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// Copyright 2017 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 <set>
#include "base/base_export.h"
#include "base/memory/ref_counted.h"
#include "base/trace_event/memory_dump_provider.h"
namespace base {
class SequencedTaskRunner;
namespace trace_event {
// Wraps a MemoryDumpProvider (MDP), which is registered via
// MemoryDumpManager(MDM)::RegisterDumpProvider(), holding the extra information
// required to deal with it (which task runner it should be invoked onto,
// whether it has been disabled, etc.)
// More importantly, having a refptr to this object guarantees that a MDP that
// is not thread-bound (hence which can only be unregistered via
// MDM::UnregisterAndDeleteDumpProviderSoon()) will stay alive as long as the
// refptr is held.
// Lifetime:
// At any time, there is at most one instance of this class for each instance
// of a given MemoryDumpProvider, but there might be several scoped_refptr
// holding onto each of this. Specifically:
// - In nominal conditions, there is a refptr for each registered MDP in the
// MDM's |dump_providers_| list.
// - In most cases, the only refptr (in the |dump_providers_| list) is destroyed
// by MDM::UnregisterDumpProvider().
// - However, when MDM starts a dump, the list of refptrs is copied into the
// ProcessMemoryDumpAsyncState. That list is pruned as MDP(s) are invoked.
// - If UnregisterDumpProvider() is called on a non-thread-bound MDP while a
// dump is in progress, the extar extra of the handle is destroyed in
// MDM::SetupNextMemoryDump() or MDM::InvokeOnMemoryDump(), when the copy
// inside ProcessMemoryDumpAsyncState is erase()-d.
// - The PeakDetector can keep extra refptrs when enabled.
struct BASE_EXPORT MemoryDumpProviderInfo
: public RefCountedThreadSafe<MemoryDumpProviderInfo> {
// Define a total order based on the |task_runner| affinity, so that MDPs
// belonging to the same SequencedTaskRunner are adjacent in the set.
struct Comparator {
bool operator()(const scoped_refptr<MemoryDumpProviderInfo>& a,
const scoped_refptr<MemoryDumpProviderInfo>& b) const;
using OrderedSet =
std::set<scoped_refptr<MemoryDumpProviderInfo>, Comparator>;
MemoryDumpProviderInfo(MemoryDumpProvider* dump_provider,
const char* name,
scoped_refptr<SequencedTaskRunner> task_runner,
const MemoryDumpProvider::Options& options,
bool whitelisted_for_background_mode);
// It is safe to access the const fields below from any thread as they are
// never mutated.
MemoryDumpProvider* const dump_provider;
// The |options| arg passed to MDM::RegisterDumpProvider().
const MemoryDumpProvider::Options options;
// Human readable name, not unique (distinct MDP instances might have the same
// name). Used for debugging, testing and whitelisting for BACKGROUND mode.
const char* const name;
// The task runner on which the MDP::OnMemoryDump call should be posted onto.
// Can be nullptr, in which case the MDP will be invoked on a background
// thread handled by MDM.
const scoped_refptr<SequencedTaskRunner> task_runner;
// True if the dump provider is whitelisted for background mode.
const bool whitelisted_for_background_mode;
// These fields below, instead, are not thread safe and can be mutated only:
// - On the |task_runner|, when not null (i.e. for thread-bound MDPS).
// - By the MDM's background thread (or in any other way that guarantees
// sequencing) for non-thread-bound MDPs.
// Used to transfer ownership for UnregisterAndDeleteDumpProviderSoon().
// nullptr in all other cases.
std::unique_ptr<MemoryDumpProvider> owned_dump_provider;
// For fail-safe logic (auto-disable failing MDPs).
int consecutive_failures;
// Flagged either by the auto-disable logic or during unregistration.
bool disabled;
friend class base::RefCountedThreadSafe<MemoryDumpProviderInfo>;
} // namespace trace_event
} // namespace base