Add support for defining properties from member variables.

This associates properties with member variables and
avoids writing getter and setter methods manually.
The metaCall() method directly accesses the member variable,
so additional method calls can be avoided.
The metaCall() setter code also supports NOTIFY signals,
which means the according signal is emitted when the property
gets written.

Task-number: QTBUG-16852

Change-Id: I88a1f237ea53a1e9cf65fc9ef2e207718eb8b6c3
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>

3 files changed, 40 insertions, 11 deletions

diff --git a/src/tools/moc/generator.cpp b/src/tools/moc/generator.cpp
index 06efd77adc..083b095094 100644
--- a/src/tools/moc/generator.cpp
+++ b/src/tools/moc/generator.cpp
@@ -719,7 +719,9 @@ void Generator::generateProperties()
         uint flags = Invalid;
         if (!isBuiltinType(p.type))
             flags |= EnumOrFlag;
-        if (!p.read.isEmpty())
+        if (!p.member.isEmpty() && !p.constant)
+            flags |= Writable;
+        if (!p.read.isEmpty() || !p.member.isEmpty())
             flags |= Readable;
         if (!p.write.isEmpty()) {
             flags |= Writable;
@@ -893,12 +895,12 @@ void Generator::generateMetacall()
         bool needUser = false;
         for (int i = 0; i < cdef->propertyList.size(); ++i) {
             const PropertyDef &p = cdef->propertyList.at(i);
-            needGet |= !p.read.isEmpty();
+            needGet |= !p.read.isEmpty() || !p.member.isEmpty();
             if (!p.read.isEmpty())
                 needTempVarForGet |= (p.gspec != PropertyDef::PointerSpec
                                       && p.gspec != PropertyDef::ReferenceSpec);
 
-            needSet |= !p.write.isEmpty();
+            needSet |= !p.write.isEmpty() || (!p.member.isEmpty() && !p.constant);
             needReset |= !p.reset.isEmpty();
             needDesignable |= p.designable.endsWith(')');
             needScriptable |= p.scriptable.endsWith(')');
@@ -917,7 +919,7 @@ void Generator::generateMetacall()
             fprintf(out, "        switch (_id) {\n");
             for (int propindex = 0; propindex < cdef->propertyList.size(); ++propindex) {
                 const PropertyDef &p = cdef->propertyList.at(propindex);
-                if (p.read.isEmpty())
+                if (p.read.isEmpty() && p.member.isEmpty())
                     continue;
                 QByteArray prefix;
                 if (p.inPrivateClass.size()) {
@@ -933,9 +935,12 @@ void Generator::generateMetacall()
                 else if (cdef->enumDeclarations.value(p.type, false))
                     fprintf(out, "        case %d: *reinterpret_cast<int*>(_v) = QFlag(%s%s()); break;\n",
                             propindex, prefix.constData(), p.read.constData());
-                else
+                else if (!p.read.isEmpty())
                     fprintf(out, "        case %d: *reinterpret_cast< %s*>(_v) = %s%s(); break;\n",
                             propindex, p.type.constData(), prefix.constData(), p.read.constData());
+                else
+                    fprintf(out, "        case %d: *reinterpret_cast< %s*>(_v) = %s%s; break;\n",
+                            propindex, p.type.constData(), prefix.constData(), p.member.constData());
             }
             fprintf(out, "        }\n");
         }
@@ -952,7 +957,9 @@ void Generator::generateMetacall()
             fprintf(out, "        switch (_id) {\n");
             for (int propindex = 0; propindex < cdef->propertyList.size(); ++propindex) {
                 const PropertyDef &p = cdef->propertyList.at(propindex);
-                if (p.write.isEmpty())
+                if (p.constant)
+                    continue;
+                if (p.write.isEmpty() && p.member.isEmpty())
                     continue;
                 QByteArray prefix;
                 if (p.inPrivateClass.size()) {
@@ -962,9 +969,25 @@ void Generator::generateMetacall()
                 if (cdef->enumDeclarations.value(p.type, false)) {
                     fprintf(out, "        case %d: %s%s(QFlag(*reinterpret_cast<int*>(_v))); break;\n",
                             propindex, prefix.constData(), p.write.constData());
-                } else {
+                } else if (!p.write.isEmpty()) {
                     fprintf(out, "        case %d: %s%s(*reinterpret_cast< %s*>(_v)); break;\n",
                             propindex, prefix.constData(), p.write.constData(), p.type.constData());
+                } else {
+                    fprintf(out, "        case %d:\n", propindex);
+                    fprintf(out, "            if (%s%s != *reinterpret_cast< %s*>(_v)) {\n",
+                            prefix.constData(), p.member.constData(), p.type.constData());
+                    fprintf(out, "                %s%s = *reinterpret_cast< %s*>(_v);\n",
+                            prefix.constData(), p.member.constData(), p.type.constData());
+                    if (!p.notify.isEmpty() && p.notifyId != -1) {
+                        const FunctionDef &f = cdef->signalList.at(p.notifyId);
+                        if (f.arguments.size() == 0)
+                            fprintf(out, "                emit %s();\n", p.notify.constData());
+                        else if (f.arguments.size() == 1 && f.arguments.at(0).normalizedType == p.type)
+                            fprintf(out, "                emit %s(%s%s);\n",
+                                    p.notify.constData(), prefix.constData(), p.member.constData());
+                    }
+                    fprintf(out, "            }\n");
+                    fprintf(out, "            break;\n");
                 }
             }
             fprintf(out, "        }\n");
diff --git a/src/tools/moc/moc.cpp b/src/tools/moc/moc.cpp
index 5fbbd57c22..788033800f 100644
--- a/src/tools/moc/moc.cpp
+++ b/src/tools/moc/moc.cpp
@@ -1059,6 +1059,12 @@ void Moc::createPropertyDef(PropertyDef &propDef)
                 v2 = "()";
         }
         switch (l[0]) {
+        case 'M':
+            if (l == "MEMBER")
+                propDef.member = v;
+            else
+                error(2);
+            break;
         case 'R':
             if (l == "READ")
                 propDef.read = v;
@@ -1099,11 +1105,11 @@ void Moc::createPropertyDef(PropertyDef &propDef)
             error(2);
         }
     }
-    if (propDef.read.isNull()) {
+    if (propDef.read.isNull() && propDef.member.isNull()) {
         QByteArray msg;
         msg += "Property declaration ";
         msg += propDef.name;
-        msg += " has no READ accessor function. The property will be invalid.";
+        msg += " has no READ accessor function or associated MEMBER variable. The property will be invalid.";
         warning(msg.constData());
     }
     if (propDef.constant && !propDef.write.isNull()) {
@@ -1515,7 +1521,7 @@ void Moc::checkProperties(ClassDef *cdef)
     //
     for (int i = 0; i < cdef->propertyList.count(); ++i) {
         PropertyDef &p = cdef->propertyList[i];
-        if (p.read.isEmpty())
+        if (p.read.isEmpty() && p.member.isEmpty())
             continue;
         for (int j = 0; j < cdef->publicList.count(); ++j) {
             const FunctionDef &f = cdef->publicList.at(j);
diff --git a/src/tools/moc/moc.h b/src/tools/moc/moc.h
index 07f8c7c620..cfa56c4da2 100644
--- a/src/tools/moc/moc.h
+++ b/src/tools/moc/moc.h
@@ -127,7 +127,7 @@ struct FunctionDef
 struct PropertyDef
 {
     PropertyDef():notifyId(-1), constant(false), final(false), gspec(ValueSpec), revision(0){}
-    QByteArray name, type, read, write, reset, designable, scriptable, editable, stored, user, notify, inPrivateClass;
+    QByteArray name, type, member, read, write, reset, designable, scriptable, editable, stored, user, notify, inPrivateClass;
     int notifyId;
     bool constant;
     bool final;