/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 */
#include "cache.h"
#include "exec_cmd.h"
#include "tag.h"
#include "tree.h"
#include "builtin.h"

static void flush_buffer(const char *buf, unsigned long size)
{
        while (size > 0) {
                long ret = xwrite(1, buf, size);
                if (ret < 0) {
                        /* Ignore epipe */
                        if (errno == EPIPE)
                                break;
                        die("git-cat-file: %s", strerror(errno));
                } else if (!ret) {
                        die("git-cat-file: disk full?");
                }
                size -= ret;
                buf += ret;
        }
}

static int pprint_tag(const unsigned char *sha1, const char *buf, unsigned long size)
{
        /* the parser in tag.c is useless here. */
        const char *endp = buf + size;
        const char *cp = buf;

        while (cp < endp) {
                char c = *cp++;
                if (c != '\n')
                        continue;
                if (7 <= endp - cp && !memcmp("tagger ", cp, 7)) {
                        const char *tagger = cp;

                        /* Found the tagger line.  Copy out the contents
                         * of the buffer so far.
                         */
                        flush_buffer(buf, cp - buf);

                        /*
                         * Do something intelligent, like pretty-printing
                         * the date.
                         */
                        while (cp < endp) {
                                if (*cp++ == '\n') {
                                        /* tagger to cp is a line
                                         * that has ident and time.
                                         */
                                        const char *sp = tagger;
                                        char *ep;
                                        unsigned long date;
                                        long tz;
                                        while (sp < cp && *sp != '>')
                                                sp++;
                                        if (sp == cp) {
                                                /* give up */
                                                flush_buffer(tagger,
                                                             cp - tagger);
                                                break;
                                        }
                                        while (sp < cp &&
                                               !('0' <= *sp && *sp <= '9'))
                                                sp++;
                                        flush_buffer(tagger, sp - tagger);
                                        date = strtoul(sp, &ep, 10);
                                        tz = strtol(ep, NULL, 10);
                                        sp = show_date(date, tz);
                                        flush_buffer(sp, strlen(sp));
                                        xwrite(1, "\n", 1);
                                        break;
                                }
                        }
                        break;
                }
                if (cp < endp && *cp == '\n')
                        /* end of header */
                        break;
        }
        /* At this point, we have copied out the header up to the end of
         * the tagger line and cp points at one past \n.  It could be the
         * next header line after the tagger line, or it could be another
         * \n that marks the end of the headers.  We need to copy out the
         * remainder as is.
         */
        if (cp < endp)
                flush_buffer(cp, endp - cp);
        return 0;
}

int cmd_cat_file(int argc, const char **argv, char **envp)
{
        unsigned char sha1[20];
        char type[20];
        void *buf;
        unsigned long size;
        int opt;

        setup_git_directory();
        git_config(git_default_config);
        if (argc != 3)
                usage("git-cat-file [-t|-s|-e|-p|<type>] <sha1>");
        if (get_sha1(argv[2], sha1))
                die("Not a valid object name %s", argv[2]);

        opt = 0;
        if ( argv[1][0] == '-' ) {
                opt = argv[1][1];
                if ( !opt || argv[1][2] )
                        opt = -1; /* Not a single character option */
        }

        buf = NULL;
        switch (opt) {
        case 't':
                if (!sha1_object_info(sha1, type, NULL)) {
                        printf("%s\n", type);
                        return 0;
                }
                break;

        case 's':
                if (!sha1_object_info(sha1, type, &size)) {
                        printf("%lu\n", size);
                        return 0;
                }
                break;

        case 'e':
                return !has_sha1_file(sha1);

        case 'p':
                if (sha1_object_info(sha1, type, NULL))
                        die("Not a valid object name %s", argv[2]);

                /* custom pretty-print here */
                if (!strcmp(type, tree_type))
                        return cmd_ls_tree(2, argv + 1, NULL);

                buf = read_sha1_file(sha1, type, &size);
                if (!buf)
                        die("Cannot read object %s", argv[2]);
                if (!strcmp(type, tag_type))
                        return pprint_tag(sha1, buf, size);

                /* otherwise just spit out the data */
                break;
        case 0:
                buf = read_object_with_reference(sha1, argv[1], &size, NULL);
                break;

        default:
                die("git-cat-file: unknown option: %s\n", argv[1]);
        }

        if (!buf)
                die("git-cat-file %s: bad file", argv[2]);

        flush_buffer(buf, size);
        return 0;
}