template <typename DerivedDataSource, typename DataSourceTraits = DefaultDataSourceTraits>class DataSource
Defined at line 264 of file ../../third_party/perfetto/include/perfetto/tracing/data_source.h
Templated base class meant to be derived by embedders to create a custom data
source. DerivedDataSource must be the type of the derived class itself, e.g.:
class MyDataSource : public DataSource
<MyDataSource
> {...}.
|DataSourceTraits| allows customizing the behavior of the data source. See
|DefaultDataSourceTraits|.
Public Members
static BufferExhaustedPolicy kBufferExhaustedPolicystatic const bool kBufferExhaustedPolicyConfigurablestatic const bool kSupportsMultipleInstancesstatic const bool kRequiresCallbacksUnderLockPublic Methods
template <typename Lambda>void Trace (Lambda tracing_fn)The main tracing method. Tracing code should call this passing a lambda as
argument, with the following signature: void(TraceContext).
The lambda will be called synchronously (i.e., always before Trace()
returns) only if tracing is enabled and the data source has been enabled in
the tracing config.
The lambda can be called more than once per Trace() call, in the case of
concurrent tracing sessions (or even if the data source is instantiated
twice within the same trace config).
Defined at line 403 of file ../../third_party/perfetto/include/perfetto/tracing/data_source.h
template <typename Traits = DefaultTracePointTraits, typename Callback>void CallIfEnabled (Callback callback, typename Traits::TracePointData trace_point_data)An efficient trace point guard for checking if this data source is active.
|callback| is a function which will only be called if there are active
instances. It is given an instance state parameter, which should be passed
to TraceWithInstances() to actually record trace data.
Defined at line 415 of file ../../third_party/perfetto/include/perfetto/tracing/data_source.h
template <typename Traits = DefaultTracePointTraits, typename Lambda>void TraceWithInstances (uint32_t cached_instances, Lambda tracing_fn, typename Traits::TracePointData trace_point_data)The "lower half" of a trace point which actually performs tracing after
this data source has been determined to be active.
|instances| must be the instance state value retrieved through
CallIfEnabled().
|tracing_fn| will be called to record trace data as in Trace().
|trace_point_data| is an optional parameter given to |Traits::
GetActiveInstances| to make it possible to use custom storage for
the data source enabled state. This is, for example, used by TrackEvent to
implement per-tracing category enabled states.
Defined at line 449 of file ../../third_party/perfetto/include/perfetto/tracing/data_source.h
template <class... Args>bool Register (const DataSourceDescriptor & descriptor, const Args &... constructor_args)Registers the data source on all tracing backends, including ones that
connect after the registration. Doing so enables the data source to receive
Setup/Start/Stop notifications and makes the Trace() method work when
tracing is enabled and the data source is selected.
This must be called after Tracing::Initialize().
Can return false to signal failure if attemping to register more than
kMaxDataSources (32) data sources types or if tracing hasn't been
initialized.
The optional |constructor_args| will be passed to the data source when it
is constructed.
Defined at line 482 of file ../../third_party/perfetto/include/perfetto/tracing/data_source.h
void UpdateDescriptor (const DataSourceDescriptor & descriptor)Updates the data source descriptor.
Defined at line 518 of file ../../third_party/perfetto/include/perfetto/tracing/data_source.h
Records
Friends
template <typename DerivedDataSource, typename DataSourceTraits = DefaultDataSourceTraits>class TrackEventtemplate <typename DerivedDataSourcetypename DataSourceTraits = DefaultDataSourceTraits>class DataSourceInternalForTest