SelectHelper.h revision 341825
1//===-- SelectHelper.h ------------------------------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9 10#ifndef liblldb_SelectHelper_h_ 11#define liblldb_SelectHelper_h_ 12 13#include "lldb/Utility/Status.h" // for Status 14#include "lldb/lldb-types.h" // for socket_t 15 16#include "llvm/ADT/DenseMap.h" 17#include "llvm/ADT/Optional.h" 18 19#include <chrono> 20 21class SelectHelper { 22public: 23 // Defaults to infinite wait for select unless you call SetTimeout() 24 SelectHelper(); 25 26 // Call SetTimeout() before calling SelectHelper::Select() to set the timeout 27 // based on the current time + the timeout. This allows multiple calls to 28 // SelectHelper::Select() without having to worry about the absolute timeout 29 // as this class manages to set the relative timeout correctly. 30 void SetTimeout(const std::chrono::microseconds &timeout); 31 32 // Call the FDSet*() functions before calling SelectHelper::Select() to set 33 // the file descriptors that we will watch for when calling select. This will 34 // cause FD_SET() to be called prior to calling select using the "fd" 35 // provided. 36 void FDSetRead(lldb::socket_t fd); 37 void FDSetWrite(lldb::socket_t fd); 38 void FDSetError(lldb::socket_t fd); 39 40 // Call the FDIsSet*() functions after calling SelectHelper::Select() to 41 // check which file descriptors are ready for read/write/error. This will 42 // contain the result of FD_ISSET after calling select for a given file 43 // descriptor. 44 bool FDIsSetRead(lldb::socket_t fd) const; 45 bool FDIsSetWrite(lldb::socket_t fd) const; 46 bool FDIsSetError(lldb::socket_t fd) const; 47 48 // Call the system's select() to wait for descriptors using timeout provided 49 // in a call the SelectHelper::SetTimeout(), or infinite wait if no timeout 50 // was set. 51 lldb_private::Status Select(); 52 53protected: 54 struct FDInfo { 55 FDInfo() 56 : read_set(false), write_set(false), error_set(false), 57 read_is_set(false), write_is_set(false), error_is_set(false) {} 58 59 void PrepareForSelect() { 60 read_is_set = false; 61 write_is_set = false; 62 error_is_set = false; 63 } 64 65 bool read_set : 1, write_set : 1, error_set : 1, read_is_set : 1, 66 write_is_set : 1, error_is_set : 1; 67 }; 68 llvm::DenseMap<lldb::socket_t, FDInfo> m_fd_map; 69 llvm::Optional<std::chrono::steady_clock::time_point> m_end_time; 70}; 71 72#endif // liblldb_SelectHelper_h_ 73