blob: 055f86abf0adc15b5305659c94dc6866a192105a [file] [log] [blame]
// 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 {
namespace {
// Extract directory name if |type_name| was file name. Otherwise, return
// |type_name|.
StringPiece ExtractDirNameFromFileName(const char* type_name) {
StringPiece result(type_name);
size_t last_seperator = result.find_last_of("\\/");
// If |type_name| was a not a file path, the seperator will not be found, so
// the whole type name is returned.
if (last_seperator == StringPiece::npos)
return result;
// Remove the file name from the path.
result.remove_suffix(result.length() - last_seperator);
// Remove the parent directory references.
const char kParentDirectory[] = "..";
const size_t kParentDirectoryLength = 3; // '../' or '..\'.
while (result.starts_with(kParentDirectory)) {
return result;
} // namespace
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.)
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);
// TODO(ssid): the type name is misused for file name in
// some cases.
StringPiece type_info = ExtractDirNameFromFileName(it->first);
// |EscapeJSONString| appends, it does not overwrite |buffer|.
bool put_in_quotes = true;
EscapeJSONString(type_info, put_in_quotes, &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>);
sizeof(TypeNameDeduplicator) + map_size);
} // namespace trace_event
} // namespace base