[tracing] Simplify the MemoryAllocatorDump API

base/trace_event/memory_allocator_dump.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_TRACE_EVENT_MEMORY_ALLOCATOR_DUMP_H_
 #define BASE_TRACE_EVENT_MEMORY_ALLOCATOR_DUMP_H_
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/values.h"
 
 namespace base {
 namespace trace_event {
 
 class MemoryDumpManager;
 class ProcessMemoryDump;
 class TracedValue;
 
 // Data model for user-land memory allocator dumps.
 class BASE_EXPORT MemoryAllocatorDump {
  public:
-  // Returns the absolute name for a given (|allocator_name|,|heap_name|) tuple.
-  static std::string GetAbsoluteName(const std::string& allocator_name,
-                                     const std::string& heap_name);
-
-  // Use as argument for |heap_name| when the allocator has only one root heap.
-  static const char kRootHeap[];
-
   // MemoryAllocatorDump is owned by ProcessMemoryDump.
-  MemoryAllocatorDump(const std::string& allocator_name,
-                      const std::string& heap_name,
+  MemoryAllocatorDump(const std::string& absolute_name,
                       ProcessMemoryDump* process_memory_dump);
   ~MemoryAllocatorDump();
 
-  // Name of the allocator, a plain string with no separators (e.g, "malloc").
-  const std::string& allocator_name() const { return allocator_name_; }
+  // Standard attribute name to model total space requested by the allocator
+  // (e.g., amount of pages requested to the system).
+  static const char kNameOuterSize[];
 
-  // Name of the heap being dumped, either: "heap", "heap/subheap" or kRootHeap
-  // if the allocator has just one root heap.
-  const std::string& heap_name() const { return heap_name_; }
+  // Standard attribute name to model space for allocated objects, without
+  // taking into account allocator metadata or fragmentation.
+  static const char kNameInnerSize[];
+
+  // Standard attribute name to model the number of objects allocated.
+  static const char kNameObjectsCount[];
+
+  static const char kTypeScalar[];    // Type name for scalar attributes.
+  static const char kTypeString[];    // Type name for string attributes.
+  static const char kUnitsBytes[];    // Unit name to represent bytes.
+  static const char kUnitsObjects[];  // Unit name to represent #objects.
 
   // Absolute name, unique within the scope of an entire ProcessMemoryDump.
-  // In practice this is "allocator_name/heap/subheap".
-  std::string GetAbsoluteName() const;
+  const std::string& absolute_name() const { return absolute_name_; }
 
-  // Inner size: Bytes requested by clients of the allocator, without accounting
-  // for any metadata or allocator-specific bookeeping structs.
-  void set_allocated_objects_size_in_bytes(uint64 value) {
-    allocated_objects_size_in_bytes_ = value;
-  }
-  uint64 allocated_objects_size_in_bytes() const {
-    return allocated_objects_size_in_bytes_;
-  }
+  // Generic attribute setter / getter.
+  void Add(const std::string& name,
+           const char* type,
+           const char* units,
+           scoped_ptr<Value> value);
+  bool Get(const std::string& name,
+           const char** out_type,
+           const char** out_units,
+           const Value** out_value) const;
 
-  // Outer size: bytes requested to the system to handle all the allocations,
-  // including any allocator-internal metadata / bookeeping structs. For
-  // instance, in the case of an allocator which gets pages to the system via
-  // mmap() or similar, this is the number of requested pages * 4k.
-  void set_physical_size_in_bytes(uint64 value) {
-    physical_size_in_bytes_ = value;
-  }
-  uint64 physical_size_in_bytes() const { return physical_size_in_bytes_; }
-
-  // Number of objects allocated, if known, or 0 if not available.
-  void set_allocated_objects_count(uint64 value) {
-    allocated_objects_count_ = value;
-  }
-  uint64 allocated_objects_count() const { return allocated_objects_count_; }
-
-  // Get/Set extra attributes. The attributes name must have been previously
-  // declared through MemoryDumpProvider.DeclareAllocatorAttribute().
-  void SetAttribute(const std::string& name, int value);
-  int GetIntegerAttribute(const std::string& name) const;
+  // Helper setter for scalar attributes.
+  void AddScalar(const std::string& name, const char* units, uint64 value);
+  void AddString(const std::string& name,
+                 const char* units,
+                 const std::string& value);
 
   // Called at trace generation time to populate the TracedValue.
   void AsValueInto(TracedValue* value) const;
 
   // Get the ProcessMemoryDump instance that owns this.
   ProcessMemoryDump* process_memory_dump() const {
     return process_memory_dump_;
   }
 
  private:
-  const std::string allocator_name_;
-  const std::string heap_name_;
+  const std::string absolute_name_;
   ProcessMemoryDump* const process_memory_dump_;  // Not owned (PMD owns this).
-  uint64 physical_size_in_bytes_;
-  uint64 allocated_objects_count_;
-  uint64 allocated_objects_size_in_bytes_;
-  DictionaryValue attributes_values_;
+  DictionaryValue attributes_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryAllocatorDump);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_MEMORY_ALLOCATOR_DUMP_H_