#include <sys/types.h>
#include <attr/xattr.h>

#define EXTATTR_NAMESPACE_USER 0
#define EXTATTR_NAMESPACE_SYSTEM 1

static VALUE NAMESPACE_USER_PREFIX, NAMESPACE_SYSTEM_PREFIX;


static VALUE
extattr_list0(ssize_t (*func)(), void *d, int namespace)
{
    ssize_t size = 65536;
    VALUE buf = rb_str_buf_new(size);
    char *ptr = RSTRING_PTR(buf);
    size = func(d, ptr, size);
    if (size < 0) { rb_sys_fail("listxattr call error"); }

    VALUE (*reduce)(void *, VALUE);
    void *first;
    VALUE list;
    if (rb_block_given_p()) {
        reduce = (VALUE (*)(void *, VALUE))rb_yield_values;
        first = (void *)1;
        list = Qnil;
    } else {
        reduce = (VALUE (*)(void *, VALUE))rb_ary_push;
        first = (void *)(list = rb_ary_new());
    }

    const char *end = ptr + size;
    while (ptr < end) {
        int len = strlen(ptr);
        VALUE name;
        if (namespace == EXTATTR_NAMESPACE_USER && len > 5 && strncmp(ptr, "user.", 5) == 0) {
            ptr += 5;
        } else if (namespace == EXTATTR_NAMESPACE_SYSTEM && len > 7 && strncmp(ptr, "system.", 7) == 0) {
            ptr += 7;
        } else {
            ptr += len + 1;
            continue;
        }

        name = rb_str_new_cstr(ptr);
        reduce(first, name);
        ptr += RSTRING_LEN(name) + 1; // 最後の『+1』は、ヌルバイトの分。
    }

    return list;
}

static VALUE
file_extattr_list0(VALUE file, int fd, int namespace)
{
    return extattr_list0(flistxattr, (void *)fd, namespace);
}

static VALUE
file_s_extattr_list0(VALUE path, int namespace)
{
    return extattr_list0(listxattr, StringValueCStr(path), namespace);
}

static VALUE
file_s_extattr_list_link0(VALUE path, int namespace)
{
    return extattr_list0(llistxattr, StringValueCStr(path), namespace);
}


static VALUE
xattr_name(int namespace, VALUE name)
{
    switch (namespace) {
    case EXTATTR_NAMESPACE_USER:
        return rb_str_plus(NAMESPACE_USER_PREFIX, name);
    case EXTATTR_NAMESPACE_SYSTEM:
        return rb_str_plus(NAMESPACE_SYSTEM_PREFIX, name);
    default:
        rb_raise(rb_eRuntimeError, "namespace error");
        return Qnil;
    }
}

static VALUE
extattr_size0(ssize_t (*func)(), void *d, int namespace, VALUE name)
{
    name = xattr_name(namespace, name);
    ssize_t size = func(d, StringValueCStr(name), NULL, 0);
    if (size < 0) { rb_sys_fail("getxattr call error"); }
    return SSIZET2NUM(size);
}

static VALUE
file_extattr_size0(VALUE file, int fd, int namespace, VALUE name)
{
    return extattr_size0(fgetxattr, (void *)fd, namespace, name);
}

static VALUE
file_s_extattr_size0(VALUE path, int namespace, VALUE name)
{
    return extattr_size0(getxattr, StringValueCStr(path), namespace, name);
}

static VALUE
file_s_extattr_size_link0(VALUE path, int namespace, VALUE name)
{
    return extattr_size0(lgetxattr, StringValueCStr(path), namespace, name);
}


static VALUE
extattr_get0(ssize_t (*func)(), void *d, int namespace, VALUE name)
{
    name = xattr_name(namespace, name);
    ssize_t size = 65536;
    VALUE buf = rb_str_buf_new(size);
    char *ptr = RSTRING_PTR(buf);
    size = func(d, StringValueCStr(name), ptr, size);
    if (size < 0) { rb_sys_fail("getxattr call error"); }
    rb_str_set_len(buf, size);
    return buf;
}

static VALUE
file_extattr_get0(VALUE file, int fd, int namespace, VALUE name)
{
    return extattr_get0(fgetxattr, (void *)fd, namespace, name);
}

static VALUE
file_s_extattr_get0(VALUE path, int namespace, VALUE name)
{
    return extattr_get0(getxattr, StringValueCStr(path), namespace, name);
}

static VALUE
file_s_extattr_get_link0(VALUE path, int namespace, VALUE name)
{
    return extattr_get0(lgetxattr, StringValueCStr(path), namespace, name);
}


static VALUE
extattr_set0(int (*func)(), void *d, int namespace, VALUE name, VALUE data)
{
    name = xattr_name(namespace, name);
    int status = func(d, StringValueCStr(name), RSTRING_PTR(data), RSTRING_LEN(data));
    if (status < 0) { rb_sys_fail("getxattr call error"); }
    return Qnil;
}

static VALUE
file_extattr_set0(VALUE file, int fd, int namespace, VALUE name, VALUE data)
{
    return extattr_set0(fsetxattr, (void *)fd, namespace, name, data);
}

static VALUE
file_s_extattr_set0(VALUE path, int namespace, VALUE name, VALUE data)
{
    return extattr_set0(setxattr, StringValueCStr(path), namespace, name, data);
}

static VALUE
file_s_extattr_set_link0(VALUE path, int namespace, VALUE name, VALUE data)
{
    return extattr_set0(lsetxattr, StringValueCStr(path), namespace, name, data);
}


static VALUE
extattr_delete0(int (*func)(), void *d, int namespace, VALUE name)
{
    name = xattr_name(namespace, name);
    int status = func(d, StringValueCStr(name));
    if (status < 0) { rb_sys_fail("removexattr call error"); }
    return Qnil;
}

static VALUE
file_extattr_delete0(VALUE file, int fd, int namespace, VALUE name)
{
    return extattr_delete0(fremovexattr, (void *)fd, namespace, name);
}

static VALUE
file_s_extattr_delete0(VALUE path, int namespace, VALUE name)
{
    return extattr_delete0(removexattr, StringValueCStr(path), namespace, name);
}

static VALUE
file_s_extattr_delete_link0(VALUE path, int namespace, VALUE name)
{
    return extattr_delete0(lremovexattr, StringValueCStr(path), namespace, name);
}


static void
setup(void)
{
    NAMESPACE_USER_PREFIX = rb_str_new_cstr("user.");
    NAMESPACE_SYSTEM_PREFIX = rb_str_new_cstr("system.");

    rb_gc_register_mark_object(NAMESPACE_USER_PREFIX);
    rb_gc_register_mark_object(NAMESPACE_SYSTEM_PREFIX);
}