start breaking up git struct

pkg/commands/oscommands/gui_io.go

@@ -0,0 +1,49 @@
+package oscommands
+
+import (
+	"io"
+	"io/ioutil"
+
+	"github.com/sirupsen/logrus"
+)
+
+// this struct captures some IO stuff
+type guiIO struct {
+	// this is for logging anything we want. It'll be written to a log file for the sake
+	// of debugging.
+	log *logrus.Entry
+
+	// this is for us to log the command we're about to run e.g. 'git push'. The GUI
+	// will write this to a log panel so that the user can see which commands are being
+	// run.
+	// The isCommandLineCommand arg is there so that we can style the log differently
+	// depending on whether we're directly outputting a command we're about to run that
+	// will be run on the command line, or if we're using something from Go's standard lib.
+	logCommandFn func(str string, isCommandLineCommand bool)
+	// this is for us to directly write the output of a command. We will do this for
+	// certain commands like 'git push'. The GUI will write this to a command output panel.
+	// We need a new cmd writer per command, hence it being a function.
+	newCmdWriterFn func() io.Writer
+	// this allows us to request info from the user like username/password, in the event
+	// that a command requests it.
+	// the 'credential' arg is something like 'username' or 'password'
+	promptForCredentialFn func(credential string) string
+}
+
+func NewGuiIO(log *logrus.Entry, logCommandFn func(string, bool), newCmdWriterFn func() io.Writer, promptForCredentialFn func(string) string) *guiIO {
+	return &guiIO{
+		log:                   log,
+		logCommandFn:          logCommandFn,
+		newCmdWriterFn:        newCmdWriterFn,
+		promptForCredentialFn: promptForCredentialFn,
+	}
+}
+
+func NewNullGuiIO(log *logrus.Entry) *guiIO {
+	return &guiIO{
+		log:                   log,
+		logCommandFn:          func(string, bool) {},
+		newCmdWriterFn:        func() io.Writer { return ioutil.Discard },
+		promptForCredentialFn: func(string) string { return "" },
+	}
+}