refs #4909 improvied the weak assignment operator to create weak references to hashes and lists

Author: davidnich

CMakeLists.txt

@@ -507,6 +507,8 @@ set(LIBQORE_CPP_SRC
     lib/ThreadClosureVariableStack.cpp
     lib/ThreadLocalVariableData.cpp
     lib/WeakReferenceNode.cpp
+    lib/WeakListReferenceNode.cpp
+    lib/WeakHashReferenceNode.cpp
     lib/QoreProgram.cpp
     lib/QoreProgramHelper.cpp
     lib/QoreNamespace.cpp

Makefile.am

@@ -867,6 +867,8 @@ noinst_HEADERS = \
 	include/qore/intern/QoreHashListIterator.h \
 	include/qore/intern/QoreListHashIterator.h \
 	include/qore/intern/WeakReferenceNode.h \
+	include/qore/intern/WeakHashReferenceNode.h \
+	include/qore/intern/WeakListReferenceNode.h \
 	include/qore/intern/SingleValueIterator.h \
 	include/qore/intern/RangeIterator.h \
 	include/qore/intern/ThreadPool.h \

doxygen/lang/900_release_notes.dox.tmpl

@@ -102,6 +102,8 @@
         (<a href="https://github.com/qorelanguage/qore/issues/4825">issue 4825</a>)
       - fixed a bug where any additionalProperties would cause all properties to be accepted
         (<a href="https://github.com/qorelanguage/qore/issues/4823">issue 4823</a>)
+    - improved the weak assignment operator to allow weak references to hashes and list containers
+      (<a href="https://github.com/qorelanguage/qore/issues/4909">issue 4909</a>)
     - fixed a bug in deterministic garbage collection with class copy() methods
       (<a href="https://github.com/qorelanguage/qore/issues/4905">issue 4905</a>)
     - fixed a bug where %Qore would raise recusive constant exceptions when parsing in cases where values were not in

include/qore/QoreHashNode.h

@@ -389,6 +389,18 @@ class QoreHashNode : public AbstractQoreNode {
 
     static const qore_type_t TYPE = NT_HASH;
 
+    //! Increments the weak reference count for this object
+    /** @since %Qore 2.0
+    */
+    DLLEXPORT void weakRef();
+
+    //! Decrements the weak reference count for this object
+    /** @return if \c true then the object was deleted
+
+        @since %Qore 2.0
+    */
+    DLLEXPORT bool weakDeref();
+
     //! initializes during parsing
     DLLLOCAL virtual int parseInit(QoreValue& val, QoreParseContext& parse_context);
 

include/qore/QoreListNode.h

@@ -412,6 +412,18 @@ class QoreListNode : public AbstractQoreNode {
     */
     DLLEXPORT const QoreTypeInfo* getTypeInfo() const;
 
+    //! Increments the weak reference count for this object
+    /** @since %Qore 2.0
+    */
+    DLLEXPORT void weakRef();
+
+    //! Decrements the weak reference count for this object
+    /** @return if \c true then the object was deleted
+
+        @since %Qore 2.0
+    */
+    DLLEXPORT bool weakDeref();
+
     // needed only while parsing
     //! this function is not exported in the qore library
     DLLLOCAL QoreListNode(bool i);

include/qore/QoreValue.h

@@ -643,28 +643,28 @@ class ValueEvalRefHolder : public ValueOptionalRefHolder {
 
     //! creates the object with with no evaluation
     /** @since %Qore 0.8.13.1
-     */
+    */
     DLLEXPORT ValueEvalRefHolder(ExceptionSink* xs);
 
     //! evaluates the argument, returns -1 for error, 0 = OK
     /** @since %Qore 0.8.13.1
-     */
+    */
     DLLEXPORT int eval(const AbstractQoreNode* exp);
 
     //! evaluates the argument, returns -1 for error, 0 = OK
     /** @since %Qore 0.9
-     */
+    */
     DLLEXPORT int eval(const QoreValue exp);
 
 protected:
     //! evaluates the argument, returns -1 for error, 0 = OK
     /** @since %Qore 0.8.13.1
-     */
+    */
     DLLLOCAL int evalIntern(const AbstractQoreNode* exp);
 
     //! evaluates the argument, returns -1 for error, 0 = OK
     /** @since %Qore 0.9
-     */
+    */
     DLLLOCAL int evalIntern(const QoreValue& exp);
 };
 

include/qore/intern/LocalVar.h

@@ -39,6 +39,8 @@
 #include "qore/intern/RSet.h"
 #include "qore/ReferenceNode.h"
 #include "qore/intern/WeakReferenceNode.h"
+#include "qore/intern/WeakHashReferenceNode.h"
+#include "qore/intern/WeakListReferenceNode.h"
 
 #include <atomic>
 
@@ -184,6 +186,16 @@ class LocalVarValue : public VarValueBase {
             return val.get<WeakReferenceNode>()->get();
         }
 
+        if (val.getType() == NT_WEAKREF_HASH) {
+            needs_deref = false;
+            return val.get<WeakHashReferenceNode>()->get();
+        }
+
+        if (val.getType() == NT_WEAKREF_LIST) {
+            needs_deref = false;
+            return val.get<WeakListReferenceNode>()->get();
+        }
+
         return val.getReferencedValue(needs_deref);
     }
 
@@ -202,6 +214,14 @@ class LocalVarValue : public VarValueBase {
             return val.get<WeakReferenceNode>()->get()->refSelf();
         }
 
+        if (val.getType() == NT_WEAKREF_HASH) {
+            return val.get<WeakHashReferenceNode>()->get()->refSelf();
+        }
+
+        if (val.getType() == NT_WEAKREF_LIST) {
+            return val.get<WeakListReferenceNode>()->get()->refSelf();
+        }
+
         return val.getReferencedValue();
     }
 };
@@ -275,6 +295,16 @@ struct ClosureVarValue : public VarValueBase, public RObject {
             return val.get<WeakReferenceNode>()->get();
         }
 
+        if (val.getType() == NT_WEAKREF_HASH) {
+            needs_deref = false;
+            return val.get<WeakHashReferenceNode>()->get();
+        }
+
+        if (val.getType() == NT_WEAKREF_LIST) {
+            needs_deref = false;
+            return val.get<WeakListReferenceNode>()->get();
+        }
+
         return val.getReferencedValue();
     }
 
@@ -291,6 +321,14 @@ struct ClosureVarValue : public VarValueBase, public RObject {
             return val.get<WeakReferenceNode>()->get()->refSelf();
         }
 
+        if (val.getType() == NT_WEAKREF_HASH) {
+            return val.get<WeakHashReferenceNode>()->get();
+        }
+
+        if (val.getType() == NT_WEAKREF_LIST) {
+            return val.get<WeakListReferenceNode>()->get();
+        }
+
         return val.getReferencedValue();
     }
 

include/qore/intern/ParseNode.h

@@ -34,6 +34,8 @@
 #define _QORE_PARSENODE_H
 
 #include "qore/intern/WeakReferenceNode.h"
+#include "qore/intern/WeakHashReferenceNode.h"
+#include "qore/intern/WeakListReferenceNode.h"
 
 class ParseNode : public SimpleQoreNode {
 public:

include/qore/intern/QoreAssignmentOperatorNode.h

@@ -35,7 +35,8 @@
 class QoreAssignmentOperatorNode : public QoreBinaryLValueOperatorNode {
 OP_COMMON
 public:
-    DLLLOCAL QoreAssignmentOperatorNode(const QoreProgramLocation* loc, QoreValue left, QoreValue right) : QoreBinaryLValueOperatorNode(loc, left, right) {
+    DLLLOCAL QoreAssignmentOperatorNode(const QoreProgramLocation* loc, QoreValue left, QoreValue right) :
+            QoreBinaryLValueOperatorNode(loc, left, right) {
     }
 
     DLLLOCAL virtual QoreOperatorNode* copyBackground(ExceptionSink* xsink) const {

include/qore/intern/QoreHashNodeIntern.h

@@ -124,9 +124,11 @@ class qore_hash_private {
     const TypedHashDecl* hashdecl = nullptr;
     const QoreTypeInfo* complexTypeInfo = nullptr;
     unsigned obj_count = 0;
+    QoreReferenceCounter weakRefs;
 #ifdef DEBUG
     bool is_obj = false;
 #endif
+    bool valid = true;
 
     DLLLOCAL qore_hash_private() {
     }
@@ -137,6 +139,14 @@ class qore_hash_private {
         assert(member_list.empty());
     }
 
+    DLLLOCAL int checkValid(ExceptionSink* xsink) {
+        if (!valid) {
+            xsink->raiseException("HASH-ERROR", "Cannot modify a hash that has already gone out of scope");
+            return -1;
+        }
+        return 0;
+    }
+
     DLLLOCAL QoreValue getKeyValueIntern(const char* key) const;
 
     DLLLOCAL QoreValue getKeyValueExistence(const char* key, bool& exists, ExceptionSink* xsink) const;
@@ -478,6 +488,7 @@ class qore_hash_private {
         member_list.clear();
         hm.clear();
         obj_count = 0;
+        valid = false;
         return true;
     }
 
@@ -534,6 +545,17 @@ class qore_hash_private {
         return hashdecl;
     }
 
+    DLLLOCAL void weakRef() {
+        weakRefs.ROreference();
+    }
+
+    DLLLOCAL bool weakDeref() {
+        if (weakRefs.ROdereference()) {
+            return true;
+        }
+        return false;
+    }
+
     DLLLOCAL static QoreHashNode* getPlainHash(QoreHashNode* h) {
         if (!h->priv->hashdecl && !h->priv->complexTypeInfo)
             return h;