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      1 // Copyright 2015 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef BASE_PROCESS_PORT_PROVIDER_MAC_H_
      6 #define BASE_PROCESS_PORT_PROVIDER_MAC_H_
      7 
      8 #include <mach/mach.h>
      9 
     10 #include "base/base_export.h"
     11 #include "base/macros.h"
     12 #include "base/observer_list.h"
     13 #include "base/process/process_handle.h"
     14 #include "base/synchronization/lock.h"
     15 
     16 namespace base {
     17 
     18 // Abstract base class that provides a mapping from ProcessHandle (pid_t) to the
     19 // Mach task port. This replicates task_for_pid(), which requires root
     20 // privileges.
     21 class BASE_EXPORT PortProvider {
     22  public:
     23   PortProvider();
     24   virtual ~PortProvider();
     25 
     26   class Observer {
     27    public:
     28     virtual ~Observer() {};
     29     // Called by the PortProvider to notify observers that the task port was
     30     // received for a given process.
     31     // No guarantees are made about the thread on which this notification will
     32     // be sent.
     33     // Observers must not call AddObserver() or RemoveObserver() in this
     34     // callback, as doing so will deadlock.
     35     virtual void OnReceivedTaskPort(ProcessHandle process) = 0;
     36   };
     37 
     38   // Returns the mach task port for |process| if possible, or else
     39   // |MACH_PORT_NULL|.
     40   virtual mach_port_t TaskForPid(ProcessHandle process) const = 0;
     41 
     42   // Observer interface.
     43   void AddObserver(Observer* observer);
     44   void RemoveObserver(Observer* observer);
     45 
     46  protected:
     47   // Called by subclasses to send a notification to observers.
     48   void NotifyObservers(ProcessHandle process);
     49 
     50  private:
     51   // ObserverList is not thread-safe, so |lock_| ensures consistency of
     52   // |observer_list_|.
     53   base::Lock lock_;
     54   base::ObserverList<Observer> observer_list_;
     55 
     56   DISALLOW_COPY_AND_ASSIGN(PortProvider);
     57 };
     58 
     59 }  // namespace base
     60 
     61 #endif  // BASE_PROCESS_PORT_PROVIDER_MAC_H_
     62