Provide access to TileDB shared libraries in downstream packages

New helper function to provide access to `libtiledb` used by tiledb-r
for downstream packages. This builds off the prototype code @LTLA
provided

resolves #780

R/Init.R

@@ -53,6 +53,10 @@
   ## set a preference for allocation size defaults
   .pkgenv[["allocation_size"]] <- load_allocation_size_preference()
 
+  # cache package name and path
+  .pkgenv[["pkgname"]] <- pkgname
+  .pkgenv[["libname"]] <- libname
+
   ## call setter for Rcpp plugin support
   .set_compile_link_options()
 
@@ -121,7 +125,6 @@ inlineCxxPlugin <- function(...) {
   }
 }
 
-
 #' @importFrom utils read.table
 .getLinuxFlavor <- function() {
   res <- NA_character_

R/Version.R

@@ -41,3 +41,45 @@ tiledb_version <- function(compact = FALSE) {
     libtiledb_version()
   }
 }
+
+#' Compiler Arguments for Using \code{libtiledb}
+#'
+#' @param opt A single character value with the package configuration variable
+#' to fetch; choose from
+#' \itemize{
+#'  \item \dQuote{\code{PKG_CXX_FLAGS}}: compiler flags for \code{libtiledb}
+#'  \item \dQuote{\code{PKG_CXX_LIBS}}: linking flags for \code{libtiledb}
+#' }
+#'
+#' @return ...
+#'
+#' @keywords internal
+#'
+#' @export
+#'
+#' @examples
+#' .pkg_config()
+#' .pkg_config("PKG_CXX_LIBS")
+#'
+.pkg_config <- function(opt = c("PKG_CXX_FLAGS", "PKG_CXX_LIBS")) {
+  opt <- match.arg(opt)
+  if (nzchar(lib <- system.file("tiledb", package = .pkgenv$pkgname, lib.loc = .pkgenv$libname))) {
+    pkgdir <- system.file(package = .pkgenv$pkgname, lib.loc = .pkgenv$libname)
+    return(switch(
+      EXPR = opt,
+      PKG_CXX_FLAGS = sprintf("-I%s/include -I%s/include", pkgdir, lib),
+      PKG_CXX_LIBS = sprintf("-ltiledb -L%s/lib -L%s/lib", pkgdir, lib)
+    ))
+  }
+  if (nzchar(pkgconfig <- Sys.which("pkg-config"))) {
+    if (!system2(pkgconfig, args = c("--exists", "tiledb"))) {
+      flag <- switch(EXPR = opt, PKG_CXX_FLAGS = "--cflags", PKG_CXX_LIBS = "--libs")
+      return(system2(pkgconfig, args = c(flag, "tiledb"), stdout = TRUE))
+    }
+  }
+  return(switch(
+    EXPR = opt,
+    PKG_CXX_FLAGS = "",
+    PKG_CXX_LIBS = "-ltiledb"
+  ))
+}

TileDB-R.Rproj

@@ -12,6 +12,9 @@ Encoding: UTF-8
 RnwWeave: Sweave
 LaTeX: pdfLaTeX
 
+AutoAppendNewline: Yes
+StripTrailingWhitespace: Yes
+
 BuildType: Package
 PackageUseDevtools: Yes
 PackageInstallArgs: --no-multiarch --with-keep.source --install-tests