diff options
Diffstat (limited to 'base/trace_event/heap_profiler_type_name_deduplicator.cc')
-rw-r--r-- | base/trace_event/heap_profiler_type_name_deduplicator.cc | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/base/trace_event/heap_profiler_type_name_deduplicator.cc b/base/trace_event/heap_profiler_type_name_deduplicator.cc new file mode 100644 index 0000000000..e7f57c8ae0 --- /dev/null +++ b/base/trace_event/heap_profiler_type_name_deduplicator.cc @@ -0,0 +1,76 @@ +// 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 "base/trace_event/heap_profiler_type_name_deduplicator.h" + +#include <stddef.h> +#include <stdlib.h> +#include <string> +#include <utility> + +#include "base/json/string_escape.h" +#include "base/strings/stringprintf.h" +#include "base/trace_event/trace_event_memory_overhead.h" + +namespace base { +namespace trace_event { + +TypeNameDeduplicator::TypeNameDeduplicator() { + // A null pointer has type ID 0 ("unknown type"); + type_ids_.insert(std::make_pair(nullptr, 0)); +} + +TypeNameDeduplicator::~TypeNameDeduplicator() {} + +int TypeNameDeduplicator::Insert(const char* type_name) { + auto result = type_ids_.insert(std::make_pair(type_name, 0)); + auto& elem = result.first; + bool did_not_exist_before = result.second; + + if (did_not_exist_before) { + // The type IDs are assigned sequentially and they are zero-based, so + // |size() - 1| is the ID of the new element. + elem->second = static_cast<int>(type_ids_.size() - 1); + } + + return elem->second; +} + +void TypeNameDeduplicator::AppendAsTraceFormat(std::string* out) const { + out->append("{"); // Begin the type names dictionary. + + auto it = type_ids_.begin(); + std::string buffer; + + // Write the first entry manually; the null pointer must not be dereferenced. + // (The first entry is the null pointer because a |std::map| is ordered.) + it++; + out->append("\"0\":\"[unknown]\""); + + for (; it != type_ids_.end(); it++) { + // Type IDs in the trace are strings, write them as stringified keys of + // a dictionary. + SStringPrintf(&buffer, ",\"%d\":", it->second); + + // |EscapeJSONString| appends, it does not overwrite |buffer|. + bool put_in_quotes = true; + EscapeJSONString(it->first, put_in_quotes, &buffer); + out->append(buffer); + } + + out->append("}"); // End the type names dictionary. +} + +void TypeNameDeduplicator::EstimateTraceMemoryOverhead( + TraceEventMemoryOverhead* overhead) { + // The size here is only an estimate; it fails to take into account the size + // of the tree nodes for the map, but as an estimate this should be fine. + size_t map_size = type_ids_.size() * sizeof(std::pair<const char*, int>); + + overhead->Add("TypeNameDeduplicator", + sizeof(TypeNameDeduplicator) + map_size); +} + +} // namespace trace_event +} // namespace base |