Two small infrastructure extensions for passing information into the

logging framework.

- To enable passing a type into a bif, there's now a new
  BroType-derived class TypeType and a corresponding TYPE_TYPE tag.
  With that, a Val can now have a type as its value.

  This is experimental for now.

- RecordVal's get a new method CoerceTo() to coerce their value into a
  another record type with the usual semantics. Most of the code in
  there was previously in RecordContructorExpr::InitVal(), which is
  now calling the new CoerceTo() method.

src/Expr.cc

@@ -284,7 +284,7 @@ Val* NameExpr::Eval(Frame* f) const
 	Val* v;
 
 	if ( id->AsType() )
-		RunTime("cannot evaluate type name");
+		return new Val(id->AsType(), true);
 
 	if ( id->IsGlobal() )
 		v = id->ID_Val();
@@ -3309,48 +3309,12 @@ RecordConstructorExpr::RecordConstructorExpr(ListExpr* constructor_list)
 
 Val* RecordConstructorExpr::InitVal(const BroType* t, Val* aggr) const
 	{
-	if ( ! aggr )
-		aggr = new RecordVal(const_cast<RecordType*>(t->AsRecordType()));
-
-	if ( record_promotion_compatible(t->AsRecordType(), Type()->AsRecordType()) )
-		{
-		RecordVal* ar = aggr->AsRecordVal();
-		RecordType* ar_t = aggr->Type()->AsRecordType();
-
 	RecordVal* rv = Eval(0)->AsRecordVal();
-		RecordType* rv_t = rv->Type()->AsRecordType();
+	RecordVal* ar = rv->CoerceTo(t->AsRecordType(), aggr);
 
-		int i;
-		for ( i = 0; i < rv_t->NumFields(); ++i )
+	if ( ar )
 		{
-			int t_i = ar_t->FieldOffset(rv_t->FieldName(i));
-
-			if ( t_i < 0 )
-				{
-				char buf[512];
-				safe_snprintf(buf, sizeof(buf),
-					      "orphan field \"%s\" in initialization",
-					      rv_t->FieldName(i));
-				Error(buf);
-				break;
-				}
-
-			else
-				ar->Assign(t_i, rv->Lookup(i)->Ref());
-			}
-
-		for ( i = 0; i < ar_t->NumFields(); ++i )
-			if ( ! ar->Lookup(i) &&
-			     ! ar_t->FieldDecl(i)->FindAttr(ATTR_OPTIONAL) )
-				{
-				char buf[512];
-				safe_snprintf(buf, sizeof(buf),
-					      "non-optional field \"%s\" missing in initialization", ar_t->FieldName(i));
-				Error(buf);
-				}
-
 		Unref(rv);
-
 		return ar;
 		}
 

src/Type.cc

@@ -95,6 +95,7 @@ BroType::BroType(TypeTag t, bool arg_base_type)
 	case TYPE_FUNC:
 	case TYPE_FILE:
 	case TYPE_VECTOR:
+	case TYPE_TYPE:
 		internal_tag = TYPE_INTERNAL_OTHER;
 		break;
 
@@ -1426,6 +1427,9 @@ int same_type(const BroType* t1, const BroType* t2, int is_init)
 	case TYPE_FILE:
 		return same_type(t1->YieldType(), t2->YieldType(), is_init);
 
+	case TYPE_TYPE:
+		return same_type(t1, t2, is_init);
+
 	case TYPE_UNION:
 		error("union type in same_type()");
 	}
@@ -1514,6 +1518,7 @@ int is_assignable(BroType* t)
 	case TYPE_VECTOR:
 	case TYPE_FILE:
 	case TYPE_TABLE:
+	case TYPE_TYPE:
 		return 1;
 
 	case TYPE_VOID:

src/Type.h

@@ -31,6 +31,7 @@ typedef enum {
 	TYPE_FUNC,
 	TYPE_FILE,
 	TYPE_VECTOR,
+	TYPE_TYPE,
 	TYPE_ERROR
 #define NUM_TYPES (int(TYPE_ERROR) + 1)
 } TypeTag;
@@ -59,6 +60,7 @@ class ListExpr;
 class EnumType;
 class Serializer;
 class VectorType;
+class TypeType;
 
 const int DOES_NOT_MATCH_INDEX = 0;
 const int MATCHES_INDEX_SCALAR = 1;
@@ -151,6 +153,7 @@ public:
 		CHECK_TYPE_TAG(TYPE_SUBNET, "BroType::AsSubNetType");
 		return (const SubNetType*) this;
 		}
+
 	SubNetType* AsSubNetType()
 		{
 		CHECK_TYPE_TAG(TYPE_SUBNET, "BroType::AsSubNetType");
@@ -192,6 +195,18 @@ public:
 		return (VectorType*) this;
 		}
 
+	const TypeType* AsTypeType() const
+	        {
+		CHECK_TYPE_TAG(TYPE_TYPE, "BroType::AsTypeType");
+		return (TypeType*) this;
+		}
+
+	TypeType* AsTypeType()
+	        {
+		CHECK_TYPE_TAG(TYPE_TYPE, "BroType::AsTypeType");
+		return (TypeType*) this;
+		}
+
 	int IsSet() const
 		{
 		return tag == TYPE_TABLE && (YieldType() == 0);
@@ -359,6 +374,19 @@ protected:
 	ID* return_value;
 };
 
+class TypeType : public BroType {
+public:
+	TypeType(BroType* t) : BroType(TYPE_TYPE)	{ type = t->Ref(); }
+	~TypeType()	{ Unref(type); }
+
+	BroType* Type()	{ return type; }
+
+protected:
+	TypeType()	{}
+
+	BroType* type;
+};
+
 class TypeDecl {
 public:
 	TypeDecl(BroType* t, const char* i, attr_list* attrs = 0);

src/Val.cc

@@ -2892,6 +2892,62 @@ Val* RecordVal::Lookup(int field) const
 	return (*AsRecord())[field];
 	}
 
+RecordVal* RecordVal::CoerceTo(const RecordType* t, Val* aggr) const
+	{
+	if ( ! record_promotion_compatible(t->AsRecordType(), Type()->AsRecordType()) )
+		return 0;
+
+	if ( ! aggr )
+		aggr = new RecordVal(const_cast<RecordType*>(t->AsRecordType()));
+
+	RecordVal* ar = aggr->AsRecordVal();
+	RecordType* ar_t = aggr->Type()->AsRecordType();
+
+	const RecordType* rv_t = Type()->AsRecordType();
+
+	int i;
+	for ( i = 0; i < rv_t->NumFields(); ++i )
+		{
+		int t_i = ar_t->FieldOffset(rv_t->FieldName(i));
+
+		if ( t_i < 0 )
+			{
+			char buf[512];
+			safe_snprintf(buf, sizeof(buf),
+					"orphan field \"%s\" in initialization",
+					rv_t->FieldName(i));
+			Error(buf);
+			break;
+			}
+
+		else
+			ar->Assign(t_i, Lookup(i)->Ref());
+		}
+
+	for ( i = 0; i < ar_t->NumFields(); ++i )
+		if ( ! ar->Lookup(i) &&
+			 ! ar_t->FieldDecl(i)->FindAttr(ATTR_OPTIONAL) )
+			{
+			char buf[512];
+			safe_snprintf(buf, sizeof(buf),
+					"non-optional field \"%s\" missing in initialization", ar_t->FieldName(i));
+			Error(buf);
+			}
+
+	return ar;
+	}
+
+RecordVal* RecordVal::CoerceTo(RecordType* t)
+	{
+	if ( same_type(Type(), t) )
+		{
+		this->Ref();
+		return this;
+		}
+
+	return CoerceTo(t, 0);
+	}
+
 void RecordVal::Describe(ODesc* d) const
 	{
 	const val_list* vl = AsRecord();

src/Val.h

@@ -39,6 +39,7 @@ class TableVal;
 class RecordVal;
 class ListVal;
 class StringVal;
+class EnumVal;
 class MutableVal;
 
 class StateAccess;
@@ -163,6 +164,15 @@ public:
 	// class has ref'd it.
 	Val(BroFile* f);
 
+	Val(BroType* t, bool type_type) // Extra arg to differentiate from protected version.
+		{
+		type = new TypeType(t->Ref());
+		attribs = 0;
+#ifdef DEBUG
+		bound_id = 0;
+#endif
+		}
+
 	Val()
 		{
 		val.int_val = 0;
@@ -245,6 +255,12 @@ public:
 		return &val.subnet_val;
 		}
 
+	const BroType* AsType() const
+		{
+		CHECK_TAG(type->Tag(), TYPE_TYPE, "Val::Type", type_name)
+		return type;
+		}
+
 	// ... in network byte order
 	const addr_type AsAddr() const
 		{
@@ -295,6 +311,7 @@ public:
 	CONVERTER(TYPE_LIST, ListVal*, AsListVal)
 	CONVERTER(TYPE_STRING, StringVal*, AsStringVal)
 	CONVERTER(TYPE_VECTOR, VectorVal*, AsVectorVal)
+	CONVERTER(TYPE_ENUM, EnumVal*, AsEnumVal)
 
 #define CONST_CONVERTER(tag, ctype, name) \
 	const ctype name() const \
@@ -921,6 +938,15 @@ public:
 	void SetOrigin(BroObj* o)	{ origin = o; }
 	BroObj* GetOrigin() const	{ return origin; }
 
+	// Returns a new value representing the value coerced to the given type.
+	// If coercion is not possible, returns 0. The non-const version may
+	// return the current value ref'ed if its type matches directly.
+	//
+	// *aggr* is optional; if non-zero, we add to it. See Expr::InitVal(). We
+	// leave it out in the non-const version to make the choice unambigious.
+	RecordVal* CoerceTo(const RecordType* other, Val* aggr) const;
+	RecordVal* CoerceTo(RecordType* other);
+
 	unsigned int MemoryAllocation() const;
 
 protected: