2 Copyright (C) 2010 Paul Davis
3 Author: Robin Gareus <robin@gareus.org>
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 #ifndef __ardour_system_exec_h__
21 #define __ardour_system_exec_h__
24 #define STDIN_FILENO 0
27 #define STDOUT_FILENO 1
30 #define STDERR_FILENO 2
36 #ifdef NOPBD /* outside ardour */
37 #include <sigc++/bind.h>
38 #include <sigc++/signal.h>
40 #include <pbd/signals.h>
43 /** @class: SystemExec
44 * @brief execute an external command
46 * This class allows launche an external command-line application
47 * opening a full-duplex connection to its standard I/O.
49 * In Ardour context it is used to launch xjadeo and ffmpeg.
51 * The \ref write_to_stdin function provides for injecting data into STDIN
52 * of the child-application while output of the program to STDOUT/STDERR is
53 * forwarded using the \ref ReadStdout signal.
54 * \ref Terminated is sent if the child application exits.
60 /** prepare execution of a program with 'execve'
62 * This function takes over the existing environment variable and provides
63 * an easy way to speciy command-line arguments for the new process.
65 * Note: The argument parser does not interpret quotation-marks and splits
66 * arugments on whitespace. The argument string can be empty.
67 * The alternative constructor below allows to specify quoted parameters
70 * @param c program pathname that identifies the new process image file.
71 * @param a string of commandline-arguments to be passed to the new program.
73 SystemExec (std::string c, std::string a = "");
74 /** similar to \ref SystemExec but allows to specify custom arguments
76 * @param c program pathname that identifies the new process image file.
77 * @param a array of argument strings passed to the new program as 'argv'.
78 * it must be terminated by a null pointer (see the 'evecve'
79 * POSIX-C documentation for more information)
80 * The array must be dynamically allocated using malloc or strdup.
81 * Unless they're NULL, the array itself and each of its content
82 * memory is freed() in the destructor.
85 SystemExec (std::string c, char ** a);
86 virtual ~SystemExec ();
88 /** fork and execute the given program
90 * @param stderr_mode select what to do with program's standard error
92 * '0': keep STDERR; mix it with parent-process' STDERR
93 * '1': ignore STDERR of child-program
94 * '2': merge STDERR into STDOUT and send it with the
96 * @return If the process is already running or was launched successfully
97 * the function returns zero (0). A negative number indicates an error.
99 int start (int stderr_mode = 1);
100 /** kill running child-process
102 * if a child process exists trt to shut it down by closing its STDIN.
103 * if the program dies not react try SIGTERM and eventually SIGKILL
106 /** check if the child programm is (still) running.
108 * This function calls waitpid(WNOHANG) to check the state of the
110 * @return true if the program is (still) running.
113 /** call the waitpid system-call with the pid of the child-program
115 * Basically what \ref terminate uses internally.
117 * This function is only useful if you want to control application
118 * termination yourself (eg timeouts or progress-dialog).
119 * @param option flags - see waitpid manual
120 * @return status info from waitpid call (not waitpid's return value)
121 * or -1 if the child-program is not running.
123 int wait (int options=0);
124 /** closes both STDIN and STDOUT connections to/from
126 * With the output-interposer thread gone, the program
128 * used by \ref terminate()
131 /** write into child-program's STDIN
132 * @param d data to write
133 * @param len length of data to write, if it is 0 (zero), d.length() is
134 * used to determine the number of bytes to transmit.
135 * @return number of bytes written.
137 int write_to_stdin (std::string d, size_t len=0);
139 /** The ReadStdout signal is emitted when the application writes to STDOUT.
140 * it passes the written data and its length in bytes as arguments to the bound
143 #ifdef NOPBD /* outside ardour */
144 sigc::signal<void, std::string,size_t> ReadStdout;
146 PBD::Signal2<void, std::string,size_t> ReadStdout;
149 /** The Terminated signal is emitted when application terminates. */
150 #ifdef NOPBD /* outside ardour */
151 sigc::signal<void> Terminated;
153 PBD::Signal0<void> Terminated;
156 /** interposer to emit signal for writes to STDOUT/ERR.
158 * Thread that reads the stdout of the forked
159 * process and signal-sends it to the main thread.
160 * It also emits the Terminated() signal once
161 * the the forked process closes it's stdout.
163 * Note: it's actually 'private' function but used
164 * by the internal pthread, which only has a pointer
165 * to this instance and thus can only access public fn.
167 void output_interposer ();
170 std::string cmd; ///< path to command - set when creating the class
171 int nicelevel; ///< process nice level - defaults to 0
173 void make_argp(std::string);
181 PROCESS_INFORMATION *pid;
186 void make_wargs(char **);
190 pthread_mutex_t write_lock;
192 int fdin; ///< file-descriptor for writing to child's STDIN. This variable is identical to pin[1] but also used as status check if the stdin pipe is open: <0 means closed.
197 pthread_t thread_id_tt;
201 #endif /* __ardour_system_exec_h__ */