Changed data structures for root management. Added ObjectScanner to abstract object scanning.

js2/src/collector.cpp

@@ -47,13 +47,13 @@ Collector::~Collector()
 }
 
 void
-Collector::addRoot(void* root, size_type n)
+Collector::addRoot(pointer* root, size_type n)
 {
-    mRoots.push_back(RootSegment(pointer(root), n));
+    mRoots.push_back(RootSegment(root, n));
 }
 
 void
-Collector::removeRoot(void* root)
+Collector::removeRoot(pointer* root)
 {
     for (RootSegments::iterator i = mRoots.begin(), e = mRoots.end(); i != e; ++i) {
         if (i->first == root) {
@@ -118,8 +118,8 @@ Collector::collect()
     for (RootSegments::iterator i = mRoots.begin(), e = mRoots.end(); i != e; ++i) {
         RootSegment& r = *i;
         
-        pointer* refs = (pointer*) r.first;
-        pointer* limit = (pointer*) (r.first + r.second);
+        pointer* refs = r.first;
+        pointer* limit = r.first + r.second;
         while (refs < limit) {
             pointer& ref = *refs++;
             if (ref) {
@@ -200,7 +200,7 @@ void testCollector()
     Collector gc;
     
     ConsCell* head = 0;
-    gc.addRoot(&head, sizeof(ConsCell*));
+    gc.addRoot(reinterpret_cast<Collector::pointer*>(&head));
     
     const uint32 kCellCount = 100;
     

js2/src/collector.h

@@ -58,7 +58,7 @@ namespace JavaScript
         kObjectSpaceSize = 1024 * 1024,
         kFloatSpaceSize = kObjectSpaceSize / sizeof(float64)
     };
-
+    
     // collector entry points.
     class Collector {
     public:
@@ -67,6 +67,20 @@ namespace JavaScript
         typedef char *pointer;
         typedef const char *const_pointer;
 
+        /**
+         * Abstract class used by clients of the collector to scan objects.
+         */
+        class ObjectScanner {
+        public:
+            /**
+             * For each object associated with this scanner, the collector
+             * will call the scan method until it returns NULL. The return
+             * value should be a pointer to a slot in the object that
+             * contains a valid pointer or NULL.
+             */
+            virtual pointer* scan(size_type& offset) = 0;
+        };
+        
         struct ObjectHeader {
             size_type mSize;
             pointer mType;
@@ -75,8 +89,12 @@ namespace JavaScript
         Collector();
         ~Collector();
 
-        void addRoot(void* root, size_type n);
-        void removeRoot(void* root);
+        /**
+         * Adds a root, which is required to be a densely packed array of pointers.
+         * Each element of a root array must contain either a valid pointer or NULL.
+         */
+        void addRoot(pointer* root, size_type count = 1);
+        void removeRoot(pointer* root);
 
         pointer allocateObject(size_type n, pointer type = 0);
         float64* allocateFloat64(float64 value = 0.0);
@@ -139,7 +157,7 @@ namespace JavaScript
         Space<char> mObjectSpace;
         Space<float64> mFloatSpace;
 
-        typedef pair<pointer, size_type> RootSegment;
+        typedef pair<pointer*, size_type> RootSegment;
         typedef deque<RootSegment> RootSegments;
         RootSegments mRoots;