async: use std http client with loop

src/async/tcp.zig

@@ -0,0 +1,62 @@
+const std = @import("std");
+const net = std.net;
+const Stream = @import("stream.zig").Stream;
+const Loop = @import("jsruntime").Loop;
+
+const ConnectCmd = struct {
+    const Self = @This();
+
+    loop: *Loop,
+    socket: std.os.socket_t,
+    err: ?anyerror = null,
+    done: bool = false,
+
+    fn run(self: *Self, addr: std.net.Address) !void {
+        self.loop.connect(*Self, self, callback, self.socket, addr);
+    }
+
+    fn callback(self: *Self, _: std.os.socket_t, err: ?anyerror) void {
+        self.err = err;
+        self.done = true;
+    }
+
+    fn wait(self: *Self) !void {
+        while (!self.done) try self.loop.tick();
+        if (self.err) |err| return err;
+    }
+};
+
+pub fn tcpConnectToHost(alloc: std.mem.Allocator, loop: *Loop, name: []const u8, port: u16) !Stream {
+    // TODO async resolve
+    const list = try net.getAddressList(alloc, name, port);
+    defer list.deinit();
+
+    if (list.addrs.len == 0) return error.UnknownHostName;
+
+    for (list.addrs) |addr| {
+        return tcpConnectToAddress(loop, addr) catch |err| switch (err) {
+            error.ConnectionRefused => {
+                continue;
+            },
+            else => return err,
+        };
+    }
+    return std.os.ConnectError.ConnectionRefused;
+}
+
+pub fn tcpConnectToAddress(loop: *Loop, addr: net.Address) !Stream {
+    const sockfd = try loop.open(addr.any.family, std.os.SOCK.STREAM, std.os.IPPROTO.TCP);
+    errdefer std.os.closeSocket(sockfd);
+
+    var cmd = ConnectCmd{
+        .loop = loop,
+        .socket = sockfd,
+    };
+    try cmd.run(addr);
+    try cmd.wait();
+
+    return Stream{
+        .loop = loop,
+        .handle = sockfd,
+    };
+}