core/java/jdwp: Overhaul of the JDWP library.

Add a debug mode which prints every send and recv.
Add string helpers for the majority of the message types.
Flesh out thread-reference APIs.
Reimplement the event request API to be more strict about thread suspension.

core/java/jdwp/BUILD.bazel

@@ -32,6 +32,7 @@ go_library(
         "cmdset_vm.go",
         "cmdsets.go",
         "coder.go",
+        "debug.go",
         "errors.go",
         "event.go",
         "event_kind.go",
@@ -45,6 +46,7 @@ go_library(
         "recv.go",
         "suspend_policy.go",
         "tag.go",
+        "thread_status.go",
         "type_tag.go",
         "types.go",
         "value.go",

core/java/jdwp/cmdset_arrayreference.go

@@ -17,7 +17,7 @@ package jdwp
 // GetArrayLength returns the length of the specified array.
 func (c *Connection) GetArrayLength(id ArrayID) (int, error) {
 	var res int
-	err := c.get(cmdSetArrayReference, 1, id, &res)
+	err := c.get(cmdArrayReferenceLength, id, &res)
 	return res, err
 }
 
@@ -29,7 +29,7 @@ func (c *Connection) GetArrayValues(id ArrayID, first, length int) ([]Value, err
 		Length int
 	}{id, first, length}
 	var res []Value
-	err := c.get(cmdSetArrayReference, 2, req, &res)
+	err := c.get(cmdArrayReferenceGetValues, req, &res)
 	return res, err
 }
 
@@ -40,5 +40,5 @@ func (c *Connection) SetArrayValues(id ArrayID, first int, values interface{}) e
 		First  int
 		Values interface{}
 	}{id, first, values}
-	return c.get(cmdSetArrayReference, 3, req, nil)
+	return c.get(cmdArrayReferenceSetValues, req, nil)
 }

core/java/jdwp/cmdset_arraytype.go

@@ -21,6 +21,6 @@ func (c *Connection) NewArray(ty ArrayTypeID, length int) (TaggedObjectID, error
 		Length int
 	}{ty, length}
 	var res TaggedObjectID
-	err := c.get(cmdSetArrayType, 1, req, &res)
+	err := c.get(cmdArrayTypeNewInstance, req, &res)
 	return res, err
 }

core/java/jdwp/cmdset_classobjectreference.go

@@ -23,6 +23,6 @@ func (c *Connection) ReflectedType(id ClassObjectID) (ReferenceTypeID, error) {
 		Kind byte
 		ID   ReferenceTypeID
 	}
-	err := c.get(cmdSetClassObjectReference, 1, req, &res)
+	err := c.get(cmdClassObjectReferenceReflectedType, req, &res)
 	return res.ID, err
 }

core/java/jdwp/cmdset_classtype.go

@@ -23,7 +23,7 @@ type InvokeResult struct {
 // GetSuperClass returns the immediate super class of the specified class.
 func (c *Connection) GetSuperClass(class ClassID) (ClassID, error) {
 	var res ClassID
-	err := c.get(cmdSetClassType, 1, class, &res)
+	err := c.get(cmdClassTypeSuperclass, class, &res)
 	return res, err
 }
 
@@ -37,7 +37,7 @@ func (c *Connection) InvokeStaticMethod(class ClassID, method MethodID, thread T
 		Options InvokeOptions
 	}{class, thread, method, args, options}
 	var res InvokeResult
-	err := c.get(cmdSetClassType, 3, req, &res)
+	err := c.get(cmdClassTypeInvokeMethod, req, &res)
 	return res, err
 }
 
@@ -57,6 +57,6 @@ func (c *Connection) NewInstance(class ClassID, constructor MethodID, thread Thr
 		Options     InvokeOptions
 	}{class, thread, constructor, args, options}
 	var res NewInstanceResult
-	err := c.get(cmdSetClassType, 4, req, &res)
+	err := c.get(cmdClassTypeNewInstance, req, &res)
 	return res, err
 }

core/java/jdwp/cmdset_eventrequest.go

@@ -14,13 +14,28 @@
 
 package jdwp
 
+import (
+	"context"
+	"fmt"
+
+	"github.com/google/gapid/core/event/task"
+)
+
 // EventRequestID is an identifier of an event request.
 type EventRequestID int
 
 const cmdCompositeEvent = cmdID(100)
 
-// SetEvent sets an event request.
-func (c *Connection) SetEvent(kind EventKind, suspendPolity SuspendPolicy, modifiers ...EventModifier) (EventRequestID, error) {
+// WatchEvents sets an event watcher, calling handler for each received event.
+// WatchEvents will continue to watch for events until handler returns false or
+// the context is cancelled.
+func (c *Connection) WatchEvents(
+	ctx context.Context,
+	kind EventKind,
+	suspendPolity SuspendPolicy,
+	handler func(Event) bool,
+	modifiers ...EventModifier) error {
+
 	req := struct {
 		Kind          EventKind
 		SuspendPolicy SuspendPolicy
@@ -30,22 +45,64 @@ func (c *Connection) SetEvent(kind EventKind, suspendPolity SuspendPolicy, modif
 		SuspendPolicy: suspendPolity,
 		Modifiers:     modifiers,
 	}
-	var res EventRequestID
-	err := c.get(cmdSetEventRequest, 1, req, &res)
-	return res, err
-}
 
-// ClearEvent cancels an event request.
-func (c *Connection) ClearEvent(kind EventKind, id EventRequestID) error {
-	req := struct {
+	var id EventRequestID
+	err := c.get(cmdEventRequestSet, req, &id)
+	if err != nil {
+		return err
+	}
+
+	events := make(chan Event, 8)
+	c.Lock()
+	c.events[id] = events
+	c.Unlock()
+
+	defer func() {
+		c.Lock()
+		delete(c.events, id)
+		c.Unlock()
+	}()
+
+	if err := c.ResumeAll(); err != nil {
+		return err
+	}
+
+run: // Consume events until the handler returns false or the context is cancelled.
+	for {
+		select {
+		case event := <-events:
+			if !handler(event) {
+				break run
+			}
+		case <-task.ShouldStop(ctx):
+			break run
+		}
+	}
+
+	//  Clear the event.
+	clear := struct {
 		Kind EventKind
 		ID   EventRequestID
 	}{
 		Kind: kind,
 		ID:   id,
 	}
-	err := c.get(cmdSetEventRequest, 2, req, nil)
-	return err
+
+	if err := c.get(cmdEventRequestClear, clear, nil); err != nil {
+		return err
+	}
+
+flush: // Consume any remaining events in the pipe.
+	for {
+		select {
+		case event := <-events:
+			handler(event)
+		default:
+			break flush
+		}
+	}
+
+	return nil
 }
 
 // EventModifier is the interface implemented by all event modifier types.
@@ -126,3 +183,36 @@ func (ExceptionOnlyEventModifier) modKind() uint8 { return 8 }
 func (FieldOnlyEventModifier) modKind() uint8     { return 9 }
 func (StepEventModifier) modKind() uint8          { return 10 }
 func (InstanceOnlyEventModifier) modKind() uint8  { return 11 }
+
+func (m CountEventModifier) String() string {
+	return fmt.Sprintf("CountEventModifier<%v>", int(m))
+}
+func (m ThreadOnlyEventModifier) String() string {
+	return fmt.Sprintf("ThreadOnlyEventModifier<%v>", int(m))
+}
+func (m ClassOnlyEventModifier) String() string {
+	return fmt.Sprintf("ClassOnlyEventModifier<%v>", int(m))
+}
+func (m ClassMatchEventModifier) String() string {
+	return fmt.Sprintf("ClassMatchEventModifier<%v>", string(m))
+}
+func (m ClassExcludeEventModifier) String() string {
+	return fmt.Sprintf("ClassExcludeEventModifier<%v>", string(m))
+}
+func (m LocationOnlyEventModifier) String() string {
+	return fmt.Sprintf("LocationOnlyEventModifier<%v>", Location(m))
+}
+func (m ExceptionOnlyEventModifier) String() string {
+	return fmt.Sprintf("ExceptionOnlyEventModifier<Exception: %v, Caught: %v, Uncaught: %v>",
+		m.ExceptionOrNull, m.Caught, m.Uncaught)
+}
+func (m FieldOnlyEventModifier) String() string {
+	return fmt.Sprintf("FieldOnlyEventModifier<Type: %v, Field: %v>", m.Type, m.Field)
+}
+func (m StepEventModifier) String() string {
+	return fmt.Sprintf("StepEventModifier<Thread: %v, Size: %v, Depth: %v>",
+		m.Thread, m.Size, m.Depth)
+}
+func (m InstanceOnlyEventModifier) String() string {
+	return fmt.Sprintf("InstanceOnlyEventModifier<%v>", ObjectID(m))
+}

core/java/jdwp/cmdset_method.go

@@ -14,14 +14,14 @@
 
 package jdwp
 
-// VariableTable returns all of the variables that are present
-// in the given Method.
+// VariableTable returns all of the variables that are present in the given
+// Method.
 func (c *Connection) VariableTable(classTy ReferenceTypeID, method MethodID) (VariableTable, error) {
 	req := struct {
 		Class  ReferenceTypeID
 		Method MethodID
 	}{classTy, method}
 	var res VariableTable
-	err := c.get(cmdSetMethod, 2, req, &res)
+	err := c.get(cmdMethodTypeVariableTable, req, &res)
 	return res, err
 }

core/java/jdwp/cmdset_objectreference.go

@@ -23,14 +23,14 @@ type ObjectType struct {
 // GetObjectType returns the type of the specified object.
 func (c *Connection) GetObjectType(object ObjectID) (ObjectType, error) {
 	var res ObjectType
-	err := c.get(cmdSetObjectReference, 1, object, &res)
+	err := c.get(cmdObjectReferenceReferenceType, object, &res)
 	return res, err
 }
 
 // GetFieldValues returns the values of all the instance fields.
 func (c *Connection) GetFieldValues(obj ObjectID, fields ...FieldID) ([]Value, error) {
 	var res []Value
-	err := c.get(cmdSetObjectReference, 2, struct {
+	err := c.get(cmdObjectReferenceGetValues, struct {
 		Obj    ObjectID
 		Fields []FieldID
 	}{obj, fields}, &res)
@@ -48,16 +48,16 @@ func (c *Connection) InvokeMethod(object ObjectID, class ClassID, method MethodI
 		Options InvokeOptions
 	}{object, thread, class, method, args, options}
 	var res InvokeResult
-	err := c.get(cmdSetObjectReference, 6, req, &res)
+	err := c.get(cmdObjectReferenceInvokeMethod, req, &res)
 	return res, err
 }
 
 // DisableGC disables garbage collection for the specified object.
 func (c *Connection) DisableGC(object ObjectID) error {
-	return c.get(cmdSetObjectReference, 7, object, nil)
+	return c.get(cmdObjectReferenceDisableCollection, object, nil)
 }
 
 // EnableGC enables garbage collection for the specified object.
 func (c *Connection) EnableGC(object ObjectID) error {
-	return c.get(cmdSetObjectReference, 8, object, nil)
+	return c.get(cmdObjectReferenceEnableCollection, object, nil)
 }

core/java/jdwp/cmdset_referencetypes.go

@@ -17,28 +17,28 @@ package jdwp
 // GetTypeSignature returns the Java type signature for the specified type.
 func (c *Connection) GetTypeSignature(ty ReferenceTypeID) (string, error) {
 	var res string
-	err := c.get(cmdSetReferenceType, 1, ty, &res)
+	err := c.get(cmdReferenceTypeSignature, ty, &res)
 	return res, err
 }
 
 // GetFields returns all the fields for the specified type.
 func (c *Connection) GetFields(ty ReferenceTypeID) (Fields, error) {
 	var res Fields
-	err := c.get(cmdSetReferenceType, 4, ty, &res)
+	err := c.get(cmdReferenceTypeFields, ty, &res)
 	return res, err
 }
 
 // GetMethods returns all the methods for the specified type.
 func (c *Connection) GetMethods(ty ReferenceTypeID) (Methods, error) {
 	var res Methods
-	err := c.get(cmdSetReferenceType, 5, ty, &res)
+	err := c.get(cmdReferenceTypeMethods, ty, &res)
 	return res, err
 }
 
 // GetStaticFieldValues returns the values of all the requests static fields.
 func (c *Connection) GetStaticFieldValues(ty ReferenceTypeID, fields ...FieldID) ([]Value, error) {
 	var res []Value
-	err := c.get(cmdSetReferenceType, 6, struct {
+	err := c.get(cmdReferenceTypeGetValues, struct {
 		Ty     ReferenceTypeID
 		Fields []FieldID
 	}{ty, fields}, &res)
@@ -49,6 +49,6 @@ func (c *Connection) GetStaticFieldValues(ty ReferenceTypeID, fields ...FieldID)
 // type.
 func (c *Connection) GetImplemented(ty ReferenceTypeID) ([]InterfaceID, error) {
 	var res []InterfaceID
-	err := c.get(cmdSetReferenceType, 10, ty, &res)
+	err := c.get(cmdReferenceTypeInterfaces, ty, &res)
 	return res, err
 }

core/java/jdwp/cmdset_stackframe.go

@@ -22,7 +22,7 @@ func (c *Connection) GetThisObject(thread ThreadID, frame FrameID) (TaggedObject
 		Frame  FrameID
 	}{thread, frame}
 	res := TaggedObjectID{}
-	err := c.get(cmdSetStackFrame, 3, req, &res)
+	err := c.get(cmdStackFrameThisObject, req, &res)
 	return res, err
 }
 
@@ -40,7 +40,7 @@ func (c *Connection) GetValues(thread ThreadID, frame FrameID, slots []VariableR
 		Slots  []VariableRequest
 	}{thread, frame, slots}
 	res := ValueSlice{}
-	err := c.get(cmdSetStackFrame, 1, req, &res)
+	err := c.get(cmdStackFrameGetValues, req, &res)
 	return res, err
 }
 
@@ -57,6 +57,6 @@ func (c *Connection) SetValues(thread ThreadID, frame FrameID, slots []VariableA
 		Slots  []VariableAssignmentRequest
 	}{thread, frame, slots}
 
-	err := c.get(cmdSetStackFrame, 2, req, nil)
+	err := c.get(cmdStackFrameSetValues, req, nil)
 	return err
 }

core/java/jdwp/cmdset_stringreference.go

@@ -17,6 +17,6 @@ package jdwp
 // GetString returns the string text for the given StringID.
 func (c *Connection) GetString(id StringID) (string, error) {
 	var res string
-	err := c.get(cmdSetStringReference, 1, id, &res)
+	err := c.get(cmdStringReferenceValue, id, &res)
 	return res, err
 }