/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 * Copyright (C) Junio C Hamano, 2005
 */
#include "builtin.h"
#include "blob.h"
#include "quote.h"
#include "parse-options.h"
#include "exec_cmd.h"

/*
 * This is to create corrupt objects for debugging and as such it
 * needs to bypass the data conversion performed by, and the type
 * limitation imposed by, index_fd() and its callees.
 */
static int hash_literally(unsigned char *sha1, int fd, const char *type, unsigned flags)
{
        struct strbuf buf = STRBUF_INIT;
        int ret;

        if (strbuf_read(&buf, fd, 4096) < 0)
                ret = -1;
        else
                ret = hash_sha1_file_literally(buf.buf, buf.len, type, sha1, flags);
        strbuf_release(&buf);
        return ret;
}

static void hash_fd(int fd, const char *type, const char *path, unsigned flags,
                    int literally)
{
        struct stat st;
        unsigned char sha1[20];

        if (fstat(fd, &st) < 0 ||
            (literally
             ? hash_literally(sha1, fd, type, flags)
             : index_fd(sha1, fd, &st, type_from_string(type), path, flags)))
                die((flags & HASH_WRITE_OBJECT)
                    ? "Unable to add %s to database"
                    : "Unable to hash %s", path);
        printf("%s\n", sha1_to_hex(sha1));
        maybe_flush_or_die(stdout, "hash to stdout");
}

static void hash_object(const char *path, const char *type, const char *vpath,
                        unsigned flags, int literally)
{
        int fd;
        fd = open(path, O_RDONLY);
        if (fd < 0)
                die_errno("Cannot open '%s'", path);
        hash_fd(fd, type, vpath, flags, literally);
}

static void hash_stdin_paths(const char *type, int no_filters, unsigned flags,
                             int literally)
{
        struct strbuf buf = STRBUF_INIT;
        struct strbuf unquoted = STRBUF_INIT;

        while (strbuf_getline(&buf, stdin) != EOF) {
                if (buf.buf[0] == '"') {
                        strbuf_reset(&unquoted);
                        if (unquote_c_style(&unquoted, buf.buf, NULL))
                                die("line is badly quoted");
                        strbuf_swap(&buf, &unquoted);
                }
                hash_object(buf.buf, type, no_filters ? NULL : buf.buf, flags,
                            literally);
        }
        strbuf_release(&buf);
        strbuf_release(&unquoted);
}

int cmd_hash_object(int argc, const char **argv, const char *prefix)
{
        static const char * const hash_object_usage[] = {
                N_("git hash-object [-t <type>] [-w] [--path=<file> | --no-filters] [--stdin] [--] <file>..."),
                N_("git hash-object  --stdin-paths"),
                NULL
        };
        const char *type = blob_type;
        int hashstdin = 0;
        int stdin_paths = 0;
        int no_filters = 0;
        int literally = 0;
        int nongit = 0;
        unsigned flags = HASH_FORMAT_CHECK;
        const char *vpath = NULL;
        const struct option hash_object_options[] = {
                OPT_STRING('t', NULL, &type, N_("type"), N_("object type")),
                OPT_BIT('w', NULL, &flags, N_("write the object into the object database"),
                        HASH_WRITE_OBJECT),
                OPT_COUNTUP( 0 , "stdin", &hashstdin, N_("read the object from stdin")),
                OPT_BOOL( 0 , "stdin-paths", &stdin_paths, N_("read file names from stdin")),
                OPT_BOOL( 0 , "no-filters", &no_filters, N_("store file as is without filters")),
                OPT_BOOL( 0, "literally", &literally, N_("just hash any random garbage to create corrupt objects for debugging Git")),
                OPT_STRING( 0 , "path", &vpath, N_("file"), N_("process file as it were from this path")),
                OPT_END()
        };
        int i;
        int prefix_length = -1;
        const char *errstr = NULL;

        argc = parse_options(argc, argv, NULL, hash_object_options,
                             hash_object_usage, 0);

        if (flags & HASH_WRITE_OBJECT)
                prefix = setup_git_directory();
        else
                prefix = setup_git_directory_gently(&nongit);

        prefix_length = prefix ? strlen(prefix) : 0;
        if (vpath && prefix)
                vpath = prefix_filename(prefix, prefix_length, vpath);

        git_config(git_default_config, NULL);

        if (stdin_paths) {
                if (hashstdin)
                        errstr = "Can't use --stdin-paths with --stdin";
                else if (argc)
                        errstr = "Can't specify files with --stdin-paths";
                else if (vpath)
                        errstr = "Can't use --stdin-paths with --path";
        }
        else {
                if (hashstdin > 1)
                        errstr = "Multiple --stdin arguments are not supported";
                if (vpath && no_filters)
                        errstr = "Can't use --path with --no-filters";
        }

        if (errstr) {
                error("%s", errstr);
                usage_with_options(hash_object_usage, hash_object_options);
        }

        if (hashstdin)
                hash_fd(0, type, vpath, flags, literally);

        for (i = 0 ; i < argc; i++) {
                const char *arg = argv[i];

                if (0 <= prefix_length)
                        arg = prefix_filename(prefix, prefix_length, arg);
                hash_object(arg, type, no_filters ? NULL : vpath ? vpath : arg,
                            flags, literally);
        }

        if (stdin_paths)
                hash_stdin_paths(type, no_filters, flags, literally);

        return 0;
}