From 47a957070235ef86383446ef28eb91c6f75efce6 Mon Sep 17 00:00:00 2001
From: Elio Campitelli <eliocampitelli@gmail.com>
Date: Tue, 8 Oct 2024 17:50:25 +1100
Subject: [PATCH] Adds ephemeral files

---
 NEWS.md                 |  1 +
 R/cdo.R                 | 22 ++++++++++++++++++++--
 pkg_build/extra-R/cdo.R | 22 ++++++++++++++++++++--
 3 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index a9fa42e..2f2d08f 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -5,3 +5,4 @@
 -   Added options management. `cdo_options_use()` will use options for an operation. `cdo_option_set()` will set global options to use for all operations. `cdo_options_clear()` will clear the global options.
 -   The new `cdo_operator()` allows the user to define an arbitrary operator in case the some operator is missing in the package. Operators are run with the `cdo()` function.
 -   Added operators with zero outputs.
+-   By default, temporay files output are deleted when not accessible from the R session.
diff --git a/R/cdo.R b/R/cdo.R
index 81cba9d..c314f23 100644
--- a/R/cdo.R
+++ b/R/cdo.R
@@ -144,7 +144,7 @@ get_output_length <- function(x) {
 #'
 #' @param operation a CDO operation
 #' @param output an output file or base string for output files. Defaults to
-#' temporary files.
+#' temporary files that will be deleted when its bond variable is garbage collected.
 #' @param options character vector with CDO options.
 #' @param verbose whether to print the command being executed.
 #'
@@ -186,6 +186,22 @@ cdo_execute <- function(operation,
   return(operation$output)
 }
 
+
+ephemeral_files <- R6::R6Class("ephemeral_files", public = list(
+  files = NA,
+  initialize = function(files) {
+    self$files <- files
+    return(self)
+  },
+  print = function() {
+    cat("Will be deleted when garbage collected\n")
+  },
+
+  finalize = function() {
+    file.remove(self$files)
+  })
+)
+
 temp_output <- function(operation) {
   if (operation$operator$n_output == Inf) {
     n <- 1
@@ -193,7 +209,9 @@ temp_output <- function(operation) {
     n <- operation$operator$n_output
   }
 
-  replicate(n, tempfile())
+  files <- replicate(n, tempfile())
+  attr(files, "ephemeral") <- ephemeral_files$new(files)
+  files
 }
 
 
diff --git a/pkg_build/extra-R/cdo.R b/pkg_build/extra-R/cdo.R
index 81cba9d..c314f23 100644
--- a/pkg_build/extra-R/cdo.R
+++ b/pkg_build/extra-R/cdo.R
@@ -144,7 +144,7 @@ get_output_length <- function(x) {
 #'
 #' @param operation a CDO operation
 #' @param output an output file or base string for output files. Defaults to
-#' temporary files.
+#' temporary files that will be deleted when its bond variable is garbage collected.
 #' @param options character vector with CDO options.
 #' @param verbose whether to print the command being executed.
 #'
@@ -186,6 +186,22 @@ cdo_execute <- function(operation,
   return(operation$output)
 }
 
+
+ephemeral_files <- R6::R6Class("ephemeral_files", public = list(
+  files = NA,
+  initialize = function(files) {
+    self$files <- files
+    return(self)
+  },
+  print = function() {
+    cat("Will be deleted when garbage collected\n")
+  },
+
+  finalize = function() {
+    file.remove(self$files)
+  })
+)
+
 temp_output <- function(operation) {
   if (operation$operator$n_output == Inf) {
     n <- 1
@@ -193,7 +209,9 @@ temp_output <- function(operation) {
     n <- operation$operator$n_output
   }
 
-  replicate(n, tempfile())
+  files <- replicate(n, tempfile())
+  attr(files, "ephemeral") <- ephemeral_files$new(files)
+  files
 }