The hosts' Save, Dump and DumpThemes writes and their shell reaper are host_io's, once, where the tty, the gui and the detached session each had a copy

writeFile, writeDump and dumpThemes were byte-for-byte the same in tty.zig, gui.zig and detached/server.zig but for how each reaches its core, and the gui's and the session's reapers the same but for a pid <= 0 against == 0 (a pid is never negative there). Each vtable entry is now a line calling host_io's. ttyTaken, fgName, killJob and ptyResize stay each shell's: they are already one call to host_io each, and what differs is how a shell reaches its pty (an optional with a file, an optional with an fd, a bounds-checked array). macos.zig keeps its copies (no macOS build here to check it). No behaviour changes.

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

4 files changed, 66 insertions, 99 deletions

diff --git a/src/detached/server.zig b/src/detached/server.zig
index de26db13..d8379793 100644
--- a/src/detached/server.zig
+++ b/src/detached/server.zig
@@ -587,24 +587,11 @@ pub const Session = struct {
 
     fn writeFile(ctx: ?*anyopaque, pane: u8, path: []const u8, bytes: []const u8) void {
         const s = of(ctx);
-        filesystem.write(s.core, path, bytes) catch |err|
-            return s.core.saveFailed(pane, path, err);
-        if (s.core.panes[pane]) |pn| if (pn.file) |f| if (std.mem.eql(u8, f.path, path)) {
-            if (s.watches[pane]) |*w| if (w.serial == pn.serial) switch (w.generation) {
-                .text => w.generation = .{ .text = std.hash.Wyhash.hash(0, bytes) },
-                .pdf => {},
-            };
-        };
-        var mbuf: [256]u8 = undefined;
-        s.core.setMessage(pane, message.stamp(&mbuf, "saved", path));
+        host_io.writeFile(s.core, &s.watches, pane, path, bytes);
     }
 
     fn writeDump(ctx: ?*anyopaque, bytes: []const u8) void {
-        const s = of(ctx);
-        var pbuf: [1024:0]u8 = undefined;
-        const path = pardes.dump.outPath(&pbuf, s.core.settings.dump_dir.get()) orelse return s.core.dumpFailed(s.core.settings.dump_dir.get(), error.NoDumpDirectory);
-        filesystem.write(s.core, path, bytes) catch |err| return s.core.dumpFailed(path, err);
-        s.core.setLastDump(path);
+        host_io.writeDump(of(ctx).core, bytes);
     }
 
     fn watchFile(ctx: ?*anyopaque, pane: u8, _: []const u8, on: bool, mode: pardes.WatchMode) void {
@@ -621,14 +608,7 @@ pub const Session = struct {
 
     fn dumpThemes(ctx: ?*anyopaque, pane: u8) void {
         const s = of(ctx);
-        const config_dir = s.core.opts.config_dir orelse return;
-        const out_dir = pardes.config.User.dumpThemes(s.io, s.gpa, config_dir, pardes.themes) catch |err| {
-            s.core.reportError(pane, "dump themes", err);
-            return;
-        };
-        defer s.gpa.free(out_dir);
-        var mbuf: [256]u8 = undefined;
-        s.core.setMessage(pane, message.stamp(&mbuf, "dumped themes", out_dir));
+        host_io.dumpThemes(s.core, s.io, s.gpa, pane);
     }
 
     fn setClipboard(ctx: ?*anyopaque, text: []const u8) void {
@@ -761,20 +741,8 @@ pub const Session = struct {
 
     fn harvest(s: *Session) void {
         const now = monotonicMs();
-        for (&s.retired_shells) |*shell| reapShell(&shell.pid, &shell.kill_at, now);
-        for (&s.ptys) |*pty| if (pty.fd < 0) reapShell(&pty.pid, &pty.kill_at, now);
-    }
-
-    fn reapShell(pid: *posix.pid_t, kill_at: *i64, now: i64) void {
-        if (pid.* == 0) return;
-        const result = libc.waitpid(pid.*, null, libc.W.NOHANG);
-        if (result > 0 or (result < 0 and libc.errno(result) == .CHILD)) {
-            pid.* = 0;
-            kill_at.* = 0;
-        } else if (kill_at.* != 0 and now >= kill_at.*) {
-            _ = libc.kill(pid.*, libc.SIG.KILL);
-            kill_at.* = 0;
-        }
+        for (&s.retired_shells) |*shell| host_io.reapRetired(&shell.pid, &shell.kill_at, now);
+        for (&s.ptys) |*pty| if (pty.fd < 0) host_io.reapRetired(&pty.pid, &pty.kill_at, now);
     }
 
     fn inotify(s: *Session) c_int {
diff --git a/src/gui/gui.zig b/src/gui/gui.zig
index 8b100cd8..8fd8d360 100644
--- a/src/gui/gui.zig
+++ b/src/gui/gui.zig
@@ -4060,9 +4060,9 @@ const Shell = struct {
 
     fn reap(s: *Shell) void {
         const now = shellClock();
-        for (&s.retired_shells) |*child| reapShell(&child.pid, &child.kill_at, now);
+        for (&s.retired_shells) |*child| host_io.reapRetired(&child.pid, &child.kill_at, now);
         for (s.ptys) |*slot| if (slot.*) |*pt| if (pt.fd < 0) {
-            reapShell(&pt.pid, &pt.kill_at, now);
+            host_io.reapRetired(&pt.pid, &pt.kill_at, now);
             if (pt.pid == 0) slot.* = null;
         };
     }
@@ -4085,7 +4085,7 @@ const Shell = struct {
         _ = libc.close(pt.fd);
         pt.fd = -1;
         const now = shellClock();
-        reapShell(&pt.pid, &pt.kill_at, now);
+        host_io.reapRetired(&pt.pid, &pt.kill_at, now);
         if (pt.pid == 0) {
             s.ptys[pane] = null;
             return;
@@ -4662,25 +4662,11 @@ fn killJob(ctx: ?*anyopaque, pane: u8) bool {
 
 fn writeFile(ctx: ?*anyopaque, pane: u8, path: []const u8, bytes: []const u8) void {
     const s = shellOf(ctx);
-    filesystem.write(s.core, path, bytes) catch |err|
-        return s.core.saveFailed(pane, path, err);
-    if (s.core.panes[pane]) |pane_state| if (pane_state.file) |f| {
-        if (std.mem.eql(u8, f.path, path))
-            if (s.watches[pane]) |*w| if (w.serial == pane_state.serial) switch (w.generation) {
-                .text => w.generation = .{ .text = std.hash.Wyhash.hash(0, bytes) },
-                .pdf => {},
-            };
-    };
-    var mbuf: [256]u8 = undefined;
-    s.core.setMessage(pane, message.stamp(&mbuf, "saved", path));
+    host_io.writeFile(s.core, s.watches, pane, path, bytes);
 }
 
 fn writeDump(ctx: ?*anyopaque, bytes: []const u8) void {
-    const s = shellOf(ctx);
-    var pbuf: [1024:0]u8 = undefined;
-    const path = pardes.dump.outPath(&pbuf, s.core.settings.dump_dir.get()) orelse return s.core.dumpFailed(s.core.settings.dump_dir.get(), error.NoDumpDirectory);
-    filesystem.write(s.core, path, bytes) catch |err| return s.core.dumpFailed(path, err);
-    s.core.setLastDump(path);
+    host_io.writeDump(shellOf(ctx).core, bytes);
 }
 
 fn watchFile(ctx: ?*anyopaque, pane: u8, _: []const u8, on: bool, mode: pardes.WatchMode) void {
@@ -4704,14 +4690,7 @@ fn watchTheme(ctx: ?*anyopaque, generation: u32, on: bool) void {
 
 fn dumpThemes(ctx: ?*anyopaque, pane: u8) void {
     const s = shellOf(ctx);
-    const config_dir = s.core.opts.config_dir orelse return;
-    const out_dir = config.User.dumpThemes(s.io, s.gpa, config_dir, pardes.themes) catch |err| {
-        s.core.reportError(pane, "dump themes", err);
-        return;
-    };
-    defer s.gpa.free(out_dir);
-    var mbuf: [256]u8 = undefined;
-    s.core.setMessage(pane, message.stamp(&mbuf, "dumped themes", out_dir));
+    host_io.dumpThemes(s.core, s.io, s.gpa, pane);
 }
 
 fn putClipboard(gpa: std.mem.Allocator, text: []const u8) void {
@@ -4826,18 +4805,6 @@ fn shellClock() i64 {
     return @as(i64, ts.sec) * std.time.ms_per_s + @divTrunc(ts.nsec, std.time.ns_per_ms);
 }
 
-fn reapShell(pid: *libc.pid_t, kill_at: *i64, now: i64) void {
-    if (pid.* <= 0) return;
-    const result = libc.waitpid(pid.*, null, libc.W.NOHANG);
-    if (result > 0 or (result < 0 and libc.errno(result) == .CHILD)) {
-        pid.* = 0;
-        kill_at.* = 0;
-    } else if (kill_at.* != 0 and now >= kill_at.*) {
-        _ = libc.kill(pid.*, libc.SIG.KILL);
-        kill_at.* = 0;
-    }
-}
-
 fn accumulateWheelDelta(pending: f32, raw_y: f32) f32 {
     if (!std.math.isFinite(raw_y)) return pending;
     const next = pending - raw_y;
diff --git a/src/host_io.zig b/src/host_io.zig
index 05ccca09..ac25e63c 100644
--- a/src/host_io.zig
+++ b/src/host_io.zig
@@ -5,6 +5,7 @@ const libc = std.c;
 const pardes = @import("pardes.zig");
 const ninep_io = @import("9p_io.zig");
 const filesystem = @import("fs.zig");
+const file_watch = @import("file_watch.zig");
 
 pub const Host = struct {
     ctx: ?*anyopaque = null,
@@ -2522,3 +2523,54 @@ test "a full-screen program takes the tty until it quits" {
     }
     if (ran == 0) return error.SkipZigTest;
 }
+
+// ---- what every host's vtable does alike ----
+
+/// A Save's write: the file written through the core's filesystem, the
+/// pane's watch told the new text is the editor's own (so it is no outside
+/// change), and "saved" said on the pane.
+pub fn writeFile(core: *pardes.Pardes, watches: *file_watch.Table, pane: u8, path: []const u8, bytes: []const u8) void {
+    filesystem.write(core, path, bytes) catch |err|
+        return core.saveFailed(pane, path, err);
+    if (core.panes[pane]) |pn| if (pn.file) |f| if (std.mem.eql(u8, f.path, path)) {
+        if (watches[pane]) |*w| if (w.serial == pn.serial) switch (w.generation) {
+            .text => w.generation = .{ .text = std.hash.Wyhash.hash(0, bytes) },
+            .pdf => {},
+        };
+    };
+    var mbuf: [256]u8 = undefined;
+    core.setMessage(pane, pardes.Messages.Message.stamp(&mbuf, "saved", path));
+}
+
+/// A Dump's write, into the DumpDir.
+pub fn writeDump(core: *pardes.Pardes, bytes: []const u8) void {
+    var pbuf: [1024:0]u8 = undefined;
+    const path = pardes.dump.outPath(&pbuf, core.settings.dump_dir.get()) orelse return core.dumpFailed(core.settings.dump_dir.get(), error.NoDumpDirectory);
+    filesystem.write(core, path, bytes) catch |err| return core.dumpFailed(path, err);
+    core.setLastDump(path);
+}
+
+/// DumpThemes: the built-in themes written below the config directory.
+pub fn dumpThemes(core: *pardes.Pardes, io: std.Io, gpa: std.mem.Allocator, pane: u8) void {
+    const config_dir = core.opts.config_dir orelse return;
+    const out_dir = pardes.config.User.dumpThemes(io, gpa, config_dir, pardes.themes) catch |err| {
+        core.reportError(pane, "dump themes", err);
+        return;
+    };
+    defer gpa.free(out_dir);
+    var mbuf: [256]u8 = undefined;
+    core.setMessage(pane, pardes.Messages.Message.stamp(&mbuf, "dumped themes", out_dir));
+}
+
+/// A retired shell reaped once it has exited, killed once its grace is up.
+pub fn reapRetired(pid: *std.c.pid_t, kill_at: *i64, now: i64) void {
+    if (pid.* <= 0) return;
+    const result = std.c.waitpid(pid.*, null, std.c.W.NOHANG);
+    if (result > 0 or (result < 0 and std.c.errno(result) == .CHILD)) {
+        pid.* = 0;
+        kill_at.* = 0;
+    } else if (kill_at.* != 0 and now >= kill_at.*) {
+        _ = std.c.kill(pid.*, std.c.SIG.KILL);
+        kill_at.* = 0;
+    }
+}
diff --git a/src/tty/tty.zig b/src/tty/tty.zig
index 3441bc29..ef7f2761 100644
--- a/src/tty/tty.zig
+++ b/src/tty/tty.zig
@@ -1791,24 +1791,11 @@ const Shell = struct {
 
     fn writeFile(ctx: ?*anyopaque, pane: u8, path: []const u8, bytes: []const u8) void {
         const s = of(ctx);
-        filesystem.write(s.core, path, bytes) catch |err|
-            return s.core.saveFailed(pane, path, err);
-        if (s.core.panes[pane]) |pn| if (pn.file) |f| if (std.mem.eql(u8, f.path, path)) {
-            if (s.watches[pane]) |*w| if (w.serial == pn.serial) switch (w.generation) {
-                .text => w.generation = .{ .text = std.hash.Wyhash.hash(0, bytes) },
-                .pdf => {},
-            };
-        };
-        var mbuf: [256]u8 = undefined;
-        s.core.setMessage(pane, message.stamp(&mbuf, "saved", path));
+        host_io.writeFile(s.core, &s.watches, pane, path, bytes);
     }
 
     fn writeDump(ctx: ?*anyopaque, bytes: []const u8) void {
-        const s = of(ctx);
-        var pbuf: [1024:0]u8 = undefined;
-        const path = pardes.dump.outPath(&pbuf, s.core.settings.dump_dir.get()) orelse return s.core.dumpFailed(s.core.settings.dump_dir.get(), error.NoDumpDirectory);
-        filesystem.write(s.core, path, bytes) catch |err| return s.core.dumpFailed(path, err);
-        s.core.setLastDump(path);
+        host_io.writeDump(of(ctx).core, bytes);
     }
 
     fn watchFile(ctx: ?*anyopaque, pane: u8, _: []const u8, on: bool, mode: pardes.WatchMode) void {
@@ -1825,14 +1812,7 @@ const Shell = struct {
 
     fn dumpThemes(ctx: ?*anyopaque, pane: u8) void {
         const s = of(ctx);
-        const config_dir = s.core.opts.config_dir orelse return;
-        const out_dir = pardes.config.User.dumpThemes(s.io, s.gpa, config_dir, pardes.themes) catch |err| {
-            s.core.reportError(pane, "dump themes", err);
-            return;
-        };
-        defer s.gpa.free(out_dir);
-        var mbuf: [256]u8 = undefined;
-        s.core.setMessage(pane, message.stamp(&mbuf, "dumped themes", out_dir));
+        host_io.dumpThemes(s.core, s.io, s.gpa, pane);
     }
 
     fn setClipboard(ctx: ?*anyopaque, text: []const u8) void {