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// Copyright 2019 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 <memory>
#include "base/base_export.h"
#include "base/optional.h"
#include "base/profiler/frame.h"
#include "base/profiler/module_cache.h"
#include "base/time/time.h"
namespace base {
// The ProfileBuilder interface allows the user to record profile information on
// the fly in whatever format is desired. Functions are invoked by the profiler
// on its own thread so must not block or perform expensive operations.
class BASE_EXPORT ProfileBuilder {
ProfileBuilder() = default;
virtual ~ProfileBuilder() = default;
// Gets the ModuleCache to be used by the StackSamplingProfiler when looking
// up modules from addresses.
virtual ModuleCache* GetModuleCache() = 0;
struct BASE_EXPORT MetadataItem {
MetadataItem(uint64_t name_hash, Optional<int64_t> key, int64_t value);
MetadataItem(const MetadataItem& other);
MetadataItem& operator=(const MetadataItem& other);
// The hash of the metadata name, as produced by HashMetricName().
uint64_t name_hash;
// The key if specified when setting the item.
Optional<int64_t> key;
// The value of the metadata item.
int64_t value;
static constexpr size_t MAX_METADATA_COUNT = 50;
typedef std::array<MetadataItem, MAX_METADATA_COUNT> MetadataItemArray;
class MetadataProvider {
MetadataProvider() = default;
virtual ~MetadataProvider() = default;
virtual size_t GetItems(ProfileBuilder::MetadataItemArray* const items) = 0;
// Records metadata to be associated with the current sample. To avoid
// deadlock on locks taken by the suspended profiled thread, implementations
// of this method must not execute any code that could take a lock, including
// heap allocation or use of CHECK/DCHECK/LOG statements. Generally
// implementations should simply atomically copy metadata state to be
// associated with the sample.
virtual void RecordMetadata(MetadataProvider* metadata_provider) {}
// Applies the specified metadata |item| to samples collected in the range
// [period_start, period_end), iff the profile already captured execution that
// covers that range entirely. This restriction avoids bias in the results
// towards samples in the middle of the period, at the expense of excluding
// periods overlapping the start or end of the profile. |period_end| must be
// <= TimeTicks::Now().
virtual void ApplyMetadataRetrospectively(TimeTicks period_start,
TimeTicks period_end,
const MetadataItem& item) {}
// Records a new set of frames. Invoked when sampling a sample completes.
virtual void OnSampleCompleted(std::vector<Frame> frames,
TimeTicks sample_timestamp) = 0;
// Finishes the profile construction with |profile_duration| and
// |sampling_period|. Invoked when sampling a profile completes.
virtual void OnProfileCompleted(TimeDelta profile_duration,
TimeDelta sampling_period) = 0;
} // namespace base