copy-to.r

#' Copy a local data frame to a remote src.
#'
#' This function uploads a local data frame into a remote data source, creating
#' the table definition as needed. Wherever possible, the new object will be
#' temporary, limited to the current connection to the source.
#'
#' @param dest remote data source
#' @param df local data frame
#' @param name name for new remote table.
#' @param ... other parameters passed to methods.
#' @return a \code{tbl} object in the remote source
#' @export
copy_to <- function(dest, df, name = deparse(substitute(df)), ...) {
  UseMethod("copy_to")
}

#' Copy tables to same source, if necessary.
#'
#' @param x,y \code{y} will be copied to \code{x}, if neccessary.
#' @param copy If \code{x} and \code{y} are not from the same data source,
#'   and \code{copy} is \code{TRUE}, then \code{y} will be copied into the
#'   same src as \code{x}.  This allows you to join tables across srcs, but
#'   it is a potentially expensive operation so you must opt into it.
#' @param ... Other arguments passed on to methods.
#' @export
auto_copy <- function(x, y, copy = FALSE, ...) {
  if (same_src(x, y)) return(y)

  if (!copy) {
    stop("x and y don't share the same src. Set copy = TRUE to copy y into ",
      "x's source (this may be time consuming).", call. = FALSE)
  }

  UseMethod("auto_copy")
}