#   Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011, 2012

#    Rocky Bernstein <rocky@gnu.org>

#

########################################################

# Things to make the cdda_interface library

########################################################

#

# From libtool documentation amended with guidance from N. Boullis:

#

#  1. Start with version information of `0:0:0' for each libtool library.

#

#  2. It is probably not a good idea to update the version information

#     several times between public releases, but rather once per public

#     release. (This seems to be more an aesthetic consideration than

#     a hard technical one.)

#

#  3. If the library source code has changed at all since the last

#     update, then increment REVISION (`C:R:A' becomes `C:R+1:A').

#

#  4. If any interfaces have been added, removed, or changed since the

#     last update, increment CURRENT, and set REVISION to 0.

#

#  5. If any interfaces have been added since the last public release,

#     then increment AGE.

#

#  6. If any interfaces have been removed or changed since the last

#     public release, then set AGE to 0. A changed interface means an

#     incompatibility with previous versions.

EXTRA_DIST = libcdio_cdda.sym

libcdio_cdda_la_CURRENT = 2

libcdio_cdda_la_REVISION = 0

libcdio_cdda_la_AGE = 0

noinst_HEADERS  = common_interface.h drive_exceptions.h low_interface.h \

		  smallft.h utils.h

libcdio_cdda_sources =  common_interface.c cddap_interface.c interface.c \

	scan_devices.c	smallft.c toc.c utils.c drive_exceptions.c

lib_LTLIBRARIES = libcdio_cdda.la

libcdio_cdda_la_SOURCES = $(libcdio_cdda_sources)

libcdio_cdda_la_ldflags = -version-info $(libcdio_cdda_la_CURRENT):$(libcdio_cdda_la_REVISION):$(libcdio_cdda_la_AGE) @LT_NO_UNDEFINED@

AM_CPPFLAGS = $(LIBCDIO_PARANOIA_CFLAGS) $(LIBCDIO_CFLAGS)

FLAGS=@LIBCDIO_CFLAGS@ @UCDROM_H@ @TYPESIZES@ @CFLAGS@

OPT=$(FLAGS)

DEBUG=$(FLAGS) -DCDDA_TEST

## test:

##	$(MAKE) libcdio_cdda.a CFLAGS="$(DEBUG)"

##	$(CC) $(DEBUG) -c test_interface.c

##	$(LD) $(DEBUG) test_interface.o $(LDFLAGS) -o cdda_test $(LIBS) libcdio_cdda.a

LIBS = $(LIBCDIO_LIBS) @LIBS@ @COS_LIB@

########################################################

# Things to version the symbols in the libraries

########################################################

# An explanation of the versioning problem from Nicolas Boullis and

# the versioned symbol solution he uses below...

#

# Currently, libvcdinfo uses the cdio_open function from libcdio.

# Let's imagine a program foobar that uses both the vcdinfo_open

# function from libvcdinfo and the cdio_open function from libcdio.

# Currently, libcdio has SONAME libcdio.so.0, libvcdinfo has SONAME

# libvcdinfo.so.0 and requires libcdio.so.0, and foobar requires both

# libvcdinfo.so.0 and libcdio.so.0. Everything looks fine.

#

# Now, for some reason, you decide to change the cdio_open function.

# That's your right, but you have to bump the CURRENT version and (if I

# understand it correctly, athough this is not that clear in libtool's

# documentation) set the AGE to 0. Anyway, this bumps the SONAME, which is

# sane since the interface changes incompatibly.

# Now, you have a new libcdio with SONAME libcdio.so.1. But libvcdinfo and

# foobar still require libcdio.so.0. Everything is still fine.

# Now, after some minor changes, the author of foobar recompiles foobar.

# Then, foobar now requires libvcdinfo.so.0 and libcdio.so.1. And foobar

# now segfaults...

# What is happening? When you run foobar, if brings both libvcdinfo.so.0

# and libcdio.so.1, but libvcdinfo.so.0 also brings libcdio.so.0. So you

# have both libcdio.so.0 and libcdio.so.1 that bring their symbols to the

# global namespace. Hence, you have to incompatible versions of the

# cdio_open function in the name space. When foobar calls cdio_open, it

# may choose the wrong function, and segfaults...

# With versioned symbols, the cdio_open function from libcdio.so.0 may be

# known as (something that looks like) cdio_open@@CDIO_0. An the cdio_open

# function from libcdio.so.1 as cdio_open@@CDIO_1. Both versions of

# libcdio would still be brought in by the most recent foobar, but foobar

# (and libvcdinfo) know which versioned function to use and then use the

# good one.

# This is some simple versioning where every symbol is versioned with

# something that looks like the SONAME of the library. More complex (and

# better) versioning is possible; it is for example what is used by glibc.

# But good complex versioning is something that requires much more

# work...

# The below is a impliments symbol versioning.  First of all, I

# compute MAJOR as CURENT - AGE; that is what is used within libtool

# (at least on GNU/Linux systems) for the number in the SONAME.  The

# nm command gives the list of symbols known in each of the object

# files that will be part of the shared library. And the sed command

# extracts from this list those symbols that will be shared. (This sed

# command comes from libtool.)

libcdio_cdda_la_MAJOR = $(shell expr $(libcdio_cdda_la_CURRENT) - $(libcdio_cdda_la_AGE))

if VERSION_SCRIPT

if BUILD_VERSIONED_LIBS

libcdio_cdda_la_LDFLAGS = $(libcdio_cdda_la_ldflags) -Wl,--version-script=libcdio_cdda.la.ver

libcdio_cdda_la_DEPENDENCIES = libcdio_cdda.la.ver

libcdio_cdda.la.ver: $(libcdio_cdda_la_OBJECTS) $(srcdir)/libcdio_cdda.sym

	echo 'CDIO_CDDA_$(libcdio_cdda_la_MAJOR) { ' > $@

	objs=`for obj in $(libcdio_cdda_la_OBJECTS); do sed -ne "s/^pic_object='\(.*\)'$$/\1/p" $$obj; done`; \

	if test -n "$$objs" ; then \

	  nm $${objs} | sed -n -e 's/^.*[ 	][ABCDGIRSTW][ABCDGIRSTW]*[ 	][ 	]*\([_A-Za-z][_A-Za-z0-9]*\)$$/\1/p' | sort -u | { first=true; while read symbol; do if grep -q "^$${symbol}\$$" $(srcdir)/libcdio_cdda.sym; then if test $$first = true; then echo "  global:"; first=false; fi; echo "    $${symbol};"; fi; done; } >> $@; \

	  nm $${objs} | sed -n -e 's/^.*[ 	][ABCDGIRSTW][ABCDGIRSTW]*[ 	][ 	]*\([_A-Za-z][_A-Za-z0-9]*\)$$/\1/p' | sort -u | { first=true; while read symbol; do if grep -q "^$${symbol}\$$" $(srcdir)/libcdio_cdda.sym; then :; else if test $$first = true; then echo "  local:"; first=false; fi; echo "    $${symbol};"; fi; done; } >> $@; \

	fi

	echo '};' >> $@

else !BUILD_VERSIONED_LIBS

libcdio_cdda_la_LDFLAGS = $(libcdio_cdda_la_ldflags)

endif !BUILD_VERSIONED_LIBS

else !VERSION_SCRIPT

libcdio_cdda_la_LDFLAGS = $(libcdio_cdda_la_ldflags)

endif !VERSION_SCRIPT

MOSTLYCLEANFILES = libcdio_cdda.la.ver