gofix: handle xml.Unmarshal in xmlapi fix

This improves the handling of xml.Unmarshal in
the xmlapi fix by guessing some of the common
types used on it.

This also fixes a bug in the partial typechecker.
In an expression such as f(&a), it'd mark a as
having &T rather than *T.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5572058

diff --git a/src/cmd/gofix/typecheck.go b/src/cmd/gofix/typecheck.go
index 1614a90d33f6fbbe66af321c73a0ee832804ba08..8e54314d14559503b323a093018f602fbc2e2600 100644 (file)
--- a/src/cmd/gofix/typecheck.go
+++ b/src/cmd/gofix/typecheck.go
@@ -493,7 +493,7 @@ func typecheck1(cfg *TypeConfig, f interface{}, typeof map[interface{}]string, a
                        // &x for x of type T has type *T.
                        t := typeof[n.X]
                        if t != "" && n.Op == token.AND {
-                               typeof[n] = "&" + t
+                               typeof[n] = "*" + t
                        }
 
                case *ast.CompositeLit:

diff --git a/src/cmd/gofix/xmlapi.go b/src/cmd/gofix/xmlapi.go
index 5621d0107eb8efc2c1429da7c65288dd81d376fd..e74425914da3bde019b16aec202b6e2dc0697c01 100644 (file)
--- a/src/cmd/gofix/xmlapi.go
+++ b/src/cmd/gofix/xmlapi.go
@@ -25,10 +25,24 @@ http://codereview.appspot.com/5574053
 
 var xmlapiTypeConfig = &TypeConfig{
        Func: map[string]string{
-               "xml.NewParser": "xml.Parser",
+               "xml.NewParser":         "*xml.Parser",
+               "os.Open":               "*os.File",
+               "os.OpenFile":           "*os.File",
+               "bytes.NewBuffer":       "*bytes.Buffer",
+               "bytes.NewBufferString": "*bytes.Buffer",
+               "bufio.NewReader":       "*bufio.Reader",
+               "bufio.NewReadWriter":   "*bufio.ReadWriter",
        },
 }
 
+var isReader = map[string]bool{
+       "*os.File":          true,
+       "*bytes.Buffer":     true,
+       "*bufio.Reader":     true,
+       "*bufio.ReadWriter": true,
+       "io.Reader":         true,
+}
+
 func xmlapi(f *ast.File) bool {
        if !imports(f, "encoding/xml") {
                return false
@@ -39,7 +53,7 @@ func xmlapi(f *ast.File) bool {
        fixed := false
        walk(f, func(n interface{}) {
                s, ok := n.(*ast.SelectorExpr)
-               if ok && typeof[s.X] == "xml.Parser" && s.Sel.Name == "Unmarshal" {
+               if ok && typeof[s.X] == "*xml.Parser" && s.Sel.Name == "Unmarshal" {
                        s.Sel.Name = "DecodeElement"
                        fixed = true
                        return
@@ -58,10 +72,11 @@ func xmlapi(f *ast.File) bool {
                case len(call.Args) == 2 && isPkgDot(call.Fun, "xml", "Marshal"):
                        *call = xmlMarshal(call.Args)
                        fixed = true
-               // Can't fix without further diving into the type of call.Args[0].
-               //case len(call.Args) == 2 && isPkgDot(call.Fun, "xml", "Unmarshal"):
-               //      *call = xmlUnmarshal(call.Args)
-               //      fixed = true
+               case len(call.Args) == 2 && isPkgDot(call.Fun, "xml", "Unmarshal"):
+                       if isReader[typeof[call.Args[0]]] {
+                               *call = xmlUnmarshal(call.Args)
+                               fixed = true
+                       }
                case len(call.Args) == 1 && isPkgDot(call.Fun, "xml", "NewParser"):
                        sel := call.Fun.(*ast.SelectorExpr).Sel
                        sel.Name = "NewDecoder"

diff --git a/src/cmd/gofix/xmlapi_test.go b/src/cmd/gofix/xmlapi_test.go
index abf989c3e7da528da571a5537f6c932e61404f06..6486c8124840c9105e845fbfa9b77a1f77c30b3c 100644 (file)
--- a/src/cmd/gofix/xmlapi_test.go
+++ b/src/cmd/gofix/xmlapi_test.go
@@ -19,12 +19,32 @@ func f() {
        xml.Marshal(a, b)
        xml.Unmarshal(a, b)
 
+       var buf1 bytes.Buffer
+       buf2 := &bytes.Buffer{}
+       buf3 := bytes.NewBuffer(data)
+       buf4 := bytes.NewBufferString(data)
+       buf5 := bufio.NewReader(r)
+       xml.Unmarshal(&buf1, v)
+       xml.Unmarshal(buf2, v)
+       xml.Unmarshal(buf3, v)
+       xml.Unmarshal(buf4, v)
+       xml.Unmarshal(buf5, v)
+
+       f := os.Open("foo.xml")
+       xml.Unmarshal(f, v)
+
        p1 := xml.NewParser(stream)
        p1.Unmarshal(v, start)
 
-       var p2 xml.Parser
+       var p2 *xml.Parser
        p2.Unmarshal(v, start)
 }
+
+func g(r io.Reader, f *os.File, b []byte) {
+       xml.Unmarshal(r, v)
+       xml.Unmarshal(f, v)
+       xml.Unmarshal(b, v)
+}
 `,
                Out: `package main
 
@@ -34,12 +54,32 @@ func f() {
        xml.NewEncoder(a).Encode(b)
        xml.Unmarshal(a, b)
 
+       var buf1 bytes.Buffer
+       buf2 := &bytes.Buffer{}
+       buf3 := bytes.NewBuffer(data)
+       buf4 := bytes.NewBufferString(data)
+       buf5 := bufio.NewReader(r)
+       xml.NewDecoder(&buf1).Decode(v)
+       xml.NewDecoder(buf2).Decode(v)
+       xml.NewDecoder(buf3).Decode(v)
+       xml.NewDecoder(buf4).Decode(v)
+       xml.NewDecoder(buf5).Decode(v)
+
+       f := os.Open("foo.xml")
+       xml.NewDecoder(f).Decode(v)
+
        p1 := xml.NewDecoder(stream)
        p1.DecodeElement(v, start)
 
-       var p2 xml.Decoder
+       var p2 *xml.Decoder
        p2.DecodeElement(v, start)
 }
+
+func g(r io.Reader, f *os.File, b []byte) {
+       xml.NewDecoder(r).Decode(v)
+       xml.NewDecoder(f).Decode(v)
+       xml.Unmarshal(b, v)
+}
 `,
        },
 }