fileReadStreamingPosix

fn fileReadStreamingPosix(file: File, data: []const []u8) File.ReadStreamingError!usize

File

Code

fn fileReadStreamingPosix(file: File, data: []const []u8) File.ReadStreamingError!usize {
    var iovecs_buffer: [max_iovecs_len]posix.iovec = undefined;
    var i: usize = 0;
    for (data) |buf| {
        if (iovecs_buffer.len - i == 0) break;
        if (buf.len != 0) {
            iovecs_buffer[i] = .{ .base = buf.ptr, .len = buf.len };
            i += 1;
        }
    }
    if (i == 0) return 0;
    const dest = iovecs_buffer[0..i];
    assert(dest[0].len > 0);

    if (native_os == .wasi and !builtin.link_libc) {
        const syscall: Syscall = try .start();
        while (true) {
            var nread: usize = undefined;
            switch (std.os.wasi.fd_read(file.handle, dest.ptr, dest.len, &nread)) {
                .SUCCESS => {
                    syscall.finish();
                    if (nread == 0) return error.EndOfStream;
                    return nread;
                },
                .INTR, .TIMEDOUT => {
                    try syscall.checkCancel();
                    continue;
                },
                .BADF => return syscall.fail(error.IsDir), // File operation on directory.
                .IO => return syscall.fail(error.InputOutput),
                .ISDIR => return syscall.fail(error.IsDir),
                .NOBUFS => return syscall.fail(error.SystemResources),
                .NOMEM => return syscall.fail(error.SystemResources),
                .NOTCONN => return syscall.fail(error.SocketUnconnected),
                .CONNRESET => return syscall.fail(error.ConnectionResetByPeer),
                .NOTCAPABLE => return syscall.fail(error.AccessDenied),
                .INVAL => |err| return syscall.errnoBug(err),
                .FAULT => |err| return syscall.errnoBug(err),
                else => |err| return syscall.unexpectedErrno(err),
            }
        }
    }

    const syscall: Syscall = try .start();
    while (true) {
        const rc = posix.system.readv(file.handle, dest.ptr, @intCast(dest.len));
        switch (posix.errno(rc)) {
            .SUCCESS => {
                syscall.finish();
                if (rc == 0) return error.EndOfStream;
                return @intCast(rc);
            },
            .INTR, .TIMEDOUT => {
                try syscall.checkCancel();
                continue;
            },
            .BADF => {
                syscall.finish();
                if (native_os == .wasi) return error.IsDir; // File operation on directory.
                return error.NotOpenForReading;
            },
            .AGAIN => return syscall.fail(error.WouldBlock),
            .IO => return syscall.fail(error.InputOutput),
            .ISDIR => return syscall.fail(error.IsDir),
            .NOBUFS => return syscall.fail(error.SystemResources),
            .NOMEM => return syscall.fail(error.SystemResources),
            .NOTCONN => return syscall.fail(error.SocketUnconnected),
            .CONNRESET => return syscall.fail(error.ConnectionResetByPeer),
            .INVAL => |err| return syscall.errnoBug(err),
            .FAULT => |err| return syscall.errnoBug(err),
            else => |err| return syscall.unexpectedErrno(err),
        }
    }
}