Repo created

TMessagesProj/jni/voip/webrtc/base/profiler/suspendable_thread_delegate.h

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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.
+
+#ifndef BASE_PROFILER_SUSPENDABLE_THREAD_DELEGATE_H_
+#define BASE_PROFILER_SUSPENDABLE_THREAD_DELEGATE_H_
+
+#include <vector>
+
+#include "base/base_export.h"
+#include "base/profiler/register_context.h"
+#include "base/profiler/thread_delegate.h"
+
+namespace base {
+
+// Platform-specific thread and stack manipulation delegate, for use by the
+// platform-independent stack copying/walking implementation in
+// StackSamplerImpl for suspension-based stack copying.
+//
+// IMPORTANT NOTE: Most methods in this interface are invoked while the target
+// thread is suspended so must not do any allocation from the heap, including
+// indirectly via use of DCHECK/CHECK or other logging statements. Otherwise the
+// implementation can deadlock on heap locks acquired by the target thread
+// before it was suspended. These functions are commented with "NO HEAP
+// ALLOCATIONS".
+class BASE_EXPORT SuspendableThreadDelegate : public ThreadDelegate {
+ public:
+  // Implementations of this interface should suspend the thread for the
+  // object's lifetime. NO HEAP ALLOCATIONS between the time the thread is
+  // suspended and resumed.
+  class BASE_EXPORT ScopedSuspendThread {
+   public:
+    ScopedSuspendThread() = default;
+    virtual ~ScopedSuspendThread() = default;
+
+    ScopedSuspendThread(const ScopedSuspendThread&) = delete;
+    ScopedSuspendThread& operator=(const ScopedSuspendThread&) = delete;
+
+    virtual bool WasSuccessful() const = 0;
+  };
+
+  SuspendableThreadDelegate() = default;
+
+  // Creates an object that holds the thread suspended for its lifetime.
+  virtual std::unique_ptr<ScopedSuspendThread> CreateScopedSuspendThread() = 0;
+
+  // Gets the register context for the thread.
+  // NO HEAP ALLOCATIONS.
+  virtual bool GetThreadContext(RegisterContext* thread_context) = 0;
+
+  // Returns true if the thread's stack can be copied, where the bottom address
+  // of the thread is at |stack_pointer|.
+  // NO HEAP ALLOCATIONS.
+  virtual bool CanCopyStack(uintptr_t stack_pointer) = 0;
+};
+
+}  // namespace base
+
+#endif  // BASE_PROFILER_SUSPENDABLE_THREAD_DELEGATE_H_