Remove half-baked support for "passthrough encoders"

The correct way is to just not configure an encoder for a stream, which
is what the documentation already states. Encoder sections now require
a program name to be set or the configuration will not load.

Fixes a segfault in ezstream.c, as reported by Tom McCallum via Github.

examples/ezstream-video.xml

@@ -17,7 +17,7 @@
     <stream>
       <mountpoint>/video.ogg</mountpoint>
       <format>Theora</format>
-      <encoder>PassThrough</encoder>
+      <!-- No encoder configured (see below). -->
     </stream>
   </streams>
 
@@ -30,19 +30,14 @@
   <decoders>
     <decoder>
       <name>Theora-192x128</name>
-      <!-- Reencode into Ogg Theora directly -->
+      <!--
+        Reencodes into Ogg Theora directly. The stream should be configured
+        without an encoder, so that the decoder output is passed through as-is.
+        -->
       <program>ffmpeg2theora -x 192 -y 128 -a 0 -v 4 --title @M@ -o - @T@</program>
       <file_ext>.avi</file_ext>
       <file_ext>.mpg</file_ext>
     </decoder>
   </decoders>
 
-  <encoders>
-    <encoder>
-      <name>PassThrough</name>
-      <format>Theora</format>
-      <!-- Do not set an encoder program to pass through data as-is -->
-    </encoder>
-  </encoders>
-
 </ezstream>

src/cfg_encoder.c

@@ -210,16 +210,17 @@ cfg_encoder_set_format_str(struct cfg_encoder *e,
 int
 cfg_encoder_set_program(struct cfg_encoder *e,
     struct cfg_encoder_list *not_used, const char *program,
-    const char **not_used2)
+    const char **errstrp)
 {
 	(void)not_used;
-	(void)not_used2;
+
+	if (!program || !program[0]) {
+		if (errstrp)
+			*errstrp = "empty";
+		return (-1);
+	}
 
 	xfree(e->program);
-
-	if (!program || !program[0])
-		e->program = NULL;
-	else
 	e->program = xstrdup(program);
 
 	return (0);
@@ -234,8 +235,11 @@ cfg_encoder_validate(struct cfg_encoder *e, const char **errstrp)
 		return (-1);
 	}
 
-	if (!e->program)
+	if (!e->program) {
-		return (0);
+		if (errstrp)
+			*errstrp = "program not set";
+		return (-1);
+	}
 
 	CHECKPH_PROHIBITED(e->program, PLACEHOLDER_TRACK);
 	CHECKPH_PROHIBITED(e->program, PLACEHOLDER_STRING);

src/ezstream-cfgmigrate.c

@@ -309,27 +309,6 @@ _parse_ezconfig0(EZCONFIG *ez)
 				cfg_encoder_list_remove(enc_list, &enc);
 				warnings++;
 			}
-		} else {
-			if (ed->format &&
-			    0 == strcasecmp(ed->format, "THEORA")) {
-				cfg_encoder_t	enc;
-
-				enc = cfg_encoder_list_find(enc_list,
-				    ed->format);
-				if (NULL == enc)
-					enc = cfg_encoder_list_get(enc_list,
-					    CFG_DEFAULT);
-				ENTITY_SET(enc, enc_list, cfg_encoder_set_name,
-				    "<format> (encoder)", ed->format);
-				ENTITY_SET(enc, enc_list, cfg_encoder_set_format_str,
-				    "<format> (encoder)", ed->format);
-				if (0 > cfg_encoder_validate(enc, &err_str)) {
-					log_warning("%s: %s: %s", v0_cfgfile,
-					    "<encdec> (encoder)", err_str);
-					cfg_encoder_list_remove(enc_list, &enc);
-					warnings++;
-				}
-			}
 		}
 		if (ed->decoder) {
 			cfg_decoder_t	dec = NULL;

tests/check_cfg_encoder.c

@@ -52,13 +52,8 @@ END_TEST
 
 START_TEST(test_encoder_set_program)
 {
-	cfg_encoder_t	 enc = cfg_encoder_list_get(encoders, "test_encoder_set_program");
+	TEST_XSTRDUP_T(cfg_encoder_t, cfg_encoder_list_get, encoders,
-
+	    cfg_encoder_set_program, cfg_encoder_get_program);
-	ck_assert_int_eq(cfg_encoder_set_program(enc, encoders, NULL, NULL), 0);
-	ck_assert_ptr_eq(cfg_encoder_get_program(enc), NULL);
-
-	ck_assert_int_eq(cfg_encoder_set_program(enc, encoders, "test", NULL), 0);
-	ck_assert_str_eq(cfg_encoder_get_program(enc), "test");
 }
 END_TEST
 
@@ -94,14 +89,25 @@ END_TEST
 START_TEST(test_encoder_validate)
 {
 	cfg_encoder_t	 enc = cfg_encoder_list_get(encoders, "test_encoder_validate");
+	cfg_encoder_t	 enc2 = cfg_encoder_list_get(encoders, "test_encoder_validate_2");;
 	const char	*errstr;
 
+	errstr = NULL;
+	ck_assert_int_ne(cfg_encoder_set_name(enc2, encoders,
+	    "test_encoder_validate", &errstr), 0);
+	ck_assert_str_eq(errstr, "already exists");
+
 	ck_assert_int_ne(cfg_encoder_validate(enc, NULL), 0);
 	ck_assert_int_ne(cfg_encoder_validate(enc, &errstr), 0);
 	ck_assert_str_eq(errstr, "format not set");
 
 	ck_assert_int_eq(cfg_encoder_set_format(enc, CFG_STREAM_VORBIS), 0);
 
+	ck_assert_int_ne(cfg_encoder_validate(enc, &errstr), 0);
+	ck_assert_str_eq(errstr, "program not set");
+
+	ck_assert_int_eq(cfg_encoder_set_program(enc, encoders, "test", NULL),
+	    0);
 	ck_assert_int_eq(cfg_encoder_validate(enc, NULL), 0);
 
 	ck_assert_int_eq(cfg_encoder_set_program(enc, encoders,