build: reimplement the OSS checks using a more declarative approach

The OSS checks were a big mess and quite buggy. This reimplementes them using
a declarative approach and clearly distinguishing between the various OSS
implementations. The code should now almost be auto-documenting.

We currently support the following implementations of OSS:
 * platform-specific (with `sys/soundcard.h`)
 * SunAudio (default on NetBSD and useable on OpenBSD even if we have sndio
   support there).
 * 4Front (default on FreeBSD)

Since now each OSS check also checks for the appropriate soundcard header,
remove the old soundcard check.

Many thanks to @bugmen0t for in depth info about all the BSDs.
Check #380 and #359 for more info on this commit.

waftools/checks/custom.py

@@ -1,6 +1,8 @@
 from waftools.checks.generic import *
+from waflib import Utils
+import os
 
-__all__ = ["check_pthreads", "check_iconv", "check_lua", "check_oss"]
+__all__ = ["check_pthreads", "check_iconv", "check_lua", "check_oss_4front"]
 
 pthreads_program = load_fragment('pthreads.c')
 
@@ -72,56 +74,23 @@ def check_lua(ctx, dependency_identifier):
             return True
     return False
 
-# from here on there is the OSS check.. just stop reading here unless you want
+def __get_osslibdir():
-# to die inside a little
-def __fail_oss_check__(ctx):
-    ctx.define('PATH_DEV_DSP', '')
-    ctx.define('PATH_DEV_MIXER', '')
-    return False
-
-def __get_osslibdir__():
-    from waflib import Utils
     cmd = ['sh', '-c', '. /etc/oss.conf && echo $OSSLIBDIR']
     p = Utils.subprocess.Popen(cmd, stdin=Utils.subprocess.PIPE,
                                     stdout=Utils.subprocess.PIPE,
                                     stderr=Utils.subprocess.PIPE)
     return p.communicate()[0].decode().rstrip()
 
-def __get_osscflags__():
+def check_oss_4front(ctx, dependency_identifier):
-    import os
+    oss_libdir = __get_osslibdir()
-    osscflags = ''
-    osslibdir = __get_osslibdir__()
-    if osslibdir:
-        ossincdir   = os.path.join(osslibdir, 'include')
-        soundcard_h = os.path.join(ossincdir, 'sys', 'soundcard.h')
-        if os.path.exists(soundcard_h):
-            osscflags = '-I{0}'.format(ossincdir)
-    return osscflags
 
-def __check_oss_headers__(ctx, dependency_identifier):
+    soundcard_h = os.path.join(oss_libdir, "include/sys/soundcard.h")
-    fn = check_cc(fragment=load_fragment('oss_audio_header.c'),
+    include_dir = os.path.join(oss_libdir, "include")
-                  use='soundcard', cflags=__get_osscflags__())
-    fn(ctx, dependency_identifier)
-    return True
 
-def __check_oss_bsd__(ctxdependency_identifier):
+    fn = check_cc(header_name=soundcard_h,
-    # add the oss audio library through a check
+                  defines=['PATH_DEV_DSP="/dev/dsp"',
-    ctx.define('PATH_DEV_DSP', '/dev/sound')
+                           'PATH_DEV_MIXER="/dev/mixer"'],
-    if check_cc(lib='ossaudio')(ctx, dependency_identifier):
+                  cflags='-I{0}'.format(include_dir),
-        return True
+                  fragment=load_fragment('oss_audio.c'))
-    else:
-        return __fail_oss_check__(ctx)
 
-def check_oss(ctx, dependency_identifier):
+    return fn(ctx, dependency_identifier)
-    func = check_cc(fragment=load_fragment('oss_audio.c'), use='soundcard',
-                    cflags=__get_osscflags__())
-    if func(ctx, dependency_identifier):
-        ctx.define('PATH_DEV_DSP',   '/dev/dsp')
-        ctx.define('PATH_DEV_MIXER', '/dev/mixer')
-
-        if ctx.env.DEST_OS in ['openbsd', 'netbsd']:
-            return __check_oss_bsd_library__(ctx, dependency_identifier)
-        else:
-            return __check_oss_headers__(ctx, dependency_identifier)
-
-    return __fail_oss_check__(ctx)

waftools/fragments/oss_audio.c

@@ -1,10 +1,4 @@
-#if HAVE_SOUNDCARD_H
-#include <soundcard.h>
-#endif
-
-#if HAVE_SYS_SOUNDCARD_H
 #include <sys/soundcard.h>
-#endif
 
 int main(int argc, char **argv) {
     return SNDCTL_DSP_SETFRAGMENT;

waftools/fragments/oss_audio_header.c

@@ -1,13 +0,0 @@
-#if HAVE_SOUNDCARD_H
-#include <soundcard.h>
-#endif
-
-#if HAVE_SYS_SOUNDCARD_H
-#include <sys/soundcard.h>
-#endif
-
-#ifdef OPEN_SOUND_SYSTEM
-int main(void) {{ return 0; }}
-#else
-#error Not the real thing
-#endif

waftools/fragments/oss_audio_sunaudio.c

@@ -0,0 +1,6 @@
+#include <soundcard.h>
+
+int main(int argc, char **argv) {
+    return SNDCTL_DSP_SETFRAGMENT;
+}
+

wscript

@@ -116,10 +116,6 @@ iconv support use --disable-iconv.",
         'desc': 'w32 priority API',
         'deps_any': [ 'os-win32', 'os-cygwin'],
         'func': check_true
-    }, {
-        'name': 'soundcard',
-        'desc': 'soundcard.h',
-        'func': check_headers('soundcard.h', 'sys/soundcard.h')
     }, {
         'name': 'videoio',
         'desc': 'videoio.h',
@@ -386,10 +382,36 @@ audio_output_features = [
         'desc': 'SDL (1.x)',
         'deps_neg': [ 'sdl2' ],
         'func': check_pkg_config('sdl')
+    }, {
+        'name': 'oss-audio-native',
+        'desc': 'OSS (platform-specific OSS implementation)',
+        'func': check_cc(header_name='sys/soundcard.h',
+                         defines=['PATH_DEV_DSP="/dev/dsp"',
+                                  'PATH_DEV_MIXER="/dev/mixer"'],
+                         fragment=load_fragment('oss_audio.c')),
+        'groups' : [ 'oss-audio' ]
+    }, {
+        'name': 'oss-audio-sunaudio',
+        'desc': 'OSS (emulation on top of SunAudio)',
+        'func': check_cc(header_name='soundcard.h',
+                         lib='ossaudio',
+                         defines=['PATH_DEV_DSP="/dev/sound"',
+                                  'PATH_DEV_MIXER="/dev/mixer"'],
+                         fragment=load_fragment('oss_audio_sunaudio.c')),
+        'deps_neg': [ 'oss-audio-native' ],
+        'groups' : [ 'oss-audio' ]
+    }, {
+        'name': 'oss-audio-4front',
+        'desc': 'OSS (implementation from opensound.com)',
+        'func': check_oss_4front,
+        'deps_neg': [ 'oss-audio-native', 'oss-audio-sunaudio' ],
+        'groups' : [ 'oss-audio' ]
     }, {
         'name': '--oss-audio',
         'desc': 'OSS audio output',
-        'func': check_oss
+        'func': check_true,
+        'deps_any': [ 'oss-audio-native', 'oss-audio-sunaudio',
+                      'oss-audio-4front' ]
     }, {
         'name': '--audio-select',
         'desc': 'audio select()',
@@ -772,6 +794,14 @@ def configure(ctx):
 
     ctx.parse_dependencies(scripting_features)
 
+    ctx.define('HAVE_SYS_SOUNDCARD_H',
+               '(HAVE_OSS_AUDIO_NATIVE || HAVE_OSS_AUDIO_4FRONT)',
+               quote=False)
+
+    ctx.define('HAVE_SOUNDCARD_H',
+               'HAVE_OSS_AUDIO_SUNAUDIO',
+               quote=False)
+
     ctx.load('generators.headers')
 
     if not ctx.dependency_satisfied('build-date'):