From 17c46bdd5555180ef6918d07ae0dd330d3f8f854 Mon Sep 17 00:00:00 2001
From: Arni Magnusson <thisisarni@gmail.com>
Date: Thu, 24 Oct 2024 03:27:04 +1100
Subject: [PATCH] Add argument 'force' to dos2unix() and unix2dos()

---
 NEWS.md         |  5 +++--
 R/dos2unix.R    | 21 +++++++++++++++++++--
 R/unix2dos.R    | 13 +++++++++++--
 man/dos2unix.Rd | 13 +++++++++++--
 4 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 2b82fe6..0decf4e 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -8,10 +8,11 @@
 * Added function taf.libraries() to load all packages from TAF library. Code
   contributed by Iago Mosqueira.
 
+* Added argument 'force' to dos2unix() and unix2dos().
+
 * Added argument 'quiet' to make(). Renamed argument 'debug' to 'details'.
 
-* Added argument 'gitignore' to taf.skeleton() for writing a .gitignore file,
-  enabled by default.
+* Added argument 'gitignore' to taf.skeleton().
 
 * Improved draft.software() so it supports packages from r-universe. Code
   contributed by Iago Mosqueira.
diff --git a/R/dos2unix.R b/R/dos2unix.R
index f5304b0..799ff62 100644
--- a/R/dos2unix.R
+++ b/R/dos2unix.R
@@ -3,6 +3,14 @@
 #' Convert line endings in a text file between Dos (CRLF) and Unix (LF) format.
 #'
 #' @param file a filename.
+#' @param force whether to proceed with the conversion when the file is not a
+#'        standard text file.
+#'
+#' @details
+#' The default value of \code{force = FALSE} is a safety feature that can avoid
+#' corrupting files that are not standard text files, such as binary files. A
+#' standard text file is one that can be read using \code{\link{readLines}}
+#' without producing warnings.
 #'
 #' @return No return value, called for side effects.
 #'
@@ -27,9 +35,18 @@
 #'
 #' @export
 
-dos2unix <- function(file)
+dos2unix <- function(file, force=FALSE)
 {
-  txt <- readLines(file)
+  if(!force)
+  {
+    owarn <- options(warn=2)  # treat warnings from readLines() as errors
+    on.exit(options(owarn))
+  }
+
+  txt <- try(readLines(file), silent=TRUE)
+  if(inherits(txt, "try-error"))
+    stop("file is not a standard text file")
+
   con <- file(file, open="wb")
   writeLines(txt, con, sep="\n")
   close(con)
diff --git a/R/unix2dos.R b/R/unix2dos.R
index 4a3c28e..1fadc3d 100644
--- a/R/unix2dos.R
+++ b/R/unix2dos.R
@@ -2,9 +2,18 @@
 #'
 #' @export
 
-unix2dos <- function(file)
+unix2dos <- function(file, force=FALSE)
 {
-  txt <- readLines(file)
+  if(!force)
+  {
+    owarn <- options(warn=2)  # treat warnings from readLines() as errors
+    on.exit(options(owarn))
+  }
+
+  txt <- try(readLines(file), silent=TRUE)
+  if(inherits(txt, "try-error"))
+    stop("file is not a standard text file")
+
   con <- file(file, open="wb")
   writeLines(txt, con, sep="\r\n")
   close(con)
diff --git a/man/dos2unix.Rd b/man/dos2unix.Rd
index 4b05b71..8551bc5 100644
--- a/man/dos2unix.Rd
+++ b/man/dos2unix.Rd
@@ -5,12 +5,15 @@
 \alias{unix2dos}
 \title{Convert Line Endings}
 \usage{
-dos2unix(file)
+dos2unix(file, force = FALSE)
 
-unix2dos(file)
+unix2dos(file, force = FALSE)
 }
 \arguments{
 \item{file}{a filename.}
+
+\item{force}{whether to proceed with the conversion when the file is not a
+standard text file.}
 }
 \value{
 No return value, called for side effects.
@@ -18,6 +21,12 @@ No return value, called for side effects.
 \description{
 Convert line endings in a text file between Dos (CRLF) and Unix (LF) format.
 }
+\details{
+The default value of \code{force = FALSE} is a safety feature that can avoid
+corrupting files that are not standard text files, such as binary files. A
+standard text file is one that can be read using \code{\link{readLines}}
+without producing warnings.
+}
 \examples{
 \dontrun{
 file <- "test.txt"