input: sr_input_scan_*() now return a status code.

SR_OK: a match was found.
SR_ERR: no match.
SR_ERR_DATA: a match was found but the module cannot handle the input.
SR_OK_CONTINUE: some module didn't have enough data to be sure.

include/libsigrok/proto.h

@@ -133,8 +133,8 @@ SR_API const struct sr_option **sr_input_options_get(const struct sr_input_modul
 SR_API void sr_input_options_free(const struct sr_option **options);
 SR_API struct sr_input *sr_input_new(const struct sr_input_module *imod,
 		GHashTable *options);
-SR_API const struct sr_input *sr_input_scan_buffer(GString *buf);
+SR_API int sr_input_scan_buffer(GString *buf, const struct sr_input **in);
-SR_API const struct sr_input *sr_input_scan_file(const char *filename);
+SR_API int sr_input_scan_file(const char *filename, const struct sr_input **in);
 SR_API struct sr_dev_inst *sr_input_dev_inst_get(const struct sr_input *in);
 SR_API int sr_input_send(const struct sr_input *in, GString *buf);
 SR_API int sr_input_free(const struct sr_input *in);

src/input/chronovu_la8.c

@@ -44,9 +44,9 @@ static int format_match(GHashTable *metadata)
 	size = GPOINTER_TO_INT(g_hash_table_lookup(metadata,
 			GINT_TO_POINTER(SR_INPUT_META_FILESIZE)));
 	if (size == CHRONOVU_LA8_FILESIZE)
-		return TRUE;
+		return SR_OK;
 
-	return FALSE;
+	return SR_ERR;
 }
 
 static int init(struct sr_input *in, GHashTable *options)

src/input/csv.c

@@ -138,9 +138,9 @@ static int format_match(GHashTable *metadata)
 
 	buf = g_hash_table_lookup(metadata, GINT_TO_POINTER(SR_INPUT_META_MIMETYPE));
 	if (!strcmp(buf, "text/csv"))
-		return TRUE;
+		return SR_OK;
 
-	return FALSE;
+	return SR_ERR;
 }
 
 static void strip_comment(char *buf, const GString *prefix)

src/input/input.c

@@ -308,8 +308,8 @@ static gboolean check_required_metadata(const uint8_t *metadata, uint8_t *avail)
  * the input modules to find a match. This is format-dependent, but
  * 128 bytes is normally enough.
  *
- * If an input module is found, an instance is created and returned.
+ * If an input module is found, an instance is created into *in.
- * Otherwise, NULL is returned.
+ * Otherwise, *in contains NULL.
  *
  * If an instance is created, it has the given buffer used for scanning
  * already submitted to it, to be processed before more data is sent.
@@ -318,19 +318,20 @@ static gboolean check_required_metadata(const uint8_t *metadata, uint8_t *avail)
  * it again later.
  *
  */
-SR_API const struct sr_input *sr_input_scan_buffer(GString *buf)
+SR_API int sr_input_scan_buffer(GString *buf, const struct sr_input **in)
 {
-	struct sr_input *in;
 	const struct sr_input_module *imod;
 	GHashTable *meta;
 	unsigned int m, i;
+	int ret;
 	uint8_t mitem, avail_metadata[8];
 
 	/* No more metadata to be had from a buffer. */
 	avail_metadata[0] = SR_INPUT_META_HEADER;
 	avail_metadata[1] = 0;
 
-	in = NULL;
+	*in = NULL;
+	ret = SR_ERR;
 	for (i = 0; input_module_list[i]; i++) {
 		imod = input_module_list[i];
 		if (!imod->metadata[0]) {
@@ -353,54 +354,61 @@ SR_API const struct sr_input *sr_input_scan_buffer(GString *buf)
 			g_hash_table_destroy(meta);
 			continue;
 		}
-		if (!imod->format_match(meta)) {
+		sr_spew("Trying module %s.", imod->id);
-			/* Module didn't recognize this buffer. */
+		ret = imod->format_match(meta);
-			g_hash_table_destroy(meta);
-			continue;
-		}
 		g_hash_table_destroy(meta);
+		if (ret == SR_ERR_DATA) {
+			/* Module recognized this buffer, but cannot handle it. */
+			break;
+		} else if (ret == SR_ERR) {
+			/* Module didn't recognize this buffer. */
+			continue;
+		} else if (ret != SR_OK) {
+			/* Can be SR_OK_CONTINUE. */
+			return ret;
+		}
 
 		/* Found a matching module. */
-		in = sr_input_new(imod, NULL);
+		sr_spew("Module %s matched.", imod->id);
-		g_string_insert_len(in->buf, 0, buf->str, buf->len);
+		*in = sr_input_new(imod, NULL);
+		g_string_insert_len((*in)->buf, 0, buf->str, buf->len);
 		break;
 	}
 
-	return in;
+	return ret;
 }
 
 /**
  * Try to find an input module that can parse the given file.
  *
- * If an input module is found, an instance is created and returned.
+ * If an input module is found, an instance is created into *in.
- * Otherwise, NULL is returned.
+ * Otherwise, *in contains NULL.
  *
  */
-SR_API const struct sr_input *sr_input_scan_file(const char *filename)
+SR_API int sr_input_scan_file(const char *filename, const struct sr_input **in)
 {
-	struct sr_input *in;
 	const struct sr_input_module *imod;
 	GHashTable *meta;
 	GString *header_buf;
 	struct stat st;
 	unsigned int midx, m, i;
-	int fd;
+	int fd, ret;
 	ssize_t size;
 	uint8_t mitem, avail_metadata[8];
 
 	if (!filename || !filename[0]) {
 		sr_err("Invalid filename.");
-		return NULL;
+		return SR_ERR_ARG;
 	}
 
 	if (!g_file_test(filename, G_FILE_TEST_EXISTS)) {
 		sr_err("No such file.");
-		return NULL;
+		return SR_ERR_ARG;
 	}
 
 	if (stat(filename, &st) < 0) {
 		sr_err("%s", strerror(errno));
-		return NULL;
+		return SR_ERR_ARG;
 	}
 
 	midx = 0;
@@ -409,7 +417,8 @@ SR_API const struct sr_input *sr_input_scan_file(const char *filename)
 	avail_metadata[midx++] = SR_INPUT_META_HEADER;
 	/* TODO: MIME type */
 
-	in = NULL;
+	*in = NULL;
+	ret = SR_ERR;
 	header_buf = g_string_sized_new(128);
 	for (i = 0; input_module_list[i]; i++) {
 		g_string_truncate(header_buf, 0);
@@ -430,17 +439,16 @@ SR_API const struct sr_input *sr_input_scan_file(const char *filename)
 			if (!mitem)
 				/* Metadata list is 0-terminated. */
 				break;
-			if (mitem == SR_INPUT_META_FILENAME)
+			if (mitem == SR_INPUT_META_FILENAME) {
 				g_hash_table_insert(meta, GINT_TO_POINTER(mitem),
 						(gpointer)filename);
-			else if (mitem == SR_INPUT_META_FILESIZE) {
+			} else if (mitem == SR_INPUT_META_FILESIZE) {
-				sr_dbg("inserting fs %d", st.st_size);
 				g_hash_table_insert(meta, GINT_TO_POINTER(mitem),
 						GINT_TO_POINTER(st.st_size));
 			} else if (mitem == SR_INPUT_META_HEADER) {
 				if ((fd = open(filename, O_RDONLY)) < 0) {
 					sr_err("%s", strerror(errno));
-					return NULL;
+					return SR_ERR;
 				}
 				size = read(fd, header_buf->str, 128);
 				header_buf->len = size;
@@ -448,7 +456,7 @@ SR_API const struct sr_input *sr_input_scan_file(const char *filename)
 				if (size <= 0) {
 					g_string_free(header_buf, TRUE);
 					sr_err("%s", strerror(errno));
-					return NULL;
+					return SR_ERR;
 				}
 				g_hash_table_insert(meta, GINT_TO_POINTER(mitem), header_buf);
 			}
@@ -459,17 +467,28 @@ SR_API const struct sr_input *sr_input_scan_file(const char *filename)
 			g_hash_table_destroy(meta);
 			continue;
 		}
-		if (!imod->format_match(meta))
+		sr_spew("Trying module %s.", imod->id);
+		ret = imod->format_match(meta);
+		g_hash_table_destroy(meta);
+		if (ret == SR_ERR_DATA) {
+			/* Module recognized this buffer, but cannot handle it. */
+			break;
+		} else if (ret == SR_ERR) {
 			/* Module didn't recognize this buffer. */
 			continue;
+		} else if (ret != SR_OK) {
+			/* Can be SR_OK_CONTINUE. */
+			return ret;
+		}
 
 		/* Found a matching module. */
-		in = sr_input_new(imod, NULL);
+		sr_spew("Module %s matched.", imod->id);
+		*in = sr_input_new(imod, NULL);
 		break;
 	}
 	g_string_free(header_buf, TRUE);
 
-	return in;
+	return ret;
 }
 
 /**

src/input/vcd.c

@@ -257,7 +257,7 @@ static int format_match(GHashTable *metadata)
 	g_free(name);
 	g_free(contents);
 
-	return status;
+	return status ? SR_OK : SR_ERR;
 }
 
 /* Send N samples of the given value. */

src/input/wav.c

@@ -57,7 +57,7 @@ static int parse_wav_header(GString *buf, struct context *inc)
 	unsigned int fmt_code, samplesize, num_channels, unitsize;
 
 	if (buf->len < MIN_DATA_CHUNK_OFFSET)
-		return SR_ERR;
+		return SR_OK_CONTINUE;
 
 	fmt_code = RL16(buf->str + 20);
 	samplerate = RL32(buf->str + 24);
@@ -65,7 +65,7 @@ static int parse_wav_header(GString *buf, struct context *inc)
 	samplesize = RL16(buf->str + 32);
 	if (samplesize != 1 && samplesize != 2 && samplesize != 4) {
 		sr_err("Only 8, 16 or 32 bits per sample supported.");
-		return SR_ERR;
+		return SR_ERR_DATA;
 	}
 
 	num_channels = RL16(buf->str + 22);
@@ -77,7 +77,7 @@ static int parse_wav_header(GString *buf, struct context *inc)
 	} else if (fmt_code == WAVE_FORMAT_IEEE_FLOAT) {
 		if (unitsize != 4) {
 			sr_err("only 32-bit floats supported.");
-			return SR_ERR;
+			return SR_ERR_DATA;
 		}
 	} else if (fmt_code == WAVE_FORMAT_EXTENSIBLE) {
 		if (buf->len < 70)
@@ -94,17 +94,17 @@ static int parse_wav_header(GString *buf, struct context *inc)
 		}
 		if (RL16(buf->str + 34) != RL16(buf->str + 38)) {
 			sr_err("Reduced valid bits per sample not supported.");
-			return SR_ERR;
+			return SR_ERR_DATA;
 		}
 		/* Real format code is the first two bytes of the GUID. */
 		fmt_code = RL16(buf->str + 44);
 		if (fmt_code != WAVE_FORMAT_PCM && fmt_code != WAVE_FORMAT_IEEE_FLOAT) {
 			sr_err("Only PCM and floating point samples are supported.");
-			return SR_ERR;
+			return SR_ERR_DATA;
 		}
 	} else {
 		sr_err("Only PCM and floating point samples are supported.");
-		return SR_ERR;
+		return SR_ERR_DATA;
 	}
 
 	if (inc) {
@@ -122,22 +122,23 @@ static int parse_wav_header(GString *buf, struct context *inc)
 static int format_match(GHashTable *metadata)
 {
 	GString *buf;
+	int ret;
 
 	buf = g_hash_table_lookup(metadata, GINT_TO_POINTER(SR_INPUT_META_HEADER));
 	if (strncmp(buf->str, "RIFF", 4))
-		return FALSE;
+		return SR_ERR;
 	if (strncmp(buf->str + 8, "WAVE", 4))
-		return FALSE;
+		return SR_ERR;
 	if (strncmp(buf->str + 12, "fmt ", 4))
-		return FALSE;
+		return SR_ERR;
 	/*
 	 * Only gets called when we already know this is a WAV file, so
 	 * this parser can log error messages.
 	 */
-	if (parse_wav_header(buf, NULL) != SR_OK)
+	if ((ret = parse_wav_header(buf, NULL)) != SR_OK)
-		return FALSE;
+		return ret;
 
-	return TRUE;
+	return SR_OK;
 }
 
 static int init(struct sr_input *in, GHashTable *options)
@@ -179,7 +180,7 @@ static int initial_receive(struct sr_input *in)
 	struct sr_channel *ch;
 	struct sr_config *src;
 	struct context *inc;
-	int i;
+	int ret, i;
 	char channelname[8];
 
 	if (!in->buf)
@@ -187,8 +188,8 @@ static int initial_receive(struct sr_input *in)
 		return SR_ERR;
 
 	inc = in->priv = g_malloc(sizeof(struct context));
-	if (parse_wav_header(in->buf, inc) != SR_OK)
+	if ((ret = parse_wav_header(in->buf, inc)) != SR_OK)
-		return SR_ERR;
+		return ret;
 
 	for (i = 0; i < inc->num_channels; i++) {
 		snprintf(channelname, 8, "CH%d", i + 1);

src/libsigrok-internal.h

@@ -263,8 +263,13 @@ struct sr_input_module {
 	 *
 	 * @param[in] metadata Metadata the module can use to identify the stream.
 	 *
-	 * @retval TRUE This module knows the format.
+	 * @retval SR_OK This module knows the format.
-	 * @retval FALSE This module does not know the format.
+	 * @retval SR_OK_CONTINUE There wasn't enough data for this module to
+	 *   positively identify the format.
+	 * @retval SR_ERR_DATA This module knows the format, but cannot handle it.
+	 *   This means the stream is either corrupt, or indicates a feature
+	 *   that the module does not support.
+	 * @retval SR_ERR This module does not know the format.
 	 */
 	int (*format_match) (GHashTable *metadata);