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      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 <stdint.h>
      9 
     10 #include <memory>
     11 #include <string>
     12 
     13 #include "base/base_export.h"
     14 #include "base/logging.h"
     15 #include "base/macros.h"
     16 #include "base/trace_event/memory_allocator_dump_guid.h"
     17 #include "base/values.h"
     18 
     19 namespace base {
     20 namespace trace_event {
     21 
     22 class MemoryDumpManager;
     23 class ProcessMemoryDump;
     24 class TracedValue;
     25 
     26 // Data model for user-land memory allocator dumps.
     27 class BASE_EXPORT MemoryAllocatorDump {
     28  public:
     29   enum Flags {
     30     DEFAULT = 0,
     31 
     32     // A dump marked weak will be discarded by TraceViewer.
     33     WEAK = 1 << 0,
     34   };
     35 
     36   // MemoryAllocatorDump is owned by ProcessMemoryDump.
     37   MemoryAllocatorDump(const std::string& absolute_name,
     38                       ProcessMemoryDump* process_memory_dump,
     39                       const MemoryAllocatorDumpGuid& guid);
     40   MemoryAllocatorDump(const std::string& absolute_name,
     41                       ProcessMemoryDump* process_memory_dump);
     42   ~MemoryAllocatorDump();
     43 
     44   // Standard attribute |name|s for the AddScalar and AddString() methods.
     45   static const char kNameSize[];          // To represent allocated space.
     46   static const char kNameObjectCount[];   // To represent number of objects.
     47 
     48   // Standard attribute |unit|s for the AddScalar and AddString() methods.
     49   static const char kUnitsBytes[];    // Unit name to represent bytes.
     50   static const char kUnitsObjects[];  // Unit name to represent #objects.
     51 
     52   // Constants used only internally and by tests.
     53   static const char kTypeScalar[];  // Type name for scalar attributes.
     54   static const char kTypeString[];  // Type name for string attributes.
     55 
     56   // Setters for scalar attributes. Some examples:
     57   // - "size" column (all dumps are expected to have at least this one):
     58   //     AddScalar(kNameSize, kUnitsBytes, 1234);
     59   // - Some extra-column reporting internal details of the subsystem:
     60   //    AddScalar("number_of_freelist_entires", kUnitsObjects, 42)
     61   // - Other informational column (will not be auto-added in the UI)
     62   //    AddScalarF("kittens_ratio", "ratio", 42.0f)
     63   void AddScalar(const char* name, const char* units, uint64_t value);
     64   void AddScalarF(const char* name, const char* units, double value);
     65   void AddString(const char* name, const char* units, const std::string& value);
     66 
     67   // Absolute name, unique within the scope of an entire ProcessMemoryDump.
     68   const std::string& absolute_name() const { return absolute_name_; }
     69 
     70   // Called at trace generation time to populate the TracedValue.
     71   void AsValueInto(TracedValue* value) const;
     72 
     73   // Get the ProcessMemoryDump instance that owns this.
     74   ProcessMemoryDump* process_memory_dump() const {
     75     return process_memory_dump_;
     76   }
     77 
     78   // Use enum Flags to set values.
     79   void set_flags(int flags) { flags_ |= flags; }
     80   void clear_flags(int flags) { flags_ &= ~flags; }
     81   int flags() { return flags_; }
     82 
     83   // |guid| is an optional global dump identifier, unique across all processes
     84   // within the scope of a global dump. It is only required when using the
     85   // graph APIs (see TODO_method_name) to express retention / suballocation or
     86   // cross process sharing. See crbug.com/492102 for design docs.
     87   // Subsequent MemoryAllocatorDump(s) with the same |absolute_name| are
     88   // expected to have the same guid.
     89   const MemoryAllocatorDumpGuid& guid() const { return guid_; }
     90 
     91   TracedValue* attributes_for_testing() const { return attributes_.get(); }
     92 
     93  private:
     94   const std::string absolute_name_;
     95   ProcessMemoryDump* const process_memory_dump_;  // Not owned (PMD owns this).
     96   std::unique_ptr<TracedValue> attributes_;
     97   MemoryAllocatorDumpGuid guid_;
     98   int flags_;  // See enum Flags.
     99 
    100   // A local buffer for Sprintf conversion on fastpath. Avoids allocating
    101   // temporary strings on each AddScalar() call.
    102   std::string string_conversion_buffer_;
    103 
    104   DISALLOW_COPY_AND_ASSIGN(MemoryAllocatorDump);
    105 };
    106 
    107 }  // namespace trace_event
    108 }  // namespace base
    109 
    110 #endif  // BASE_TRACE_EVENT_MEMORY_ALLOCATOR_DUMP_H_
    111