From ad10b477304448e0310a90215fdfab07b4dd337f Mon Sep 17 00:00:00 2001
From: clover caruso <git@paperclover.net>
Date: Thu, 10 Sep 2026 21:08:05 -0700
Subject: [PATCH] refactor: expose active-revision, page and parent accessors

Add Space::active, Document::{active, pages_in}, Revision::parents and
RevisionIndex::{active, resolve_active}, replacing the hand-rolled default-
context lookups, page filters and parent walks across the core, offline,
notebook and SMB crates. Derive Clone and PartialEq for Layout, Format and
Tag and read table-cell indents (0x1c001c12), matching the canvas branch.

Validation: 298 workspace tests, Clippy, fmt and the fuzz workspace build.

Assisted-by: claude-fable-5.1
---
 crates/onestore-notebook/src/lib.rs       | 16 +----
 crates/onestore-offline/src/formatting.rs |  3 +-
 crates/onestore-offline/src/lib.rs        | 32 ++--------
 crates/onestore-offline/src/outline.rs    | 15 +----
 crates/onestore-offline/src/pages.rs      |  3 +-
 crates/onestore-offline/src/paragraph.rs  | 15 +----
 crates/onestore-offline/src/sync.rs       |  6 +-
 crates/onestore-offline/src/tree.rs       | 19 ++----
 crates/onestore-smb/src/tests.rs          |  2 +-
 crates/onestore/src/document.rs           | 77 +++++++++++++++++++----
 crates/onestore/src/edit.rs               | 65 +++++--------------
 crates/onestore/src/formatting.rs         | 13 +---
 crates/onestore/src/insertion.rs          | 17 ++---
 crates/onestore/src/objects.rs            | 11 +---
 crates/onestore/src/outline.rs            | 17 ++---
 crates/onestore/src/paragraph.rs          | 34 +++-------
 crates/onestore/src/revisions.rs          | 18 ++++++
 crates/onestore/src/tree.rs               | 33 ++++------
 crates/onestore/src/write.rs              | 18 +-----
 crates/onestore/src/write/tests.rs        |  8 +--
 crates/onestore/src/write/tests/multi.rs  |  6 +-
 crates/onestore/tests/document.rs         |  2 +-
 22 files changed, 161 insertions(+), 269 deletions(-)

diff --git a/crates/onestore-notebook/src/lib.rs b/crates/onestore-notebook/src/lib.rs
index 07aeb6c94d12ffd829c54bdb5bbeb74f59eed3c5..68a31a7c239c406376e6f23a0e014af8f3f7e120 100644
--- a/crates/onestore-notebook/src/lib.rs
+++ b/crates/onestore-notebook/src/lib.rs
@@ -2,7 +2,7 @@
 #![doc = include_str!("../README.md")]
 
 use onestore::{
-    ExGuid, FileType, RevisionIndex, Store,
+    FileType, RevisionIndex, Store,
     document::{Document, Kind},
 };
 use serde::Serialize;
@@ -251,19 +251,7 @@ fn scan(
         let parsed = (|| {
             let index = RevisionIndex::parse(&store)?;
             let document = Document::parse(&index)?;
-            let revision = document
-                .spaces
-                .get(&document.root)
-                .and_then(|space| {
-                    space
-                        .contexts
-                        .get(&ExGuid::default())
-                        .and_then(|id| space.revisions.get(id))
-                })
-                .ok_or(onestore::Error {
-                    offset: 0,
-                    message: "Missing active notebook root revision",
-                })?;
+            let revision = document.active(document.root)?;
             if expected == FileType::Section {
                 if revision
                     .roots
diff --git a/crates/onestore-offline/src/formatting.rs b/crates/onestore-offline/src/formatting.rs
index 8b0dc1f4db0ec5b1220f0dc79b0234431116d706..c229f53032d87d21e919e5ec87d8b665608fd62f 100644
--- a/crates/onestore-offline/src/formatting.rs
+++ b/crates/onestore-offline/src/formatting.rs
@@ -68,8 +68,7 @@ fn observe(
     let store = Store::parse(source)?;
     let index = RevisionIndex::parse(&store)?;
     let document = Document::parse(&index)?;
-    let space = &document.spaces[&space];
-    let revision = &space.revisions[&space.contexts[&ExGuid::default()]];
+    let revision = document.active(space)?;
     let mut spans: Vec<Span> = Vec::new();
     let mut start = 0;
     for run in revision.text_runs(object)? {
diff --git a/crates/onestore-offline/src/lib.rs b/crates/onestore-offline/src/lib.rs
index 2a40bbbbf863c44622d622b2d3c8002392be4090..58a57badb609e2b9223be5f3d70d81c645050297 100644
--- a/crates/onestore-offline/src/lib.rs
+++ b/crates/onestore-offline/src/lib.rs
@@ -305,29 +305,11 @@ fn active_paths(
     pages: &[ExGuid],
     objects: &[ExGuid],
 ) -> Option<Vec<Vec<ExGuid>>> {
-    use std::collections::{BTreeMap, BTreeSet};
-    let mut pending = pages.to_vec();
-    let mut seen = BTreeSet::new();
-    let mut parents = BTreeMap::<_, Vec<_>>::new();
-    while let Some(id) = pending.pop() {
-        if !seen.insert(id) {
-            continue;
-        }
-        let node = view.nodes.get(&id)?;
-        for child in node
-            .children
-            .iter()
-            .chain(&node.content)
-            .chain(&node.structure)
-        {
-            parents.entry(*child).or_default().push(id);
-            pending.push(*child);
-        }
-    }
+    let parents = view.parents(pages).ok()?;
     objects
         .iter()
         .map(|object| {
-            if !seen.contains(object) {
+            if !parents.contains_key(object) && !pages.contains(object) {
                 return None;
             }
             let mut path = Vec::new();
@@ -352,14 +334,8 @@ fn paragraph(source: &[u8], space: ExGuid, object: ExGuid) -> Result<Option<Stri
     let index = RevisionIndex::parse(&store)?;
     let document = Document::parse(&index)?;
     let node = document
-        .spaces
-        .get(&space)
-        .and_then(|space| {
-            space
-                .contexts
-                .get(&ExGuid::default())
-                .and_then(|revision| space.revisions.get(revision))
-        })
+        .active(space)
+        .ok()
         .and_then(|revision| revision.nodes.get(&object));
     Ok(match node.map(|node| &node.kind) {
         Some(Kind::RichText { text, .. }) => Some(text.clone()),
diff --git a/crates/onestore-offline/src/outline.rs b/crates/onestore-offline/src/outline.rs
index 5be997d22e39d5ed6c184032a4c50d3ad847dc77..5fa33be61a594dbe9287427862e6ff50ea1020fd 100644
--- a/crates/onestore-offline/src/outline.rs
+++ b/crates/onestore-offline/src/outline.rs
@@ -27,21 +27,10 @@ fn observe(
     let store = Store::parse(source)?;
     let index = RevisionIndex::parse(&store)?;
     let document = Document::parse(&index)?;
-    let Some(space_view) = document.spaces.get(&space) else {
+    let Ok(view) = document.active(space) else {
         return Ok(None);
     };
-    let Some(view) = space_view
-        .contexts
-        .get(&ExGuid::default())
-        .and_then(|rid| space_view.revisions.get(rid))
-    else {
-        return Ok(None);
-    };
-    let pages: Vec<_> = document
-        .pages()?
-        .into_iter()
-        .filter_map(|(sid, page)| (sid == space).then_some(page))
-        .collect();
+    let pages = document.pages_in(space)?;
     if pages.len() != 1 {
         return Ok(None);
     }
diff --git a/crates/onestore-offline/src/pages.rs b/crates/onestore-offline/src/pages.rs
index 12bf7d1af435862b25d8ec0e2b847cc0ee34b481..f77536addde20c68f8e8f0c76a2c315d7f883cbb 100644
--- a/crates/onestore-offline/src/pages.rs
+++ b/crates/onestore-offline/src/pages.rs
@@ -19,8 +19,7 @@ fn observe(source: &[u8]) -> Result<Option<(ExGuid, PageOrder)>> {
     let document = Document::parse(&index)?;
     let mut pages = Vec::new();
     for (sid, _) in document.pages()? {
-        let space = &document.spaces[&sid];
-        let view = &space.revisions[&space.contexts[&ExGuid::default()]];
+        let view = document.active(sid)?;
         let Some(metadata) = view.roots.get(&2).and_then(|id| view.nodes.get(id)) else {
             return Ok(None);
         };
diff --git a/crates/onestore-offline/src/paragraph.rs b/crates/onestore-offline/src/paragraph.rs
index 8f6f4e6e85fc21ea6467b2e995d349f8e3d1d2a9..f97975e1da365fc07b4d823454389c00e2ce9810 100644
--- a/crates/onestore-offline/src/paragraph.rs
+++ b/crates/onestore-offline/src/paragraph.rs
@@ -30,21 +30,10 @@ fn observe(source: &[u8], space: ExGuid, texts: &[ExGuid]) -> Result<Option<Vec<
     let store = Store::parse(source)?;
     let index = RevisionIndex::parse(&store)?;
     let document = Document::parse(&index)?;
-    let Some(section) = document.spaces.get(&space) else {
+    let Ok(view) = document.active(space) else {
         return Ok(None);
     };
-    let Some(view) = section
-        .contexts
-        .get(&ExGuid::default())
-        .and_then(|id| section.revisions.get(id))
-    else {
-        return Ok(None);
-    };
-    let pages: Vec<_> = document
-        .pages()?
-        .into_iter()
-        .filter_map(|(sid, page)| (sid == space).then_some(page))
-        .collect();
+    let pages = document.pages_in(space)?;
     let Some(paths) = active_paths(view, &pages, texts) else {
         return Ok(None);
     };
diff --git a/crates/onestore-offline/src/sync.rs b/crates/onestore-offline/src/sync.rs
index 26b25e1bc353ef2ceabebe60f0cd48769a9e6560..199845ff7184d5d3ca9d7b468fcde94d8d599468 100644
--- a/crates/onestore-offline/src/sync.rs
+++ b/crates/onestore-offline/src/sync.rs
@@ -127,7 +127,7 @@ impl Replica {
                         EditStatus::AwaitingConfirmation { revision },
                     )));
                 }
-                revision = index.spaces[&intent.space].labels[&(ExGuid::default(), 1)];
+                revision = index.active(intent.space)?;
             }
             if let Err(error) = remote.confirm(&snapshot) {
                 if error.state == CommitState::Committed {
@@ -182,7 +182,7 @@ impl Replica {
         if prepared.as_bytes() == snapshot {
             let store = Store::parse(&snapshot)?;
             let index = RevisionIndex::parse(&store)?;
-            let revision = index.spaces[&intent.space].labels[&(ExGuid::default(), 1)];
+            let revision = index.active(intent.space)?;
             if let Err(error) = remote.confirm(&snapshot) {
                 if error.state == CommitState::Committed {
                     self.acknowledge(intent.id, revision, &snapshot)?;
@@ -194,7 +194,7 @@ impl Replica {
         }
         let store = Store::parse(prepared.as_bytes())?;
         let index = RevisionIndex::parse(&store)?;
-        let revision = index.spaces[&intent.space].labels[&(ExGuid::default(), 1)];
+        let revision = index.active(intent.space)?;
         let before_store = Store::parse(&snapshot)?;
         let before = RevisionIndex::parse(&before_store)?;
         let mut revisions: BTreeMap<_, _> = index
diff --git a/crates/onestore-offline/src/tree.rs b/crates/onestore-offline/src/tree.rs
index f696f9bdae9f023d64d2a534c9b0848f59bf5bdb..83282746bbf20c1b3fb92b862b8ed02b3b4c35a5 100644
--- a/crates/onestore-offline/src/tree.rs
+++ b/crates/onestore-offline/src/tree.rs
@@ -168,18 +168,10 @@ fn observe(
     let store = Store::parse(source)?;
     let index = RevisionIndex::parse(&store)?;
     let document = Document::parse(&index)?;
-    let Some(section) = document.spaces.get(&space) else {
+    let Ok(view) = document.active(space) else {
         return Ok(None);
     };
-    let Some(rid) = section.contexts.get(&ExGuid::default()) else {
-        return Ok(None);
-    };
-    let view = &section.revisions[rid];
-    let pages: Vec<_> = document
-        .pages()?
-        .into_iter()
-        .filter_map(|(sid, page)| (sid == space).then_some(page))
-        .collect();
+    let pages = document.pages_in(space)?;
     if pages.len() != 1 {
         return Ok(None);
     }
@@ -217,7 +209,7 @@ fn observe(
             .collect(),
         destination,
         content: if intent.destination().is_none() {
-            let sha256 = fingerprint(&store, &index.resolve(space, *rid)?, object, legacy)?;
+            let sha256 = fingerprint(&store, &index.resolve_active(space)?, object, legacy)?;
             Some(if legacy {
                 Content::Legacy(sha256)
             } else {
@@ -232,7 +224,7 @@ fn observe(
 fn mutable_objects(source: &[u8], space: ExGuid) -> Result<BTreeSet<ExGuid>> {
     let store = Store::parse(source)?;
     let index = RevisionIndex::parse(&store)?;
-    let raw = index.resolve(space, index.spaces[&space].labels[&(ExGuid::default(), 1)])?;
+    let raw = index.resolve_active(space)?;
     Ok(raw
         .reachable()?
         .into_iter()
@@ -468,8 +460,7 @@ mod tests {
         let index = RevisionIndex::parse(&store).unwrap();
         let document = Document::parse(&index).unwrap();
         let (sid, _) = document.pages().unwrap()[0];
-        let space = &document.spaces[&sid];
-        let view = &space.revisions[&space.contexts[&ExGuid::default()]];
+        let view = document.active(sid).unwrap();
         let text = *view.nodes.iter().find(|(_, node)| matches!(&node.kind, Kind::RichText { text, .. } if text == "AlphaOmega")).unwrap().0;
         let directory = tempfile::tempdir().unwrap();
         let path = directory.path().join("legacy.sqlite");
diff --git a/crates/onestore-smb/src/tests.rs b/crates/onestore-smb/src/tests.rs
index d89f1f700cf10d5dce2faa89148f988358af06d9..94b3dbd9638288fc2ea2c0fc69b6a8a6f13a3f22 100644
--- a/crates/onestore-smb/src/tests.rs
+++ b/crates/onestore-smb/src/tests.rs
@@ -137,7 +137,7 @@ fn text(bytes: &[u8]) -> (ExGuid, ExGuid, String) {
     doc.spaces
         .iter()
         .find_map(|(sid, space)| {
-            let revision = &space.revisions[&space.contexts[&ExGuid::default()]];
+            let revision = space.active().unwrap();
             revision
                 .nodes
                 .iter()
diff --git a/crates/onestore/src/document.rs b/crates/onestore/src/document.rs
index b8313ad7c825bb33b38e8bf6b715dc454d4d8068..ae45a94f981cc9842b3d1ff4e406376ab72e461e 100644
--- a/crates/onestore/src/document.rs
+++ b/crates/onestore/src/document.rs
@@ -30,6 +30,18 @@ pub struct Space<'a> {
     pub revisions: BTreeMap<ExGuid, Revision<'a>>,
 }
 
+impl<'a> Space<'a> {
+    /// The revision of the default context, which is the current content of the space.
+    pub fn active(&self) -> Option<&Revision<'a>> {
+        self.revisions.get(self.contexts.get(&ExGuid::default())?)
+    }
+
+    pub fn into_active(mut self) -> Option<Revision<'a>> {
+        self.revisions
+            .remove(self.contexts.get(&ExGuid::default())?)
+    }
+}
+
 #[derive(Debug, Serialize)]
 pub struct Revision<'a> {
     pub roots: BTreeMap<u32, ExGuid>,
@@ -61,7 +73,7 @@ pub struct Element<'a> {
     pub extra: Vec<Vec<Field<'a>>>,
 }
 
-#[derive(Debug, Default, Serialize)]
+#[derive(Debug, Default, Clone, PartialEq, Serialize)]
 pub struct Layout {
     pub x: Option<f32>,
     pub y: Option<f32>,
@@ -73,7 +85,7 @@ pub struct Layout {
 
 macro_rules! format_fields {
     ($($field:ident: $value:ty),* $(,)?) => {
-        #[derive(Debug, Default, Serialize)]
+        #[derive(Debug, Default, Clone, PartialEq, Serialize)]
         pub struct Format { $(pub $field: Option<$value>),* }
 
         impl Format {
@@ -208,7 +220,36 @@ impl Revision<'_> {
     }
 }
 
-#[derive(Debug, Serialize)]
+impl Revision<'_> {
+    /// Maps every element reachable from `roots` through children, content and structure
+    /// references to its referencing parents, in visiting order.
+    pub fn parents(&self, roots: &[ExGuid]) -> Result<BTreeMap<ExGuid, Vec<ExGuid>>> {
+        let mut pending: Vec<_> = roots.to_vec();
+        let mut seen = BTreeSet::new();
+        let mut parents = BTreeMap::<_, Vec<_>>::new();
+        while let Some(id) = pending.pop() {
+            if !seen.insert(id) {
+                continue;
+            }
+            let element = self
+                .nodes
+                .get(&id)
+                .ok_or_else(|| invalid("Page content is unavailable"))?;
+            for child in element
+                .children
+                .iter()
+                .chain(&element.content)
+                .chain(&element.structure)
+            {
+                parents.entry(*child).or_default().push(id);
+                pending.push(*child);
+            }
+        }
+        Ok(parents)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize)]
 /// Tag dates count seconds since 1980-01-01 UTC; status retains the ActionItemStatus bits.
 pub struct Tag {
     pub definition: Option<ExGuid>,
@@ -308,6 +349,7 @@ pub enum Kind<'a> {
     Row,
     Cell {
         shading: Option<u32>,
+        indents: Vec<f32>,
     },
     Image {
         container: Option<ExGuid>,
@@ -547,17 +589,25 @@ fn measurements(bytes: Option<&[u8]>, header: usize) -> Result<Vec<f32>> {
 impl<'a> Document<'a> {
     /// Active (object space, page) identities in section order, excluding history and conflicts.
     /// Encrypted sections return no visible pages; table-of-contents files return an error.
+    /// The active revision of one object space.
+    pub fn active(&self, space: ExGuid) -> Result<&Revision<'a>> {
+        self.spaces
+            .get(&space)
+            .and_then(Space::active)
+            .ok_or_else(|| invalid("Object space has no active revision"))
+    }
+
+    /// Active page objects declared in one page space, in section order.
+    pub fn pages_in(&self, space: ExGuid) -> Result<Vec<ExGuid>> {
+        Ok(self
+            .pages()?
+            .into_iter()
+            .filter_map(|(sid, page)| (sid == space).then_some(page))
+            .collect())
+    }
+
     pub fn pages(&self) -> Result<Vec<(ExGuid, ExGuid)>> {
-        let active = |sid| {
-            self.spaces
-                .get(&sid)
-                .and_then(|s| {
-                    s.contexts
-                        .get(&ExGuid::default())
-                        .and_then(|rid| s.revisions.get(rid))
-                })
-                .ok_or_else(|| invalid("Section page has no active revision"))
-        };
+        let active = |sid| self.active(sid);
         let root = active(self.root)?;
         let section = root
             .roots
@@ -1084,6 +1134,7 @@ impl<'a> Element<'a> {
             0x60023 => Kind::Row,
             0x60024 => Kind::Cell {
                 shading: f.u32(0x14001e26)?,
+                indents: measurements(f.bytes(0x1c001c12)?, 4)?,
             },
             0x60011 => Kind::Image {
                 container: f.one(0x20001c3f)?,
diff --git a/crates/onestore/src/edit.rs b/crates/onestore/src/edit.rs
index 89c4427f84f9e6578bdc92e82ad1af5fb82eaab9..9b23042318ed2bdc97a37c87bfa0ae1c54a63920 100644
--- a/crates/onestore/src/edit.rs
+++ b/crates/onestore/src/edit.rs
@@ -44,11 +44,7 @@ pub fn replace_text(
     let store = Store::parse(source)?;
     let index = RevisionIndex::parse(&store)?;
     index.validate_current()?;
-    let rid = *index
-        .spaces
-        .get(&space)
-        .and_then(|s| s.labels.get(&(ExGuid::default(), 1)))
-        .ok_or_else(|| invalid("Object space has no active default revision"))?;
+    let rid = index.active(space)?;
     let raw = index.resolve(space, rid)?;
     if !raw.reachable()?.contains(&object) {
         return Err(invalid("Object is not reachable in the active revision"));
@@ -59,11 +55,7 @@ pub fn replace_text(
         .get(&space)
         .and_then(|s| s.revisions.get(&rid))
         .ok_or_else(|| invalid("The active document revision is unavailable"))?;
-    let pages: Vec<_> = document
-        .pages()?
-        .into_iter()
-        .filter_map(|(sid, page)| (sid == space).then_some(page))
-        .collect();
+    let pages = document.pages_in(space)?;
     let parents = editable_parents(revision, &pages, object)?;
     let node = revision
         .nodes
@@ -317,37 +309,23 @@ pub(crate) fn editable_parents(
     object: ExGuid,
 ) -> Result<std::collections::BTreeMap<ExGuid, Vec<ExGuid>>, Error> {
     let invalid = |message| Error { offset: 0, message };
-    let mut pending: Vec<_> = pages.iter().map(|page| (*page, false)).collect();
+    let parents = revision.parents(pages)?;
+    if !parents.contains_key(&object) && !pages.contains(&object) {
+        return Err(invalid("Select content on an active editable page"));
+    }
+    let mut pending = vec![object];
     let mut seen = std::collections::BTreeSet::new();
-    let mut parents = std::collections::BTreeMap::<_, Vec<_>>::new();
-    let mut editable = false;
-    while let Some((id, read_only)) = pending.pop() {
-        if !seen.insert((id, read_only)) {
+    while let Some(id) = pending.pop() {
+        if !seen.insert(id) {
             continue;
         }
-        let element = revision
-            .nodes
-            .get(&id)
-            .ok_or_else(|| invalid("Page content is unavailable"))?;
-        let read_only = read_only || element.extra[0].iter().any(|field| field.id == 0x88001cde);
-        if id == object {
-            if read_only {
-                return Err(invalid("This page or its content is read-only"));
-            }
-            editable = true;
-        }
-        for child in element
-            .children
+        if revision.nodes[&id].extra[0]
             .iter()
-            .chain(&element.content)
-            .chain(&element.structure)
+            .any(|field| field.id == 0x88001cde)
         {
-            parents.entry(*child).or_default().push(id);
-            pending.push((*child, read_only));
+            return Err(invalid("This page or its content is read-only"));
         }
-    }
-    if !editable {
-        return Err(invalid("Select content on an active editable page"));
+        pending.extend(parents.get(&id).into_iter().flatten().copied());
     }
     Ok(parents)
 }
@@ -358,21 +336,8 @@ pub(crate) fn page_title(
     text_update: Option<(ExGuid, &str)>,
 ) -> Result<Option<(ExGuid, bool, String)>, Error> {
     let invalid = |message| Error { offset: 0, message };
-    let mut pending = pages.to_vec();
-    let mut seen = std::collections::BTreeSet::new();
-    while let Some(id) = pending.pop() {
-        if !seen.insert(id) {
-            continue;
-        }
-        let node = &revision.nodes[&id];
-        pending.extend(
-            node.children
-                .iter()
-                .chain(&node.content)
-                .chain(&node.structure)
-                .copied(),
-        );
-    }
+    let parents = revision.parents(pages)?;
+    let seen: std::collections::BTreeSet<_> = parents.keys().chain(pages).copied().collect();
     let titles: Vec<_> = revision
         .nodes
         .iter()
diff --git a/crates/onestore/src/formatting.rs b/crates/onestore/src/formatting.rs
index 2056257ebc1c7ec761798c5e611542230379929d..14009351ee40ed34ae53aa12dfbb55fb71792cb8 100644
--- a/crates/onestore/src/formatting.rs
+++ b/crates/onestore/src/formatting.rs
@@ -96,17 +96,8 @@ pub(crate) fn format_text(
     let index = RevisionIndex::parse(&store)?;
     index.validate_current()?;
     let document = Document::parse(&index)?;
-    let semantic = document
-        .spaces
-        .get(&space)
-        .ok_or_else(|| invalid("The active page is unavailable"))?;
-    let rid = semantic.contexts[&ExGuid::default()];
-    let view = &semantic.revisions[&rid];
-    let pages: Vec<_> = document
-        .pages()?
-        .into_iter()
-        .filter_map(|(sid, page)| (sid == space).then_some(page))
-        .collect();
+    let view = document.active(space)?;
+    let pages = document.pages_in(space)?;
     let parents = editable_parents(view, &pages, object)?;
     let node = &view.nodes[&object];
     let Kind::RichText {
diff --git a/crates/onestore/src/insertion.rs b/crates/onestore/src/insertion.rs
index 8543533ec3a70cf6c945fcc7ebc7241aedc8d6ed..38ccedb89e0665d1182366002935cd3b7dffb01a 100644
--- a/crates/onestore/src/insertion.rs
+++ b/crates/onestore/src/insertion.rs
@@ -195,24 +195,15 @@ impl Insertion {
         let index = RevisionIndex::parse(&store)?;
         index.validate_current()?;
         let mut document = Document::parse(&index)?;
-        let pages: Vec<_> = document
-            .pages()?
-            .into_iter()
-            .filter_map(|(sid, id)| (sid == space).then_some(id))
-            .collect();
+        let pages = document.pages_in(space)?;
         let [page] = pages.as_slice() else {
             return Err(invalid("Insertion requires a single active page"));
         };
-        let semantic_space = document
+        let mut view = document
             .spaces
             .remove(&space)
+            .and_then(crate::document::Space::into_active)
             .ok_or_else(|| invalid("The active page is unavailable"))?;
-        let rid = semantic_space.contexts[&ExGuid::default()];
-        let mut view = semantic_space
-            .revisions
-            .into_iter()
-            .find_map(|(id, revision)| (id == rid).then_some(revision))
-            .unwrap();
         let parents = editable_parents(&view, &pages, self.parent)?;
         let parent = &view.nodes[&self.parent];
         let position = match self.placement {
@@ -372,7 +363,7 @@ impl Insertion {
                 },
             );
         }
-        let raw = index.resolve(space, rid)?;
+        let raw = index.resolve_active(space)?;
         if new.keys().any(|id| raw.objects.contains_key(id)) {
             return Err(invalid(
                 "An insertion identity is already present; reconcile the existing edit",
diff --git a/crates/onestore/src/objects.rs b/crates/onestore/src/objects.rs
index 02d0e02dcea389d053a1cb5724a6162d8233ad10..3460a0f2c37583ea1c27b9aa57c1640115cc8031 100644
--- a/crates/onestore/src/objects.rs
+++ b/crates/onestore/src/objects.rs
@@ -200,15 +200,8 @@ impl<'a> RevisionIndex<'a> {
                                 message: "Object references its own object space",
                             });
                         }
-                        let rid = self
-                            .spaces
-                            .get(&target)
-                            .and_then(|space| space.labels.get(&(ExGuid::default(), 1)))
-                            .ok_or(Error {
-                                offset: 0,
-                                message: "Object-space reference has no default revision",
-                            })?;
-                        targets.insert((target, *rid));
+                        let rid = self.active(target)?;
+                        targets.insert((target, rid));
                     }
                     for context in references.contexts {
                         if !space.labels.contains_key(&(context, 1)) {
diff --git a/crates/onestore/src/outline.rs b/crates/onestore/src/outline.rs
index c58fe5569c1d023b63b4943689972f39becbf974..b17661e4de6ebea601e6bf94ee36083d4df3b283 100644
--- a/crates/onestore/src/outline.rs
+++ b/crates/onestore/src/outline.rs
@@ -58,18 +58,14 @@ impl OutlineEdit {
         let index = RevisionIndex::parse(&store)?;
         index.validate_current()?;
         let mut document = Document::parse(&index)?;
-        let pages: Vec<_> = document
-            .pages()?
-            .into_iter()
-            .filter_map(|(sid, page)| (sid == space).then_some(page))
-            .collect();
+        let pages = document.pages_in(space)?;
         let [page] = pages.as_slice() else {
             return Err(invalid("Outline editing requires a single active page"));
         };
-        let mut semantic = document.spaces.remove(&space).unwrap();
-        let view = semantic
-            .revisions
-            .remove(&semantic.contexts[&ExGuid::default()])
+        let view = document
+            .spaces
+            .remove(&space)
+            .and_then(crate::document::Space::into_active)
             .unwrap();
         let parents = editable_parents(&view, &pages, object)?;
         let node = &view.nodes[&object];
@@ -151,8 +147,7 @@ mod tests {
         let index = RevisionIndex::parse(&store).unwrap();
         let document = Document::parse(&index).unwrap();
         let (sid, page) = document.pages().unwrap()[0];
-        let space = &document.spaces[&sid];
-        let view = &space.revisions[&space.contexts[&ExGuid::default()]];
+        let view = document.active(sid).unwrap();
         let outline = *view.nodes[&page]
             .children
             .iter()
diff --git a/crates/onestore/src/paragraph.rs b/crates/onestore/src/paragraph.rs
index cdc8749091018e43582d70c34420beeb3f32eac6..86ffcdb169df8f55723c3b43e9ad00a2a63a5856 100644
--- a/crates/onestore/src/paragraph.rs
+++ b/crates/onestore/src/paragraph.rs
@@ -84,24 +84,15 @@ impl ParagraphSplit {
         let index = RevisionIndex::parse(&store)?;
         index.validate_current()?;
         let mut document = Document::parse(&index)?;
-        let pages: Vec<_> = document
-            .pages()?
-            .into_iter()
-            .filter_map(|(sid, page)| (sid == space).then_some(page))
-            .collect();
+        let pages = document.pages_in(space)?;
         let [_] = pages.as_slice() else {
             return Err(invalid("Splitting requires a single active page"));
         };
-        let semantic = document
+        let view = document
             .spaces
             .remove(&space)
+            .and_then(crate::document::Space::into_active)
             .ok_or_else(|| invalid("The active page is unavailable"))?;
-        let rid = semantic.contexts[&ExGuid::default()];
-        let view = semantic
-            .revisions
-            .into_iter()
-            .find_map(|(id, view)| (id == rid).then_some(view))
-            .unwrap();
         let parents = editable_parents(&view, &pages, self.text)?;
         let [paragraph] = parents
             .get(&self.text)
@@ -147,7 +138,7 @@ impl ParagraphSplit {
             }
             pending.extend(parents.get(&id).into_iter().flatten().copied());
         }
-        let raw = index.resolve(space, rid)?;
+        let raw = index.resolve_active(space)?;
         let (text, runs) = ordinary_text(&view, &raw, self.text)?;
         let node = &view.nodes[&self.text];
         let length = u32::try_from(text.encode_utf16().count())
@@ -419,24 +410,15 @@ impl ParagraphJoin {
         let index = RevisionIndex::parse(&store)?;
         index.validate_current()?;
         let mut document = Document::parse(&index)?;
-        let pages: Vec<_> = document
-            .pages()?
-            .into_iter()
-            .filter_map(|(sid, page)| (sid == space).then_some(page))
-            .collect();
+        let pages = document.pages_in(space)?;
         if pages.len() != 1 {
             return Err(invalid("Joining requires a single active page"));
         }
-        let semantic = document
+        let view = document
             .spaces
             .remove(&space)
+            .and_then(crate::document::Space::into_active)
             .ok_or_else(|| invalid("The active page is unavailable"))?;
-        let rid = semantic.contexts[&ExGuid::default()];
-        let view = semantic
-            .revisions
-            .into_iter()
-            .find_map(|(id, view)| (id == rid).then_some(view))
-            .unwrap();
         let parents = editable_parents(&view, &pages, self.left)?;
         editable_parents(&view, &pages, self.right)?;
         let parent = |id| -> Result<ExGuid, Error> {
@@ -500,7 +482,7 @@ impl ParagraphJoin {
                 "Joining these child indentation levels requires a hierarchy edit",
             ));
         }
-        let raw = index.resolve(space, rid)?;
+        let raw = index.resolve_active(space)?;
         let (a, a_runs) = ordinary_text(&view, &raw, self.left)?;
         let (b, b_runs) = ordinary_text(&view, &raw, self.right)?;
         let length = u32::try_from(a.encode_utf16().count())
diff --git a/crates/onestore/src/revisions.rs b/crates/onestore/src/revisions.rs
index 1ac8274d5fcd37eb0ffcdc9d80886798b0f44b4e..3ffbcee3e6aff1e89ceba5436280aa9e8cfc2fe2 100644
--- a/crates/onestore/src/revisions.rs
+++ b/crates/onestore/src/revisions.rs
@@ -396,3 +396,21 @@ impl<'a> RevisionIndex<'a> {
         })
     }
 }
+
+impl<'a> RevisionIndex<'a> {
+    /// The revision labelled current in the default context of one object space.
+    pub fn active(&self, space: ExGuid) -> Result<ExGuid> {
+        self.spaces
+            .get(&space)
+            .and_then(|space| space.labels.get(&(ExGuid::default(), 1)))
+            .copied()
+            .ok_or(Error {
+                offset: 0,
+                message: "Object space has no active default revision",
+            })
+    }
+
+    pub fn resolve_active(&self, space: ExGuid) -> Result<crate::ResolvedRevision<'a>> {
+        self.resolve(space, self.active(space)?)
+    }
+}
diff --git a/crates/onestore/src/tree.rs b/crates/onestore/src/tree.rs
index 04a19f7240b3467ccae01078b17a0db0a91bf492..34aff9ec5cfa65598dd2d0e4dd600b06fd033893 100644
--- a/crates/onestore/src/tree.rs
+++ b/crates/onestore/src/tree.rs
@@ -100,20 +100,14 @@ impl TreeEdit {
         let index = RevisionIndex::parse(&store)?;
         index.validate_current()?;
         let mut document = Document::parse(&index)?;
-        let pages: Vec<_> = document
-            .pages()?
-            .into_iter()
-            .filter_map(|(sid, page)| (sid == space).then_some(page))
-            .collect();
+        let pages = document.pages_in(space)?;
         let [page] = pages.as_slice() else {
             return Err(invalid("Tree editing requires a single active page"));
         };
-        let semantic = document.spaces.remove(&space).unwrap();
-        let rid = semantic.contexts[&ExGuid::default()];
-        let mut view = semantic
-            .revisions
-            .into_iter()
-            .find_map(|(id, view)| (id == rid).then_some(view))
+        let mut view = document
+            .spaces
+            .remove(&space)
+            .and_then(crate::document::Space::into_active)
             .unwrap();
         let parents = editable_parents(&view, &pages, self.object)?;
         let path = checked_path(&view, &parents, *page, self.object)?;
@@ -279,7 +273,7 @@ impl TreeEdit {
                     .copied(),
             );
         }
-        let raw = index.resolve(space, rid)?;
+        let raw = index.resolve_active(space)?;
         let active_parents = editable_parents(&view, &pages, *page)?;
         let modified = current_timestamps()?.0.to_le_bytes();
         let mut changed = BTreeMap::new();
@@ -431,8 +425,7 @@ mod tests {
         let index = RevisionIndex::parse(&store).unwrap();
         let document = Document::parse(&index).unwrap();
         let (sid, page) = document.pages().unwrap()[0];
-        let space = &document.spaces[&sid];
-        let view = &space.revisions[&space.contexts[&ExGuid::default()]];
+        let view = document.active(sid).unwrap();
         let outline = *view.nodes[&page]
             .children
             .iter()
@@ -453,8 +446,7 @@ mod tests {
         let store = Store::parse(repeated.as_bytes()).unwrap();
         let index = RevisionIndex::parse(&store).unwrap();
         let document = Document::parse(&index).unwrap();
-        let space = &document.spaces[&sid];
-        let view = &space.revisions[&space.contexts[&ExGuid::default()]];
+        let view = document.active(sid).unwrap();
         assert_eq!(view.nodes[&outline].children, [second.object(), first]);
         assert_eq!(
             view.nodes[&first].latest_author,
@@ -472,8 +464,7 @@ mod tests {
         let index = RevisionIndex::parse(&store).unwrap();
         let document = Document::parse(&index).unwrap();
         let (sid, page) = document.pages().unwrap()[0];
-        let space = &document.spaces[&sid];
-        let view = &space.revisions[&space.contexts[&ExGuid::default()]];
+        let view = document.active(sid).unwrap();
         let outline = *view.nodes[&page]
             .children
             .iter()
@@ -527,8 +518,7 @@ mod tests {
             let index = RevisionIndex::parse(&store).unwrap();
             index.validate_current().unwrap();
             let document = Document::parse(&index).unwrap();
-            let space = &document.spaces[&sid];
-            let view = &space.revisions[&space.contexts[&ExGuid::default()]];
+            let view = document.active(sid).unwrap();
             assert_eq!(view.nodes[&outline].children, [a, second.object()]);
             assert_eq!(view.nodes[&outline].child_level, Some(2));
             assert_eq!(view.nodes[&a].child_level, Some(1));
@@ -557,8 +547,7 @@ mod tests {
         let index = RevisionIndex::parse(&store).unwrap();
         let document = Document::parse(&index).unwrap();
         let (sid, page) = document.pages().unwrap()[0];
-        let space = &document.spaces[&sid];
-        let view = &space.revisions[&space.contexts[&ExGuid::default()]];
+        let view = document.active(sid).unwrap();
         let outline = *view.nodes[&page]
             .children
             .iter()
diff --git a/crates/onestore/src/write.rs b/crates/onestore/src/write.rs
index 73af1ed174e0ac4f3e31968a01747c7bcc97b61d..e0e48f8134b444cf99fe6c9aac8c8e1e5eda3946 100644
--- a/crates/onestore/src/write.rs
+++ b/crates/onestore/src/write.rs
@@ -596,14 +596,7 @@ pub(crate) fn write_revision(
     edit: impl FnOnce(&crate::ResolvedRevision<'_>) -> Result<BTreeMap<ExGuid, PropertyObject>>,
 ) -> Result<Vec<u8>> {
     write_revisions(source, |index| {
-        let rid = *index
-            .spaces
-            .get(&space)
-            .and_then(|space| space.labels.get(&(ExGuid::default(), 1)))
-            .ok_or(Error {
-                offset: 0,
-                message: "Object space has no active default revision",
-            })?;
+        let rid = index.active(space)?;
         let revision = index.resolve(space, rid)?;
         Ok(BTreeMap::from([(
             space,
@@ -680,14 +673,7 @@ pub(crate) fn write_revisions(
     for (space, change) in changes {
         let (rid, mut revision, mut replacements) = match change {
             RevisionEdit::Update(objects) => {
-                let rid = *index
-                    .spaces
-                    .get(&space)
-                    .and_then(|space| space.labels.get(&(ExGuid::default(), 1)))
-                    .ok_or(Error {
-                        offset: 0,
-                        message: "Object space has no active default revision",
-                    })?;
+                let rid = index.active(space)?;
                 (Some(rid), index.resolve(space, rid)?, objects)
             }
             RevisionEdit::Create { roots, objects } => {
diff --git a/crates/onestore/src/write/tests.rs b/crates/onestore/src/write/tests.rs
index 704da0bc7f6f4f64c7d34cc456a12627fa91c0fa..02a27edb8c68f6c4c47e85818a5c1540e48d69c5 100644
--- a/crates/onestore/src/write/tests.rs
+++ b/crates/onestore/src/write/tests.rs
@@ -144,7 +144,7 @@ fn document_insertions_and_formatting_respect_readonly_ancestors() {
     .unwrap();
     let document = crate::document::Document::parse(&index).unwrap();
     let space = &document.spaces[&sid];
-    let view = &space.revisions[&space.contexts[&ExGuid::default()]];
+    let view = space.active().unwrap();
     let text = view.nodes[&paragraph].content[0];
     let join = crate::ParagraphJoin::new(text, right.text_object(), "Author").unwrap();
     assert!(PreparedEdit::join(&protected, sid, &join).is_err());
@@ -861,7 +861,7 @@ fn character_formatting_preserves_inheritance_and_associated_data() {
                 let index = RevisionIndex::parse(&store).unwrap();
                 let document = Document::parse(&index).unwrap();
                 let space = &document.spaces[&sid];
-                let view = &space.revisions[&space.contexts[&ExGuid::default()]];
+                let view = space.active().unwrap();
                 let Kind::RichText { runs, .. } = &view.nodes[&text].kind else {
                     panic!()
                 };
@@ -888,7 +888,7 @@ fn character_formatting_preserves_inheritance_and_associated_data() {
         let index = RevisionIndex::parse(&store).unwrap();
         let doc = Document::parse(&index).unwrap();
         let s = &doc.spaces[&sid];
-        let view = &s.revisions[&s.contexts[&ExGuid::default()]];
+        let view = s.active().unwrap();
         let runs = view.text_runs(text).unwrap();
         assert_eq!(runs.len(), 1);
         assert_eq!(runs[0].format.font.as_deref(), Some("Georgia"));
@@ -909,7 +909,7 @@ fn character_formatting_preserves_inheritance_and_associated_data() {
             let previous = RevisionIndex::parse(&previous).unwrap();
             let previous_doc = Document::parse(&previous).unwrap();
             let s = &previous_doc.spaces[&sid];
-            let previous_view = &s.revisions[&s.contexts[&ExGuid::default()]];
+            let previous_view = s.active().unwrap();
             assert_eq!(
                 format!("{:?}", view.nodes[&text].extra),
                 format!("{:?}", previous_view.nodes[&text].extra)
diff --git a/crates/onestore/src/write/tests/multi.rs b/crates/onestore/src/write/tests/multi.rs
index e3bec7129975a4c305656a2b0fdfda4fcda071c9..73c89104d36bd36b25694610cdd1bdbc0901fa33 100644
--- a/crates/onestore/src/write/tests/multi.rs
+++ b/crates/onestore/src/write/tests/multi.rs
@@ -28,7 +28,7 @@ fn nest(source: &[u8]) -> Vec<u8> {
             index.spaces[&index.root].labels[&(ExGuid::default(), 1)],
         )?;
         let view = &document.spaces[&index.root];
-        let view = &view.revisions[&view.contexts[&ExGuid::default()]];
+        let view = view.active().unwrap();
         let root = section.roots[&1];
         let parent = *view.nodes[&root]
             .children
@@ -126,7 +126,7 @@ fn nesting_publishes_section_order_and_page_levels_in_one_transaction() {
     assert_eq!(changed_spaces, 3);
     for (ordinal, (sid, _)) in pages.iter().enumerate() {
         let view = &document.spaces[sid];
-        let view = &view.revisions[&view.contexts[&ExGuid::default()]];
+        let view = view.active().unwrap();
         let Kind::Metadata { level, .. } = view.nodes[&view.roots[&2]].kind else {
             panic!()
         };
@@ -151,7 +151,7 @@ fn nesting_publishes_section_order_and_page_levels_in_one_transaction() {
         }
     }
     let root = &document.spaces[&document.root];
-    let root = &root.revisions[&root.contexts[&ExGuid::default()]];
+    let root = root.active().unwrap();
     assert_eq!(
         root.nodes[&root.roots[&1]]
             .children
diff --git a/crates/onestore/tests/document.rs b/crates/onestore/tests/document.rs
index 997d6b84477bf30521c8a0f4b39bdb89bd7278cc..7618bc53e72e74b9593890cd753ddeabdd2ae781 100644
--- a/crates/onestore/tests/document.rs
+++ b/crates/onestore/tests/document.rs
@@ -17,7 +17,7 @@ fn documented_cell_shading_survives_native_2010_ignoring_its_display() {
         .flat_map(|s| s.revisions.values())
         .flat_map(|r| r.nodes.values())
         .filter_map(|n| match n.kind {
-            Kind::Cell { shading } => shading,
+            Kind::Cell { shading, .. } => shading,
             _ => None,
         })
         .collect();
-- 
2.54.0