From 6a1529fc7e5d9022fa95434cc90809173d9708ed Mon Sep 17 00:00:00 2001
From: Andreas Stöckel <astoecke@techfak.uni-bielefeld.de>
Date: Tue, 3 Feb 2015 21:42:48 +0100
Subject: Added "checkIsa" function to Type that allows to check for an isa
 relationship.

---
 src/core/model/Typesystem.cpp | 47 ++++++++++++++++++++++++++++++++++++++++++
 src/core/model/Typesystem.hpp | 48 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+)

(limited to 'src')

diff --git a/src/core/model/Typesystem.cpp b/src/core/model/Typesystem.cpp
index 7af3e54..7dd5613 100644
--- a/src/core/model/Typesystem.cpp
+++ b/src/core/model/Typesystem.cpp
@@ -67,6 +67,19 @@ bool Type::build(Variant &data, Logger &logger) const
 	return build(data, logger, NullMagicCallback);
 }
 
+bool Type::doCheckIsa(Handle<const Type> type) const
+{
+	return false;
+}
+
+bool Type::checkIsa(Handle<const Type> type) const
+{
+	if (type.get() == this) {
+		return true;
+	}
+	return doCheckIsa(type);
+}
+
 /* Class BoolType */
 
 bool BoolType::doBuild(Variant &data, Logger &logger,
@@ -445,6 +458,19 @@ bool StructType::doValidate(Logger &logger) const
 	       continueValidationCheckDuplicates(attributes, logger);
 }
 
+bool StructType::doCheckIsa(Handle<const Type> type) const
+{
+	Handle<StructType> parent = parentStructure;
+	while (parent != nullptr) {
+		if (parent == type) {
+			return true;
+		}
+		parent = parent->parentStructure;
+	}
+	return false;
+}
+
+
 Rooted<StructType> StructType::createValidated(
     Manager &mgr, std::string name, Handle<Typesystem> system,
     Handle<StructType> parentStructure, const NodeVector<Attribute> &attributes,
@@ -579,6 +605,27 @@ bool ArrayType::doBuild(Variant &data, Logger &logger,
 	return res;
 }
 
+bool ArrayType::doCheckIsa(Handle<const Type> type) const
+{
+	Handle<const Type> t1{this};
+	Handle<const Type> t2{type};
+
+	// Unwrap the array types until only the innermost type is left
+	while (t1->isa(RttiTypes::ArrayType) && t2->isa(RttiTypes::ArrayType)) {
+		t1 = t1.cast<const ArrayType>()->innerType;
+		t2 = t2.cast<const ArrayType>()->innerType;
+	}
+
+	// Abort if only one of the to types is an array type
+	if (t1->isa(RttiTypes::ArrayType) || t2->isa(RttiTypes::ArrayType)) {
+		return false;
+	}
+
+	// Run the isa test on the inntermost type
+	return t1->checkIsa(t2);
+}
+
+
 /* Class UnknownType */
 
 bool UnknownType::doBuild(Variant &, Logger &, const MagicCallback &) const
diff --git a/src/core/model/Typesystem.hpp b/src/core/model/Typesystem.hpp
index b14ff62..7581626 100644
--- a/src/core/model/Typesystem.hpp
+++ b/src/core/model/Typesystem.hpp
@@ -108,6 +108,18 @@ protected:
 	virtual bool doBuild(Variant &data, Logger &logger,
 	                     const MagicCallback &magicCallback) const = 0;
 
+	/**
+	 * May be overriden to check whether an instance of this type logically is
+	 * an instance of the given type. Default implementation always returns
+	 * false.
+	 *
+	 * @param type is the type that should be checked for the "isa"
+	 * relationship.
+	 * @return true if an instance of this type also is an instance of the given
+	 * type, false otherwise.
+	 */
+	virtual bool doCheckIsa(Handle<const Type> type) const;
+
 public:
 	/**
 	 * Set to true, if this type descriptor is a primitive type.
@@ -122,6 +134,10 @@ public:
 	 */
 	virtual Variant create() const = 0;
 
+	/**
+	 * Pure virtual function
+	 */
+
 	/**
 	 * Validates and completes the given variant which was read from a
 	 * user-supplied source.
@@ -165,6 +181,18 @@ public:
 		return build(data, logger);
 	}
 
+	/**
+	 * May be overriden to check whether an instance of this type logically is
+	 * an instance of the given type. This always evaluates to true if the given
+	 * type points at this type descriptor.
+	 *
+	 * @param type is the type that should be checked for the "isa"
+	 * relationship.
+	 * @return true if an instance of this type also is an instance of the given
+	 * type, false otherwise.
+	 */
+	bool checkIsa(Handle<const Type> type) const;
+
 	/**
 	 * Returns the underlying Typesystem instance.
 	 *
@@ -700,6 +728,16 @@ protected:
 	 */
 	bool doValidate(Logger &logger) const override;
 
+	/**
+	 * Returns true if this type has the given type as parent (directly or
+	 * indirectly).
+	 *
+	 * @param type is the type that should be checked for the "isa"
+	 * relationship.
+	 * @return true if the given type is a parent of this type, false otherwise.
+	 */
+	bool doCheckIsa(Handle<const Type> type) const override;
+
 public:
 	/**
 	 * Constructor of the StructType class, creates a new instance
@@ -867,6 +905,16 @@ protected:
 	bool doBuild(Variant &data, Logger &logger,
 	             const MagicCallback &magicCallback) const override;
 
+	/**
+	 * Returns true if this type is equivalent to another given ArrayType.
+	 *
+	 * @param type is the type that should be checked for the "isa"
+	 * relationship.
+	 * @return true if the given type is equivalent to this type, false
+	 * otherwise.
+	 */
+	bool doCheckIsa(Handle<const Type> type) const override;
+
 public:
 	/**
 	 * Constructor of the ArrayType class.
-- 
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