/*
 * Copyright (c) 2006 Franck Bui-Huu
 */
#include "cache.h"
#include "builtin.h"
#include "archive.h"
#include "pkt-line.h"
#include "sideband.h"

static const char upload_archive_usage[] =
        "git upload-archive <repo>";

static const char deadchild[] =
"git upload-archive: archiver died with error";

static const char lostchild[] =
"git upload-archive: archiver process was lost";

#define MAX_ARGS (64)

static int run_upload_archive(int argc, const char **argv, const char *prefix)
{
        const char *sent_argv[MAX_ARGS];
        const char *arg_cmd = "argument ";
        char *p, buf[4096];
        int sent_argc;
        int len;

        if (argc != 2)
                usage(upload_archive_usage);

        if (strlen(argv[1]) + 1 > sizeof(buf))
                die("insanely long repository name");

        strcpy(buf, argv[1]); /* enter-repo smudges its argument */

        if (!enter_repo(buf, 0))
                die("'%s' does not appear to be a git repository", buf);

        /* put received options in sent_argv[] */
        sent_argc = 1;
        sent_argv[0] = "git-upload-archive";
        for (p = buf;;) {
                /* This will die if not enough free space in buf */
                len = packet_read_line(0, p, (buf + sizeof buf) - p);
                if (len == 0)
                        break;  /* got a flush */
                if (sent_argc > MAX_ARGS - 2)
                        die("Too many options (>%d)", MAX_ARGS - 2);

                if (p[len-1] == '\n') {
                        p[--len] = 0;
                }
                if (len < strlen(arg_cmd) ||
                    strncmp(arg_cmd, p, strlen(arg_cmd)))
                        die("'argument' token or flush expected");

                len -= strlen(arg_cmd);
                memmove(p, p + strlen(arg_cmd), len);
                sent_argv[sent_argc++] = p;
                p += len;
                *p++ = 0;
        }
        sent_argv[sent_argc] = NULL;

        /* parse all options sent by the client */
        return write_archive(sent_argc, sent_argv, prefix, 0);
}

static void error_clnt(const char *fmt, ...)
{
        char buf[1024];
        va_list params;
        int len;

        va_start(params, fmt);
        len = vsprintf(buf, fmt, params);
        va_end(params);
        send_sideband(1, 3, buf, len, LARGE_PACKET_MAX);
        die("sent error to the client: %s", buf);
}

static ssize_t process_input(int child_fd, int band)
{
        char buf[16384];
        ssize_t sz = read(child_fd, buf, sizeof(buf));
        if (sz < 0) {
                if (errno != EAGAIN && errno != EINTR)
                        error_clnt("read error: %s\n", strerror(errno));
                return sz;
        }
        send_sideband(1, band, buf, sz, LARGE_PACKET_MAX);
        return sz;
}

int cmd_upload_archive(int argc, const char **argv, const char *prefix)
{
        pid_t writer;
        int fd1[2], fd2[2];
        /*
         * Set up sideband subprocess.
         *
         * We (parent) monitor and read from child, sending its fd#1 and fd#2
         * multiplexed out to our fd#1.  If the child dies, we tell the other
         * end over channel #3.
         */
        if (pipe(fd1) < 0 || pipe(fd2) < 0) {
                int err = errno;
                packet_write(1, "NACK pipe failed on the remote side\n");
                die("upload-archive: %s", strerror(err));
        }
        writer = fork();
        if (writer < 0) {
                int err = errno;
                packet_write(1, "NACK fork failed on the remote side\n");
                die("upload-archive: %s", strerror(err));
        }
        if (!writer) {
                /* child - connect fd#1 and fd#2 to the pipe */
                dup2(fd1[1], 1);
                dup2(fd2[1], 2);
                close(fd1[1]); close(fd2[1]);
                close(fd1[0]); close(fd2[0]); /* we do not read from pipe */

                exit(run_upload_archive(argc, argv, prefix));
        }

        /* parent - read from child, multiplex and send out to fd#1 */
        close(fd1[1]); close(fd2[1]); /* we do not write to pipe */
        packet_write(1, "ACK\n");
        packet_flush(1);

        while (1) {
                struct pollfd pfd[2];
                ssize_t processed[2] = { 0, 0 };
                int status;

                pfd[0].fd = fd1[0];
                pfd[0].events = POLLIN;
                pfd[1].fd = fd2[0];
                pfd[1].events = POLLIN;
                if (poll(pfd, 2, -1) < 0) {
                        if (errno != EINTR) {
                                error("poll failed resuming: %s",
                                      strerror(errno));
                                sleep(1);
                        }
                        continue;
                }
                if (pfd[0].revents & POLLIN)
                        /* Data stream ready */
                        processed[0] = process_input(pfd[0].fd, 1);
                if (pfd[1].revents & POLLIN)
                        /* Status stream ready */
                        processed[1] = process_input(pfd[1].fd, 2);
                /* Always finish to read data when available */
                if (processed[0] || processed[1])
                        continue;

                if (waitpid(writer, &status, 0) < 0)
                        error_clnt("%s", lostchild);
                else if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
                        error_clnt("%s", deadchild);
                packet_flush(1);
                break;
        }
        return 0;
}