2 files changed, 276 insertions, 0 deletions
diff --git a/pkg/state/pretty/pretty.go b/pkg/state/pretty/pretty.go
new file mode 100644
index 000000000..cf37aaa49
--- /dev/null
+++ b/pkg/state/pretty/pretty.go
@@ -0,0 +1,273 @@
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package pretty is a pretty-printer for state streams.
+package pretty
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"reflect"
+	"strings"
+
+	"gvisor.dev/gvisor/pkg/state"
+	"gvisor.dev/gvisor/pkg/state/wire"
+)
+
+func formatRef(x *wire.Ref, graph uint64, html bool) string {
+	baseRef := fmt.Sprintf("g%dr%d", graph, x.Root)
+	fullRef := baseRef
+	if len(x.Dots) > 0 {
+		// See wire.Ref; Type valid if Dots non-zero.
+		typ, _ := formatType(x.Type, graph, html)
+		var buf strings.Builder
+		buf.WriteString("(*")
+		buf.WriteString(typ)
+		buf.WriteString(")(")
+		buf.WriteString(baseRef)
+		for _, component := range x.Dots {
+			switch v := component.(type) {
+			case *wire.FieldName:
+				buf.WriteString(".")
+				buf.WriteString(string(*v))
+			case wire.Index:
+				buf.WriteString(fmt.Sprintf("[%d]", v))
+			default:
+				panic(fmt.Sprintf("unreachable: switch should be exhaustive, unhandled case %v", reflect.TypeOf(component)))
+			}
+		}
+		buf.WriteString(")")
+		fullRef = buf.String()
+	}
+	if html {
+		return fmt.Sprintf("<a href=\"#%s\">%s</a>", baseRef, fullRef)
+	}
+	return fullRef
+}
+
+func formatType(t wire.TypeSpec, graph uint64, html bool) (string, bool) {
+	switch x := t.(type) {
+	case wire.TypeID:
+		base := fmt.Sprintf("g%dt%d", graph, x)
+		if html {
+			return fmt.Sprintf("<a href=\"#%s\">%s</a>", base, base), true
+		}
+		return fmt.Sprintf("%s", base), true
+	case wire.TypeSpecNil:
+		return "", false // Only nil type.
+	case *wire.TypeSpecPointer:
+		element, _ := formatType(x.Type, graph, html)
+		return fmt.Sprintf("(*%s)", element), true
+	case *wire.TypeSpecArray:
+		element, _ := formatType(x.Type, graph, html)
+		return fmt.Sprintf("[%d](%s)", x.Count, element), true
+	case *wire.TypeSpecSlice:
+		element, _ := formatType(x.Type, graph, html)
+		return fmt.Sprintf("([]%s)", element), true
+	case *wire.TypeSpecMap:
+		key, _ := formatType(x.Key, graph, html)
+		value, _ := formatType(x.Value, graph, html)
+		return fmt.Sprintf("(map[%s]%s)", key, value), true
+	default:
+		panic(fmt.Sprintf("unreachable: unknown type %T", t))
+	}
+}
+
+// format formats a single object, for pretty-printing. It also returns whether
+// the value is a non-zero value.
+func format(graph uint64, depth int, encoded wire.Object, html bool) (string, bool) {
+	switch x := encoded.(type) {
+	case wire.Nil:
+		return "nil", false
+	case *wire.String:
+		return fmt.Sprintf("%q", *x), *x != ""
+	case *wire.Complex64:
+		return fmt.Sprintf("%f+%fi", real(*x), imag(*x)), *x != 0.0
+	case *wire.Complex128:
+		return fmt.Sprintf("%f+%fi", real(*x), imag(*x)), *x != 0.0
+	case *wire.Ref:
+		return formatRef(x, graph, html), x.Root != 0
+	case *wire.Type:
+		tabs := "\n" + strings.Repeat("\t", depth)
+		items := make([]string, 0, len(x.Fields)+2)
+		items = append(items, fmt.Sprintf("type %s {", x.Name))
+		for i := 0; i < len(x.Fields); i++ {
+			items = append(items, fmt.Sprintf("\t%d: %s,", i, x.Fields[i]))
+		}
+		items = append(items, "}")
+		return strings.Join(items, tabs), true // No zero value.
+	case *wire.Slice:
+		return fmt.Sprintf("%s{len:%d,cap:%d}", formatRef(&x.Ref, graph, html), x.Length, x.Capacity), x.Capacity != 0
+	case *wire.Array:
+		if len(x.Contents) == 0 {
+			return "[]", false
+		}
+		items := make([]string, 0, len(x.Contents)+2)
+		zeros := make([]string, 0) // used to eliminate zero entries.
+		items = append(items, "[")
+		tabs := "\n" + strings.Repeat("\t", depth)
+		for i := 0; i < len(x.Contents); i++ {
+			item, ok := format(graph, depth+1, x.Contents[i], html)
+			if !ok {
+				zeros = append(zeros, fmt.Sprintf("\t%s,", item))
+				continue
+			}
+			if len(zeros) > 0 {
+				items = append(items, zeros...)
+				zeros = nil
+			}
+			items = append(items, fmt.Sprintf("\t%s,", item))
+		}
+		if len(zeros) > 0 {
+			items = append(items, fmt.Sprintf("\t... (%d zeros),", len(zeros)))
+		}
+		items = append(items, "]")
+		return strings.Join(items, tabs), len(zeros) < len(x.Contents)
+	case *wire.Struct:
+		typ, _ := formatType(x.TypeID, graph, html)
+		if x.Fields() == 0 {
+			return fmt.Sprintf("struct[%s]{}", typ), false
+		}
+		items := make([]string, 0, 2)
+		items = append(items, fmt.Sprintf("struct[%s]{", typ))
+		tabs := "\n" + strings.Repeat("\t", depth)
+		allZero := true
+		for i := 0; i < x.Fields(); i++ {
+			element, ok := format(graph, depth+1, *x.Field(i), html)
+			allZero = allZero && !ok
+			items = append(items, fmt.Sprintf("\t%d: %s,", i, element))
+			i++
+		}
+		items = append(items, "}")
+		return strings.Join(items, tabs), !allZero
+	case *wire.Map:
+		if len(x.Keys) == 0 {
+			return "map{}", false
+		}
+		items := make([]string, 0, len(x.Keys)+2)
+		items = append(items, "map{")
+		tabs := "\n" + strings.Repeat("\t", depth)
+		for i := 0; i < len(x.Keys); i++ {
+			key, _ := format(graph, depth+1, x.Keys[i], html)
+			value, _ := format(graph, depth+1, x.Values[i], html)
+			items = append(items, fmt.Sprintf("\t%s: %s,", key, value))
+		}
+		items = append(items, "}")
+		return strings.Join(items, tabs), true
+	case *wire.Interface:
+		typ, typOk := formatType(x.Type, graph, html)
+		element, elementOk := format(graph, depth+1, x.Value, html)
+		return fmt.Sprintf("interface[%s]{%s}", typ, element), typOk || elementOk
+	default:
+		// Must be a primitive; use reflection.
+		return fmt.Sprintf("%v", encoded), true
+	}
+}
+
+// printStream is the basic print implementation.
+func printStream(w io.Writer, r wire.Reader, html bool) (err error) {
+	// current graph ID.
+	var graph uint64
+
+	if html {
+		fmt.Fprintf(w, "<pre>")
+		defer fmt.Fprintf(w, "</pre>")
+	}
+
+	defer func() {
+		if r := recover(); r != nil {
+			if rErr, ok := r.(error); ok {
+				err = rErr // Override return.
+				return
+			}
+			panic(r) // Propagate.
+		}
+	}()
+
+	for {
+		// Find the first object to begin generation.
+		length, object, err := state.ReadHeader(r)
+		if err == io.EOF {
+			// Nothing else to do.
+			break
+		} else if err != nil {
+			return err
+		}
+		if !object {
+			graph++ // Increment the graph.
+			if length > 0 {
+				fmt.Fprintf(w, "(%d bytes non-object data)\n", length)
+				io.Copy(ioutil.Discard, &io.LimitedReader{
+					R: r,
+					N: int64(length),
+				})
+			}
+			continue
+		}
+
+		// Read & unmarshal the object.
+		//
+		// Note that this loop must match the general structure of the
+		// loop in decode.go. But we don't register type information,
+		// etc. and just print the raw structures.
+		var (
+			oid uint64 = 1
+			tid uint64 = 1
+		)
+		for oid <= length {
+			// Unmarshal the object.
+			encoded := wire.Load(r)
+
+			// Is this a type?
+			if _, ok := encoded.(*wire.Type); ok {
+				str, _ := format(graph, 0, encoded, html)
+				tag := fmt.Sprintf("g%dt%d", graph, tid)
+				if html {
+					// See below.
+					tag = fmt.Sprintf("<a name=\"%s\">%s</a><a href=\"#%s\">&#9875;</a>", tag, tag, tag)
+				}
+				if _, err := fmt.Fprintf(w, "%s = %s\n", tag, str); err != nil {
+					return err
+				}
+				tid++
+				continue
+			}
+
+			// Format the node.
+			str, _ := format(graph, 0, encoded, html)
+			tag := fmt.Sprintf("g%dr%d", graph, oid)
+			if html {
+				// Create a little tag with an anchor next to it for linking.
+				tag = fmt.Sprintf("<a name=\"%s\">%s</a><a href=\"#%s\">&#9875;</a>", tag, tag, tag)
+			}
+			if _, err := fmt.Fprintf(w, "%s = %s\n", tag, str); err != nil {
+				return err
+			}
+			oid++
+		}
+	}
+
+	return nil
+}
+
+// PrintText reads the stream from r and prints text to w.
+func PrintText(w io.Writer, r wire.Reader) error {
+	return printStream(w, r, false /* html */)
+}
+
+// PrintHTML reads the stream from r and prints html to w.
+func PrintHTML(w io.Writer, r wire.Reader) error {
+	return printStream(w, r, true /* html */)
+}
diff --git a/pkg/state/pretty/pretty_state_autogen.go b/pkg/state/pretty/pretty_state_autogen.go
new file mode 100644
index 000000000..e772e34a4
--- /dev/null
+++ b/pkg/state/pretty/pretty_state_autogen.go
@@ -0,0 +1,3 @@
+// automatically generated by stateify.
+
+package pretty