R/zzz.r

In rggobi: Interface Between R and 'GGobi'

# Check structs
# Validates GGobi and Rggobi views of internal data structures
#
# This function is called when the Rggobi library is loaded and it verifies
# that the sizes of the different internal data structures for GGobi are the
# same for both the GGobi shared library/DLL and the Rggobi package. This is
# important as the two shared libraries are compiled separately and may have
# different compilation flags, etc. that make them incompatible. This
# function simply compares the sizes of the two views of the structures and
# raises a warning if they do not agree.
#
# Essentially, you should never notice this function. A warning implies that
# you need to re-install Rggobi against the version of GGobi you are using.
#
# @value TRUE if the sizes in the two libraries are the same, otherwise a named logical vector indicating which structures are different
#
# @keyword programming
# @keyword internal
ggobi_check_structs <- function() {
	ours   <- .Call(.ggobi.symbol("getStructSizes"), TRUE,  PACKAGE = "rggobi")
	theirs <- .Call(.ggobi.symbol("getStructSizes"), FALSE, PACKAGE = "rggobi")

	which <- match(names(ours), names(theirs))
	if(any(is.na(which)))
		stop(paste("No information about some struct(s):", paste("`", names(ours)[is.na(which)],"'", collapse=", ", sep="")))

	ok <- ours == theirs[which]
	if(!all(ok)) {
		warning("Some structs have different size: ",
      paste(paste(names(ours)[!ok], "(", ours[!ok], "!=", theirs[which][!ok], ")"), collapse=", "),
      ". You may have an incompatible version of GGobi installed.", call.=FALSE)
		return(ok)
	}

	TRUE
}

# check that rggobi and GGobi by major.minor versions are the same
# to ensure binary compatibility
# also make sure GGobi is later than 2.1.6, since that is where
# we started the above version policy
.check_versions <- function() {
  versions <- c(
    rggobi = packageDescription("rggobi", fields = c("Version")),
    ggobi  = ggobi_version()$"version string"
  )
  if (compareVersion(versions["ggobi"], "2.1.6") < 0)
    warning("Your GGobi is too old - please update to the latest version")
  # strip micro version and rev
  versions <- sub("\\.[^.]*$", "", sub("-.*", "", versions))
  ver_comp <- compareVersion(versions["rggobi"], versions["ggobi"])
  if (ver_comp != 0) {
    if (ver_comp < 0)
      versions <- rev(versions)
    warning("Your ", names(versions)[1], " version (", versions[1],
            ") is later than your ", names(versions)[2], " version (",
            versions[2], "). Please try to update your ",
            names(versions)[2], ".")
  }
  ver_comp == 0
}

.onLoad <- function(libname, pkgname) {
	ggobi_check_structs()
  .check_versions()

	TRUE
}