From f8020f19a3d5591fa4f065c3638cd1962f2fb637 Mon Sep 17 00:00:00 2001
From: Yihui Xie <xie@yihui.name>
Date: Tue, 16 Nov 2021 22:19:52 -0600
Subject: [PATCH] add a wrapper function `system3()` based on `system2()` to
 mark the character output of `system2()` as UTF-8 if appropriate

to avoid problems like https://github.com/rstudio/blogdown/commit/e4a3f38548f489f48a6706d4c7296b70cf024af6
---
 DESCRIPTION    |  2 +-
 NAMESPACE      |  1 +
 NEWS.md        |  2 ++
 R/command.R    | 25 +++++++++++++++++++++++++
 man/system3.Rd | 30 ++++++++++++++++++++++++++++++
 5 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 man/system3.Rd

diff --git a/DESCRIPTION b/DESCRIPTION
index 6ea98da..dec280f 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: xfun
 Type: Package
 Title: Supporting Functions for Packages Maintained by 'Yihui Xie'
-Version: 0.28.5
+Version: 0.28.6
 Authors@R: c(
   person("Yihui", "Xie", role = c("aut", "cre", "cph"), email = "xie@yihui.name", comment = c(ORCID = "0000-0003-0645-5666")),
   person("Wush", "Wu", role = "ctb"),
diff --git a/NAMESPACE b/NAMESPACE
index 97e4233..dd8f1c2 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -104,6 +104,7 @@ export(strict_list)
 export(stringsAsStrings)
 export(strings_please)
 export(submit_cran)
+export(system3)
 export(tinify)
 export(tojson)
 export(tree)
diff --git a/NEWS.md b/NEWS.md
index d9415ba..bb4b3c7 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -6,6 +6,8 @@
 
 - Added functions `rest_api_raw()` and `rest_api()` to get data from a REST API; also added the function `github_api()` to get data from the Github API based on `rest_api_raw()`.
 
+- Added a wrapper function `system3()` based on `system2()` to mark the character output of `system2()` as UTF-8 if appropriate.
+
 # CHANGES IN xfun VERSION 0.28
 
 - Added a new function `url_accessible()` to test if a URL can be downloaded.
diff --git a/R/command.R b/R/command.R
index 02ae0c1..79ec5cd 100644
--- a/R/command.R
+++ b/R/command.R
@@ -1,3 +1,28 @@
+#' Run \code{system2()} and mark its character output as UTF-8 if appropriate
+#'
+#' This is a wrapper function based on \code{system2()}. If \code{system2()}
+#' returns character output (e.g., with the argument \code{stdout = TRUE}),
+#' check if the output is encoded in UTF-8. If it is, mark it with UTF-8
+#' explicitly.
+#' @param ... Passed to \code{\link{system2}()}.
+#' @return The value returned by \code{system2()}.
+#' @export
+#' @examplesIf interactive()
+#' a = shQuote(c('-e', 'print(intToUtf8(c(20320, 22909)))'))
+#' x2 = system2('Rscript', a, stdout = TRUE)
+#' Encoding(x2)  # unknown
+#'
+#' x3 = xfun::system3('Rscript', a, stdout = TRUE)
+#' # encoding of x3 should be UTF-8 if the current locale is UTF-8
+#' !l10n_info()[['UTF-8']] || Encoding(x3) == 'UTF-8'  # should be TRUE
+system3 = function(...) {
+  res = system2(...)
+  if (is.character(res)) {
+    if (all(is_utf8(res))) Encoding(res) = 'UTF-8'
+  }
+  if (is.integer(res) && res == 0) invisible(res) else res
+}
+
 #' Run OptiPNG on all PNG files under a directory
 #'
 #' Call the command \command{optipng} via \code{system2()} to optimize all PNG
diff --git a/man/system3.Rd b/man/system3.Rd
new file mode 100644
index 0000000..121cff2
--- /dev/null
+++ b/man/system3.Rd
@@ -0,0 +1,30 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/command.R
+\name{system3}
+\alias{system3}
+\title{Run \code{system2()} and mark its character output as UTF-8 if appropriate}
+\usage{
+system3(...)
+}
+\arguments{
+\item{...}{Passed to \code{\link{system2}()}.}
+}
+\value{
+The value returned by \code{system2()}.
+}
+\description{
+This is a wrapper function based on \code{system2()}. If \code{system2()}
+returns character output (e.g., with the argument \code{stdout = TRUE}),
+check if the output is encoded in UTF-8. If it is, mark it with UTF-8
+explicitly.
+}
+\examples{\dontshow{if (interactive()) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
+a = shQuote(c("-e", "print(intToUtf8(c(20320, 22909)))"))
+x2 = system2("Rscript", a, stdout = TRUE)
+Encoding(x2)  # unknown
+
+x3 = xfun::system3("Rscript", a, stdout = TRUE)
+# encoding of x3 should be UTF-8 if the current locale is UTF-8
+!l10n_info()[["UTF-8"]] || Encoding(x3) == "UTF-8"  # should be TRUE
+\dontshow{\}) # examplesIf}
+}