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#' Set the random seed for widget element ids
#'
#' Set a random seed for generating widget element ids. Calling this
#' function rather than relying on the default behavior ensures
#' stable widget ids across sessions.
#'
#' @inheritParams base::set.seed
#'
#' @export
setWidgetIdSeed <- function(seed, kind = NULL, normal.kind = NULL) {
sysSeed <- .GlobalEnv$.Random.seed
on.exit({
.globals$idSeed <- .GlobalEnv$.Random.seed
if (!is.null(sysSeed))
.GlobalEnv$.Random.seed <- sysSeed
else
rm(".Random.seed", envir = .GlobalEnv)
})
set.seed(seed, kind = kind, normal.kind = normal.kind)
}
# create a new unique widget id
createWidgetId <- function(bytes = 10) {
# Note what the system's random seed is before we start, so we can restore it after
sysSeed <- .GlobalEnv$.Random.seed
# Replace system seed with our own seed
if (!is.null(.globals$idSeed)) {
.GlobalEnv$.Random.seed <- .globals$idSeed
}
on.exit({
# Change our own seed to match the current seed
.globals$idSeed <- .GlobalEnv$.Random.seed
# Restore the system seed--we were never here
if(!is.null(sysSeed))
.GlobalEnv$.Random.seed <- sysSeed
else
rm(".Random.seed", envir = .GlobalEnv)
})
paste(
format(as.hexmode(sample(256, bytes, replace = TRUE)-1), width=2),
collapse = "")
}
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