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#ifndef UTILITY__PSTREAM_HH__
#define UTILITY__PSTREAM_HH__
#include <unistd.h>
#include <signal.h> // kill
#include <sys/types.h>
#include <sys/wait.h>
#include <stdarg.h>
#include <iostream>
namespace Utility {
class processbuf : public std::streambuf
{
protected:
int pid;
int sink[2];
int source[2];
/* output */
virtual int_type overflow (int_type c) {
if (c != EOF) {
char cc = c;
if (write (sink[1], &cc, 1) != 1)
return EOF;
}
else {
close_sink();
return EOF;
}
return c;
}
virtual std::streamsize xsputn (const char* s, std::streamsize num) {
return write (sink[1], s, num);
}
/* input */
char buffer [2];
virtual int_type underflow () {
if (gptr() < egptr())
return *gptr();
int numPutback = gptr() - eback();
if (numPutback > 1)
numPutback = 1;
buffer[0] = buffer[1];
int num = read (source[0], &buffer[1], 1);
if (num <= 0)
return EOF;
setg (buffer + 1 - numPutback, buffer + 1, buffer + 1 + num);
return *gptr();
}
public:
processbuf () {
setg (buffer+1, buffer+1, buffer+1);
}
processbuf (const char* file, char* const argv[]) {
setg (buffer+1, buffer+1, buffer+1);
exec (file, argv);
}
~processbuf () {
close(source[0]); close(sink[1]);
waitpid(pid, NULL, 0);
}
void exec (const char* file, const char* arg, va_list ap) {
const char* args[10];
// convert va_list into static char* array -sigh
int i = 0;
args[i++] = arg;
for (; i < ((int) sizeof(args))-1; ++i) {
const char* s = va_arg(ap, const char*);
if (s != NULL) {
// std::cout << "Got: " << s << std::endl;
args[i] = s;
}
else
break;
}
args[i] = NULL;
exec (file, (char* const*)args);
}
void exec (const char* file, char* const argv[]) {
pipe (sink);
pipe (source);
if ((pid = fork()) == 0) {
dup2(sink[0],0); close(sink[0]); close(sink[1]);
dup2(source[1],1); close(source[0]); close(source[1]);
execvp(file, argv);
perror(file);
_exit(1);
}
close(source[1]); close(sink[0]);
}
void close_sink () {
close(sink[1]);
}
void terminate (int signal) {
close(source[0]);
close(sink[1]);
kill(pid, signal);
}
};
class postream : public std::ostream
{
public:
postream (const char* file, char* const argv[])
: std::ostream(&buf), buf(file, argv){
}
postream (const char* file, const char* args, ...)
: std::ostream(&buf) {
va_list ap, aq;
va_start (ap, args);
va_copy (aq, ap);
buf.exec (file, args, ap);
va_end (aq);
va_end (ap);
}
void terminate (int signal=SIGTERM) {
buf.terminate (signal);
}
protected:
processbuf buf;
};
class pistream : public std::istream
{
public:
pistream (const char* file, char* const argv[])
: std::istream(&buf), buf(file, argv) {
}
pistream (const char* file, const char* args, ...)
: std::istream(&buf) {
va_list ap, aq;
va_start (ap, args);
va_copy (aq, ap);
buf.exec (file, args, ap);
va_end (aq);
va_end (ap);
}
pistream (...)
: std::istream(&buf) {
// buf(", "");
}
void terminate (int signal=SIGTERM) {
buf.terminate (signal);
}
protected:
processbuf buf;
};
class pstream : public std::iostream
{
public:
pstream (const char* file, char* const argv[])
: std::iostream(&buf), buf(file, argv) {
}
pstream (const char* file, const char* args, ...)
: std::iostream(&buf) {
va_list ap, aq;
va_start (ap, args);
va_copy (aq, ap);
buf.exec (file, args, ap);
va_end (aq);
va_end (ap);
}
void close_sink () {
buf.close_sink ();
}
void terminate (int signal=SIGTERM) {
buf.terminate (signal);
}
protected:
processbuf buf;
};
}
#endif
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