Go fix tool for client API changes.

README.md

@@ -11,7 +11,8 @@ There is some example code that demonstrates usage of the library in `client.go`
 
 Please note: this branch has been feature-frozen for a while. Check out master
 for some interesting (but not backwards-compatible) changes that will become
-the new go1 branch when they're stable.
+the new go1 branch when they're stable. See `fix/goirc.go` and the README there
+for a quick way to migrate.
 
 ### Using the framework
 

fix/README.md

@@ -0,0 +1,35 @@
+## client api changes
+
+`goirc.go` is a fix compatible with `go tool fix` that attempts to
+programaticallly change old client code to work with the newer, shinier
+API. It might even work, depending on the complexity of your code. You'll
+need to have a Go source tree in the path specified by GOROOT. GOOS and
+GOARCH may not be set in your environment; use your head.
+
+### To install:
+
+    cd $GOROOT/src/cmd/fix
+    ln -s $GOPATH/src/github.com/fluffle/goirc/fix/goirc.go
+    go build
+    mv fix $GOROOT/pkg/tool/$GOOS_$GOARCH
+
+### To fix:
+
+    go tool fix -r goirc -diff /path/to/code
+    <check diffs>
+    go tool fix -r goirc /path/to/code
+
+### Things that aren't fixed by this
+
+This fix doesn't take care of some bad design decisions I made:
+
+  - conn.State is left as-is. If you're using this you'll need to rewrite
+    things to get scope into your handlers in a different fashion.
+  - conn.ER and conn.ED are left as-is. These should be completely removed
+    (and probably shouldn't have been left accessible in the first place).
+
+It's also quite likely that this won't produce the nicest "fixed" code. In
+particular, if you're seeing lots of lines like `conn.Config().XXX = "foo"`,
+you probably want to consider creating a `Config` struct and then passing
+it to `client.Client()`.
+

fix/goirc.go

@@ -0,0 +1,199 @@
+package main
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+	"strings"
+)
+
+// DISCLAIMER: will probably not fix everything. Notable omissions:
+//   - conn.State will not be removed, if you were using it.
+//   - conn.ER/ED will not be removed; exposing them was a Bad Idea, and
+//     the required changes are quite a challenge to express programatically.
+
+func init() {
+	register(goircFix)
+}
+
+var goircFix = fix{
+	"goirc",
+	"2013-03-24",
+	goircNewApi,
+	`Update code that uses goirc/client to new API.`,
+}
+
+var goircConstants = map[string]string{
+	`"REGISTER"`: "REGISTER",
+	`"CONNECTED"`: "CONNECTED",
+	`"DISCONNECTED"`: "DISCONNECTED",
+	`"ACTION"`: "ACTION",
+	`"AWAY"`: "AWAY",
+	`"CTCP"`: "CTCP",
+	`"CTCPREPLY"`: "CTCPREPLY",
+	`"INVITE"`: "INVITE",
+	`"JOIN"`: "JOIN",
+	`"KICK"`: "KICK",
+	`"MODE"`: "MODE",
+	`"NICK"`: "NICK",
+	`"NOTICE"`: "NOTICE",
+	`"OPER"`: "OPER",
+	`"PART"`: "PART",
+	`"PASS"`: "PASS",
+	`"PING"`: "PING",
+	`"PONG"`: "PONG",
+	`"PRIVMSG"`: "PRIVMSG",
+	`"QUIT"`: "QUIT",
+	`"TOPIC"`: "TOPIC",
+	`"USER"`: "USER",
+	`"VERSION"`: "VERSION",
+	`"VHOST"`: "VHOST",
+	`"WHO"`: "WHO",
+	`"WHOIS"`: "WHOIS",
+}
+
+var goircStructToConfig = map[string]string{
+	"Host":      "Server",
+	"Network":   "Server",
+	"NewNick":   "NewNick",
+	"SSL":	     "SSL",
+	"SSLConfig": "SSLConfig",
+	"PingFreq":  "PingFreq",
+	"Flood":     "Flood",
+}
+
+var goircStructToMethod = map[string]string{
+	"Me":        "Me",
+	"ST":        "StateTracker",
+	"Connected": "Connected",
+}
+
+var goircMethodRename = map[string]string{
+	"AddHandler": "HandleFunc",
+	"Connect":    "ConnectTo",
+}
+
+func addCall(t ast.Expr, method string) *ast.CallExpr {
+	return &ast.CallExpr{
+		Fun: &ast.SelectorExpr{
+			X:   t,
+			Sel: ast.NewIdent(method),
+		},
+	}
+}
+
+func goircNewApi(f *ast.File) bool {
+	state := stateApi(f)
+	client := clientApi(f)
+	return client || state
+}
+
+func stateApi(f *ast.File) bool {
+	spec := importSpec(f, "github.com/fluffle/goirc/state")
+	if spec == nil {
+		return false
+	}
+	stateImport := "state"
+	if spec.Name != nil {
+		stateImport = spec.Name.Name
+	}
+	return renameFixTab(f, []rename{
+		{"github.com/fluffle/goirc/state", "",
+			stateImport + ".StateTracker", stateImport + ".Tracker"},
+		{"github.com/fluffle/goirc/state", "",
+			stateImport + ".MockStateTracker", stateImport + ".MockTracker"},
+	})
+}
+
+func clientApi(f *ast.File) bool {
+	spec := importSpec(f, "github.com/fluffle/goirc/client")
+	if spec == nil {
+		return false
+	}
+	clientImport := "client"
+	if spec.Name != nil {
+		clientImport = spec.Name.Name
+	}
+	fixed := false
+
+	maybeReplaceBasicLit := func (expr *ast.Expr) {
+		str, ok := (*expr).(*ast.BasicLit)
+		if !ok || str == nil || str.Kind != token.STRING { return }
+		if repl, ok := goircConstants[strings.ToUpper(str.Value)]; ok {
+			*expr = &ast.SelectorExpr{
+				ast.NewIdent(clientImport),
+				ast.NewIdent(repl),
+			}
+			fixed = true
+		}
+	}
+
+	maybeReplaceConnSelectors := func (expr *ast.Expr) {
+		sel, ok := (*expr).(*ast.SelectorExpr)
+		if !ok || !isClientConn(sel.X, clientImport) { return }
+		name := sel.Sel.String()
+		if rep, ok := goircStructToConfig[name]; ok {
+			sel.X   = addCall(sel.X, "Config")
+			sel.Sel = ast.NewIdent(rep)
+			fixed = true
+		} else if meth, ok := goircStructToMethod[name]; ok {
+			*expr = addCall(sel.X, meth)
+			fixed = true
+		} else if meth, ok := goircMethodRename[name]; ok {
+			sel.Sel = ast.NewIdent(meth)
+			fixed = true
+		}
+	}
+
+	walk(f, func(n interface{}) {
+		if expr, ok := n.(*ast.Expr); ok {
+			maybeReplaceBasicLit(expr)
+			maybeReplaceConnSelectors(expr)
+		}
+		if expr, ok := n.(*ast.CallExpr); ok {
+			if sel, ok := n.(*ast.SelectorExpr); ok &&
+				isPkgDot(sel, clientImport, "Client") {
+				// s/Client/SimpleClient/
+				sel.Sel = ast.NewIdent("SimpleClient")
+				// and delete the last arg from args
+				expr.Args = expr.Args[:3]
+				fixed = true
+			}
+		}
+	})
+	return fixed
+}
+
+func isClientConn(t ast.Expr, pkg string) bool {
+	id, ok := t.(*ast.Ident)
+	if !ok || id.Obj == nil { return false }
+	switch dec := id.Obj.Decl.(type) {
+	case *ast.ValueSpec:
+		// Declared with var X Type
+		return dec.Type != nil && isPtrPkgDot(dec.Type, pkg, "Conn")
+	case *ast.AssignStmt:
+		// Declared with X := Expr producing Type
+		// NOTE: not taking care of multiple-assignment case atm!
+		switch rhs := dec.Rhs[0].(type) {
+		case *ast.CallExpr:
+			// X := client.Client() or client.SimpleClient()
+			return isPkgDot(rhs.Fun, pkg, "Client") ||
+				isPkgDot(rhs.Fun, pkg, "SimpleClient")
+		case *ast.UnaryExpr:
+			// X := &client.Conn{}
+			lit, ok := rhs.X.(*ast.CompositeLit)
+			return ok && isPkgDot(lit.Type, pkg, "Conn")
+		case *ast.CompositeLit:
+			// X := client.Conn{}
+			return isPkgDot(lit.Type, pkg, "Conn")
+		default:
+			fmt.Printf("rhs: %#v\n", rhs)
+		}
+	case *ast.Field:
+		// Declared with func f(X Type)
+		return isPkgDot(dec.Type, pkg, "Conn")
+	default:
+		fmt.Printf("dec: %#v\n", dec)
+	}
+	return false
+}