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 a6369f4d4bd60778035e3d4597a22c45334bb774..4e9d6c124c148a5e92569696d32e51031b0ba06e 100644 (file)
--- 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);