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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 #include "base/trace_event/heap_profiler_type_name_deduplicator.h" |
| 6 |
| 7 #include <stdlib.h> |
| 8 #include <string> |
| 9 #include <utility> |
| 10 |
| 11 #include "base/json/string_escape.h" |
| 12 #include "base/strings/stringprintf.h" |
| 13 #include "base/trace_event/trace_event_memory_overhead.h" |
| 14 |
| 15 namespace base { |
| 16 namespace trace_event { |
| 17 |
| 18 TypeNameDeduplicator::TypeNameDeduplicator() { |
| 19 // A null pointer has type ID 0 ("unknown type"); |
| 20 type_ids_.insert(std::make_pair(nullptr, 0)); |
| 21 } |
| 22 |
| 23 TypeNameDeduplicator::~TypeNameDeduplicator() {} |
| 24 |
| 25 int TypeNameDeduplicator::Insert(const char* type_name) { |
| 26 auto result = type_ids_.insert(std::make_pair(type_name, 0)); |
| 27 auto& elem = result.first; |
| 28 bool did_not_exist_before = result.second; |
| 29 |
| 30 if (did_not_exist_before) { |
| 31 // The type IDs are assigned sequentially and they are zero-based, so |
| 32 // |size() - 1| is the ID of the new element. |
| 33 elem->second = static_cast<int>(type_ids_.size() - 1); |
| 34 } |
| 35 |
| 36 return elem->second; |
| 37 } |
| 38 |
| 39 void TypeNameDeduplicator::AppendAsTraceFormat(std::string* out) const { |
| 40 out->append("{"); // Begin the type names dictionary. |
| 41 |
| 42 auto it = type_ids_.begin(); |
| 43 std::string buffer; |
| 44 |
| 45 // Write the first entry manually; the null pointer must not be dereferenced. |
| 46 // (The first entry is the null pointer because a |std::map| is ordered.) |
| 47 it++; |
| 48 out->append("\"0\":\"[unknown]\""); |
| 49 |
| 50 for (; it != type_ids_.end(); it++) { |
| 51 // Type IDs in the trace are strings, write them as stringified keys of |
| 52 // a dictionary. |
| 53 SStringPrintf(&buffer, ",\"%d\":", it->second); |
| 54 |
| 55 // |EscapeJSONString| appends, it does not overwrite |buffer|. |
| 56 bool put_in_quotes = true; |
| 57 EscapeJSONString(it->first, put_in_quotes, &buffer); |
| 58 out->append(buffer); |
| 59 } |
| 60 |
| 61 out->append("}"); // End the type names dictionary. |
| 62 } |
| 63 |
| 64 void TypeNameDeduplicator::EstimateTraceMemoryOverhead( |
| 65 TraceEventMemoryOverhead* overhead) { |
| 66 // The size here is only an estimate; it fails to take into account the size |
| 67 // of the tree nodes for the map, but as an estimate this should be fine. |
| 68 size_t map_size = type_ids_.size() * sizeof(std::pair<const char*, int>); |
| 69 |
| 70 overhead->Add("TypeNameDeduplicator", |
| 71 sizeof(TypeNameDeduplicator) + map_size); |
| 72 } |
| 73 |
| 74 } // namespace trace_event |
| 75 } // namespace base |
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