Use client allocator to own incoming messages to a client

src/server/Client.zig

@@ -10,6 +10,8 @@ pub const Msgs = union(enum) {
 };
 
 connect: ?Message.Connect,
+// Used to own messages that we receive in our queues.
+alloc: std.mem.Allocator,
 
 // Messages for this client to receive.
 recv_queue: *Queue(Message),
@@ -20,6 +22,7 @@ to_client: *std.Io.Writer,
 
 pub fn init(
     connect: ?Message.Connect,
+    alloc: std.mem.Allocator,
     recv_queue: *Queue(Message),
     msg_queue: *Queue(Msgs),
     in: *std.Io.Reader,
@@ -27,6 +30,7 @@ pub fn init(
 ) Client {
     return .{
         .connect = connect,
+        .alloc = alloc,
         .recv_queue = recv_queue,
         .msg_queue = msg_queue,
         .from_client = in,
@@ -41,7 +45,7 @@ pub fn deinit(self: *Client, alloc: std.mem.Allocator) void {
     self.* = undefined;
 }
 
-pub fn start(self: *Client, io: std.Io, alloc: std.mem.Allocator) !void {
+pub fn start(self: *Client, io: std.Io) !void {
     var msgs_buf: [1024]Msgs = undefined;
 
     var recv_msgs_task = io.concurrent(Queue(Msgs).get, .{ self.msg_queue, io, &msgs_buf, 1 }) catch @panic("Concurrency unavailable");
@@ -58,15 +62,15 @@ pub fn start(self: *Client, io: std.Io, alloc: std.mem.Allocator) !void {
                 for (0..msgs.len) |i| {
                     const msg = msgs[i];
                     defer switch (msg) {
-                        .MSG => |m| m.deinit(alloc),
+                        .MSG => |m| m.deinit(self.alloc),
-                        .HMSG => |h| h.deinit(alloc),
+                        .HMSG => |h| h.deinit(self.alloc),
                     };
                     errdefer for (msgs[i + 1 ..]) |mg| switch (mg) {
                         .MSG => |m| {
-                            m.deinit(alloc);
+                            m.deinit(self.alloc);
                         },
                         .HMSG => |h| {
-                            h.deinit(alloc);
+                            h.deinit(self.alloc);
                         },
                     };
                     switch (msg) {

src/server/Server.zig

@@ -19,11 +19,16 @@ pub const Client = @import("./Client.zig");
 const Msgs = Client.Msgs;
 const Server = @This();
 
+const builtin = @import("builtin");
+const safe_build = builtin.mode == .Debug or builtin.mode == .ReleaseSafe;
+
 pub const Subscription = struct {
     subject: []const u8,
     client_id: usize,
     sid: []const u8,
     queue: *Queue(Msgs),
+    // used to alloc messages in the queue
+    alloc: Allocator,
 
     fn deinit(self: Subscription, alloc: Allocator) void {
         alloc.free(self.subject);
@@ -47,6 +52,7 @@ pub fn deinit(server: *Server, io: Io, alloc: Allocator) void {
     for (server.subscriptions.items) |sub| {
         sub.deinit(alloc);
     }
+    // TODO drain subscription queues
     server.subscriptions.deinit(alloc);
     server.clients.deinit(alloc);
 }
@@ -135,44 +141,44 @@ fn handleConnection(
 ) !void {
     defer stream.close(io);
 
-    // TODO: use a client allocator for things that should only live for as long as the client?
+    var dba: std.heap.DebugAllocator(.{}) = .init;
-    // I had this before, but it seemed to have made lifetimes harder to track.
+    dba.backing_allocator = server_allocator;
-    // Messages made sense to parse using a client allocator, but that makes it hard to free
+    defer _ = dba.deinit();
-    // messages when done processing them (usually outside the client process, ie: publish).
+    const alloc = if (safe_build) dba.allocator() else server_allocator;
 
     // Set up client writer
-    const w_buffer: []u8 = try server_allocator.alloc(u8, w_buf_size);
+    const w_buffer: []u8 = try alloc.alloc(u8, w_buf_size);
-    defer server_allocator.free(w_buffer);
+    defer alloc.free(w_buffer);
     var writer = stream.writer(io, w_buffer);
     const out = &writer.interface;
 
     // Set up client reader
-    const r_buffer: []u8 = try server_allocator.alloc(u8, r_buf_size);
+    const r_buffer: []u8 = try alloc.alloc(u8, r_buf_size);
-    defer server_allocator.free(r_buffer);
+    defer alloc.free(r_buffer);
     var reader = stream.reader(io, r_buffer);
     const in = &reader.interface;
 
     // Set up buffer queue
-    const qbuf: []Message = try server_allocator.alloc(Message, 16);
+    const qbuf: []Message = try alloc.alloc(Message, 16);
-    defer server_allocator.free(qbuf);
+    defer alloc.free(qbuf);
     var recv_queue: Queue(Message) = .init(qbuf);
     defer recv_queue.close(io);
 
-    const mbuf: []Msgs = try server_allocator.alloc(Msgs, w_buf_size / @sizeOf(Msgs));
+    const mbuf: []Msgs = try alloc.alloc(Msgs, w_buf_size / @sizeOf(Msgs));
-    defer server_allocator.free(mbuf);
+    defer alloc.free(mbuf);
     var msgs_queue: Queue(Msgs) = .init(mbuf);
     defer {
         msgs_queue.close(io);
         while (msgs_queue.getOne(io)) |msg| {
             switch (msg) {
-                .MSG => |m| m.deinit(server_allocator),
+                .MSG => |m| m.deinit(alloc),
-                .HMSG => |h| h.deinit(server_allocator),
+                .HMSG => |h| h.deinit(alloc),
             }
         } else |_| {}
     }
 
     // Create client
-    var client: Client = .init(null, &recv_queue, &msgs_queue, in, out);
+    var client: Client = .init(null, alloc, &recv_queue, &msgs_queue, in, out);
     defer client.deinit(server_allocator);
 
     try server.addClient(server_allocator, id, &client);
@@ -182,7 +188,7 @@ fn handleConnection(
     // try recv_queue.putOne(io, .PONG);
     try recv_queue.putOne(io, .{ .INFO = server.info });
 
-    var client_task = try io.concurrent(Client.start, .{ &client, io, server_allocator });
+    var client_task = try io.concurrent(Client.start, .{ &client, io });
     defer client_task.cancel(io) catch {};
 
     // Messages are owned by the server after they are received from the client
@@ -195,16 +201,16 @@ fn handleConnection(
             .PUB => |pb| {
                 @branchHint(.likely);
                 defer pb.deinit(server_allocator);
-                try server.publishMessage(io, server_allocator, &client, msg);
+                try server.publishMessage(io, &client, msg);
             },
             .HPUB => |hp| {
                 @branchHint(.likely);
                 defer hp.deinit(server_allocator);
-                try server.publishMessage(io, server_allocator, &client, msg);
+                try server.publishMessage(io, &client, msg);
             },
             .SUB => |sub| {
                 defer sub.deinit(server_allocator);
-                try server.subscribe(io, server_allocator, id, &msgs_queue, sub);
+                try server.subscribe(io, server_allocator, client, id, sub);
             },
             .UNSUB => |unsub| {
                 defer unsub.deinit(server_allocator);
@@ -264,7 +270,7 @@ test subjectMatches {
     try expect(subjectMatches("foo.>", "foo.bar.baz"));
 }
 
-fn publishMessage(server: *Server, io: Io, alloc: Allocator, source_client: *Client, msg: Message) !void {
+fn publishMessage(server: *Server, io: Io, source_client: *Client, msg: Message) !void {
     defer if (source_client.connect) |c| {
         if (c.verbose) {
             source_client.send(io, .@"+OK") catch {};
@@ -283,12 +289,12 @@ fn publishMessage(server: *Server, io: Io, alloc: Allocator, source_client: *Cli
             switch (msg) {
                 .PUB => |pb| {
                     try subscription.queue.putOne(io, .{
-                        .MSG = try pb.toMsg(alloc, subscription.sid),
+                        .MSG = try pb.toMsg(subscription.alloc, subscription.sid),
                     });
                 },
                 .HPUB => |hp| {
                     try subscription.queue.putOne(io, .{
-                        .HMSG = try hp.toHMsg(alloc, subscription.sid),
+                        .HMSG = try hp.toHMsg(subscription.alloc, subscription.sid),
                     });
                 },
                 else => unreachable,
@@ -301,8 +307,8 @@ fn subscribe(
     server: *Server,
     io: Io,
     gpa: Allocator,
+    client: Client,
     id: usize,
-    queue: *Queue(Msgs),
     msg: Message.Sub,
 ) !void {
     try server.subs_lock.lock(io);
@@ -315,7 +321,8 @@ fn subscribe(
         .subject = subject,
         .client_id = id,
         .sid = sid,
-        .queue = queue,
+        .queue = client.msg_queue,
+        .alloc = client.alloc,
     });
 }