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// 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.
#include <stddef.h>
#include <memory>
#include <set>
#include <unordered_map>
#include "base/base_export.h"
#include "base/macros.h"
#include "base/trace_event/heap_profiler_allocation_context.h"
namespace base {
namespace trace_event {
class HeapProfilerSerializationState;
class StackFrameDeduplicator;
class TracedValue;
class TypeNameDeduplicator;
// Aggregates |metrics_by_context|, recursively breaks down the heap, and
// returns a traced value with an "entries" array that can be dumped in the
// trace log, following the format described in The
// number of entries is kept reasonable because long tails are not included.
BASE_EXPORT std::unique_ptr<TracedValue> ExportHeapDump(
const std::unordered_map<AllocationContext, AllocationMetrics>&
const HeapProfilerSerializationState& heap_profiler_serialization_state);
namespace internal {
namespace {
struct Bucket;
// An entry in the "entries" array as described in
struct BASE_EXPORT Entry {
size_t size;
size_t count;
// References a backtrace in the stack frame deduplicator. -1 means empty
// backtrace (the root of the tree).
int stack_frame_id;
// References a type name in the type name deduplicator. -1 indicates that
// the size is the cumulative size for all types (the root of the tree).
int type_id;
// Comparison operator to enable putting |Entry| in a |std::set|.
BASE_EXPORT bool operator<(Entry lhs, Entry rhs);
// Serializes entries to an "entries" array in a traced value.
BASE_EXPORT std::unique_ptr<TracedValue> Serialize(const std::set<Entry>& dump);
// Helper class to dump a snapshot of an |AllocationRegister| or other heap
// bookkeeping structure into a |TracedValue|. This class is intended to be
// used as a one-shot local instance on the stack.
class BASE_EXPORT HeapDumpWriter {
// The |stack_frame_deduplicator| and |type_name_deduplicator| are not owned.
// The heap dump writer assumes exclusive access to them during the lifetime
// of the dump writer. The heap dumps are broken down for allocations bigger
// than |breakdown_threshold_bytes|.
HeapDumpWriter(StackFrameDeduplicator* stack_frame_deduplicator,
TypeNameDeduplicator* type_name_deduplicator,
uint32_t breakdown_threshold_bytes);
// Aggregates allocations to compute the total size of the heap, then breaks
// down the heap recursively. This produces the values that should be dumped
// in the "entries" array. The number of entries is kept reasonable because
// long tails are not included. Use |Serialize| to convert to a traced value.
const std::set<Entry>& Summarize(
const std::unordered_map<AllocationContext, AllocationMetrics>&
// Inserts an |Entry| for |Bucket| into |entries_|. Returns false if the
// entry was present before, true if it was not.
bool AddEntryForBucket(const Bucket& bucket);
// Recursively breaks down a bucket into smaller buckets and adds entries for
// the buckets worth dumping to |entries_|.
void BreakDown(const Bucket& bucket);
// The collection of entries that is filled by |Summarize|.
std::set<Entry> entries_;
// Helper for generating the |stackFrames| dictionary. Not owned, must outlive
// this heap dump writer instance.
StackFrameDeduplicator* const stack_frame_deduplicator_;
// Helper for converting type names to IDs. Not owned, must outlive this heap
// dump writer instance.
TypeNameDeduplicator* const type_name_deduplicator_;
// Minimum size of an allocation for which an allocation bucket will be
// broken down with children.
uint32_t breakdown_threshold_bytes_;
} // namespace internal
} // namespace trace_event
} // namespace base