Rework pub and hpub parse

support hpub in general, and properly support reply subjects

src/server/message_parser.zig

@@ -415,64 +415,82 @@ fn parsePub(alloc: std.mem.Allocator, in: *std.Io.Reader) !Message {
     const subject: []const u8 = try readSubject(alloc, in);
     errdefer alloc.free(subject);
 
-    const second = blk: {
+    const States = enum {
+        before_second,
+        in_second,
+        after_second,
+        in_third,
+        in_end,
+    };
+
+    var second: std.ArrayList(u8) = .empty;
+    defer second.deinit(alloc);
+    var third: ?std.ArrayList(u8) = null;
+    defer if (third) |*t| t.deinit(alloc);
+    var payload: std.Io.Writer.Allocating = .init(alloc);
+
+    sw: switch (@as(States, .before_second)) {
+        .before_second => {
             // Drop whitespace
-        while (in.peekByte()) |byte| {
+            const byte = try in.peekByte();
             if (std.ascii.isWhitespace(byte)) {
                 in.toss(1);
-            } else break;
+                continue :sw .before_second;
-        } else |err| return err;
-
-        var acc: std.ArrayList(u8) = .empty;
-        errdefer acc.deinit(alloc);
-        while (in.peekByte()) |byte| {
-            if (std.ascii.isWhitespace(byte)) break;
-            try acc.append(alloc, byte);
-            in.toss(1);
-        } else |err| return err;
-
-        break :blk try acc.toOwnedSlice(alloc);
-    };
-    defer alloc.free(second);
-
-    const byte_count: usize, const reply_to: ?[]const u8 =
-        if (std.fmt.parseUnsigned(usize, second, 10)) |s| blk: {
-            try expectStreamBytes(in, "\r\n");
-            break :blk .{ s, null };
-        } else |_| .{
-            blk: {
-                var byte_count_list: std.ArrayList(u8) = .empty;
-                defer byte_count_list.deinit(alloc);
-                try in.discardAll(1); // discard space
-                while (in.peekByte()) |byte| {
-                    if (std.ascii.isWhitespace(byte)) {
-                        try expectStreamBytes(in, "\r\n");
-                        break;
             }
-                    defer in.toss(1);
+            continue :sw .in_second;
-                    if (std.ascii.isDigit(byte)) {
-                        try byte_count_list.append(alloc, byte);
-                    } else {
-                        return error.InvalidStream;
-                    }
-                } else |err| return err;
-                break :blk try std.fmt.parseUnsigned(usize, byte_count_list.items, 10);
         },
-            try alloc.dupe(u8, second),
+        .in_second => {
+            const byte = try in.peekByte();
+            if (!std.ascii.isWhitespace(byte)) {
+                try second.append(alloc, byte);
+                in.toss(1);
+                continue :sw .in_second;
+            }
+            continue :sw .after_second;
+        },
+        .after_second => {
+            const byte = try in.peekByte();
+            if (byte == '\r') {
+                continue :sw .in_end;
+            } else if (std.ascii.isWhitespace(byte)) {
+                in.toss(1);
+                continue :sw .after_second;
+            }
+            third = .empty;
+            continue :sw .in_third;
+        },
+        .in_third => {
+            const byte = try in.peekByte();
+            if (byte == '\r') {
+                continue :sw .in_end;
+            } else if (std.ascii.isDigit(byte)) {
+                try third.?.append(alloc, byte);
+                in.toss(1);
+                continue :sw .in_third;
+            }
+            return error.InvalidStream;
+        },
+        .in_end => {
+            try expectStreamBytes(in, "\r\n");
+        },
+    }
+
+    const reply_to: ?[]const u8, const bytes: usize =
+        if (third) |t| .{
+            try alloc.dupe(u8, second.items),
+            try std.fmt.parseUnsigned(usize, t.items, 10),
+        } else .{
+            null,
+            try std.fmt.parseUnsigned(usize, second.items, 10),
         };
 
-    const payload = blk: {
+    try in.streamExact(&payload.writer, bytes);
-        const bytes = try alloc.alloc(u8, byte_count);
-        errdefer alloc.free(bytes);
-        try in.readSliceAll(bytes);
     try expectStreamBytes(in, "\r\n");
-        break :blk bytes;
-    };
 
     return .{
         .@"pub" = .{
             .subject = subject,
-            .payload = payload,
+            .payload = try payload.toOwnedSlice(),
             .reply_to = reply_to,
         },
     };
@@ -515,7 +533,7 @@ test parsePub {
         try std.testing.expectEqualDeep(
             Message{ .@"pub" = .{
                 .subject = "foo",
-                .reply_to = "reply.to",
+                .reply_to = "5",
                 .payload = "bar",
             } },
             res,
@@ -530,95 +548,175 @@ fn parseHPub(alloc: std.mem.Allocator, in: *std.Io.Reader) !Message {
     const subject: []const u8 = try readSubject(alloc, in);
     errdefer alloc.free(subject);
 
-    const second = blk: {
+    const States = enum {
+        before_second,
+        in_second,
+        after_second,
+        in_third,
+        after_third,
+        in_fourth,
+        in_end,
+    };
+
+    var second: std.ArrayList(u8) = .empty;
+    defer second.deinit(alloc);
+    var third: std.ArrayList(u8) = .empty;
+    defer third.deinit(alloc);
+    var fourth: ?std.ArrayList(u8) = null;
+    defer if (fourth) |*f| f.deinit(alloc);
+    var payload: std.Io.Writer.Allocating = .init(alloc);
+
+    sw: switch (@as(States, .before_second)) {
+        .before_second => {
             // Drop whitespace
-        while (in.peekByte()) |byte| {
+            const byte = try in.peekByte();
             if (std.ascii.isWhitespace(byte)) {
                 in.toss(1);
-            } else break;
+                continue :sw .before_second;
-        } else |err| return err;
-
-        var acc: std.ArrayList(u8) = .empty;
-        errdefer acc.deinit(alloc);
-        while (in.peekByte()) |byte| {
-            if (std.ascii.isWhitespace(byte)) break;
-            try acc.append(alloc, byte);
-            in.toss(1);
-        } else |err| return err;
-
-        break :blk try acc.toOwnedSlice(alloc);
-    };
-    errdefer alloc.free(second);
-
-    const header_byte_count: usize, const reply_to: ?[]const u8 =
-        if (std.fmt.parseUnsigned(usize, second, 10)) |s| blk: {
-            try expectStreamBytes(in, "\r\n");
-            break :blk .{ s, null };
-        } else |_| .{
-            blk: {
-                var byte_count_list: std.ArrayList(u8) = .empty;
-                defer byte_count_list.deinit(alloc);
-                try in.discardAll(1); // discard space
-                while (in.peekByte()) |byte| {
-                    if (std.ascii.isWhitespace(byte)) {
-                        try expectStreamBytes(in, "\r\n");
-                        break;
             }
-                    defer in.toss(1);
+            continue :sw .in_second;
-                    if (std.ascii.isDigit(byte)) {
-                        try byte_count_list.append(alloc, byte);
-                    } else {
-                        return error.InvalidStream;
-                    }
-                } else |err| return err;
-                break :blk try std.fmt.parseUnsigned(usize, byte_count_list.items, 10);
         },
-            second,
+        .in_second => {
-        };
+            const byte = try in.peekByte();
-
+            if (!std.ascii.isWhitespace(byte)) {
-    std.log.debug("buffered: '{s}'", .{in.buffered()});
+                try second.append(alloc, byte);
-
+                in.toss(1);
-    // Parse byte count
+                continue :sw .in_second;
-    const byte_count = blk: {
+            }
-        var byte_count_list: std.ArrayList(u8) = .empty;
+            continue :sw .after_second;
-        defer byte_count_list.deinit(alloc);
+        },
-        while (in.peekByte()) |byte| {
+        .after_second => {
-            if (std.ascii.isWhitespace(byte)) {
+            const byte = try in.peekByte();
-                try expectStreamBytes(in, "\r\n");
+            if (byte == '\r') {
-                break;
+                continue :sw .in_end;
+            } else if (std.ascii.isWhitespace(byte)) {
+                in.toss(1);
+                continue :sw .after_second;
+            }
+            third = .empty;
+            continue :sw .in_third;
+        },
+        .in_third => {
+            const byte = try in.peekByte();
+            if (!std.ascii.isWhitespace(byte)) {
+                try third.append(alloc, byte);
+                in.toss(1);
+                continue :sw .in_third;
+            }
+            continue :sw .after_third;
+        },
+        .after_third => {
+            const byte = try in.peekByte();
+            if (byte == '\r') {
+                continue :sw .in_end;
+            } else if (std.ascii.isWhitespace(byte)) {
+                in.toss(1);
+                continue :sw .after_third;
+            }
+            fourth = .empty;
+            continue :sw .in_fourth;
+        },
+        .in_fourth => {
+            const byte = try in.peekByte();
+            if (byte == '\r') {
+                continue :sw .in_end;
+            } else if (std.ascii.isDigit(byte)) {
+                try fourth.?.append(alloc, byte);
+                in.toss(1);
+                continue :sw .in_fourth;
             }
-            defer in.toss(1);
-
-            if (std.ascii.isDigit(byte)) {
-                try byte_count_list.append(alloc, byte);
-            } else {
             return error.InvalidStream;
-            }
+        },
-        } else |err| return err;
+        .in_end => {
-
-        break :blk try std.fmt.parseUnsigned(usize, byte_count_list.items, 10);
-    };
-
-    const payload = blk: {
-        const bytes = try alloc.alloc(u8, byte_count);
-        errdefer alloc.free(bytes);
-        try in.readSliceAll(bytes);
             try expectStreamBytes(in, "\r\n");
-        break :blk bytes;
+        },
+    }
+
+    const reply_to: ?[]const u8, const header_bytes: usize, const total_bytes: usize =
+        if (fourth) |f| .{
+            try alloc.dupe(u8, second.items),
+            try std.fmt.parseUnsigned(usize, third.items, 10),
+            try std.fmt.parseUnsigned(usize, f.items, 10),
+        } else .{
+            null,
+            try std.fmt.parseUnsigned(usize, second.items, 10),
+            try std.fmt.parseUnsigned(usize, third.items, 10),
         };
 
+    try in.streamExact(&payload.writer, total_bytes);
+    try expectStreamBytes(in, "\r\n");
+
     return .{
         .hpub = .{
-            .header_bytes = header_byte_count,
+            .header_bytes = header_bytes,
             .@"pub" = .{
                 .subject = subject,
-                .payload = payload,
+                .payload = try payload.toOwnedSlice(),
                 .reply_to = reply_to,
             },
         },
     };
 }
 
+test parseHPub {
+    {
+        var in: std.Io.Reader = .fixed(" foo 22 33\r\nNATS/1.0\r\nBar: Baz\r\n\r\nHello NATS!\r\n");
+        var res = try parseHPub(std.testing.allocator, &in);
+        defer res.hpub.deinit(std.testing.allocator);
+        try std.testing.expectEqualDeep(
+            Message{
+                .hpub = .{
+                    .header_bytes = 22,
+                    .@"pub" = .{
+                        .subject = "foo",
+                        .reply_to = null,
+                        .payload = "NATS/1.0\r\nBar: Baz\r\n\r\nHello NATS!",
+                    },
+                },
+            },
+            res,
+        );
+    }
+
+    {
+        var in: std.Io.Reader = .fixed(" foo reply.to 22 33\r\nNATS/1.0\r\nBar: Baz\r\n\r\nHello NATS!\r\n");
+        var res = try parseHPub(std.testing.allocator, &in);
+        defer res.hpub.deinit(std.testing.allocator);
+        try std.testing.expectEqualDeep(
+            Message{
+                .hpub = .{
+                    .header_bytes = 22,
+                    .@"pub" = .{
+                        .subject = "foo",
+                        .reply_to = "reply.to",
+                        .payload = "NATS/1.0\r\nBar: Baz\r\n\r\nHello NATS!",
+                    },
+                },
+            },
+            res,
+        );
+    }
+
+        {
+        var in: std.Io.Reader = .fixed(" foo 6 22 33\r\nNATS/1.0\r\nBar: Baz\r\n\r\nHello NATS!\r\n");
+        var res = try parseHPub(std.testing.allocator, &in);
+        defer res.hpub.deinit(std.testing.allocator);
+        try std.testing.expectEqualDeep(
+            Message{
+                .hpub = .{
+                    .header_bytes = 22,
+                    .@"pub" = .{
+                        .subject = "foo",
+                        .reply_to = "6",
+                        .payload = "NATS/1.0\r\nBar: Baz\r\n\r\nHello NATS!",
+                    },
+                },
+            },
+            res,
+        );
+    }
+}
+
 fn readSubject(alloc: std.mem.Allocator, in: *std.Io.Reader) ![]const u8 {
     var subject_list: std.ArrayList(u8) = try .initCapacity(alloc, 1024);
     errdefer subject_list.deinit(alloc);