pardes - keeps one +Pager per directory, refilled, named so from its first log record; streams the text in bounded writes; never loses it; handles \r, NUL and BEL as a terminal does

Each paged command made another +Pager until placement failed, and
then git's text was lost with exit 0; a 130 MB page timed out half
written and dirty; a directory whose name held a newline left a stray
+New; and the log said new +New then rename. The root ctl's `pager
<dir>` now makes the directory's +Pager (named before it is announced,
placed without the keyboard) or empties the one there; the text goes
into it a line-ended 8 MiB chunk a write, one undo step, up to the file
limit and its note, and is left clean. A directory a ctl line cannot
name pages into the session's. Any failure prints the text to stderr
with why and exits 1. A carriage return keeps a progress line's last
state and CRLF is a newline; NUL, BEL, SO and SI go; empty stdin makes
no pane.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/ninep/ctl.zig b/src/ninep/ctl.zig
index fd3418a1..82001f32 100644
--- a/src/ninep/ctl.zig
+++ b/src/ninep/ctl.zig
@@ -642,6 +642,18 @@ pub fn writeRoot(p: *Pardes, req: Req) Reply {
         var it = Messages.init(p, req.data);
         while (it.next()) |line| {
             if (line.len == 0 or exec_line.isComment(line)) continue;
+            // `pardes -`'s: the directory's +Pager made or emptied, its
+            // serial what /exec reads back.
+            if (std.mem.startsWith(u8, line, "pager ") or std.mem.eql(u8, line, "pager")) {
+                if (!apply) continue;
+                const id = pardes.panes.Output.openPager(p, p.active, std.mem.trim(u8, line["pager".len..], " \t")) catch |err|
+                    return tree.failText(req.tag, if (err == error.NoPaneRoom or err == error.NoPaneSlots) E.NOSPC else E.IO, switch (err) {
+                        error.NoPaneRoom, error.NoPaneSlots => "pager: no space for a +Pager pane",
+                        else => "pager: could not make a +Pager pane",
+                    });
+                noteResult(p, p.panes[id].?.serial);
+                continue;
+            }
             if (std.mem.startsWith(u8, line, "size ") or std.mem.eql(u8, line, "size")) {
                 const size = sizeOf(line) orelse return refuse(p, req, e_size, line);
                 // A frontend's window is the size; only a session none is