improve memory management scheme of QScriptString(Private)

Get rid of QPointer.
Use linked list of privates (like was recently done for QScriptValue).
Allocate the private on the stack when we can.

Reviewed-by: Olivier Goffart

1 files changed, 34 insertions, 19 deletions

diff --git a/src/script/api/qscriptstring.cpp b/src/script/api/qscriptstring.cpp
index 6de1d88..8c818e1 100644
--- a/src/script/api/qscriptstring.cpp
+++ b/src/script/api/qscriptstring.cpp
@@ -39,10 +39,10 @@
 **
 ****************************************************************************/
 
-#include "config.h"
 #include "qscriptstring.h"
-
 #include "qscriptstring_p.h"
+#include "qscriptengine.h"
+#include "qscriptengine_p.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -70,22 +70,6 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
-  \internal
-*/
-QScriptStringPrivate::QScriptStringPrivate(QScriptEngine *e, const JSC::Identifier &id)
-    : engine(e), identifier(id)
-{
-    ref = 0;
-}
-
-/*!
-  \internal
-*/
-QScriptStringPrivate::~QScriptStringPrivate()
-{
-}
-
-/*!
   Constructs an invalid QScriptString.
 */
 QScriptString::QScriptString()
@@ -99,6 +83,13 @@ QScriptString::QScriptString()
 QScriptString::QScriptString(const QScriptString &other)
     : d_ptr(other.d_ptr)
 {
+    if (d_func() && (d_func()->type == QScriptStringPrivate::StackAllocated)) {
+        Q_ASSERT(d_func()->ref != 1);
+        d_ptr.detach();
+        d_func()->ref = 1;
+        d_func()->type = QScriptStringPrivate::HeapAllocated;
+        d_func()->engine->registerScriptString(d_func());
+    }
 }
 
 /*!
@@ -106,6 +97,19 @@ QScriptString::QScriptString(const QScriptString &other)
 */
 QScriptString::~QScriptString()
 {
+    Q_D(QScriptString);
+    if (d) {
+        switch (d->type) {
+        case QScriptStringPrivate::StackAllocated:
+            Q_ASSERT(d->ref == 1);
+            d->ref.ref(); // avoid deletion
+            break;
+        case QScriptStringPrivate::HeapAllocated:
+            if (d->engine && (d->ref == 1))
+                d->engine->unregisterScriptString(d);
+            break;
+        }
+    }
 }
 
 /*!
@@ -113,7 +117,18 @@ QScriptString::~QScriptString()
 */
 QScriptString &QScriptString::operator=(const QScriptString &other)
 {
+    if (d_func() && d_func()->engine && (d_func()->ref == 1) && (d_func()->type == QScriptStringPrivate::HeapAllocated)) {
+        // current d_ptr will be deleted at the assignment below, so unregister it first
+        d_func()->engine->unregisterScriptString(d_func());
+    }
     d_ptr = other.d_ptr;
+    if (d_func() && (d_func()->type == QScriptStringPrivate::StackAllocated)) {
+        Q_ASSERT(d_func()->ref != 1);
+        d_ptr.detach();
+        d_func()->ref = 1;
+        d_func()->type = QScriptStringPrivate::HeapAllocated;
+        d_func()->engine->registerScriptString(d_func());
+    }
     return *this;
 }
 
@@ -137,7 +152,7 @@ bool QScriptString::operator==(const QScriptString &other) const
     if (d == other.d_func())
         return true;
     if (!d || !other.d_func())
-        return false;
+        return d == other.d_func();
     if (d->engine != other.d_func()->engine)
         return false;
     if (!d->engine)