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libpng-1.6.17/scripts/options.awk  view on Meta::CPAN

# respectively for the build to succeed.  This allows interdependencies
# between options of the form "at least one of" or "at most one of"
# to be checked.  For example:
#
# option FLOATING_POINT enables ok_math
# option FIXED_POINT enables ok_math
#   This ensures that at least one of FLOATING_POINT and FIXED_POINT
#   must be set for the build to succeed.
#
# option fail_math requires FLOATING_POINT FIXED_POINT
#   This means the build will fail if *both* FLOATING_POINT and
#   FIXED_POINT are set (this is an example; in fact both are allowed.)
#
# If all these options were given the build would require exactly one
# of the names to be enabled.

END{
   # END{} gets run on an exit (a traditional awk feature)
   if (err) exit 1

   if (pre) {
      # Record the final value of the variables
      print "deb =", deb >out
      if (everything != "") {
         print "everything =", everything >out
      }
      print "logunsupported =", logunsupported >out
      exit 0
   }

   # Do the options first (allowing options to set settings).  The dependency
   # tree is thus:
   #
   #   name     >     name
   #   name requires  name
   #   name if        name
   #   name enabledby name
   #
   # First build a list 'tree' by option of all the things on which
   # it depends.
   print "" >out
   print "/* OPTIONS */" >out
   print comment, "options", cend >out
   for (opt in enabledby) tree[opt] = 1  # may not be explicit options
   for (opt in option) if (opt != "") {
      o = option[opt]
      # option should always be one of the following values
      if (o != "on" && o != "off" && o != "disabled" && o != "enabled") {
         print "internal option error (" o ")"
         exit 1
      }
      tree[opt] = ""   # so unlisted options marked
   }
   for (opt in tree) if (opt != "") {
      if (tree[opt] == 1) {
         tree[opt] = ""
         if (option[opt] != "") {
            print "internal error (1)"
            exit 1
         }
         # Macros only listed in 'enables' remain off unless
         # one of the enabling macros is on.
         option[opt] = "disabled"
      }

      split("", list) # clear 'list'
      # Now add every requires, iffs or enabledby entry to 'list'
      # so that we can add a unique list of requirements to tree[i]
      split(requires[opt] iffs[opt] enabledby[opt], r)
      for (i in r) list[r[i]] = 1
      for (i in list) tree[opt] = tree[opt] " " i
   }

   # print the tree for extreme debugging
   if (deb > 2) for (i in tree) if (i != "") print i, "depends-on" tree[i]

   # Ok, now check all options marked explicitly 'on' or 'off':
   #
   # If an option[opt] is 'on' then turn on all requires[opt]
   # If an option[opt] is 'off' then turn off all enabledby[opt]
   #
   # Error out if we have to turn 'on' to an 'off' option or vice versa.
   npending = 0
   for (opt in option) if (opt != "") {
      if (option[opt] == "on" || option[opt] == "off") {
         pending[++npending] = opt
      }
   }

   err = 0 # set on error
   while (npending > 0) {
      opt = pending[npending--]
      if (option[opt] == "on") {
         nreqs = split(requires[opt], r)
         for (j=1; j<=nreqs; ++j) {
            if (option[r[j]] == "off") {
               print "option", opt, "turned on, but requirement", r[j], "is turned off"
               err = 1
            } else if (option[r[j]] != "on") {
               option[r[j]] = "on"
               pending[++npending] = r[j]
            }
         }
      } else {
         if (option[opt] != "off") {
            print "internal error (2)"
            exit 1
         }
         nreqs = split(enabledby[opt], r)
         for (j=1; j<=nreqs; ++j) {
            if (option[r[j]] == "on") {
               print "option", opt, "turned off, but enabled by", r[j], "which is turned on"
               err = 1
            } else if (option[r[j]] != "off") {
               option[r[j]] = "off"
               pending[++npending] = r[j]
            }
         }
      }
   }
   if (err) exit 1