Make the fuchsia mojo/public repo the source of truth.

mojo/public/cpp/utility/run_loop.h

-// Copyright 2013 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_UTILITY_RUN_LOOP_H_
-#define MOJO_PUBLIC_CPP_UTILITY_RUN_LOOP_H_
-
-#include <mojo/system/time.h>
-
-#include <map>
-#include <queue>
-
-#include "mojo/public/cpp/bindings/callback.h"
-#include "mojo/public/cpp/system/handle.h"
-#include "mojo/public/cpp/system/macros.h"
-#include "mojo/public/cpp/system/wait_set.h"
-#include "mojo/public/cpp/utility/run_loop_handler.h"
-
-namespace mojo {
-
-// Run loop (a.k.a. message loop): watches handles for signals and calls
-// handlers when they occur; can also execute posted (delayed) tasks. This class
-// is not thread-safe.
-class RunLoop {
- public:
-  RunLoop();
-  ~RunLoop();
-
-  // Returns the RunLoop for the current thread or null if not yet created.
-  static RunLoop* current();
-
-  // Registers a RunLoopHandler for the specified handle. Returns an |Id|
-  //
-  // The handler's OnHandleReady() method is invoked after one of the signals in
-  // |handle_signals| occurs. Note that the handler remains registered until
-  // explicitly removed or an error occurs.
-  //
-  // The handler's OnHandleError() method is invoked if the deadline elapses, an
-  // error is detected, or the RunLoop is being destroyed (with result
-  // MOJO_RESULT_ABORTED in this case). The handler is automatically
-  // unregistered before calling OnHandleError(), so it will not receive any
-  // further notifications.
-  //
-  // A handler may call AddHandler() again in both OnHandleReady() and
-  // OnHandleError(). Warning: If OnHandleError() was called due to the RunLoop
-  // being destroyed, the newly-added handler's OnHandleError() will also be
-  // called; this may lead to an infinite loop if it again calls AddHandler() ad
-  // infinitum.
-  RunLoopHandler::Id AddHandler(RunLoopHandler* handler,
-                                const Handle& handle,
-                                MojoHandleSignals handle_signals,
-                                MojoDeadline deadline);
-  void RemoveHandler(RunLoopHandler::Id id);
-
-  // Adds a task to be performed after delay has elapsed.
-  void PostDelayedTask(const Closure& task, MojoTimeTicks delay);
-
-  // Runs the loop servicing handles and tasks as they become ready. Returns
-  // when Quit() is invoked, or there are no more handles or tasks.
-  void Run();
-
-  // Runs the loop servicing any handles and tasks that are ready. Does not wait
-  // for handles or tasks to become ready before returning. Returns early if
-  // Quit() is invoked.
-  void RunUntilIdle();
-
-  void Quit();
-
-  // Returns the number of registered handlers. (This is mostly used for
-  // testing.)
-  size_t num_handlers() const { return handlers_.size(); }
-
- private:
-  static constexpr MojoTimeTicks kInvalidTimeTicks = 0;
-
-  // Contains the information that was passed to |AddHandler()|. These are
-  // stored in |handlers|, which is a map from |RunLoopHandler::Id|s
-  // (generated/returned by |AddHandler()| to |HandlerInfo|s. Each entry in
-  // |handlers_| also has a corresponding entry in |wait_set_| (with cookie the
-  // |RunLoopHandler::Id|).
-  struct HandlerInfo {
-    HandlerInfo(RunLoopHandler* handler,
-                MojoHandleSignals handle_signals,
-                MojoTimeTicks absolute_deadline)
-        : handler(handler),
-          handle_signals(handle_signals),
-          absolute_deadline(absolute_deadline) {}
-
-    RunLoopHandler* handler;
-    MojoHandleSignals handle_signals;
-    // |kInvalidTimeTicks| means forever/no deadline/indefinite.
-    MojoTimeTicks absolute_deadline;
-  };
-  using IdToHandlerInfoMap = std::map<RunLoopHandler::Id, HandlerInfo>;
-
-  // Contains information about a handler with a deadline. These are stored in
-  // the |handler_deadlines_| priority queue (with the earliest/lowest
-  // |RunLoopHandler::Id| at the top). If |id| is not in |handlers_|, then this
-  // deadline is no longer valid (i.e., is stale).
-  struct HandlerDeadlineInfo {
-    HandlerDeadlineInfo(RunLoopHandler::Id id, MojoTimeTicks absolute_deadline)
-        : id(id), absolute_deadline(absolute_deadline) {}
-
-    // Needed to be in a priority queue. Note that |std::priority_queue<>|'s top
-    // is the "greatest" element, whereas we want the earliest.
-    bool operator<(const HandlerDeadlineInfo& other) const {
-      return (absolute_deadline == other.absolute_deadline)
-                 ? id < other.id
-                 : absolute_deadline > other.absolute_deadline;
-    }
-
-    RunLoopHandler::Id id;
-    MojoTimeTicks absolute_deadline;
-  };
-  using HandlerDeadlineQueue = std::priority_queue<HandlerDeadlineInfo>;
-
-  // Contains information about a task posted using |PostDelayedTask()|. (Even
-  // though tasks are not handlers, we also assign them |RunLoopHandler::Id|s
-  // from the same namespace.) These are stored in the |delayed_tasks_| priority
-  // queue (with the earliest/lowest |RunLoopHandler::Id| at the top).
-  struct DelayedTaskInfo {
-    DelayedTaskInfo(RunLoopHandler::Id id,
-                    const Closure& task,
-                    MojoTimeTicks absolute_run_time);
-    ~DelayedTaskInfo();
-
-    bool operator<(const DelayedTaskInfo& other) const {
-      return (absolute_run_time == other.absolute_run_time)
-                 ? id > other.id
-                 : absolute_run_time > other.absolute_run_time;
-    }
-
-    RunLoopHandler::Id id;
-    Closure task;
-    MojoTimeTicks absolute_run_time;
-  };
-  using DelayedTaskQueue = std::priority_queue<DelayedTaskInfo>;
-
-  // Inside of |Run()|/|RunUntilIdle()| (i.e., really in |RunInternal()|), we
-  // have one of these on the stack. |current_run_state_| points to the current
-  // one. (This is needed to handle nested execution.)
-  struct RunState;
-
-  // Helper for |Run()| and |RunUntilIdle()|, which loops and executes delayed
-  // tasks and handlers as handles become "ready". It will if:
-  //   - there are no more tasks or registered handlers,
-  //   - |Quit()| is called, or
-  //   - no work is done in a given iteration if |quit_when_idle| is true.
-  void RunInternal(bool quit_when_idle);
-
-  // Executes one iteration of the run loop. Returns true if the run loop should
-  // continue.
-  bool DoIteration(bool quit_when_idle);
-
-  // Notifies handlers corresponding to the wait results in |results| (which
-  // should not be empty). Returns true if work was done (i.e., any handler was
-  // called).
-  bool NotifyResults(const std::vector<MojoWaitSetResult>& results);
-
-  // Notifies any handlers with a deadline up to |absolute_deadline| was that
-  // their deadline was exceeded. Returns true if work was done (i.e., any
-  // handler was called).
-  bool NotifyHandlersDeadlineExceeded(MojoTimeTicks absolute_deadline);
-
-  // Calculates the absolute deadline (to be turned into a relative deadline)
-  // for the wait set wait. This should only be called if |handlers_| is
-  // nonempty. Returns |kInvalidTimeTicks| for "forever"/indefinite. Sets
-  // |*is_delayed_task| to true if the deadline is for a delayed task.
-  MojoTimeTicks CalculateAbsoluteDeadline(bool* is_delayed_task);
-
-  RunLoopHandler::Id next_id_ = 1u;
-  IdToHandlerInfoMap handlers_;
-  ScopedWaitSetHandle wait_set_;
-  HandlerDeadlineQueue handler_deadlines_;
-  DelayedTaskQueue delayed_tasks_;
-
-  RunState* current_run_state_ = nullptr;
-
-  MOJO_DISALLOW_COPY_AND_ASSIGN(RunLoop);
-};
-
-}  // namespace mojo
-
-#endif  // MOJO_PUBLIC_CPP_UTILITY_RUN_LOOP_H_