4 * This file is part of LyX, the document processor.
5 * Licence details can be found in the file COPYING.
7 * \author Asger Alstrup
9 * Interface cleaned up by
10 * \author Angus Leeming
12 * Full author contact details are available in file CREDITS.
14 * An instance of Class Forkedcall represents a single child process.
16 * Class Forkedcall uses fork() and execvp() to lauch the child process.
18 * Once launched, control is returned immediately to the parent process
19 * but a Signal can be emitted upon completion of the child.
21 * The child process is not killed when the Forkedcall instance goes out of
22 * scope, but it can be killed by an explicit invocation of the kill() member
29 #include <boost/shared_ptr.hpp>
30 #include <boost/signals/signal2.hpp>
31 #include <boost/function/function0.hpp>
33 #include <sys/types.h>
51 virtual ~ForkedProcess() {}
53 virtual boost::shared_ptr<ForkedProcess> clone() const = 0;
55 /** A SignalType signal is can be emitted once the forked process
56 * has finished. It passes:
57 * the PID of the child and;
58 * the return value from the child.
60 * We use a signal rather than simply a callback function so that
61 * we can return easily to C++ methods, rather than just globally
62 * accessible functions.
64 typedef boost::signal2<void, pid_t, int> SignalType;
66 /** The signal is connected in the calling routine to the desired
67 * slot. We pass a shared_ptr rather than a reference to the signal
68 * because it is eminently possible for the instance of the calling
69 * class (and hence the signal) to be destructed before the forked
72 * It doesn't matter if the slot disappears, SigC takes care of that.
74 typedef boost::shared_ptr<SignalType> SignalTypePtr;
76 /** Invoking the following methods makes sense only if the command
77 * is running asynchronously!
80 /** gets the PID of the child process.
83 pid_t pid() const { return pid_; }
90 /** Set the return value of the child process.
93 void setRetValue(int r) { retval_ = r; }
95 /// Returns the identifying command (for display in the GUI perhaps).
96 std::string const & command() const { return command_; }
98 /// is the process running ?
101 /** Kill child prematurely.
102 * First, a SIGHUP is sent to the child.
103 * If that does not end the child process within "tolerance"
104 * seconds, the SIGKILL signal is sent to the child.
105 * When the child is dead, the callback is called.
107 void kill(int tolerance = 5);
110 /** Spawn the child process.
111 * Returns returncode from child.
113 int run(Starttype type);
115 /// Callback function
116 SignalTypePtr signal_;
118 /// identifying command (for display in the GUI perhaps).
119 std::string command_;
121 /// Process ID of child
124 /// Return value from child
127 /// generate child in background
128 virtual int generateChild() = 0;
130 /// Wait for child process to finish. Updates returncode from child.
135 class Forkedcall : public ForkedProcess {
138 virtual boost::shared_ptr<ForkedProcess> clone() const {
139 return boost::shared_ptr<ForkedProcess>(new Forkedcall(*this));
142 /** Start the child process.
144 * The command "what" is passed to execvp() for execution.
146 * There are two startscript commands available. They differ in that
147 * the second receives a signal that is executed on completion of
148 * the command. This makes sense only for a command executed
149 * in the background, ie DontWait.
151 * The other startscript command can be executed either blocking
152 * or non-blocking, but no signal will be emitted on finishing.
154 int startscript(Starttype, std::string const & what);
157 int startscript(std::string const & what, SignalTypePtr);
161 virtual int generateChild();
164 } // namespace support
167 #endif // FORKEDCALL_H