diff options
Diffstat (limited to 'src/message.zig')
| -rw-r--r-- | src/message.zig | 179 |
1 files changed, 26 insertions, 153 deletions
diff --git a/src/message.zig b/src/message.zig index edccbbf..1d8d5e1 100644 --- a/src/message.zig +++ b/src/message.zig @@ -31,7 +31,8 @@ pub const Error = error{ // ZERO COPY STUFF // &payload could be a void value that is treated as a pointer to a [*]u8 -pub const ZeroCopyMessage = packed struct { +/// All Saprus messages +pub const Message = packed struct { const Relay = packed struct { dest: @Vector(4, u8), payload: void, @@ -55,14 +56,14 @@ pub const ZeroCopyMessage = packed struct { return @as([*]u8, @ptrCast(&self.payload))[0 .. len.* - @sizeOf(Connection)]; } - fn nativeFromNetworkEndian(self: *align(1) Connection) Error!void { + fn nativeFromNetworkEndian(self: *align(1) Connection) void { self.src_port = bigToNative(@TypeOf(self.src_port), self.src_port); self.dest_port = bigToNative(@TypeOf(self.dest_port), self.dest_port); self.seq_num = bigToNative(@TypeOf(self.seq_num), self.seq_num); self.msg_id = bigToNative(@TypeOf(self.msg_id), self.msg_id); } - fn networkFromNativeEndian(self: *align(1) Connection) Error!void { + fn networkFromNativeEndian(self: *align(1) Connection) void { self.src_port = nativeToBig(@TypeOf(self.src_port), self.src_port); self.dest_port = nativeToBig(@TypeOf(self.dest_port), self.dest_port); self.seq_num = nativeToBig(@TypeOf(self.seq_num), self.seq_num); @@ -81,7 +82,8 @@ pub const ZeroCopyMessage = packed struct { const header_size = @sizeOf(switch (@"type") { .relay => Relay, .connection => Connection, - else => return error.Bad, + .file_transfer => return Error.NotImplementedSaprusType, + else => return Error.UnknownSaprusType, }); const size = payload_len + @sizeOf(Self) + header_size; const bytes = try allocator.alignedAlloc(u8, @alignOf(Self), size); @@ -121,9 +123,17 @@ pub const ZeroCopyMessage = packed struct { @intFromEnum(self.type), )); self.length = bigToNative(@TypeOf(self.length), self.length); + errdefer { + // If the payload specific headers fail, revert the top level header values + self.type = @enumFromInt(nativeToBig( + @typeInfo(@TypeOf(self.type)).@"enum".tag_type, + @intFromEnum(self.type), + )); + self.length = nativeToBig(@TypeOf(self.length), self.length); + } switch (try self.getSaprusTypePayload()) { .relay => {}, - .connection => |*con| try con.*.nativeFromNetworkEndian(), + .connection => |*con| con.*.nativeFromNetworkEndian(), // We know other values are unreachable, // because they would have returned an error from the switch condition. else => unreachable, @@ -166,179 +176,42 @@ test "testing variable length zero copy struct" { const gpa = std.testing.allocator; const payload = "Hello darkness my old friend"; - // Create a view of the byte slice as a ZeroCopyMessage - const zcm: *ZeroCopyMessage = try .init(gpa, .relay, payload.len); - defer zcm.deinit(gpa); + // Create a view of the byte slice as a Message + const msg: *Message = try .init(gpa, .relay, payload.len); + defer msg.deinit(gpa); { // Set the message values { // These are both set by the init call. - // zcm.type = .relay; - // zcm.length = payload_len; + // msg.type = .relay; + // msg.length = payload_len; } - const relay = (try zcm.getSaprusTypePayload()).relay; + const relay = (try msg.getSaprusTypePayload()).relay; relay.dest = .{ 1, 2, 3, 4 }; @memcpy(relay.getPayload(), payload); } { - const bytes = zcm.asBytes(); + const bytes = msg.asBytes(); // Print the message as hex using the network byte order - try zcm.networkFromNativeEndian(); + try msg.networkFromNativeEndian(); // We know the error from nativeFromNetworkEndian is unreachable because // it would have returned an error from networkFromNativeEndian. - defer zcm.nativeFromNetworkEndian() catch unreachable; + defer msg.nativeFromNetworkEndian() catch unreachable; std.debug.print("network bytes: {x}\n", .{bytes}); std.debug.print("bytes len: {d}\n", .{bytes.len}); } if (false) { // Illegal behavior - std.debug.print("{any}\n", .{(try zcm.getSaprusTypePayload()).connection}); + std.debug.print("{any}\n", .{(try msg.getSaprusTypePayload()).connection}); } - try std.testing.expectEqualDeep(zcm, try ZeroCopyMessage.bytesAsValue(zcm.asBytes())); + try std.testing.expectEqualDeep(msg, try Message.bytesAsValue(msg.asBytes())); } -/// All Saprus messages -pub const Message = union(PacketType) { - pub const Relay = struct { - pub const Header = packed struct { - dest: @Vector(4, u8), - }; - header: Header, - payload: []const u8, - }; - pub const Connection = struct { - pub const Header = packed struct { - src_port: u16, // random number > 1024 - dest_port: u16, // random number > 1024 - seq_num: u32 = 0, - msg_id: u32 = 0, - reserved: u8 = 0, - options: ConnectionOptions = .{}, - }; - header: Header, - payload: []const u8, - }; - relay: Relay, - file_transfer: void, // unimplemented - connection: Connection, - - /// Should be called for any Message that was declared using a function that you pass an allocator to. - pub fn deinit(self: Message, allocator: Allocator) void { - switch (self) { - .relay => |r| allocator.free(r.payload), - .connection => |c| allocator.free(c.payload), - else => unreachable, - } - } - - fn toBytesAux( - header: anytype, - payload: []const u8, - buf: *std.ArrayList(u8), - allocator: Allocator, - ) !void { - const Header = @TypeOf(header); - // Create a growable string to store the base64 bytes in. - // Doing this first so I can use the length of the encoded bytes for the length field. - var payload_list = std.ArrayList(u8).init(allocator); - defer payload_list.deinit(); - const buf_w = payload_list.writer(); - - // Write the payload bytes as base64 to the growable string. - try base64Enc.encodeWriter(buf_w, payload); - - // At this point, payload_list contains the base64 encoded payload. - - // Add the payload length to the output buf. - try buf.*.appendSlice( - asBytes(&nativeToBig(u16, @intCast(payload_list.items.len + @bitSizeOf(Header) / 8))), - ); - - // Add the header bytes to the output buf. - var header_buf: [@sizeOf(Header)]u8 = undefined; - var header_buf_stream = std.io.fixedBufferStream(&header_buf); - try header_buf_stream.writer().writeStructEndian(header, .big); - // Add the exact number of bits in the header without padding. - try buf.*.appendSlice(header_buf[0 .. @bitSizeOf(Header) / 8]); - - try buf.*.appendSlice(payload_list.items); - } - - /// Caller is responsible for freeing the returned bytes. - pub fn toBytes(self: Message, allocator: Allocator) ![]u8 { - // Create a growable list of bytes to store the output in. - var buf = std.ArrayList(u8).init(allocator); - errdefer buf.deinit(); - - // Start with writing the message type, which is the first 16 bits of every Saprus message. - try buf.appendSlice(asBytes(&nativeToBig(u16, @intFromEnum(self)))); - - // Write the proper header and payload for the given packet type. - switch (self) { - .relay => |r| try toBytesAux(r.header, r.payload, &buf, allocator), - .connection => |c| try toBytesAux(c.header, c.payload, &buf, allocator), - .file_transfer => return Error.NotImplementedSaprusType, - } - - // Collect the growable list as a slice and return it. - return buf.toOwnedSlice(); - } - - fn fromBytesAux( - comptime packet: PacketType, - len: u16, - r: std.io.FixedBufferStream([]const u8).Reader, - allocator: Allocator, - ) !Message { - const Header = @field(@FieldType(Message, @tagName(packet)), "Header"); - - // Read the header for the current message type. - var header_bytes: [@sizeOf(Header)]u8 = undefined; - _ = try r.read(header_bytes[0 .. @bitSizeOf(Header) / 8]); - var header_stream = std.io.fixedBufferStream(&header_bytes); - const header = try header_stream.reader().readStructEndian(Header, .big); - - // Read the base64 bytes into a list to be able to call the decoder on it. - const payload_buf = try allocator.alloc(u8, len - @bitSizeOf(Header) / 8); - defer allocator.free(payload_buf); - _ = try r.readAll(payload_buf); - - // Create a buffer to store the payload in, and decode the base64 bytes into the payload field. - const payload = try allocator.alloc(u8, try base64Dec.calcSizeForSlice(payload_buf)); - try base64Dec.decode(payload, payload_buf); - - // Return the type of Message specified by the `packet` argument. - return @unionInit(Message, @tagName(packet), .{ - .header = header, - .payload = payload, - }); - } - - /// Caller is responsible for calling .deinit on the returned value. - pub fn fromBytes(bytes: []const u8, allocator: Allocator) !Message { - var s = std.io.fixedBufferStream(bytes); - const r = s.reader(); - - // Read packet type - const packet_type = @as(PacketType, @enumFromInt(try r.readInt(u16, .big))); - - // Read the length of the header + base64 encoded payload. - const len = try r.readInt(u16, .big); - - switch (packet_type) { - .relay => return fromBytesAux(.relay, len, r, allocator), - .connection => return fromBytesAux(.connection, len, r, allocator), - .file_transfer => return Error.NotImplementedSaprusType, - else => return Error.UnknownSaprusType, - } - } -}; - const std = @import("std"); const Allocator = std.mem.Allocator; |