65 lines
2.2 KiB
Zig
65 lines
2.2 KiB
Zig
// SPDX-License-Identifier: MIT
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// Copyright (c) 2015-2020 Zig Contributors
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// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
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// The MIT license requires this copyright notice to be included in all copies
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// and substantial portions of the software.
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const std = @import("../std.zig");
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const io = std.io;
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const testing = std.testing;
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/// Takes a tuple of streams, and constructs a new stream that writes to all of them
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pub fn MultiWriter(comptime Writers: type) type {
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comptime var ErrSet = error{};
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inline for (@typeInfo(Writers).Struct.fields) |field| {
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const StreamType = field.field_type;
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ErrSet = ErrSet || StreamType.Error;
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}
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return struct {
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const Self = @This();
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streams: Writers,
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pub const Error = ErrSet;
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pub const Writer = io.Writer(*Self, Error, write);
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/// Deprecated: use `Writer`
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pub const OutStream = Writer;
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pub fn writer(self: *Self) Writer {
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return .{ .context = self };
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}
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/// Deprecated: use `writer`
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pub fn outStream(self: *Self) OutStream {
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return .{ .context = self };
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}
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pub fn write(self: *Self, bytes: []const u8) Error!usize {
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var batch = std.event.Batch(Error!void, self.streams.len, .auto_async).init();
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comptime var i = 0;
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inline while (i < self.streams.len) : (i += 1) {
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const stream = self.streams[i];
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// TODO: remove ptrCast: https://github.com/ziglang/zig/issues/5258
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batch.add(@ptrCast(anyframe->Error!void, &async stream.writeAll(bytes)));
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}
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try batch.wait();
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return bytes.len;
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}
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};
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}
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pub fn multiWriter(streams: anytype) MultiWriter(@TypeOf(streams)) {
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return .{ .streams = streams };
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}
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test "MultiWriter" {
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var buf1: [255]u8 = undefined;
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var fbs1 = io.fixedBufferStream(&buf1);
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var buf2: [255]u8 = undefined;
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var fbs2 = io.fixedBufferStream(&buf2);
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var stream = multiWriter(.{ fbs1.writer(), fbs2.writer() });
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try stream.writer().print("HI", .{});
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testing.expectEqualSlices(u8, "HI", fbs1.getWritten());
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testing.expectEqualSlices(u8, "HI", fbs2.getWritten());
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}
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