Changeset 57055 in webkit for trunk/JavaScriptCore/runtime

Timestamp:

Apr 3, 2010, 11:53:46 PM (15 years ago)

Author:

[email protected]

Message:

​https://bugs.webkit.org/show_bug.cgi?id=37068
Change UString to use a 0 rep for null strings instead of a null object.

Reviewed by Oliver Hunt.

No performance impact.

• JavaScriptCore.exp:
• runtime/InternalFunction.cpp:

(JSC::InternalFunction::InternalFunction):

• runtime/JSString.h:

(JSC::RopeBuilder::JSString):

• runtime/UString.cpp:

(JSC::initializeUString):

• runtime/UString.h:

(JSC::UString::UString):
(JSC::UString::data):
(JSC::UString::size):
(JSC::UString::isNull):
(JSC::UString::isEmpty):
(JSC::UString::cost):

Location:

trunk/JavaScriptCore/runtime

Files:

• InternalFunction.cpp (modified) (1 diff)
• JSString.h (modified) (4 diffs)
• UString.cpp (modified) (2 diffs)
• UString.h (modified) (5 diffs)

trunk/JavaScriptCore/runtime/InternalFunction.cpp

@@ -41 +41 @@
     : JSObject(structure)
 {
-    putDirect(globalData->propertyNames->name, jsString(globalData, name.ustring()), DontDelete | ReadOnly | DontEnum);
+    putDirect(globalData->propertyNames->name, jsString(globalData, name.isNull() ? "" : name.ustring()), DontDelete | ReadOnly | DontEnum);
 }
 

trunk/JavaScriptCore/runtime/JSString.h

@@ -117 +117 @@
             , m_fiberCount(0)
         {
+            ASSERT(!m_value.isNull());
             Heap::heap(this)->reportExtraMemoryCost(value.cost());
         }
@@ -127 +128 @@
             , m_fiberCount(0)
         {
+            ASSERT(!m_value.isNull());
         }
         JSString(JSGlobalData* globalData, PassRefPtr<UString::Rep> value, HasOtherOwnerType)
@@ -134 +136 @@
             , m_fiberCount(0)
         {
+            ASSERT(!m_value.isNull());
         }
         JSString(JSGlobalData* globalData, PassRefPtr<Rope> rope)
@@ -203 +206 @@
             , m_fiberCount(0)
         {
+            ASSERT(!m_value.isNull());
             // nasty hack because we can't union non-POD types
             m_other.m_finalizerCallback = finalizer;

trunk/JavaScriptCore/runtime/UString.cpp

@@ -59 +59 @@
 
 // The null string is immutable, except for refCount.
-UString::Rep* UString::s_nullRep;
 UString* UString::s_nullUString;
 
@@ -68 +67 @@
     UStringImpl::empty();
 
-    UString::s_nullRep = new UStringImpl(0, 0, UStringImpl::ConstructStaticString);
     UString::s_nullUString = new UString;
 }

trunk/JavaScriptCore/runtime/UString.h

@@ -49 +49 @@
     
     public:
-        UString();
+        UString() {}
         UString(const char*); // Constructor for null-terminated string.
         UString(const char*, unsigned length);
@@ -63 +63 @@
         UString(PlacementNewAdoptType)
             : m_rep(PlacementNewAdopt)
-        {
-        }
-
-        ~UString()
         {
         }
@@ -96 +92 @@
         CString UTF8String(bool strict = false) const;
 
-        const UChar* data() const { return m_rep->characters(); }
-
-        bool isNull() const { return m_rep == s_nullRep; }
-        bool isEmpty() const { return !m_rep->length(); }
+        const UChar* data() const
+        {
+            if (!m_rep)
+                return 0;
+            return m_rep->characters();
+        }
+
+        unsigned size() const
+        {
+            if (!m_rep)
+                return 0;
+            return m_rep->length();
+        }
+
+        bool isNull() const { return !m_rep; }
+        bool isEmpty() const { return !m_rep || !m_rep->length(); }
 
         bool is8Bit() const;
-
-        unsigned size() const { return m_rep->length(); }
 
         UChar operator[](unsigned pos) const;
@@ -132 +138 @@
             : m_rep(r)
         {
-            ASSERT(m_rep);
-        }
-
-        size_t cost() const { return m_rep->cost(); }
+        }
+
+        size_t cost() const
+        {
+            if (!m_rep)
+                return 0;
+            return m_rep->cost();
+        }
 
     private:
         RefPtr<Rep> m_rep;
 
-        JS_EXPORTDATA static Rep* s_nullRep;
         static UString* s_nullUString;
 
@@ -194 +203 @@
 
     int compare(const UString&, const UString&);
-
-    inline UString::UString()
-        : m_rep(s_nullRep)
-    {
-    }
 
     // Rule from ECMA 15.2 about what an array index is.