R Under development (unstable) (2023-11-16 r85542 ucrt) -- "Unsuffered Consequences"
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> library("R.utils")
Loading required package: R.oo
Loading required package: R.methodsS3
R.methodsS3 v1.8.2 (2022-06-13 22:00:14 UTC) successfully loaded. See ?R.methodsS3 for help.
R.oo v1.25.0 (2022-06-12 02:20:02 UTC) successfully loaded. See ?R.oo for help.

Attaching package: 'R.oo'

The following object is masked from 'package:R.methodsS3':

    throw

The following objects are masked from 'package:methods':

    getClasses, getMethods

The following objects are masked from 'package:base':

    attach, detach, load, save

R.utils v2.12.3 successfully loaded. See ?R.utils for help.

Attaching package: 'R.utils'

The following object is masked from 'package:utils':

    timestamp

The following objects are masked from 'package:base':

    cat, commandArgs, getOption, isOpen, nullfile, parse, warnings

> 
> createAtomically <- function(pathname, ...) {
+   cat("Pathname: ", pathname, "\n", sep="")
+ 
+   # Generate a file atomically, i.e. the file will either be
+   # complete or not created at all.  If interrupted while
+   # writing, only a temporary file will exist/remain.
+   pathnameT <- pushTemporaryFile(pathname, verbose=TRUE)
+   cat("Temporary pathname: ", pathnameT, "\n", sep="")
+ 
+   cat(file=pathnameT, "This file was created atomically:\n")
+   for (kk in 1:10) {
+     cat(file=pathnameT, kk, "\n", append=TRUE)
+     # Emulate a slow process
+     if (interactive()) Sys.sleep(0.1)
+   }
+   cat(file=pathnameT, "END OF FILE\n", append=TRUE)
+ 
+   # Rename the temporary file
+   pathname <- popTemporaryFile(pathnameT, verbose=TRUE)
+ 
+   pathname
+ } # createAtomically()
> 
> 
> pathname <- tempfile()
> 
> tryCatch({
+   # Try to interrupt the process while writing...
+   pathname <- createAtomically(pathname)
+ }, interrupt=function(intr) {
+   str(intr)
+ })
Pathname: D:\temp\Rtmp6pGjMD\file246d4300a22f
Adding temporary suffix from file...
 Pathname: D:/temp/Rtmp6pGjMD/file246d4300a22f
 Suffix: .tmp
 Rename existing file?: FALSE
 Temporary pathname: D:/temp/Rtmp6pGjMD/file246d4300a22f.tmp
Adding temporary suffix from file...done
Temporary pathname: D:/temp/Rtmp6pGjMD/file246d4300a22f.tmp
Dropping temporary suffix from file...
 Temporary pathname: D:/temp/Rtmp6pGjMD/file246d4300a22f.tmp
 Suffix: .tmp
 Regular expression for suffix: \.tmp$
 Pathname: D:/temp/Rtmp6pGjMD/file246d4300a22f
 Renaming existing file...
  Result: TRUE
 Renaming existing file...done
Dropping temporary suffix from file...done
> 
> # ...and this will throw an exception
> bfr <- readLines(pathname)
> cat(bfr, sep="\n")
This file was created atomically:
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
END OF FILE
> 
> proc.time()
   user  system elapsed 
   2.15   13.45   16.29