hvirtual/cinelerra/pipe.C

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#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <signal.h>

#include "bchash.h"
#include "file.h"
#include "guicast.h"
#include "interlacemodes.h"
#include "pipe.h"

extern "C" 
{
        int pipe_sigpipe_received;

        void pipe_handle_sigpipe(int signum) 
        {
                printf("Received sigpipe\n");
                pipe_sigpipe_received++;
        }
}

Pipe::Pipe(char *command, char *sub_str, char sub_char) 
{ 
        this->command = command;
        this->sub_str = sub_str;
        this->sub_char = sub_char;

        complete[0] = '\0';
        file = NULL;
        fd = -1;

        // FUTURE: could probably set to SIG_IGN once things work
        signal(SIGPIPE, pipe_handle_sigpipe);
}

Pipe::~Pipe() 
{
        close();
}

int Pipe::substitute() 
{
        if (command == NULL) 
        {
                strcpy(complete, "");
                return 0;
        }

        if (sub_str == NULL || sub_char == '\0') 
        {
                strcpy(complete, command);
                return 0;
        }

        int count = 0;
        char *c = command;
        char *f = complete;
        while (*c) 
        {
                // directly copy anything substitution char
                if (*c != sub_char) 
                {
                        *f++ = *c++;
                        continue;
                }
                
                // move over the substitution character
                c++;

                // two substitution characters in a row is literal
                if (*c == sub_char) {
                        *f++ = *c++;
                        continue;
                }

                // insert the file string at the substitution point
                if (f + strlen(sub_str) - complete > sizeof(complete))
                {
                        printf("Pipe::substitute(): max length exceeded\n");
                        return -1;
                }
                strcpy(f, sub_str);
                f += strlen(sub_str);
                count++;
        }

        return count;
}
        
        

int Pipe::open(char *mode) 
{
        if (file) close();

        if (mode == NULL) 
        {
                printf("Pipe::open(): no mode given\n");
                return 1;
        }

        if (substitute() < 0) 
                return 1;

        if (complete == NULL || strlen(complete) == 0) 
        {
                printf("Pipe::open(): no pipe to open\n");
                return 1;
        }

        printf("trying popen(%s)\n", complete);
        file = popen(complete, mode);
        if (file != NULL) 
        {
                fd = fileno(file);
                return 0;
        }

        // NOTE: popen() fails only if fork/exec fails
        //       there is no immediate way to see if command failed
        //       As such, one must expect to raise SIGPIPE on failure
        printf("Pipe::open(%s,%s) failed: %s\n", 
               complete, mode, strerror(errno));
        return 1;
}       

int Pipe::open_read() 
{
        return open("r");
}

int Pipe::open_write() 
{
        return open("w");
}

void Pipe::close() 
{
        pclose(file);
        file = 0;
        fd = -1;
}

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