| // Copyright 2017 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_PUBLIC_CPP_SYSTEM_WAIT_H_ |
| #define MOJO_PUBLIC_CPP_SYSTEM_WAIT_H_ |
| |
| #include <stddef.h> |
| |
| #include "mojo/public/c/system/types.h" |
| #include "mojo/public/cpp/system/handle.h" |
| #include "mojo/public/cpp/system/system_export.h" |
| |
| namespace mojo { |
| |
| // Blocks the calling sequence, waiting for one or more signals in |signals| to |
| // be become satisfied, not-satisfied, or permanently unsatisfiable on the |
| // handle, depending on the |condition| selected. |
| // |
| // If |signals_state| is non-null, |handle| is valid, the wait is not cancelled |
| // (see return values below), the last known signaling state of |handle| is |
| // written to |*signals_state| before returning. |
| // |
| // Return values: |
| // |MOJO_RESULT_OK| if one or more signals in |signals| has been raised on |
| // |handle| with |condition| set to |MOJO_WATCH_CONDITION_SATISFIED|, or |
| // one or more signals in |signals| has been lowered on |handle| with |
| // |condition| set to |MOJO_WATCH_CONDITION_NOT_SATISFIED|. |
| // |MOJO_RESULT_FAILED_PRECONDITION| if the state of |handle| changes such |
| // that no signals in |signals| can ever be raised again and |condition| |
| // is |MOJO_WATCH_CONDITION_SATISFIED|. |
| // |MOJO_RESULT_INVALID_ARGUMENT| if |handle| is not a valid handle. |
| // |MOJO_RESULT_CANCELLED| if the wait was cancelled because |handle| was |
| // closed by some other sequence while waiting. |
| MOJO_CPP_SYSTEM_EXPORT MojoResult |
| Wait(Handle handle, |
| MojoHandleSignals signals, |
| MojoWatchCondition condition, |
| MojoHandleSignalsState* signals_state = nullptr); |
| |
| // A pseudonym for the above Wait() which always waits on |
| // |MOJO_WATCH_CONDITION_SATISFIED|. |
| inline MojoResult Wait(Handle handle, |
| MojoHandleSignals signals, |
| MojoHandleSignalsState* signals_state = nullptr) { |
| return Wait(handle, signals, MOJO_WATCH_CONDITION_SATISFIED, signals_state); |
| } |
| |
| // Waits on |handles[0]|, ..., |handles[num_handles-1]| until: |
| // - At least one handle satisfies a signal indicated in its respective |
| // |signals[0]|, ..., |signals[num_handles-1]|. |
| // - It becomes known that no signal in some |signals[i]| will ever be |
| // satisfied. |
| // |
| // This means that |WaitMany()| behaves as if |Wait()| were called on each |
| // handle/signals pair simultaneously, completing when the first |Wait()| would |
| // complete. |
| // |
| // If |signals_states| is non-null, all other arguments are valid, and the wait |
| // is not cancelled (see return values below), the last known signaling state of |
| // each Handle |handles[i]| is written to its corresponding entry in |
| // |signals_states[i]| before returning. |
| // |
| // Returns values: |
| // |MOJO_RESULT_OK| if one of the Handles in |handles| had one or more of its |
| // correpsonding signals satisfied. |*result_index| contains the index |
| // of the Handle in question if |result_index| is non-null. |
| // |MOJO_RESULT_FAILED_PRECONDITION| if one of the Handles in |handles| |
| // changes state such that its corresponding signals become permanently |
| // unsatisfiable. |*result_index| contains the index of the handle in |
| // question if |result_index| is non-null. |
| // |MOJO_RESULT_INVALID_ARGUMENT| if any Handle in |handles| is invalid, |
| // or if either |handles| or |signals| is null. |
| // |MOJO_RESULT_CANCELLED| if the wait was cancelled because a handle in |
| // |handles| was closed by some other sequence while waiting. |
| // |*result_index| contains the index of the closed Handle if |
| // |result_index| is non-null. |
| MOJO_CPP_SYSTEM_EXPORT MojoResult |
| WaitMany(const Handle* handles, |
| const MojoHandleSignals* signals, |
| size_t num_handles, |
| size_t* result_index = nullptr, |
| MojoHandleSignalsState* signals_states = nullptr); |
| |
| } // namespace mojo |
| |
| #endif // MOJO_PUBLIC_CPP_SYSTEM_WAIT_H_ |