Matthew R. Wilson
b6fa48f37f
This is a relatively big new feature, which introduces small breaking changes to the API: * NegotiateTelnet() now returns (DevInfo, error) instead of just error. The function signature for the Tx type now has one additional DevInfo parameter. * RunTransactions() requires one additional parameter, the DevInfo (which is allowed to be nil). Otherwise, existing behavior continues to work as-is and everything still defaults to operating on the default 24x80 terminal size. See example5 for a larger-terminal-aware application. Pending some time to make sure no new bugs cropped up in this release and that the alternate screen size support works in the wild, I anticipate this will become the v1.0.0 release of go3270.
58 lines
2.0 KiB
Go
58 lines
2.0 KiB
Go
// This file is part of https://github.com/racingmars/go3270/
|
|
// Copyright 2025 by Matthew R. Wilson, licensed under the MIT license.
|
|
// See LICENSE in the project root for license information.
|
|
|
|
package go3270
|
|
|
|
import "net"
|
|
|
|
// Tx is a function that serves as one transaction in a go3270 application.
|
|
// The Tx function is called with the network connection to the client, the
|
|
// DevInfo for use with alternate screen writes, and a "data" value provided
|
|
// by the previous transaction. Tx functions return the next transaction to
|
|
// run (or nil to indicate the RunTransactions() function should terminate),
|
|
// the data to pass into the next transaction, and any error. If the error is
|
|
// non-nil, the RunTransactions() function will terminate and return the err.
|
|
// A non-nil error is _not_ passed between transactions, it terminates
|
|
// transaction processing.
|
|
type Tx func(conn net.Conn, dev DevInfo, data any) (
|
|
next Tx, newdata any, err error)
|
|
|
|
// RunTransactions begins running transaction functions, starting with the
|
|
// initial transaction, until a transaction eventually returns nil for the
|
|
// next transaction, or until a transaction function returns a non-nil error
|
|
// value. data (which may be nil, if the initial transaction does not require
|
|
// data) is passed in as the data to the initial transaction.
|
|
//
|
|
// dev is the DevInfo of the connected client, as obtained from
|
|
// NegotiateTelnet(). It is safe to pass a nil DevInfo, in which case all
|
|
// transactions will only be able to operate with the default 24x80 screen
|
|
// size.
|
|
func RunTransactions(conn net.Conn, dev DevInfo, initial Tx,
|
|
data any) error {
|
|
|
|
var next Tx
|
|
var err error
|
|
|
|
next = initial
|
|
|
|
if dev == nil {
|
|
dev = &deviceInfo{rows: 24, cols: 80, termtype: "DEFAULT"}
|
|
}
|
|
|
|
// We run transactions until there isn't a next transaction to run, or
|
|
// an error.
|
|
for {
|
|
next, data, err = next(conn, dev, data)
|
|
if err != nil {
|
|
// Error means we bail out and return the error to the caller.
|
|
return err
|
|
}
|
|
|
|
if next == nil {
|
|
// nil next transaction means we're done.
|
|
return nil
|
|
}
|
|
}
|
|
}
|