/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the
* Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifndef _EXECMD_H_INCLUDED_
#define _EXECMD_H_INCLUDED_
/* @(#$Id: execmd.h,v 1.11 2006-12-14 13:53:43 dockes Exp $ (C) 2004 J.F.Dockes */
#include <string>
#include <list>
#include <vector>
#ifndef NO_NAMESPACES
using std::list;
using std::string;
using std::vector;
#endif
/** Callback function object to advise of new data arrival (or just heartbeat) * if cnt is 0 */
class ExecCmdAdvise {
public:
virtual ~ExecCmdAdvise() {}
virtual void newData(int cnt) = 0;
};
/** Callback function object to get more input data. Data has to be provided
* in the initial input string, set it to empty to signify eof
*/
class ExecCmdProvide {
public:
virtual ~ExecCmdProvide() {}
virtual void newData() = 0;
};
/**
* Execute command possibly taking both input and output (will do
* asynchronous io as appropriate for things to work).
*
* Input to the command can be provided either once in a parameter to doexec
* or provided in chunks by setting a callback which will be called to
* request new data. In this case, the 'input' parameter to doexec may be
* empty (but not null)
*
* Output from the command is normally returned in a single string, but a
* callback can be set to be called whenever new data arrives, in which case
* it is permissible to consume the data and erase the string.
*
*/
class ExecCmd {
public:
/**
* Execute command.
*
* Both input and output can be specified, and asynchronous
* io (select-based) is used to prevent blocking. This will not
* work if input and output need to be synchronized (ie: Q/A), but
* works ok for filtering.
* The function is exception-safe. In case an exception occurs in the
* advise callback, fds and pids will be cleaned-up properly.
*
* @param cmd the program to execute. This must be an absolute file name
* or exist in the PATH.
* @param args the argument list (NOT including argv[0]).
* @param input Input to send TO the command.
* @param output Output FROM the command.
* @return the exec ouput status (0 if ok).
*/
int doexec(const string &cmd, const list<string>& args,
const string *input = 0,
string *output = 0);
/**
* Add/replace environment variable before executing command. This must
* be called before doexec to have an effect (possibly multiple
* times for several variables).
* @param envassign an environment assignment string (name=value)
*/
void putenv(const string &envassign);
/**
* Set function objects to call whenever new data is available or on
* select timeout / whenever new data is needed to send.
*/
void setAdvise(ExecCmdAdvise *adv) {m_advise = adv;}
void setProvide(ExecCmdProvide *p) {m_provide = p;}
/**
* Set select timeout in milliseconds. The default is 1 S.
*/
void setTimeout(int mS) {if (mS > 30) m_timeoutMs = mS;}
/**
* Set destination for stderr data. The default is to let it alone (will
* usually go to the terminal or to wherever the desktop messages go).
* There is currently no option to put stderr data into a program variable
* If the parameter can't be opened for writing, the command's
* stderr will be closed.
*/
void setStderr(const string &stderrFile) {m_stderrFile = stderrFile;}
/**
* Cancel/kill command. This can be called from another thread or
* from the advise callback, which could also raise an exception to
* accomplish the same thing
*/
void setCancel() {m_cancelRequest = true;}
ExecCmd()
: m_advise(0), m_provide(0), m_cancelRequest(false), m_timeoutMs(1000)
{}
/**
* Utility routine: check if/where a command is found according to the
* current PATH
*/
static bool which(const string& cmd, string& path);
private:
vector<string> m_env;
ExecCmdAdvise *m_advise;
ExecCmdProvide *m_provide;
bool m_cancelRequest;
int m_timeoutMs;
string m_stderrFile;
};
#endif /* _EXECMD_H_INCLUDED_ */