Mojo: Armed Watchers

mojo/edk/system/watcher.h

Index: mojo/edk/system/watcher.h
diff --git a/mojo/edk/system/watcher.h b/mojo/edk/system/watcher.h
deleted file mode 100644
index b6dc2e4645ad0e8d0d88fa571fedceb78ef97e9f..0000000000000000000000000000000000000000
--- a/mojo/edk/system/watcher.h
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@@ -1,88 +0,0 @@
-// Copyright 2016 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 MOJO_EDK_SYSTEM_WATCHER_H_
-#define MOJO_EDK_SYSTEM_WATCHER_H_
-
-#include "base/callback.h"
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "base/synchronization/lock.h"
-#include "mojo/public/c/system/functions.h"
-#include "mojo/public/c/system/types.h"
-
-namespace mojo {
-namespace edk {
-
-struct HandleSignalsState;
-
-// This object corresponds to a watch added by a single call to |MojoWatch()|.
-//
-// An event may occur at any time which should trigger a Watcher to run its
-// callback, but the callback needs to be deferred until all EDK locks are
-// released. At the same time, a watch may be cancelled at any time by
-// |MojoCancelWatch()| and it is not OK for the callback to be invoked after
-// that happens.
-//
-// Therefore a Watcher needs to have some associated thread-safe state to track
-// its cancellation, which is why it's ref-counted.
-class Watcher : public base::RefCountedThreadSafe<Watcher> {
- public:
-  using WatchCallback = base::Callback<void(MojoResult,
-                                            const HandleSignalsState&,
-                                            MojoWatchNotificationFlags)>;
-
-  // Constructs a new Watcher which watches for |signals| to be satisfied on a
-  // handle and which invokes |callback| either when one such signal is
-  // satisfied, or all such signals become unsatisfiable.
-  Watcher(MojoHandleSignals signals, const WatchCallback& callback);
-
-  // Runs the Watcher's callback with the given arguments if it hasn't been
-  // cancelled yet.
-  void MaybeInvokeCallback(MojoResult result,
-                           const HandleSignalsState& state,
-                           MojoWatchNotificationFlags flags);
-
-  // Notifies the Watcher of a state change. This may result in the Watcher
-  // adding a finalizer to the current RequestContext to invoke its callback,
-  // cancellation notwithstanding.
-  void NotifyForStateChange(const HandleSignalsState& signals_state);
-
-  // Notifies the Watcher of handle closure. This always results in the Watcher
-  // adding a finalizer to the current RequestContext to invoke its callback,
-  // cancellation notwithstanding.
-  void NotifyClosed();
-
-  // Explicitly cancels the watch, guaranteeing that its callback will never be
-  // be invoked again.
-  void Cancel();
-
- private:
-  friend class base::RefCountedThreadSafe<Watcher>;
-
-  ~Watcher();
-
-  // The set of signals which are watched by this Watcher.
-  const MojoHandleSignals signals_;
-
-  // The callback to invoke with a result and signal state any time signals in
-  // |signals_| are satisfied or become permanently unsatisfiable.
-  const WatchCallback callback_;
-
-  // Guards |is_cancelled_|.
-  base::Lock lock_;
-
-  // Indicates whether the watch has been cancelled. A |Watcher| may exist for a
-  // brief period of time after being cancelled if it's been attached as a
-  // RequestContext finalizer. In such cases the callback must not be invoked,
-  // hence this flag.
-  bool is_cancelled_ = false;
-
-  DISALLOW_COPY_AND_ASSIGN(Watcher);
-};
-
-}  // namespace edk
-}  // namespace mojo
-
-#endif  // MOJO_EDK_SYSTEM_WATCHER_H_