name|s for the AddScalar and AddString() methods.
  36   static const char kNameSize[];          // To represent allocated space.
  37   static const char kNameObjectCount[];   // To represent number of objects.
  38
  39   // Standard attribute |unit|s for the AddScalar and AddString() methods.
  40   static const char kUnitsBytes[];    // Unit name to represent bytes.
  41   static const char kUnitsObjects[];  // Unit name to represent #objects.
  42
  43   // Constants used only internally and by tests.
  44   static const char kTypeScalar[];  // Type name for scalar attributes.
  45   static const char kTypeString[];  // Type name for string attributes.
  46
  47   // Setters for scalar attributes. Some examples:
  48   // - "size" column (all dumps are expected to have at least this one):
  49   //     AddScalar(kNameSize, kUnitsBytes, 1234);
  50   // - Some extra-column reporting internal details of the subsystem:
  51   //    AddScalar("number_of_freelist_entires", kUnitsObjects, 42)
  52   // - Other informational column (will not be auto-added in the UI)
  53   //    AddScalarF("kittens_ratio", "ratio", 42.0f)
  54   void AddScalar(const char* name, const char* units, uint64 value);
  55   void AddScalarF(const char* name, const char* units, double value);
  56   void AddString(const char* name, const char* units, const std::string& value);
  57
  58   // Absolute name, unique within the scope of an entire ProcessMemoryDump.
  59   const std::string& absolute_name() const { return absolute_name_; }
  60
  61   // Called at trace generation time to populate the TracedValue.
  62   void AsValueInto(TracedValue* value) const;
  63
  64   // Get the ProcessMemoryDump instance that owns this.
  65   ProcessMemoryDump* process_memory_dump() const {
  66     return process_memory_dump_;
  67   }
  68
  69   // |guid| is an optional global dump identifier, unique across all processes
  70   // within the scope of a global dump. It is only required when using the
  71   // graph APIs (see TODO_method_name) to express retention / suballocation or
  72   // cross process sharing. See crbug.com/492102 for design docs.
  73   // Subsequent MemoryAllocatorDump(s) with the same |absolute_name| are
  74   // expected to have the same guid.
  75   const MemoryAllocatorDumpGuid& guid() const { return guid_; }
  76
  77   TracedValue* attributes_for_testing() const { return attributes_.get(); }
  78
  79  private:
  80   const std::string absolute_name_;
  81   ProcessMemoryDump* const process_memory_dump_;  // Not owned (PMD owns this).
  82   scoped_refptr<TracedValue> attributes_;
  83   MemoryAllocatorDumpGuid guid_;
  84
  85   // A local buffer for Sprintf conversion on fastpath. Avoids allocating
  86   // temporary strings on each AddScalar() call.
  87   std::string string_conversion_buffer_;
  88
  89   DISALLOW_COPY_AND_ASSIGN(MemoryAllocatorDump);
  90 };
  91
  92 }  // namespace trace_event
  93 }  // namespace base
  94
  95 #endif  // BASE_TRACE_EVENT_MEMORY_ALLOCATOR_DUMP_H_