http://www.ousob.com --- Legacy Redefined OuSob - File: /wwwroot/clipx/usr/include/wvstreams/wvpipe.h

/* -*- Mode: C++ -*- * Worldvisions Weaver Software: * Copyright (C) 1997-2002 Net Integration Technologies, Inc. * * Provides support for piping data to/from subprocesses. */ #ifndef __WVPIPE_H #define __WVPIPE_H #include "wvfdstream.h" #include "wvsubproc.h" /** * Implementation of a WvPipe stream. These allow you to create a new * process, attaching its stdin/stdout to a WvStream. * * Unlike pipes created with the popen() system call, you can capture * both stdin and stdout for the given process. This is because we * actually use the socketpair() call instead. If you try this, * however, you must be very careful to always use the select() call * before reading from the stream. (Think what would happen if both * ends of the pipe do a read() simultaneously!) * * Note that we do not go as far as actually using a pty. That means * programs which deliberately open /dev/tty will not be redirected. * * When the WvPipe is destroyed, it makes sure that the child process * is killed. Since it tries to do it politely (SIGTERM, wait up to * 2 seconds, SIGKILL) it can take up to 2 seconds to destroy a * WvPipe. */ class WvPipe : public WvFDStream { WvSubProc proc; protected: void setup(const char *program, const char * const *argv, bool writable, bool readable, bool catch_stderr, int stdin_fd, int stdout_fd, int stderr_fd); public: /** * default pipe constructor; if you just want to use a pipe, use this. * For each of stdin, stdout, and stderr of the child process, it can * do one of three things: * - leave it alone (ie. the same as for the parent process) * - redirect it through the WvPipe (eg. if writable==true) * - redirect it to any open file descriptor (std*_fd are only * used if the corresponding bool is false, however) * Note that you need either writable or readable set to true if you * want the pipe to close automatically (for instance, when it's * appened to the globallist). Use the ignore_read() callback if * you really don't care about its output. */ WvPipe(const char *program, const char * const *argv, bool writable, bool readable, bool catch_stderr, int stdin_fd = 0, int stdout_fd = 1, int stderr_fd = 2); /** * This constructor does much the same thing as the previous one, * except that std*_str are WvStreams instead. The target process * accesses the 'fd' member of the stream (NOT using * the WvStream read() and write() functions). * * Again, we only redirect to the given WvStreams if the corresponding * bool is false; otherwise, we redirect to the pipe. * * It is okay for the same WvStream to occur more than once. Also, * you must naturally make sure that the stream doesn't disappear * before WvPipe does! */ WvPipe(const char *program, const char * const *argv, bool writable, bool readable, bool catch_stderr, WvFDStream *stdin_str, WvFDStream *stdout_str = NULL, WvFDStream *stderr_str = NULL); /** * This constructor is the same again, except that it uses the features * of the WvFDStream class to get all its fds from one place. */ WvPipe(const char *program, const char **argv, bool writable, bool readable, bool catch_stderr, WvFDStream *stdio_str); /** kill the child process and close the stream. */ virtual ~WvPipe(); /** * send the child a signal * (signal names are defined in signal.h) */ void kill(int signum); /** wait for child to die. Returns exit_status() */ int finish(bool wait_children = true); /** returns true if child is dead. */ bool child_exited(); /** returns true if child is dead because of a signal. */ bool child_killed() const; /** * returns the exit status: * if child_killed()==true, the signal that killed the child. * if child_killed()==false, the return code of the program. */ int exit_status(); // returns pid int getpid() const { return proc.pid; }; // callback to ignore everything. see comment in wvpipe.cc. static void ignore_read(WvStream& s, void *userdata); }; #endif // __WVPIPE_H