1 //===-- MainLoop.h ----------------------------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #ifndef lldb_Host_MainLoop_h_
11 #define lldb_Host_MainLoop_h_
13 #include "lldb/Host/Config.h"
14 #include "lldb/Host/MainLoopBase.h"
15 #include "llvm/ADT/DenseMap.h"
18 #if !HAVE_PPOLL && !HAVE_SYS_EVENT_H && !defined(__ANDROID__)
19 #define SIGNAL_POLLING_UNSUPPORTED 1
22 namespace lldb_private {
24 // Implementation of the MainLoopBase class. It can monitor file descriptors
25 // for readability using ppoll, kqueue, poll or WSAPoll. On Windows it only
26 // supports polling sockets, and will not work on generic file handles or
27 // pipes. On systems without kqueue or ppoll handling singnals is not
28 // supported. In addition to the common base, this class provides the ability
29 // to invoke a given handler when a signal is received.
31 // Since this class is primarily intended to be used for single-threaded
32 // processing, it does not attempt to perform any internal synchronisation and
33 // any concurrent accesses must be protected externally. However, it is
34 // perfectly legitimate to have more than one instance of this class running on
35 // separate threads, or even a single thread (with some limitations on signal
37 // TODO: Add locking if this class is to be used in a multi-threaded context.
38 class MainLoop : public MainLoopBase {
43 typedef std::unique_ptr<SignalHandle> SignalHandleUP;
48 ReadHandleUP RegisterReadObject(const lldb::IOObjectSP &object_sp,
49 const Callback &callback,
50 Status &error) override;
52 // Listening for signals from multiple MainLoop instances is perfectly safe
53 // as long as they don't try to listen for the same signal. The callback
54 // function is invoked when the control returns to the Run() function, not
55 // when the hander is executed. This mean that you can treat the callback as
56 // a normal function and perform things which would not be safe in a signal
57 // handler. However, since the callback is not invoked synchronously, you
58 // cannot use this mechanism to handle SIGSEGV and the like.
59 SignalHandleUP RegisterSignal(int signo, const Callback &callback,
62 Status Run() override;
64 // This should only be performed from a callback. Do not attempt to terminate
65 // the processing from another thread.
66 // TODO: Add synchronization if we want to be terminated from another thread.
67 void RequestTermination() override { m_terminate_request = true; }
70 void UnregisterReadObject(IOObject::WaitableHandle handle) override;
72 void UnregisterSignal(int signo);
75 void ProcessReadObject(IOObject::WaitableHandle handle);
76 void ProcessSignal(int signo);
80 ~SignalHandle() { m_mainloop.UnregisterSignal(m_signo); }
83 SignalHandle(MainLoop &mainloop, int signo)
84 : m_mainloop(mainloop), m_signo(signo) {}
89 friend class MainLoop;
90 DISALLOW_COPY_AND_ASSIGN(SignalHandle);
96 struct sigaction old_action;
102 llvm::DenseMap<IOObject::WaitableHandle, Callback> m_read_fds;
103 llvm::DenseMap<int, SignalInfo> m_signals;
107 bool m_terminate_request : 1;
110 } // namespace lldb_private
112 #endif // lldb_Host_MainLoop_h_