Make TCP server websocket-aware

Adding HTTP & websocket awareness to the TCP server.

HTTP server handles `GET /json/version` and websocket upgrade requests.

Conceptually, websocket handling is the same code as before, but receiving
data will parse the websocket frames and writing data will wrap it in
a websocket frame.

The previous `Ctx` was split into a `Server` and a `Client`. This was
largely done to make it easy to write unit tests, since the `Client` is
a generic, all its dependencies (i.e. the server) can be mocked out. This
also makes it a bit nicer to know if there is or isn't a client (via the
server's client optional).

Added a MemoryPool for the Send object (I thought that was a nice touch!)

Removed MacOS hack on accept/conn completion usage.

Known issues:
- When framing an outgoing message, the entire message has to be duped. This
is no worse than how it was before, but it should be possible to eliminate
this in the future. Probably not part of this PR.

- Websocket parsing will reject continuation frames. I don't know of a single
client that will send a fragmented message (websocket has its own
message fragmentation), but we should probably still support this just in
case.

- I don't think the receive, timeout and close completions can safely be
re-used like we're doing. I believe they need to be associated with a specific
client socket.

- A new connection creates a new browser session. I think this is right (??),
but for the very first, we're throwing out a perfectly usable session. I'm
thinking this might be a change to how Browser/Sessions work.

- zig build test won't compile. This branch reproduces the issue with none
of these changes:
https://github.com/karlseguin/browser/tree/broken_test_build

(or, as a diff to main):
main...karlseguin:broken_test_build

Author: karlseguin

.gitmodules

@@ -28,7 +28,3 @@
 [submodule "vendor/zig-async-io"]
 	path = vendor/zig-async-io
 	url = https://github.com/lightpanda-io/zig-async-io.git/
-[submodule "vendor/websocket.zig"]
-	path = vendor/websocket.zig
-	url = https://github.com/lightpanda-io/websocket.zig.git/
-	branch = lightpanda

src/browser/loader.zig

@@ -84,7 +84,8 @@ test "basic url get" {
     var loader = Loader.init(alloc);
     defer loader.deinit();
 
-    var result = try loader.get(alloc, "https://en.wikipedia.org/wiki/Main_Page");
+    const uri = try std.Uri.parse("https://en.wikipedia.org/wiki/Main_Page");
+    var result = try loader.get(alloc, uri);
     defer result.deinit();
 
     try std.testing.expect(result.req.response.status == std.http.Status.ok);

src/cdp/runtime.zig

@@ -131,12 +131,12 @@ fn sendInspector(
             const buf = try alloc.alloc(u8, msg.json.len + 1);
             defer alloc.free(buf);
             _ = std.mem.replace(u8, msg.json, "\"awaitPromise\":true", "\"awaitPromise\":false", buf);
-            ctx.sendInspector(buf);
+            try ctx.sendInspector(buf);
             return "";
         }
     }
 
-    ctx.sendInspector(msg.json);
+    try ctx.sendInspector(msg.json);
 
     if (msg.id == null) return "";
 

src/handler.zig

@@ -24,8 +24,6 @@ const websocket = @import("websocket");
 
 const Browser = @import("browser/browser.zig").Browser;
 const server = @import("server.zig");
-const handler = @import("handler.zig");
-const MaxSize = @import("msg.zig").MaxSize;
 
 const parser = @import("netsurf");
 const apiweb = @import("apiweb.zig");
@@ -86,11 +84,9 @@ const CliMode = union(CliModeTag) {
     const Server = struct {
         execname: []const u8 = undefined,
         args: *std.process.ArgIterator = undefined,
-        addr: std.net.Address = undefined,
         host: []const u8 = Host,
         port: u16 = Port,
         timeout: u8 = Timeout,
-        tcp: bool = false, // undocumented TCP mode
 
         // default options
         const Host = "127.0.0.1";
@@ -160,10 +156,6 @@ const CliMode = union(CliModeTag) {
                     return printUsageExit(execname, 1);
                 }
             }
-            if (std.mem.eql(u8, "--tcp", opt)) {
-                _server.tcp = true;
-                continue;
-            }
 
             // unknown option
             if (std.mem.startsWith(u8, opt, "--")) {
@@ -186,10 +178,6 @@ const CliMode = union(CliModeTag) {
         if (default_mode == .server) {
 
             // server mode
-            _server.addr = std.net.Address.parseIp4(_server.host, _server.port) catch |err| {
-                log.err("address (host:port) {any}\n", .{err});
-                return printUsageExit(execname, 1);
-            };
             _server.execname = execname;
             _server.args = args;
             return CliMode{ .server = _server };
@@ -247,65 +235,19 @@ pub fn main() !void {
 
     switch (cli_mode) {
         .server => |opts| {
-
-            // Stream server
-            const addr = blk: {
-                if (opts.tcp) {
-                    break :blk opts.addr;
-                } else {
-                    const unix_path = "/tmp/lightpanda";
-                    std.fs.deleteFileAbsolute(unix_path) catch {}; // file could not exists
-                    break :blk try std.net.Address.initUnix(unix_path);
-                }
-            };
-            const socket = server.listen(addr) catch |err| {
-                log.err("Server listen error: {any}\n", .{err});
+            const address = std.net.Address.parseIp4(opts.host, opts.port) catch |err| {
+                log.err("address (host:port) {any}\n", .{err});
                 return printUsageExit(opts.execname, 1);
             };
-            defer std.posix.close(socket);
-            log.debug("Server opts: listening internally on {any}...", .{addr});
-
-            const timeout = std.time.ns_per_s * @as(u64, opts.timeout);
 
-            // loop
             var loop = try jsruntime.Loop.init(alloc);
             defer loop.deinit();
 
-            // TCP server mode
-            if (opts.tcp) {
-                return server.handle(alloc, &loop, socket, null, timeout);
-            }
-
-            // start stream server in separate thread
-            var stream = handler.Stream{
-                .ws_host = opts.host,
-                .ws_port = opts.port,
-                .addr = addr,
+            const timeout = std.time.ns_per_s * @as(u64, opts.timeout);
+            server.run(alloc, address, timeout, &loop) catch |err| {
+                log.err("Server error", .{});
+                return err;
             };
-            const cdp_thread = try std.Thread.spawn(
-                .{ .allocator = alloc },
-                server.handle,
-                .{ alloc, &loop, socket, &stream, timeout },
-            );
-
-            // Websocket server
-            var ws = try websocket.Server(handler.Handler).init(alloc, .{
-                .port = opts.port,
-                .address = opts.host,
-                .max_message_size = MaxSize + 14, // overhead websocket
-                .max_conn = 1,
-                .handshake = .{
-                    .timeout = 3,
-                    .max_size = 1024,
-                    // since we aren't using hanshake.headers
-                    // we can set this to 0 to save a few bytes.
-                    .max_headers = 0,
-                },
-            });
-            defer ws.deinit();
-
-            try ws.listen(&stream);
-            cdp_thread.join();
         },
 
         .fetch => |opts| {