"""Display Ada standard package

This script adds a new menu in /Help/GNAT Runtime/Standard to display the
Standard package. This package contains the definition of basic types
for the Ada runtime, but doesn't exist as a file on the disk since it can't
be described in pure Ada.
It properly handles older versions of GNAT, which came with a gnatpsta
command line utility, as well as new versions where the gcc driver itself
must be used.
"""

###########################################################################
# No user customization below this line
############################################################################

from GPS import *
import os
import tempfile
import os_utils
from gps_utils import *


def on_exit(process, exit_status, output):
    if exit_status == 0:
        f = file(process.standard, "w")
        f.write(output)
        f.close()
        buffer = EditorBuffer.get(File(process.standard))
        buffer.current_view().set_read_only(True)
        Editor.set_title(process.standard,
                         "package Standard", "package Standard")
        os.unlink(process.standard)


@interactive(name="Display standard.ads")
def display():
    # Two possible ways here: older versions of GNAT still have the
    # gnatpsta utility, whereas for more recent versions we need to
    # compile a file with -gnatS. Try gnatpsta first:

    dir = tempfile.mkdtemp()
    path = None

    if os_utils.locate_exec_on_path("gnatpsta") != "":
        proc = Process("gnatpsta", on_exit=on_exit)
    else:
        path = dir + "/p.ads"
        f = open(path, "w")
        f.write("package p is end p;")
        f.close()
        proc = Process(
            get_gnat_driver_cmd() + " compile -q -gnatc -gnatS " + path,
            on_exit=on_exit
        )

    proc.standard = dir + "/_standard.ads"
    proc.wait()

    if path:
        os.unlink(path)
    os.rmdir(dir)
