R/cleanup.R

In kevinushey/Kmisc: Kevin Miscellaneous

## This function:
## 1. Concatenates all .c files into <pkg>_c.c (excluding an init.c file),
## 2. Concatenates all .cpp files into <pkg>_cpp.cpp,
## This greatly speeds compilation time.
cleanup <- function() {
  
  built_file <- file.path("inst", "built")
  stopifnot(file.exists("DESCRIPTION"))
  
  ## get the package name from the DESCRIPTION file
  DESCRIPTION <- as.list(read.dcf("DESCRIPTION")[1, ])
  pkg_name <- DESCRIPTION$Package
  pkg_version <- DESCRIPTION$Version
  
  ## bail if the package has already been built
  R_LIBRARY_DIR <- Sys.getenv("R_LIBRARY_DIR")
  if (!grepl("Rbuild", R_LIBRARY_DIR) || file.exists(built_file)) {
    return(invisible(NULL))
  }
  
  ## Since we are in the R CMD build step, we can just build in the current dir
  buildDir <- getwd()
  
  ## in the build directory, 'cat' all the src files together
  ## have a separate file for .c, .cpp files
  src_files <- list.files( full.names=TRUE,
    file.path( buildDir, "src" )
  )
  
  ## but don't concatenate init.c; copy it separately
  src_files <- grep("init\\.c$", src_files, value=TRUE, invert=TRUE)
  
  ## Move RcppExports.cpp to the end
  RcppExports <- grep("RcppExports.cpp", src_files, value=TRUE, fixed=TRUE)
  src_files <- c(
    src_files[src_files != RcppExports],
    RcppExports
  )
  
  ## regex: the regex to match for picking up files
  ## ext: the file extension to use on the outputted file
  concatenate_src <- function(regex, ext) {
    files <- grep(regex, src_files, value=TRUE)
    final <- file.path(
      buildDir,
      "src",
      paste0(pkg_name, "_", gsub("\\.", "", ext), ext)
    )
    file.create(final)
    files <- files[ files != final ]
    for (file in files) {
      header <- paste("// begin file", shQuote(basename(file)), "\n\n")
      footer <- paste("\n// end file", shQuote(basename(file)), "\n\n")
      cat(header, file = final, append = TRUE)
      
      ## Use R since we can't assume the presence of cat
      tmp <- readLines(file)
      cat(tmp, sep="\n", file = final, append = TRUE)
      
      cat(footer, file = final, append = TRUE)
    }
    file.remove(files)
  }
  
  cat("Concatenating source files...\n")
  concatenate_src("\\.c$", ".c")
  concatenate_src("\\.cpp$", ".cpp")
  
  ## Create a file that signals the package has been built so we avoid the
  ## re-cleaning after installation
  file.create(built_file)
  
}