// 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. #ifndef BASE_DEBUG_TASK_TRACE_H_ #define BASE_DEBUG_TASK_TRACE_H_ #include #include #include "base/base_export.h" #include "base/containers/span.h" #include "base/debug/stack_trace.h" #include "third_party/abseil-cpp/absl/types/optional.h" namespace base { namespace debug { // Provides a snapshot of which places in the code called // base::TaskRunner::PostTask() that led to the TaskTrace() constructor call. // Analogous to base::StackTrace, but for posted tasks rather than function // calls. // // Example usage: // TaskTrace().Print(); // // Example output: // Task trace: // #0 content::ServiceWorkerContextWrapper::DidCheckHasServiceWorker() // #1 content::ServiceWorkerStorage::FindForDocumentInDB() // #2 content::ServiceWorkerStorage::FindRegistrationForDocument() // #3 content::ServiceWorkerContextWrapper::CheckHasServiceWorker() // #4 content::ManifestIconDownloader::ScaleIcon() // Task trace buffer limit hit, update PendingTask::kTaskBacktraceLength to // increase. class BASE_EXPORT TaskTrace { public: TaskTrace(); // Whether there is any trace data. bool empty() const; // Outputs to stderr via OutputToStream. void Print() const; // Outputs trace to |os|, may be called when empty() is true. void OutputToStream(std::ostream* os) const; // Resolves trace to symbols and returns as string. std::string ToString() const; // Returns the list of addresses in the task trace for testing. base::span AddressesForTesting() const; private: absl::optional stack_trace_; bool trace_overflow_ = false; }; // Forwards to TaskTrace::OutputToStream. BASE_EXPORT std::ostream& operator<<(std::ostream& os, const TaskTrace& task_trace); } // namespace debug } // namespace base #endif // BASE_DEBUG_TASK_TRACE_H_