Parallel styling of files by style_pkg & style_dir (#277)

DESCRIPTION

@@ -28,7 +28,8 @@ Imports:
     tibble (>= 1.4.2),
     tools,
     withr (>= 1.0.0),
-    xfun (>= 0.1)
+    xfun (>= 0.1),
+    future.apply
 Suggests: 
     data.tree (>= 0.1.6),
     digest,

NEWS.md

@@ -10,6 +10,11 @@ Release upon request by the CRAN team.
 - skip timing tests on CRAN as requested by CRAN team because they did not pass 
   on all machines (#603).
 
+## New features
+
+* `style_pkg()` and `style_dir()` gain the ability to run in parallel using 
+  `future` backends (#277).
+
 # styler 1.3.1
 
 Emergency release. In case multiple expressions are on one line and only 

R/transform-files.R

@@ -9,17 +9,22 @@
 #' Invisibly returns a data frame that indicates for each file considered for
 #' styling whether or not it was actually changed.
 #' @keywords internal
-transform_files <- function(files, transformers, include_roxygen_examples) {
+transform_files <- function(files,
+                            transformers,
+                            include_roxygen_examples,
+                            root = ".") {
   transformer <- make_transformer(transformers, include_roxygen_examples)
   max_char <- min(max(nchar(files), 0), getOption("width"))
   len_files <- length(files)
   if (len_files > 0L) {
     cat("Styling ", len_files, " files:\n")
   }
 
-  changed <- map_lgl(files, transform_file,
-    fun = transformer, max_char_path = max_char
+  changed <- future.apply::future_sapply(
+    files, transform_file,
+    fun = transformer, max_char_path = max_char, root = root
   )
+
   communicate_summary(changed, max_char)
   communicate_warning(changed, transformers)
   new_tibble(list(file = files, changed = changed), nrow = len_files)
@@ -43,6 +48,7 @@ transform_file <- function(path,
                            message_before = "",
                            message_after = " [DONE]",
                            message_after_if_changed = " *",
+                           root = ".",
                            ...) {
   char_after_path <- nchar(message_before) + nchar(path) + 1
   max_char_after_message_path <- nchar(message_before) + max_char_path + 1
@@ -53,6 +59,7 @@ transform_file <- function(path,
     rep_char(" ", max(0L, n_spaces_before_message_after)),
     append = FALSE
   )
+  setwd(root)
   changed <- transform_code(path, fun = fun, ...)
 
   bullet <- ifelse(is.na(changed), "warning", ifelse(changed, "info", "tick"))

R/ui-styling.R

@@ -69,6 +69,10 @@ NULL
 #'   scope = "line_breaks",
 #'   math_token_spacing = specify_math_token_spacing(zero = "'+'")
 #' )
+#' # For parallel operation:
+#' library(future)
+#' plan(multisession, workers = 4)
+#' style_pkg()
 #' }
 #' @export
 style_pkg <- function(pkg = ".",
@@ -82,7 +86,7 @@ style_pkg <- function(pkg = ".",
   pkg_root <- rprojroot::find_package_root_file(path = pkg)
   changed <- withr::with_dir(pkg_root, prettify_pkg(
     transformers,
-    filetype, exclude_files, exclude_dirs, include_roxygen_examples
+    filetype, exclude_files, exclude_dirs, include_roxygen_examples, pkg_root
   ))
   invisible(changed)
 }
@@ -91,7 +95,8 @@ prettify_pkg <- function(transformers,
                          filetype,
                          exclude_files,
                          exclude_dirs,
-                         include_roxygen_examples) {
+                         include_roxygen_examples,
+                         pkg_root = ".") {
   filetype <- set_and_assert_arg_filetype(filetype)
   r_files <- rprofile_files <- vignette_files <- readme <- NULL
   exclude_files <- set_arg_paths(exclude_files)
@@ -137,7 +142,7 @@ prettify_pkg <- function(transformers,
     c(r_files, rprofile_files, vignette_files, readme),
     exclude_files
   )
-  transform_files(files, transformers, include_roxygen_examples)
+  transform_files(files, transformers, include_roxygen_examples, pkg_root)
 }
 
 #' Style a string
@@ -184,6 +189,10 @@ style_text <- function(text,
 #' @examples
 #' \dontrun{
 #' style_dir(file_type = "r")
+#' # For parallel operation:
+#' library(future)
+#' plan(multisession, workers = 4)
+#' style_dir()
 #' }
 #' @export
 style_dir <- function(path = ".",
@@ -198,7 +207,8 @@ style_dir <- function(path = ".",
   changed <- withr::with_dir(
     path, prettify_any(
       transformers,
-      filetype, recursive, exclude_files, exclude_dirs, include_roxygen_examples
+      filetype, recursive, exclude_files, exclude_dirs,
+      include_roxygen_examples, path
     )
   )
   invisible(changed)
@@ -216,7 +226,8 @@ prettify_any <- function(transformers,
                          recursive,
                          exclude_files,
                          exclude_dirs,
-                         include_roxygen_examples) {
+                         include_roxygen_examples,
+                         path = ".") {
   exclude_files <- set_arg_paths(exclude_files)
   exclude_dirs <- set_arg_paths(exclude_dirs)
   files_root <- dir(
@@ -236,7 +247,7 @@ prettify_any <- function(transformers,
   }
   transform_files(
     setdiff(c(files_root, files_other), exclude_files),
-    transformers, include_roxygen_examples
+    transformers, include_roxygen_examples, path
   )
 }