static int s_discover_object_range_and_content_length()

in source/s3_auto_ranged_get.c [381:502]

• 92 lines of code
• 10 McCabe index (conditional complexity)

static int s_discover_object_range_and_content_length(
    struct aws_s3_meta_request *meta_request,
    struct aws_s3_request *request,
    int error_code,
    uint64_t *out_total_content_length,
    uint64_t *out_object_range_start,
    uint64_t *out_object_range_end,
    uint64_t *out_total_object_size) {
    AWS_PRECONDITION(out_total_content_length);
    AWS_PRECONDITION(out_object_range_start);
    AWS_PRECONDITION(out_object_range_end);
    AWS_PRECONDITION(out_total_object_size);

    int result = AWS_OP_ERR;

    uint64_t total_content_length = 0;
    uint64_t object_range_start = 0;
    uint64_t object_range_end = 0;
    uint64_t total_object_size = 0;

    AWS_ASSERT(request->discovers_object_size);

    switch (request->request_tag) {
        case AWS_S3_AUTO_RANGE_GET_REQUEST_TYPE_HEAD_OBJECT:
            if (error_code != AWS_ERROR_SUCCESS) {
                /* If the head request failed, there's nothing we can do, so resurface the error code. */
                aws_raise_error(error_code);
                break;
            }

            /* There should be a Content-Length header that indicates the total size of the range.*/
            if (aws_s3_parse_content_length_response_header(
                    meta_request->allocator, request->send_data.response_headers, &total_content_length)) {

                AWS_LOGF_ERROR(
                    AWS_LS_S3_META_REQUEST,
                    "id=%p Could not find content-length header for request %p",
                    (void *)meta_request,
                    (void *)request);
                break;
            }

            /* When doing a head object request, we currently assume that we did so with a message that had a Range
             * header. This means that there should also be a Content-Range header that specifies the object range and
             * total object size.*/
            if (aws_s3_parse_content_range_response_header(
                    meta_request->allocator,
                    request->send_data.response_headers,
                    &object_range_start,
                    &object_range_end,
                    &total_object_size)) {

                AWS_LOGF_ERROR(
                    AWS_LS_S3_META_REQUEST,
                    "id=%p Could not find content-range header for request %p",
                    (void *)meta_request,
                    (void *)request);
                break;
            }

            result = AWS_OP_SUCCESS;
            break;
        case AWS_S3_AUTO_RANGE_GET_REQUEST_TYPE_PART:
            AWS_ASSERT(request->part_number == 1);

            if (error_code != AWS_ERROR_SUCCESS) {
                /* If we hit an empty file while trying to discover the object-size via part, then this request failure
                 * is as designed. */
                if (s_check_empty_file_download_error(request)) {
                    AWS_LOGF_DEBUG(
                        AWS_LS_S3_META_REQUEST,
                        "id=%p Detected empty file with request %p. Sending new request without range header.",
                        (void *)meta_request,
                        (void *)request);

                    total_object_size = 0ULL;
                    total_content_length = 0ULL;

                    result = AWS_OP_SUCCESS;
                } else {
                    /* Otherwise, resurface the error code. */
                    aws_raise_error(error_code);
                }
                break;
            }

            AWS_ASSERT(request->send_data.response_headers != NULL);

            /* Parse the object size from the part response. */
            if (aws_s3_parse_content_range_response_header(
                    meta_request->allocator, request->send_data.response_headers, NULL, NULL, &total_object_size)) {

                AWS_LOGF_ERROR(
                    AWS_LS_S3_META_REQUEST,
                    "id=%p Could not find content-range header for request %p",
                    (void *)meta_request,
                    (void *)request);

                break;
            }

            /* When discovering the object size via first-part, the object range is the entire object. */
            object_range_start = 0;
            object_range_end = total_object_size - 1;
            total_content_length = total_object_size;

            result = AWS_OP_SUCCESS;
            break;
        default:
            AWS_ASSERT(false);
            break;
    }

    if (result == AWS_OP_SUCCESS) {
        *out_total_content_length = total_content_length;
        *out_object_range_start = object_range_start;
        *out_object_range_end = object_range_end;
        *out_total_object_size = total_object_size;
    }

    return result;
}