gst-plugin-transcribe: address latest review comments

audio/transcribe/src/aws_transcribe_parse.rs

@@ -38,7 +38,6 @@ use futures::future::{abortable, AbortHandle};
 use futures::prelude::*;
 use tokio::runtime;
 
-use std::borrow::Cow;
 use std::collections::VecDeque;
 use std::pin::Pin;
 use std::sync::Mutex;
@@ -89,6 +88,12 @@ struct Transcript {
     transcript: TranscriptTranscript,
 }
 
+#[derive(Deserialize, Debug)]
+#[serde(rename_all = "PascalCase")]
+struct ExceptionMessage {
+    message: String,
+}
+
 static CAT: Lazy<gst::DebugCategory> = Lazy::new(|| {
     gst::DebugCategory::new(
         "awstranscribe",
@@ -192,18 +197,18 @@ struct Transcriber {
 fn build_packet(payload: &[u8]) -> Vec<u8> {
     let headers = [
         Header {
-            name: Cow::Borrowed(":event-type"),
+            name: ":event-type".into(),
-            value: Cow::Borrowed("AudioEvent"),
+            value: "AudioEvent".into(),
             value_type: 7,
         },
         Header {
-            name: Cow::Borrowed(":content-type"),
+            name: ":content-type".into(),
-            value: Cow::Borrowed("application/octet-stream"),
+            value: "application/octet-stream".into(),
             value_type: 7,
         },
         Header {
-            name: Cow::Borrowed(":message-type"),
+            name: ":message-type".into(),
-            value: Cow::Borrowed("event"),
+            value: "event".into(),
             value_type: 7,
         },
     ];
@@ -211,18 +216,6 @@ fn build_packet(payload: &[u8]) -> Vec<u8> {
     encode_packet(payload, &headers).expect("foobar")
 }
 
-fn get_current_running_time(element: &gst::Element) -> gst::ClockTime {
-    if let Some(clock) = element.get_clock() {
-        if clock.get_time() > element.get_base_time() {
-            clock.get_time() - element.get_base_time()
-        } else {
-            0.into()
-        }
-    } else {
-        gst::CLOCK_TIME_NONE
-    }
-}
-
 impl Transcriber {
     fn set_pad_functions(sinkpad: &gst::Pad, srcpad: &gst::Pad) {
         sinkpad.set_chain_function(|pad, parent, buffer| {
@@ -272,7 +265,7 @@ impl Transcriber {
             let latency: gst::ClockTime = (self.settings.lock().unwrap().latency_ms as u64
                 - GRANULARITY_MS as u64)
                 * gst::MSECOND;
-            let now = get_current_running_time(element);
+            let now = element.get_current_running_time();
 
             while let Some(buf) = state.buffers.front() {
                 if now - buf.get_pts() > latency {
@@ -379,8 +372,43 @@ impl Transcriber {
 
             match msg {
                 Message::Binary(buf) => {
-                    let (_, pkt) = parse_packet(&buf).unwrap();
+                    let (_, pkt) = parse_packet(&buf).map_err(|err| {
+                        gst_error!(CAT, obj: element, "Failed to parse packet: {}", err);
+                        gst_error_msg!(
+                            gst::StreamError::Failed,
+                            ["Failed to parse packet: {}", err]
+                        )
+                    })?;
+
                     let payload = std::str::from_utf8(pkt.payload).unwrap();
+
+                    if packet_is_exception(&pkt) {
+                        let message: ExceptionMessage =
+                            serde_json::from_str(&payload).map_err(|err| {
+                                gst_error!(
+                                    CAT,
+                                    obj: element,
+                                    "Unexpected exception message: {} ({})",
+                                    payload,
+                                    err
+                                );
+                                gst_error_msg!(
+                                    gst::StreamError::Failed,
+                                    ["Unexpected exception message: {} ({})", payload, err]
+                                )
+                            })?;
+                        gst_error!(
+                            CAT,
+                            obj: element,
+                            "AWS raised an error: {}",
+                            message.message
+                        );
+                        Err(gst_error_msg!(
+                            gst::StreamError::Failed,
+                            ["AWS raised an error: {}", message.message]
+                        ))?;
+                    }
+
                     let mut transcript: Transcript =
                         serde_json::from_str(&payload).map_err(|err| {
                             gst_error_msg!(
@@ -683,7 +711,7 @@ impl Transcriber {
 
             if let Some(buffer) = &buffer {
                 let running_time = state.in_segment.to_running_time(buffer.get_pts());
-                let now = get_current_running_time(&element);
+                let now = element.get_current_running_time();
 
                 if now.is_some() && now < running_time {
                     delay = Some(running_time - now);

audio/transcribe/src/packet.rs

@@ -126,14 +126,24 @@ fn parse_header(input: &[u8]) -> IResult<&[u8], Header> {
     let (input, value) = map_res(take(value_length), std::str::from_utf8)(input)?;
 
     let header = Header {
-        name: Cow::Owned(name.to_string()),
+        name: name.to_string().into(),
         value_type,
-        value: Cow::Owned(value.to_string()),
+        value: value.to_string().into(),
     };
 
     Ok((input, header))
 }
 
+pub fn packet_is_exception(packet: &Packet) -> bool {
+    for header in &packet.headers {
+        if header.name == ":message-type" && header.value_type == 7 {
+            return true;
+        }
+    }
+
+    false
+}
+
 pub fn parse_packet(input: &[u8]) -> IResult<&[u8], Packet> {
     let (remainder, prelude) = parse_prelude(input)?;