Commit 0c2795ab06a608463deba57402a39ada750c526c | snowbound

author	clover caruso <git@paperclover.net> 2026-10-12 22:58:44-07:00
committer	clover caruso <git@paperclover.net> 2026-10-15 02:05:14-07:00
log	0c2795ab06a608463deba57402a39ada750c526c
tree	b5652a3ac7f9432f40660482fca902061b369927
parent	a8bb5062f1a874d388e00a07857a053ae0961320
signature	Signed by SSH key SHA256:52mNGHRsVFBDED9IAX5pe+LRWUefqTbxEReunq21QvU (~clover)

fix(ios): refresh page listings off the main thread

A section opens with its rows read on the background thread that opens it, and a
poll reporting `listed` reads the rows again off the main thread before telling the
views; the rest of the poll (save status, remote changes, rejected edits) is posted
at once. Deleting pages releases the arrangement only once the rows are read again.
New Page, arranging and moving pages still read the rows synchronously, so Undo,
drags and Make Subpage never start from rows that miss the move. A reload or a typed
title invalidates a read in flight, which reads again rather than undo it.

Refs #144

Assisted-by: gpt-6.1-sol
Assisted-by: claude-opus-5.5

2 files changed, 57 insertions(+), 29 deletions(-)

apps
- ios
  - Snowbound
    Arranging.swift
    Notebooks.swift

apps/ios/Snowbound/Arranging.swift+4-10

 @@ -152,7 +152,7 @@ enum Arranging {
             reported = moved
             release()
             for section in Section.all where section.notebook === notebook && [from, to].contains(section.tab.path) {
-                section.listed()
+                section.reloadRows()
             }
             if moved == nil { failed("Can’t Move Page") }
         }
 @@ -242,8 +242,8 @@ enum Arranging {
             }
             if !reciprocal && !reported.isEmpty { done("Move Pages") { undo() } }
             release()
-            source.listed()
+            source.reloadRows()
-            target.listed()
+            target.reloadRows()
             if !succeeded {
                 failed("Can’t Move All Pages", reported.isEmpty
                     ? "Check both sections, then try moving the remaining pages again."
 @@ -306,14 +306,8 @@ extension Section {
     /// Puts page `id` where `order` places it, as one edit; false where it isn't listed.
     func arrange(_ order: [Placed], moving id: String) -> Bool {
         guard sb_section_arrange(handle, json(order), json([id])) else { return false }
-        listed()
-        return true
-    }
-    /// Lists the pages again and tells the views.
-    func listed() {
         reloadRows()
-        NotificationCenter.default.post(name: Self.changed, object: self, userInfo: ["flags": Self.listed])
+        return true
     }
 }

apps/ios/Snowbound/Notebooks.swift+53-19

 @@ -629,7 +629,7 @@ private struct Weak<T: AnyObject> { weak var value: T? }
 /// A section open for editing: pages listed and saved through its replica.
 final class Section {
-    /// Sent on the main thread with `flags` from `sb_section_poll` after each poll.
+    /// Sent on the main thread with `flags` from `sb_section_poll`, `listed` once the rows are read again.
     static let changed = Notification.Name("SectionChanged")
     static let listed: UInt32 = 1
     static let remote: UInt32 = 2
 @@ -642,17 +642,18 @@ final class Section {
     let tab: Tab
     let handle: OpaquePointer
     private let token: Int
-    private(set) var rows: [Row] = []
+    private(set) var rows: [Row]
     private(set) var status = SaveStatus.unknown
+    private var listing: (invalidated: Bool, completions: [() -> Void])?
     static var all: [Section] { open.values.compactMap(\.value) }
-    private init(notebook: Notebook, tab: Tab, handle: OpaquePointer, token: Int) {
+    private init(notebook: Notebook, tab: Tab, handle: OpaquePointer, token: Int, rows: [Row]) {
         self.notebook = notebook
         self.tab = tab
         self.handle = handle
         self.token = token
-        reloadRows()
+        self.rows = rows
     }
     deinit {
 @@ -671,21 +672,53 @@ final class Section {
         let token = tokens
         let pointer = Int(bitPattern: library)
         let author = Author.name ?? ""
-        background({ () -> (Int, String?) in
+        background({ () -> (Int, String?, [Row]) in
             var error: UnsafeMutablePointer<CChar>?
             let handle = sb_section_open(
                 OpaquePointer(bitPattern: pointer), tab.path, author, wakeSection, UInt(token), &error)
-            return (Int(bitPattern: handle), take(error))
+            let rows = handle.flatMap { decode([Row].self, sb_section_pages($0)) } ?? []
-        }) { handle, error in
+            return (Int(bitPattern: handle), take(error), rows)
+        }) { handle, error, rows in
             guard let handle = OpaquePointer(bitPattern: handle) else { return done(nil, error) }
-            let section = Section(notebook: notebook, tab: tab, handle: handle, token: token)
+            let section = Section(notebook: notebook, tab: tab, handle: handle, token: token, rows: rows)
             open[token] = Weak(value: section)
             done(section, nil)
+            // Wakes before `open[token]` was set went unheard.
+            section.poll()
         }
     }
+    /// Lists the pages again and tells the views.
     func reloadRows() {
+        listing?.invalidated = true
         rows = decode([Row].self, sb_section_pages(handle)) ?? rows
+        NotificationCenter.default.post(name: Self.changed, object: self, userInfo: ["flags": Self.listed])
+    }
+    /// Lists the pages again off the main thread, tells the views, then runs `then`.
+    private func refreshRows(then: @escaping () -> Void = {}) {
+        guard listing == nil else {
+            listing?.invalidated = true
+            listing?.completions.append(then)
+            return
+        }
+        listing = (false, [then])
+        readRows()
+    }
+    private func readRows() {
+        background({ [self] in decode([Row].self, sb_section_pages(handle)) }) { [self] rows in
+            // A read begun before a reload or retitle would undo it.
+            if listing!.invalidated, rows != nil {
+                listing?.invalidated = false
+                return readRows()
+            }
+            self.rows = rows ?? self.rows
+            let completions = listing!.completions
+            listing = nil
+            NotificationCenter.default.post(name: Self.changed, object: self, userInfo: ["flags": Self.listed])
+            for completion in completions { completion() }
+        }
     }
     /// The row listing page or conflict page `id`, and the version when it is one.
 @@ -701,17 +734,19 @@ final class Section {
         var status: UInt8 = 0
         let flags = sb_section_poll(handle, &status)
         let changed = SaveStatus(rawValue: status) ?? .unknown
-        let unchanged = flags == 0 && changed == self.status
+        if flags & Self.listed != 0 { refreshRows() }
+        let unlisted = flags & ~Self.listed
+        let unchanged = unlisted == 0 && changed == self.status
         self.status = changed
-        if flags & Self.listed != 0 { reloadRows() }
         NotificationCenter.default.post(
             name: Self.changed, object: self,
-            userInfo: unchanged ? ["flags": flags, "unchanged": true] : ["flags": flags])
+            userInfo: unchanged ? ["flags": unlisted, "unchanged": true] : ["flags": unlisted])
     }
     /// A page's title as typed, shown in the list before the section reports it.
     func retitle(_ id: String, _ title: String) {
         guard let index = rows.firstIndex(where: { $0.id == id }), rows[index].title != title else { return }
+        listing?.invalidated = true
         rows[index].title = title
         NotificationCenter.default.post(name: Self.changed, object: self, userInfo: ["flags": UInt32(0)])
     }
 @@ -721,7 +756,6 @@ final class Section {
         let (date, time) = titleDate()
         let id = take(sb_section_new_page(handle, parent, date, time))
         reloadRows()
-        NotificationCenter.default.post(name: Self.changed, object: self, userInfo: ["flags": Self.listed])
         return id
     }
 @@ -735,13 +769,13 @@ final class Section {
             }
             return true
         }) { [self] deleted in
-            release()
+            refreshRows {
-            reloadRows()
+                release()
-            NotificationCenter.default.post(name: Self.changed, object: self, userInfo: ["flags": Self.listed])
+                if deleted { done() }
-            if deleted { done() }
+                else {
-            else {
+                    let window = UIApplication.shared.connectedScenes.lazy.compactMap { ($0 as? UIWindowScene)?.keyWindow }.first
-                let window = UIApplication.shared.connectedScenes.lazy.compactMap { ($0 as? UIWindowScene)?.keyWindow }.first
+                    window?.rootViewController?.alert("Can’t Delete", "Some pages couldn’t be deleted. Try again.")
-                window?.rootViewController?.alert("Can’t Delete", "Some pages couldn’t be deleted. Try again.")
+                }
             }
         }
     }