hls: Make crypto dependency optional when hls-crypto is auto

crypto libraries are not required for hlssink and hlssink2.
Also, hlsdemux with nonencrypted stream can work without crpyto.

Make an error only when users set "hls-crpyto" with non-auto option explicitly,
but no crpyto library was found.

configure.ac

@@ -2018,19 +2018,15 @@ AG_GST_CHECK_FEATURE(HLS, [http live streaming plugin], hls, [
     ],
     [
       dnl Try to find a valid crypto library
+      HAVE_HLS="yes"
       PKG_CHECK_MODULES(NETTLE, nettle, [
         AC_DEFINE(HAVE_NETTLE, 1, [Define if nettle is available])
-        HAVE_HLS="yes"
       ],[
         AM_PATH_LIBGCRYPT([1.2.0], [
           AC_DEFINE(HAVE_LIBGCRYPT, 1, [Define if libgcrypt is available])
-          HAVE_HLS="yes"
         ],[
           PKG_CHECK_MODULES(OPENSSL, openssl, [
             AC_DEFINE(HAVE_OPENSSL, 1, [Define if openssl is available])
-            HAVE_HLS="yes"
-          ],[
-            HAVE_HLS="no"
           ])
         ])
       ])
@@ -2511,4 +2507,3 @@ AC_OUTPUT
 
 AG_GST_OUTPUT_PLUGINS
 ORC_OUTPUT
-

ext/hls/gsthlsdemux.c

@@ -1753,7 +1753,7 @@ gst_hls_demux_stream_decrypt_end (GstHLSDemuxStream * stream)
   /* NOP */
 }
 
-#else
+#elif defined(HAVE_LIBGCRYPT)
 static gboolean
 gst_hls_demux_stream_decrypt_start (GstHLSDemuxStream * stream,
     const guint8 * key_data, const guint8 * iv_data)
@@ -1801,6 +1801,30 @@ gst_hls_demux_stream_decrypt_end (GstHLSDemuxStream * stream)
     stream->aes_ctx = NULL;
   }
 }
+
+#else
+/* NO crypto available */
+static gboolean
+gst_hls_demux_stream_decrypt_start (GstHLSDemuxStream * stream,
+    const guint8 * key_data, const guint8 * iv_data)
+{
+  GST_ERROR ("No crypto available");
+  return FALSE;
+}
+
+static gboolean
+decrypt_fragment (GstHLSDemuxStream * stream, gsize length,
+    const guint8 * encrypted_data, guint8 * decrypted_data)
+{
+  GST_ERROR ("Cannot decrypt fragment, no crypto available");
+  return FALSE;
+}
+
+static void
+gst_hls_demux_stream_decrypt_end (GstHLSDemuxStream * stream)
+{
+  return;
+}
 #endif
 
 static GstBuffer *

ext/hls/gsthlsdemux.h

@@ -34,7 +34,7 @@
 #elif defined(HAVE_NETTLE)
 #include <nettle/aes.h>
 #include <nettle/cbc.h>
-#else
+#elif defined(HAVE_LIBGCRYPT)
 #include <gcrypt.h>
 #endif
 
@@ -108,7 +108,7 @@ struct _GstHLSDemuxStream
 # endif
 #elif defined(HAVE_NETTLE)
   struct CBC_CTX (struct aes_ctx, AES_BLOCK_SIZE) aes_ctx;
-#else
+#elif defined(HAVE_LIBGCRYPT)
   gcry_cipher_hd_t aes_ctx;
 #endif
 

ext/hls/meson.build

@@ -12,45 +12,45 @@ hls_cargs = ['-DGST_USE_UNSTABLE_API']
 
 hls_crypto = get_option('hls-crypto')
 hls_option = get_option('hls')
+hls_crypto_dep = dependency('', required : false)
 # used for unit test
 hls_dep = dependency('', required : false)
 
-have_hls_crypto = false
-if not hls_option.disabled()
+if hls_option.disabled()
+  subdir_done()
+endif
+
 if ['auto', 'nettle'].contains(hls_crypto)
   hls_crypto_dep = dependency('nettle', required : false)
   if hls_crypto_dep.found()
-      have_hls_crypto = true
     hls_cargs += ['-DHAVE_NETTLE']
   endif
 endif
 
-  if not have_hls_crypto and ['auto', 'libgcrypt'].contains(hls_crypto)
+if not hls_crypto_dep.found() and ['auto', 'libgcrypt'].contains(hls_crypto)
   hls_crypto_dep = cc.find_library('gcrypt', required : false)
   if hls_crypto_dep.found()
-      have_hls_crypto = true
     hls_cargs += ['-DHAVE_LIBGCRYPT']
   endif
 endif
 
-  if not have_hls_crypto and ['auto', 'openssl'].contains(hls_crypto)
+if not hls_crypto_dep.found() and ['auto', 'openssl'].contains(hls_crypto)
   hls_crypto_dep = dependency('openssl', required : false)
   if hls_crypto_dep.found()
-      have_hls_crypto = true
     hls_cargs += ['-DHAVE_OPENSSL']
   endif
 endif
 
-  if not have_hls_crypto and hls_option.enabled()
+if not hls_crypto_dep.found()
   if hls_crypto == 'auto'
-      error('HLS plugin enabled, but found none of nettle, libgcrypt, or openssl')
+    message('Enable HLS plugin enable without crypto')
+  elif hls_option.enabled()
+    error('HLS plugin enabled with crypto, but crypto library "@0@" not found'.format(hls_crypto))
   else
-      error('HLS plugin enabled, but crypto library "@0@" not found'.format(hls_crypto))
-    endif
+    subdir_done()
   endif
 endif
 
-if have_hls_crypto
 gsthls = library('gsthls',
   hls_sources,
   c_args : gst_plugins_bad_args + hls_cargs,
@@ -65,4 +65,3 @@ if have_hls_crypto
 pkgconfig.generate(gsthls, install_dir : plugins_pkgconfig_install_dir)
 plugins += [gsthls]
 hls_dep = declare_dependency(include_directories : include_directories('.'))
-endif