Use cloud9's file-server engine instead of the private copy

src/9p.zig shrinks to an 88-line alias: the engine and the backend contract
(Req, Reply/ReplyWith, Op, Status, Attr, E, error strings) now come from
cloud9.fs. The editor's limits become cloud9.fs.Options values; the ESP32-P4
board backend drops its own copies of the contract types. No behaviour
change; fs-bench still allocates nothing per request. cloud9 re-pinned to
the commit that carries the engine.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

1 files changed, 8 insertions, 46 deletions

diff --git a/src/esp32p4_gpio.zig b/src/esp32p4_gpio.zig
index 92468581..d6c29a36 100644
--- a/src/esp32p4_gpio.zig
+++ b/src/esp32p4_gpio.zig
@@ -1,5 +1,6 @@
 //! ESP32-P4 JP1 GPIO data and its freestanding filesystem.
 const std = @import("std");
+const ninep = @import("9p.zig");
 
 // JP1: JC-ESP32P4-M3-DEV schematic, sheet 2 "Expand IO":
 // 01-esp32p4-m3/docs/schematics/2_EXPAND_IO&BAT.png
@@ -107,11 +108,7 @@ pub const Header = struct {
     }
 };
 
-pub const E = struct {
-    pub const NOENT: u16 = 2;
-    pub const NOTDIR: u16 = 20;
-    pub const INVAL: u16 = 22;
-};
+pub const E = ninep.fs.E;
 
 pub const root: u64 = 1;
 const gpio_node: u64 = 16;
@@ -167,43 +164,10 @@ const out_capacity = size: {
 pub fn Fs(comptime Pads: type) type {
     return struct {
         const Self = @This();
-        pub const name_capacity = 28;
-
-        pub const Op = enum(u8) { lookup, getattr, setattr, open, read, write, release, readdir };
-
-        pub const Status = enum(u8) { ok, again, err };
-
-        pub const Req = struct {
-            tag: u64,
-            op: Op,
-            node: u64,
-            handle: u32 = 0,
-            off: u64 = 0,
-            size: u32 = 0,
-            data: []const u8 = &.{},
-            truncate: bool = false,
-        };
-
-        pub const Reply = struct {
-            tag: u64,
-            status: Status = .ok,
-            errno: u16 = 0,
-            attr: Attr = .{},
-            handle: u32 = 0,
-            written: u32 = 0,
-
-            pub const Attr = struct {
-                name: []const u8 = "",
-                node: u64 = 0,
-                dir: bool = false,
-                size: u64 = 0,
-                mode: u16 = 0o600,
-            };
-
-            pub fn fail(tag: u64, e: u16) Reply {
-                return .{ .tag = tag, .status = .err, .errno = e };
-            }
-        };
+        pub const Op = ninep.fs.Op;
+        pub const Status = ninep.fs.Status;
+        pub const Req = ninep.fs.Req;
+        pub const Reply = ninep.fs.Reply;
 
         // Reply bytes are borrowed until the next handle call.
         pub const Answer = struct { reply: Reply, bytes: []const u8 = "" };
@@ -484,7 +448,7 @@ fn names(t: *Board, node: u64, skip: u64) ![][]const u8 {
 test "GPIO: the whole tree costs one buffer, and the table says how big" {
     try testing.expectEqual(@as(usize, 143), out_capacity);
     try testing.expectEqual(@as(usize, 143), @sizeOf(Board));
-    try testing.expectEqual(@as(usize, 28), Board.name_capacity);
+    try testing.expectEqual(@as(usize, 28), ninep.board.name_capacity);
     try testing.expect(Header.text.len > out_capacity);
 }
 
@@ -511,11 +475,9 @@ test "GPIO: stat and truncation preserve the register value and reads respect of
     try testing.expectEqualStrings(Header.text[10..22], text.bytes);
 }
 
-const ninep = @import("9p.zig");
-
 test "GPIO: a real 9P client reads a pin's value off this tree" {
     StubPads.reset();
-    const Server = ninep.Server(Board, ninep.board_fids);
+    const Server = ninep.Server(Board, ninep.board);
     var in: [1024]u8 = undefined;
     var out: [2048]u8 = undefined;
     var fsys: Board = .{};