From: Gerhard Sittig <redacted>
Date: Sun, 28 Oct 2018 09:45:42 +0000 (+0100)
Subject: input/wav: add channel list checks for file re-read
X-Git-Url: https://sigrok.org/gitaction?a=commitdiff_plain;h=2581d204e0a367a74d0903fdb3fbe32ffab42a25;p=libsigrok.git

input/wav: add channel list checks for file re-read

Do for the WAV input module what commit 08f8421a9e82 did for VCD. Check
the channel list for consistency across re-imports of the same file.
This addresses the WAV part of bug #1241.

This commit also changes the WAV module's reset() method's behaviour.
The previous implementation only created channels once, and re-used that
channel list when the file got re-read. Which could cause issues when
the file's properties changed between re-runs. This implementation
always creates the channel list upon every file import, and ensures a
consistent channel list across re-imports. This follows the approach
that was taken in all other input modules before.
---

diff --git a/src/input/wav.c b/src/input/wav.c
index a6369f4d..4e9d6c12 100644
--- a/src/input/wav.c
+++ b/src/input/wav.c
@@ -52,6 +52,7 @@ struct context {
 	int unitsize;
 	gboolean found_data;
 	gboolean create_channels;
+	GSList *prev_sr_channels;
 };
 
 static int parse_wav_header(GString *buf, struct context *inc)
@@ -306,6 +307,44 @@ static int process_buffer(struct sr_input *in)
 	return SR_OK;
 }
 
+/*
+ * Check the channel list for consistency across file re-import. See
+ * the VCD input module for more details and motivation.
+ */
+
+static void keep_header_for_reread(const struct sr_input *in)
+{
+	struct context *inc;
+
+	inc = in->priv;
+	g_slist_free_full(inc->prev_sr_channels, sr_channel_free_cb);
+	inc->prev_sr_channels = in->sdi->channels;
+	in->sdi->channels = NULL;
+}
+
+static int check_header_in_reread(const struct sr_input *in)
+{
+	struct context *inc;
+
+	if (!in)
+		return FALSE;
+	inc = in->priv;
+	if (!inc)
+		return FALSE;
+	if (!inc->prev_sr_channels)
+		return TRUE;
+
+	if (sr_channel_lists_differ(inc->prev_sr_channels, in->sdi->channels)) {
+		sr_err("Channel list change not supported for file re-read.");
+		return FALSE;
+	}
+	g_slist_free_full(in->sdi->channels, sr_channel_free_cb);
+	in->sdi->channels = inc->prev_sr_channels;
+	inc->prev_sr_channels = NULL;
+
+	return TRUE;
+}
+
 static int receive(struct sr_input *in, GString *buf)
 {
 	struct context *inc;
@@ -335,8 +374,9 @@ static int receive(struct sr_input *in, GString *buf)
 				snprintf(channelname, sizeof(channelname), "CH%d", i + 1);
 				sr_channel_new(in->sdi, i, SR_CHANNEL_ANALOG, TRUE, channelname);
 			}
+			if (!check_header_in_reread(in))
+				return SR_ERR_DATA;
 		}
-
 		inc->create_channels = FALSE;
 
 		/* sdi is ready, notify frontend. */
@@ -368,12 +408,19 @@ static int end(struct sr_input *in)
 
 static int reset(struct sr_input *in)
 {
-	memset(in->priv, 0, sizeof(struct context));
+	struct context *inc;
+
+	inc = in->priv;
+	memset(inc, 0, sizeof(*inc));
 
 	/*
-	 * We only want to create the sigrok channels once, so
-	 * inc->create_channels won't be set to TRUE this time around.
+	 * Create, and re-create channels for every iteration of file
+	 * import. Other logic will enforce a consistent set of channels
+	 * across re-import, or an appropriate error message when file
+	 * properties should change.
 	 */
+	keep_header_for_reread(in);
+	inc->create_channels = TRUE;
 
 	g_string_truncate(in->buf, 0);