92 lines
3.1 KiB
C++
92 lines
3.1 KiB
C++
// Copyright 2016 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef MOJO_PUBLIC_CPP_BINDINGS_SYNC_HANDLE_REGISTRY_H_
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#define MOJO_PUBLIC_CPP_BINDINGS_SYNC_HANDLE_REGISTRY_H_
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#include <map>
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#include "base/callback.h"
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#include "base/containers/stack_container.h"
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#include "base/macros.h"
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#include "base/memory/ref_counted.h"
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#include "base/sequence_checker.h"
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#include "base/synchronization/waitable_event.h"
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#include "mojo/public/cpp/bindings/bindings_export.h"
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#include "mojo/public/cpp/system/core.h"
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#include "mojo/public/cpp/system/wait_set.h"
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namespace mojo {
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// SyncHandleRegistry is a sequence-local storage to register handles that want
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// to be watched together.
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//
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// This class is thread unsafe.
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class MOJO_CPP_BINDINGS_EXPORT SyncHandleRegistry
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: public base::RefCounted<SyncHandleRegistry> {
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public:
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// Returns a sequence-local object.
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static scoped_refptr<SyncHandleRegistry> current();
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using HandleCallback = base::Callback<void(MojoResult)>;
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// Registers a |Handle| to be watched for |handle_signals|. If any such
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// signals are satisfied during a Wait(), the Wait() is woken up and
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// |callback| is run.
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bool RegisterHandle(const Handle& handle,
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MojoHandleSignals handle_signals,
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const HandleCallback& callback);
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void UnregisterHandle(const Handle& handle);
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// Registers a |base::WaitableEvent| which can be used to wake up
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// Wait() before any handle signals. |event| is not owned, and if it signals
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// during Wait(), |callback| is invoked. Note that |event| may be registered
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// multiple times with different callbacks.
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void RegisterEvent(base::WaitableEvent* event, const base::Closure& callback);
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// Unregisters a specific |event|+|callback| pair.
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void UnregisterEvent(base::WaitableEvent* event,
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const base::Closure& callback);
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// Waits on all the registered handles and events and runs callbacks
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// synchronously for any that become ready.
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// The method:
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// - returns true when any element of |should_stop| is set to true;
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// - returns false when any error occurs.
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bool Wait(const bool* should_stop[], size_t count);
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private:
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friend class base::RefCounted<SyncHandleRegistry>;
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using EventCallbackList = base::StackVector<base::Closure, 1>;
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using EventMap = std::map<base::WaitableEvent*, EventCallbackList>;
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SyncHandleRegistry();
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~SyncHandleRegistry();
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void RemoveInvalidEventCallbacks();
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WaitSet wait_set_;
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std::map<Handle, HandleCallback> handles_;
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EventMap events_;
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// |true| iff this registry is currently dispatching event callbacks in
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// Wait(). Used to allow for safe event registration/unregistration from event
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// callbacks.
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bool is_dispatching_event_callbacks_ = false;
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// Indicates if one or more event callbacks was unregistered during the most
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// recent event callback dispatch.
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bool remove_invalid_event_callbacks_after_dispatch_ = false;
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SEQUENCE_CHECKER(sequence_checker_);
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DISALLOW_COPY_AND_ASSIGN(SyncHandleRegistry);
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};
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} // namespace mojo
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#endif // MOJO_PUBLIC_CPP_BINDINGS_SYNC_HANDLE_REGISTRY_H_
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