extend recording_playback with an open_id

As noted in schema.sql, this can be used for disambiguation. It also may be
useful in diagnosing data integrity problems.

Also, sneak in a couple minor improvements: better diagnostics in a couple
places, fix to 1->2 upgrade procedure.

db/db.rs

@@ -584,10 +584,11 @@ pub struct LockedDatabase {
     to_delete: Vec<ListOldestSampleFilesRow>,
 }
 
+/// Represents a row of the `open` database table.
 #[derive(Copy, Clone, Debug)]
-struct Open {
-    id: u32,
-    uuid: Uuid,
+pub(crate) struct Open {
+    pub(crate) id: u32,
+    pub(crate) uuid: Uuid,
 }
 
 /// A modification to be done to a `Stream`, used within `LockedDatabase::flush`.
@@ -802,6 +803,10 @@ impl LockedDatabase {
     /// On success, for each affected sample file directory with a flush watcher set, sends a
     /// `Flush` event.
     pub(crate) fn flush(&mut self, reason: &str) -> Result<(), Error> {
+        let o = match self.open.as_ref() {
+            None => bail!("database is read-only"),
+            Some(o) => o,
+        };
         let tx = self.conn.transaction()?;
         let mut mods = FnvHashMap::with_capacity_and_hasher(self.streams_by_id.len(),
                                                             Default::default());
@@ -825,7 +830,7 @@ impl LockedDatabase {
                     if !l.synced { break; }
                     if let Some(ref r) = l.recording {
                         raw::insert_recording(
-                            &tx, CompositeId::new(stream_id, s.next_recording_id + i), &r)?;
+                            &tx, o, CompositeId::new(stream_id, s.next_recording_id + i), &r)?;
                     }
                     i += 1;
                 }

db/dir.rs

@@ -603,7 +603,9 @@ impl Syncer {
             format!("{}-{}: unflushed={} >= if={}",
                     c.short_name, s.type_.as_str(), unflushed, s.flush_if)
         };
-        let _ = db.flush(&reason);
+        if let Err(e) = db.flush(&reason) {
+            error!("flush failure on save: {:?}", e);
+        }
     }
 }
 

db/raw.rs

@@ -47,8 +47,8 @@ const INSERT_RECORDING_SQL: &'static str = r#"
 "#;
 
 const INSERT_RECORDING_PLAYBACK_SQL: &'static str = r#"
-    insert into recording_playback (composite_id,  sample_file_sha1,  video_index)
-                            values (:composite_id, :sample_file_sha1, :video_index)
+    insert into recording_playback (composite_id,  open_id,  sample_file_sha1,  video_index)
+                            values (:composite_id, :open_id, :sample_file_sha1, :video_index)
 "#;
 
 const STREAM_MIN_START_SQL: &'static str = r#"
@@ -73,7 +73,7 @@ const STREAM_MAX_START_SQL: &'static str = r#"
 "#;
 
 /// Inserts the specified recording (for from `try_flush` only).
-pub(crate) fn insert_recording(tx: &rusqlite::Transaction, id: CompositeId,
+pub(crate) fn insert_recording(tx: &rusqlite::Transaction, o: &db::Open, id: CompositeId,
                     r: &db::RecordingToInsert) -> Result<(), Error> {
     if r.time.end < r.time.start {
         bail!("end time {} must be >= start time {}", r.time.end, r.time.start);
@@ -98,6 +98,7 @@ pub(crate) fn insert_recording(tx: &rusqlite::Transaction, id: CompositeId,
     let sha1 = &r.sample_file_sha1[..];
     stmt.execute_named(&[
         (":composite_id", &id.0),
+        (":open_id", &o.id),
         (":sample_file_sha1", &sha1),
         (":video_index", &r.video_index),
     ])?;

db/schema.sql

@@ -202,6 +202,12 @@ create table recording_playback (
   -- See description on recording table.
   composite_id integer primary key references recording (composite_id),
 
+  -- The open in which this was committed to the database. For a given
+  -- composite_id, only one recording will ever be committed to the database,
+  -- but in-memory state may reflect a recording which never gets committed.
+  -- This field allows disambiguation in etags and such.
+  open_id integer not null references open (id),
+
   -- The sha1 hash of the contents of the sample file.
   sample_file_sha1 blob not null check (length(sample_file_sha1) = 20),