add a preliminary schema for object detection (#30)

db/raw.rs

@@ -226,8 +226,8 @@ pub(crate) fn insert_recording(tx: &rusqlite::Transaction, o: &db::Open, id: Com
     Ok(())
 }
 
-/// Tranfers the given recording range from the `recording` and `recording_playback` tables to the
-/// `garbage` table. `sample_file_dir_id` is assumed to be correct.
+/// Transfers the given recording range from the `recording` and associated tables to the `garbage`
+/// table. `sample_file_dir_id` is assumed to be correct.
 ///
 /// Returns the number of recordings which were deleted.
 pub(crate) fn delete_recordings(tx: &rusqlite::Transaction, sample_file_dir_id: i32,
@@ -244,19 +244,25 @@ pub(crate) fn delete_recordings(tx: &rusqlite::Transaction, sample_file_dir_id:
           :start <= composite_id and
           composite_id < :end
     "#)?;
-    let mut del1 = tx.prepare_cached(r#"
+    let mut del_playback = tx.prepare_cached(r#"
         delete from recording_playback
         where
           :start <= composite_id and
           composite_id < :end
     "#)?;
-    let mut del2 = tx.prepare_cached(r#"
+    let mut del_integrity = tx.prepare_cached(r#"
         delete from recording_integrity
         where
           :start <= composite_id and
           composite_id < :end
     "#)?;
-    let mut del3 = tx.prepare_cached(r#"
+    let mut del_detection = tx.prepare_cached(r#"
+        delete from recording_object_detection
+        where
+          :start <= composite_id and
+          composite_id < :end
+    "#)?;
+    let mut del_main = tx.prepare_cached(r#"
         delete from recording
         where
           :start <= composite_id and
@@ -271,17 +277,20 @@ pub(crate) fn delete_recordings(tx: &rusqlite::Transaction, sample_file_dir_id:
         ":start": ids.start.0,
         ":end": ids.end.0,
     };
-    let n1 = del1.execute_named(p)?;
-    if n1 != n {
-        bail!("inserted {} garbage rows but deleted {} recording_playback rows!", n, n1);
+    let n_playback = del_playback.execute_named(p)?;
+    if n_playback != n {
+        bail!("inserted {} garbage rows but deleted {} recording_playback rows!", n, n_playback);
     }
-    let n2 = del2.execute_named(p)?;
-    if n2 > n {  // fewer is okay; recording_integrity is optional.
-        bail!("inserted {} garbage rows but deleted {} recording_integrity rows!", n, n2);
+    let n_integrity = del_integrity.execute_named(p)?;
+    if n_integrity > n {  // fewer is okay; recording_integrity is optional.
+        bail!("inserted {} garbage rows but deleted {} recording_integrity rows!", n, n_integrity);
     }
-    let n3 = del3.execute_named(p)?;
-    if n3 != n {
-        bail!("deleted {} recording rows but {} recording_playback rows!", n3, n);
+    // Any number of object detection rows is okay, as there can be zero or more models per
+    // recording.
+    del_detection.execute_named(p)?;
+    let n_main = del_main.execute_named(p)?;
+    if n_main != n {
+        bail!("inserted {} garbage rows but deleted {} recording rows!", n, n_main);
     }
     Ok(n)
 }

db/schema.sql

@@ -497,5 +497,45 @@ create table signal_change (
   changes blob not null
 );
 
+create table object_detection_model (
+  id integer primary key,
+  uuid blob unique not null check (length(uuid) = 16),
+  name text not null,
+
+  -- The actual model and label mappings, in a tbd protocol buffer message
+  -- format.
+  data blob
+);
+
+-- An entry for every supported label in any model. (E.g., there is one row
+-- for "person" even if there are many models that support detecting people.)
+create table object_detection_label (
+  id integer primary key,
+  uuid blob unique not null check (length(uuid) = 16),
+  name text unique not null,
+  color text
+);
+
+create table recording_object_detection (
+  composite_id integer not null references recording (composite_id),
+  model_id integer not null references object_detection_model (id),
+
+  -- repeated:
+  -- * frame delta unsigned varint
+  -- * label unsigned varint
+  -- * xmin, xmax, ymin, ymax as fixed 8-bit numbers
+  --   (any value from knowing xmin <= xmax, ymin <= ymax?
+  --   probably not a whole byte anyway.)
+  --   although 256/300 or 256/320 is not super clean. awkward.
+  -- * score/probability/whatever-it's-called as fixed 8-bit number
+  --   linear scale?
+  frame_data blob not null,
+
+  -- Operations are almost always done on a bounded set of recordings, so
+  -- and perhaps on all models. Use composite_id as the prefix of the primary
+  -- key to make these efficient.
+  primary key (composite_id, model_id)
+);
+
 insert into version (id, unix_time,                           notes)
              values (6,  cast(strftime('%s', 'now') as int), 'db creation');

db/upgrade/v5_to_v6.rs

@@ -209,6 +209,27 @@ pub fn run(_args: &super::Args, tx: &rusqlite::Transaction) -> Result<(), Error>
           revocation_reason_detail = 'Blake2b->Blake3 upgrade'
         where
           revocation_reason is null;
+
+        create table object_detection_model (
+          id integer primary key,
+          uuid blob unique not null check (length(uuid) = 16),
+          name text not null,
+          data blob
+        );
+
+        create table object_detection_label (
+          id integer primary key,
+          uuid blob unique not null check (length(uuid) = 16),
+          name text unique not null,
+          color text
+        );
+
+        create table recording_object_detection (
+          composite_id integer not null references recording (composite_id),
+          model_id integer not null references object_detection_model (id),
+          frame_data blob not null,
+          primary key (composite_id, model_id)
+        );
     "#)?;
     Ok(())
 }

guide/schema.md

@@ -252,8 +252,7 @@ Version 6 adds over version 5:
     streams.
 *   hashes in Blake3 rather than older SHA-1 (for file integrity checksums)
     or Blake2b (for sessions).
+*   a preliminary schema for [object
+    detection](https://en.wikipedia.org/wiki/Object_detection).
 
-On upgrading to this version, sessions will be wiped.
-
-Before it is finalized, it likely will also add a schema for [object
-detection](https://en.wikipedia.org/wiki/Object_detection).
+On upgrading to this version, sessions will be revoked.