From 3ec60b85a310e93701778aae14dd655733f8faf9 Mon Sep 17 00:00:00 2001
From: Scott Lamb <slamb@slamb.org>
Date: Tue, 23 Mar 2021 09:40:52 -0700
Subject: [PATCH] extract & generalize calendar day indexes

My main goal is to support creating indexes for signals as well as
recordings. An additional goal is to just shrink db.rs a bit; it's
gotten quite large.
---
 server/db/days.rs  | 320 +++++++++++++++++++++++++++++++++++++++++++++
 server/db/db.rs    | 282 ++-------------------------------------
 server/db/lib.rs   |   1 +
 server/src/json.rs |   5 +-
 4 files changed, 332 insertions(+), 276 deletions(-)
 create mode 100644 server/db/days.rs

diff --git a/server/db/days.rs b/server/db/days.rs
new file mode 100644
index 0000000..7d8a51f
--- /dev/null
+++ b/server/db/days.rs
@@ -0,0 +1,320 @@
+// This file is part of Moonfire NVR, a security camera network video recorder.
+// Copyright (C) 2021 The Moonfire NVR Authors; see AUTHORS and LICENSE.txt.
+// SPDX-License-Identifier: GPL-v3.0-or-later WITH GPL-3.0-linking-exception.
+
+//! In-memory indexes by calendar day.
+
+use crate::recording::{self, Time};
+use failure::Error;
+use log::{error, trace};
+use std::cmp;
+use std::collections::BTreeMap;
+use std::io::Write;
+use std::ops::Range;
+use std::str;
+
+/// A calendar day in `YYYY-mm-dd` format.
+#[derive(Copy, Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
+pub struct Key([u8; 10]);
+
+impl Key {
+    fn new(tm: time::Tm) -> Result<Self, Error> {
+        let mut s = Key([0u8; 10]);
+        write!(&mut s.0[..], "{}", tm.strftime("%Y-%m-%d")?)?;
+        Ok(s)
+    }
+
+    pub fn bounds(&self) -> Range<Time> {
+        let mut my_tm = time::strptime(self.as_ref(), "%Y-%m-%d").expect("days must be parseable");
+        my_tm.tm_utcoff = 1; // to the time crate, values != 0 mean local time.
+        my_tm.tm_isdst = -1;
+        let start = Time(my_tm.to_timespec().sec * recording::TIME_UNITS_PER_SEC);
+        my_tm.tm_hour = 0;
+        my_tm.tm_min = 0;
+        my_tm.tm_sec = 0;
+        my_tm.tm_mday += 1;
+        let end = Time(my_tm.to_timespec().sec * recording::TIME_UNITS_PER_SEC);
+        start..end
+    }
+}
+
+impl AsRef<str> for Key {
+    fn as_ref(&self) -> &str {
+        str::from_utf8(&self.0[..]).expect("days are always UTF-8")
+    }
+}
+
+pub trait Value: std::fmt::Debug + Default {
+    type Change: std::fmt::Debug;
+
+    /// Applies the given change to this value.
+    fn apply(&mut self, c: &Self::Change);
+
+    fn is_empty(&self) -> bool;
+}
+
+/// In-memory state about a particular stream on a particular day.
+#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
+pub struct StreamValue {
+    /// The number of recordings that overlap with this day.
+    pub recordings: i64,
+
+    /// The total duration recorded on this day. This can be 0; because frames' durations are taken
+    /// from the time of the next frame, a recording that ends unexpectedly after a single frame
+    /// will have 0 duration of that frame and thus the whole recording.
+    pub duration: recording::Duration,
+}
+
+impl Value for StreamValue {
+    type Change = Self;
+
+    fn apply(&mut self, c: &StreamValue) {
+        self.recordings += c.recordings;
+        self.duration += c.duration;
+    }
+
+    fn is_empty(&self) -> bool {
+        self.recordings == 0
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct Map<V: Value>(BTreeMap<Key, V>);
+
+impl<V: Value> Map<V> {
+    pub fn new() -> Self {
+        Self(BTreeMap::new())
+    }
+
+    pub fn len(&self) -> usize {
+        self.0.len()
+    }
+    pub fn get(&self, k: &Key) -> Option<&V> {
+        self.0.get(k)
+    }
+
+    /// Adds non-zero `delta` to the day represented by `day` in the map `m`.
+    /// Inserts a map entry if absent; removes the entry if it has 0 entries on exit.
+    fn adjust_day(&mut self, day: Key, c: V::Change) {
+        trace!("adjust_day {} {:?}", day.as_ref(), &c);
+        use ::std::collections::btree_map::Entry;
+        match self.0.entry(day) {
+            Entry::Vacant(e) => e.insert(Default::default()).apply(&c),
+            Entry::Occupied(mut e) => {
+                let v = e.get_mut();
+                v.apply(&c);
+                if v.is_empty() {
+                    e.remove_entry();
+                }
+            }
+        }
+    }
+}
+
+impl<'a, V: Value> IntoIterator for &'a Map<V> {
+    type Item = (&'a Key, &'a V);
+    type IntoIter = std::collections::btree_map::Iter<'a, Key, V>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.0.iter()
+    }
+}
+
+impl Map<StreamValue> {
+    /// Adjusts `self` to reflect the range of the given recording.
+    /// Note that the specified range may span two days. It will never span more because the maximum
+    /// length of a recording entry is less than a day (even a 23-hour "spring forward" day).
+    ///
+    /// This function swallows/logs date formatting errors because they shouldn't happen and there's
+    /// not much that can be done about them. (The database operation has already gone through.)
+    pub(crate) fn adjust(&mut self, r: Range<Time>, sign: i64) {
+        // Find first day key.
+        let mut my_tm = time::at(time::Timespec {
+            sec: r.start.unix_seconds(),
+            nsec: 0,
+        });
+        let day = match Key::new(my_tm) {
+            Ok(d) => d,
+            Err(ref e) => {
+                error!(
+                    "Unable to fill first day key from {:?}: {}; will ignore.",
+                    my_tm, e
+                );
+                return;
+            }
+        };
+
+        // Determine the start of the next day.
+        // Use mytm to hold a non-normalized representation of the boundary.
+        my_tm.tm_isdst = -1;
+        my_tm.tm_hour = 0;
+        my_tm.tm_min = 0;
+        my_tm.tm_sec = 0;
+        my_tm.tm_mday += 1;
+        let boundary = my_tm.to_timespec();
+        let boundary_90k = boundary.sec * recording::TIME_UNITS_PER_SEC;
+
+        // Adjust the first day.
+        let first_day_delta = StreamValue {
+            recordings: sign,
+            duration: recording::Duration(sign * (cmp::min(r.end.0, boundary_90k) - r.start.0)),
+        };
+        self.adjust_day(day, first_day_delta);
+
+        if r.end.0 <= boundary_90k {
+            return;
+        }
+
+        // Fill day with the second day. This requires a normalized representation so recalculate.
+        // (The C mktime(3) already normalized for us once, but .to_timespec() discarded that
+        // result.)
+        let my_tm = time::at(boundary);
+        let day = match Key::new(my_tm) {
+            Ok(d) => d,
+            Err(ref e) => {
+                error!(
+                    "Unable to fill second day key from {:?}: {}; will ignore.",
+                    my_tm, e
+                );
+                return;
+            }
+        };
+        let second_day_delta = StreamValue {
+            recordings: sign,
+            duration: recording::Duration(sign * (r.end.0 - boundary_90k)),
+        };
+        self.adjust_day(day, second_day_delta);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{Key, Map, StreamValue};
+    use crate::recording::{self, TIME_UNITS_PER_SEC};
+    use crate::testutil;
+
+    #[test]
+    fn test_adjust_stream() {
+        testutil::init();
+        let mut m: Map<StreamValue> = Map::new();
+
+        // Create a day.
+        let test_time = recording::Time(130647162600000i64); // 2015-12-31 23:59:00 (Pacific).
+        let one_min = recording::Duration(60 * TIME_UNITS_PER_SEC);
+        let two_min = recording::Duration(2 * 60 * TIME_UNITS_PER_SEC);
+        let three_min = recording::Duration(3 * 60 * TIME_UNITS_PER_SEC);
+        let four_min = recording::Duration(4 * 60 * TIME_UNITS_PER_SEC);
+        let test_day1 = &Key(*b"2015-12-31");
+        let test_day2 = &Key(*b"2016-01-01");
+        m.adjust(test_time..test_time + one_min, 1);
+        assert_eq!(1, m.len());
+        assert_eq!(
+            Some(&StreamValue {
+                recordings: 1,
+                duration: one_min
+            }),
+            m.get(test_day1)
+        );
+
+        // Add to a day.
+        m.adjust(test_time..test_time + one_min, 1);
+        assert_eq!(1, m.len());
+        assert_eq!(
+            Some(&StreamValue {
+                recordings: 2,
+                duration: two_min
+            }),
+            m.get(test_day1)
+        );
+
+        // Subtract from a day.
+        m.adjust(test_time..test_time + one_min, -1);
+        assert_eq!(1, m.len());
+        assert_eq!(
+            Some(&StreamValue {
+                recordings: 1,
+                duration: one_min
+            }),
+            m.get(test_day1)
+        );
+
+        // Remove a day.
+        m.adjust(test_time..test_time + one_min, -1);
+        assert_eq!(0, m.len());
+
+        // Create two days.
+        m.adjust(test_time..test_time + three_min, 1);
+        assert_eq!(2, m.len());
+        assert_eq!(
+            Some(&StreamValue {
+                recordings: 1,
+                duration: one_min
+            }),
+            m.get(test_day1)
+        );
+        assert_eq!(
+            Some(&StreamValue {
+                recordings: 1,
+                duration: two_min
+            }),
+            m.get(test_day2)
+        );
+
+        // Add to two days.
+        m.adjust(test_time..test_time + three_min, 1);
+        assert_eq!(2, m.len());
+        assert_eq!(
+            Some(&StreamValue {
+                recordings: 2,
+                duration: two_min
+            }),
+            m.get(test_day1)
+        );
+        assert_eq!(
+            Some(&StreamValue {
+                recordings: 2,
+                duration: four_min
+            }),
+            m.get(test_day2)
+        );
+
+        // Subtract from two days.
+        m.adjust(test_time..test_time + three_min, -1);
+        assert_eq!(2, m.len());
+        assert_eq!(
+            Some(&StreamValue {
+                recordings: 1,
+                duration: one_min
+            }),
+            m.get(test_day1)
+        );
+        assert_eq!(
+            Some(&StreamValue {
+                recordings: 1,
+                duration: two_min
+            }),
+            m.get(test_day2)
+        );
+
+        // Remove two days.
+        m.adjust(test_time..test_time + three_min, -1);
+        assert_eq!(0, m.len());
+    }
+
+    #[test]
+    fn test_day_bounds() {
+        testutil::init();
+        assert_eq!(
+            Key(*b"2017-10-10").bounds(), // normal day (24 hrs)
+            recording::Time(135685692000000)..recording::Time(135693468000000)
+        );
+        assert_eq!(
+            Key(*b"2017-03-12").bounds(), // spring forward (23 hrs)
+            recording::Time(134037504000000)..recording::Time(134044956000000)
+        );
+        assert_eq!(
+            Key(*b"2017-11-05").bounds(), // fall back (25 hrs)
+            recording::Time(135887868000000)..recording::Time(135895968000000)
+        );
+    }
+}
diff --git a/server/db/db.rs b/server/db/db.rs
index 271f203..df5200a 100644
--- a/server/db/db.rs
+++ b/server/db/db.rs
@@ -27,9 +27,10 @@
 //!     cycles.
 
 use crate::auth;
+use crate::days;
 use crate::dir;
 use crate::raw;
-use crate::recording::{self, TIME_UNITS_PER_SEC};
+use crate::recording;
 use crate::schema;
 use crate::signal;
 use base::clock::{self, Clocks};
@@ -47,14 +48,12 @@ use std::cmp;
 use std::collections::{BTreeMap, VecDeque};
 use std::convert::TryInto;
 use std::fmt::Write as _;
-use std::io::Write;
 use std::mem;
 use std::ops::Range;
 use std::str;
 use std::string::String;
 use std::sync::Arc;
 use std::vec::Vec;
-use time;
 use uuid::Uuid;
 
 /// Expected schema version. See `guide/schema.md` for more information.
@@ -278,50 +277,6 @@ pub(crate) struct ListOldestRecordingsRow {
     pub sample_file_bytes: i32,
 }
 
-/// A calendar day in `YYYY-mm-dd` format.
-#[derive(Copy, Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
-pub struct StreamDayKey([u8; 10]);
-
-impl StreamDayKey {
-    fn new(tm: time::Tm) -> Result<Self, Error> {
-        let mut s = StreamDayKey([0u8; 10]);
-        write!(&mut s.0[..], "{}", tm.strftime("%Y-%m-%d")?)?;
-        Ok(s)
-    }
-
-    pub fn bounds(&self) -> Range<recording::Time> {
-        let mut my_tm = time::strptime(self.as_ref(), "%Y-%m-%d").expect("days must be parseable");
-        my_tm.tm_utcoff = 1; // to the time crate, values != 0 mean local time.
-        my_tm.tm_isdst = -1;
-        let start = recording::Time(my_tm.to_timespec().sec * recording::TIME_UNITS_PER_SEC);
-        my_tm.tm_hour = 0;
-        my_tm.tm_min = 0;
-        my_tm.tm_sec = 0;
-        my_tm.tm_mday += 1;
-        let end = recording::Time(my_tm.to_timespec().sec * recording::TIME_UNITS_PER_SEC);
-        start..end
-    }
-}
-
-impl AsRef<str> for StreamDayKey {
-    fn as_ref(&self) -> &str {
-        str::from_utf8(&self.0[..]).expect("days are always UTF-8")
-    }
-}
-
-/// In-memory state about a particular camera on a particular day.
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
-pub struct StreamDayValue {
-    /// The number of recordings that overlap with this day. Note that `adjust_day` automatically
-    /// prunes days with 0 recordings.
-    pub recordings: i64,
-
-    /// The total wall duration recorded on this day. This can be 0; because frames' durations are
-    /// taken from the time of the next frame, a recording that ends unexpectedly after a single
-    /// frame will have 0 duration of that frame and thus the whole recording.
-    pub duration: recording::Duration,
-}
-
 #[derive(Debug)]
 pub struct SampleFileDir {
     pub id: i32,
@@ -473,7 +428,7 @@ pub struct Stream {
 
     /// Mapping of calendar day (in the server's time zone) to a summary of committed recordings on
     /// that day.
-    pub committed_days: BTreeMap<StreamDayKey, StreamDayValue>,
+    pub committed_days: days::Map<days::StreamValue>,
     pub record: bool,
 
     /// The `cum_recordings` currently committed to the database.
@@ -538,97 +493,6 @@ pub struct CameraChange {
     pub streams: [StreamChange; 2],
 }
 
-/// Adds non-zero `delta` to the day represented by `day` in the map `m`.
-/// Inserts a map entry if absent; removes the entry if it has 0 entries on exit.
-fn adjust_day(
-    day: StreamDayKey,
-    delta: StreamDayValue,
-    m: &mut BTreeMap<StreamDayKey, StreamDayValue>,
-) {
-    use ::std::collections::btree_map::Entry;
-    match m.entry(day) {
-        Entry::Vacant(e) => {
-            e.insert(delta);
-        }
-        Entry::Occupied(mut e) => {
-            let v = e.get_mut();
-            v.recordings += delta.recordings;
-            v.duration += delta.duration;
-            if v.recordings == 0 {
-                e.remove_entry();
-            }
-        }
-    }
-}
-
-/// Adjusts the day map `m` to reflect the range of the given recording.
-/// Note that the specified range may span two days. It will never span more because the maximum
-/// length of a recording entry is less than a day (even a 23-hour "spring forward" day).
-///
-/// This function swallows/logs date formatting errors because they shouldn't happen and there's
-/// not much that can be done about them. (The database operation has already gone through.)
-fn adjust_days(
-    r: Range<recording::Time>,
-    sign: i64,
-    m: &mut BTreeMap<StreamDayKey, StreamDayValue>,
-) {
-    // Find first day key.
-    let mut my_tm = time::at(time::Timespec {
-        sec: r.start.unix_seconds(),
-        nsec: 0,
-    });
-    let day = match StreamDayKey::new(my_tm) {
-        Ok(d) => d,
-        Err(ref e) => {
-            error!(
-                "Unable to fill first day key from {:?}: {}; will ignore.",
-                my_tm, e
-            );
-            return;
-        }
-    };
-
-    // Determine the start of the next day.
-    // Use mytm to hold a non-normalized representation of the boundary.
-    my_tm.tm_isdst = -1;
-    my_tm.tm_hour = 0;
-    my_tm.tm_min = 0;
-    my_tm.tm_sec = 0;
-    my_tm.tm_mday += 1;
-    let boundary = my_tm.to_timespec();
-    let boundary_90k = boundary.sec * TIME_UNITS_PER_SEC;
-
-    // Adjust the first day.
-    let first_day_delta = StreamDayValue {
-        recordings: sign,
-        duration: recording::Duration(sign * (cmp::min(r.end.0, boundary_90k) - r.start.0)),
-    };
-    adjust_day(day, first_day_delta, m);
-
-    if r.end.0 <= boundary_90k {
-        return;
-    }
-
-    // Fill day with the second day. This requires a normalized representation so recalculate.
-    // (The C mktime(3) already normalized for us once, but .to_timespec() discarded that result.)
-    let my_tm = time::at(boundary);
-    let day = match StreamDayKey::new(my_tm) {
-        Ok(d) => d,
-        Err(ref e) => {
-            error!(
-                "Unable to fill second day key from {:?}: {}; will ignore.",
-                my_tm, e
-            );
-            return;
-        }
-    };
-    let second_day_delta = StreamDayValue {
-        recordings: sign,
-        duration: recording::Duration(sign * (r.end.0 - boundary_90k)),
-    };
-    adjust_day(day, second_day_delta, m);
-}
-
 impl Stream {
     /// Adds a single fully committed recording with the given properties to the in-memory state.
     fn add_recording(&mut self, r: Range<recording::Time>, sample_file_bytes: i32) {
@@ -639,18 +503,17 @@ impl Stream {
         self.duration += r.end - r.start;
         self.sample_file_bytes += sample_file_bytes as i64;
         self.fs_bytes += round_up(i64::from(sample_file_bytes));
-        adjust_days(r, 1, &mut self.committed_days);
+        self.committed_days.adjust(r, 1);
     }
 
     /// Returns a days map including unflushed recordings.
-    pub fn days(&self) -> BTreeMap<StreamDayKey, StreamDayValue> {
+    pub fn days(&self) -> days::Map<days::StreamValue> {
         let mut days = self.committed_days.clone();
         for u in &self.uncommitted {
             let l = u.lock();
-            adjust_days(
+            days.adjust(
                 l.start..l.start + recording::Duration(i64::from(l.wall_duration_90k)),
                 1,
-                &mut days,
             );
         }
         days
@@ -887,7 +750,7 @@ impl StreamStateChanger {
                         bytes_to_add: 0,
                         fs_bytes_to_add: 0,
                         duration: recording::Duration(0),
-                        committed_days: BTreeMap::new(),
+                        committed_days: days::Map::new(),
                         record: sc.record,
                         cum_recordings: 0,
                         cum_media_duration: recording::Duration(0),
@@ -1191,7 +1054,7 @@ impl LockedDatabase {
                 dir.garbage_needs_unlink.insert(row.id);
                 let d = recording::Duration(i64::from(row.wall_duration_90k));
                 s.duration -= d;
-                adjust_days(row.start..row.start + d, -1, &mut s.committed_days);
+                s.committed_days.adjust(row.start..row.start + d, -1);
             }
 
             // Process add_recordings.
@@ -1790,7 +1653,7 @@ impl LockedDatabase {
                     bytes_to_add: 0,
                     fs_bytes_to_add: 0,
                     duration: recording::Duration(0),
-                    committed_days: BTreeMap::new(),
+                    committed_days: days::Map::new(),
                     cum_recordings: row.get(7)?,
                     cum_media_duration: recording::Duration(row.get(8)?),
                     cum_runs: row.get(9)?,
@@ -2458,13 +2321,11 @@ impl<'db, C: Clocks + Clone> ::std::ops::DerefMut for DatabaseGuard<'db, C> {
 
 #[cfg(test)]
 mod tests {
-    use super::adjust_days; // non-public.
     use super::*;
     use crate::recording::{self, TIME_UNITS_PER_SEC};
     use crate::testutil;
     use base::clock;
     use rusqlite::Connection;
-    use std::collections::BTreeMap;
     use uuid::Uuid;
 
     fn setup_conn() -> Connection {
@@ -2566,131 +2427,6 @@ mod tests {
         // TODO: with_recording_playback.
     }
 
-    #[test]
-    fn test_adjust_days() {
-        testutil::init();
-        let mut m = BTreeMap::new();
-
-        // Create a day.
-        let test_time = recording::Time(130647162600000i64); // 2015-12-31 23:59:00 (Pacific).
-        let one_min = recording::Duration(60 * TIME_UNITS_PER_SEC);
-        let two_min = recording::Duration(2 * 60 * TIME_UNITS_PER_SEC);
-        let three_min = recording::Duration(3 * 60 * TIME_UNITS_PER_SEC);
-        let four_min = recording::Duration(4 * 60 * TIME_UNITS_PER_SEC);
-        let test_day1 = &StreamDayKey(*b"2015-12-31");
-        let test_day2 = &StreamDayKey(*b"2016-01-01");
-        adjust_days(test_time..test_time + one_min, 1, &mut m);
-        assert_eq!(1, m.len());
-        assert_eq!(
-            Some(&StreamDayValue {
-                recordings: 1,
-                duration: one_min
-            }),
-            m.get(test_day1)
-        );
-
-        // Add to a day.
-        adjust_days(test_time..test_time + one_min, 1, &mut m);
-        assert_eq!(1, m.len());
-        assert_eq!(
-            Some(&StreamDayValue {
-                recordings: 2,
-                duration: two_min
-            }),
-            m.get(test_day1)
-        );
-
-        // Subtract from a day.
-        adjust_days(test_time..test_time + one_min, -1, &mut m);
-        assert_eq!(1, m.len());
-        assert_eq!(
-            Some(&StreamDayValue {
-                recordings: 1,
-                duration: one_min
-            }),
-            m.get(test_day1)
-        );
-
-        // Remove a day.
-        adjust_days(test_time..test_time + one_min, -1, &mut m);
-        assert_eq!(0, m.len());
-
-        // Create two days.
-        adjust_days(test_time..test_time + three_min, 1, &mut m);
-        assert_eq!(2, m.len());
-        assert_eq!(
-            Some(&StreamDayValue {
-                recordings: 1,
-                duration: one_min
-            }),
-            m.get(test_day1)
-        );
-        assert_eq!(
-            Some(&StreamDayValue {
-                recordings: 1,
-                duration: two_min
-            }),
-            m.get(test_day2)
-        );
-
-        // Add to two days.
-        adjust_days(test_time..test_time + three_min, 1, &mut m);
-        assert_eq!(2, m.len());
-        assert_eq!(
-            Some(&StreamDayValue {
-                recordings: 2,
-                duration: two_min
-            }),
-            m.get(test_day1)
-        );
-        assert_eq!(
-            Some(&StreamDayValue {
-                recordings: 2,
-                duration: four_min
-            }),
-            m.get(test_day2)
-        );
-
-        // Subtract from two days.
-        adjust_days(test_time..test_time + three_min, -1, &mut m);
-        assert_eq!(2, m.len());
-        assert_eq!(
-            Some(&StreamDayValue {
-                recordings: 1,
-                duration: one_min
-            }),
-            m.get(test_day1)
-        );
-        assert_eq!(
-            Some(&StreamDayValue {
-                recordings: 1,
-                duration: two_min
-            }),
-            m.get(test_day2)
-        );
-
-        // Remove two days.
-        adjust_days(test_time..test_time + three_min, -1, &mut m);
-        assert_eq!(0, m.len());
-    }
-
-    #[test]
-    fn test_day_bounds() {
-        testutil::init();
-        assert_eq!(
-            StreamDayKey(*b"2017-10-10").bounds(), // normal day (24 hrs)
-            recording::Time(135685692000000)..recording::Time(135693468000000)
-        );
-        assert_eq!(
-            StreamDayKey(*b"2017-03-12").bounds(), // spring forward (23 hrs)
-            recording::Time(134037504000000)..recording::Time(134044956000000)
-        );
-        assert_eq!(
-            StreamDayKey(*b"2017-11-05").bounds(), // fall back (25 hrs)
-            recording::Time(135887868000000)..recording::Time(135895968000000)
-        );
-    }
-
     #[test]
     fn test_no_meta_or_version() {
         testutil::init();
diff --git a/server/db/lib.rs b/server/db/lib.rs
index ed4b7ed..fb51f99 100644
--- a/server/db/lib.rs
+++ b/server/db/lib.rs
@@ -8,6 +8,7 @@ pub mod auth;
 pub mod check;
 mod coding;
 mod compare;
+pub mod days;
 pub mod db;
 pub mod dir;
 mod fs;
diff --git a/server/src/json.rs b/server/src/json.rs
index f3007b4..5d98b24 100644
--- a/server/src/json.rs
+++ b/server/src/json.rs
@@ -6,7 +6,6 @@ use db::auth::SessionHash;
 use failure::{format_err, Error};
 use serde::ser::{Error as _, SerializeMap, SerializeSeq, Serializer};
 use serde::{Deserialize, Serialize};
-use std::collections::BTreeMap;
 use std::ops::Not;
 use uuid::Uuid;
 
@@ -86,7 +85,7 @@ pub struct Stream<'a> {
 
     #[serde(skip_serializing_if = "Option::is_none")]
     #[serde(serialize_with = "Stream::serialize_days")]
-    pub days: Option<BTreeMap<db::StreamDayKey, db::StreamDayValue>>,
+    pub days: Option<db::days::Map<db::days::StreamValue>>,
 
     #[serde(skip_serializing_if = "Option::is_none")]
     pub config: Option<StreamConfig<'a>>,
@@ -251,7 +250,7 @@ impl<'a> Stream<'a> {
     }
 
     fn serialize_days<S>(
-        days: &Option<BTreeMap<db::StreamDayKey, db::StreamDayValue>>,
+        days: &Option<db::days::Map<db::days::StreamValue>>,
         serializer: S,
     ) -> Result<S::Ok, S::Error>
     where