Issue 151 - [Typed objects] Implement dynamically-sized array types

lib/typedObjects/objectTypes.js

Index: lib/typedObjects/objectTypes.js
===================================================================
--- a/lib/typedObjects/objectTypes.js
+++ b/lib/typedObjects/objectTypes.js
@@ -12,23 +12,24 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 "use strict";
 
-let {fixedPropertyDescriptor, getViewsForType, defineProperties} = require("typedObjects/utils");
+let {fixedPropertyDescriptor, getViewsForType, defineProperties, alloc, dealloc} = require("typedObjects/utils");
 let {Reference, TypedReference} = require("typedObjects/references");
 let {uint8, uint32} = require("typedObjects/primitiveTypes");
+let {createArrayType} = require("typedObjects/arrayTypes");
 
-const STATE_UNINITIALIZED = 0;
-const STATE_CREATED = 1;
-const STATE_RELEASING = 2;
+const STATE_UNINITIALIZED = exports.STATE_UNINITIALIZED = 0;
+const STATE_CREATED = exports.STATE_CREATED = 1;
+const STATE_RELEASING = exports.STATE_RELEASING = 2;
 
 /**
  * List of registered types (typeId is the index in that array).
  */
 let types = [];
 
 function fromReference(reference)
 {
@@ -42,60 +43,27 @@ function fromReference(reference)
     });
   }
   else
     return null;
 }
 
 function create()
 {
-  let {bufferIndex, byteOffset} = this.firstFree;
-  if (bufferIndex >= 0)
-  {
-    // There is still a free spot, simply move on firstFree reference
-    [this.firstFree.bufferIndex, this.firstFree.byteOffset] =
-        [this.firstFree.targetBufferIndex, this.firstFree.targetByteOffset];
-  }
-  else
-  {
-    let viewTypes = this.viewTypes;
-    let views = this.views;
-    let byteLength = this.byteLength | 0;
-    let bufferSize = this.bufferSize | 0;
-
-    // Create new buffer and use the first element of it
-    let buffer = new ArrayBuffer(byteLength * bufferSize);
-    bufferIndex = (this.buffers.push(buffer) | 0) - 1;
-    byteOffset = 0;
-    for (let i = 0, l = viewTypes.length | 0; i < l; i++)
-      views[i].push(new viewTypes[i](buffer));
-
-    // Mark last element of the new buffer as the last free spot
-    this.firstFree.bufferIndex = bufferIndex;
-    this.firstFree.byteOffset = (bufferSize - 1) * byteLength;
-    this.firstFree.targetBufferIndex = -1;
-
-    // Make each remaining element of the new buffer point to the next one
-    for (let i = bufferSize - 2; i >= 1; i--)
-    {
-      let nextByteOffset = this.firstFree.byteOffset;
-      this.firstFree.byteOffset = nextByteOffset - byteLength;
-      this.firstFree.targetBufferIndex = bufferIndex;
-      this.firstFree.targetByteOffset = nextByteOffset;
-    }
-  }
+  let [bufferIndex, byteOffset] = alloc(this.firstFree, this.byteLength,
+      this.bufferSize, this.buffers, this.viewTypes, this.views);
 
   let result = Object.create(this.proto, {
     typeId: fixedPropertyDescriptor(this.typeId),
     bufferIndex: fixedPropertyDescriptor(bufferIndex),
     byteOffset: fixedPropertyDescriptor(byteOffset)
   });
 
   result._state = STATE_UNINITIALIZED;
-  for (let [prop, value] of this.cleanupValues)
+  for (let [prop, value] of this.initialValues)
     result[prop] = value;
   result._state = STATE_CREATED;
   result._refCount = 1;
 
   if (this.constructor)
     this.constructor.apply(result, arguments);
   return result;
 }
@@ -108,57 +76,51 @@ function free(obj)
     {
       this.destructor.call(obj);
       if (obj._refCount | 0)
         throw new Error("Reference count is no longer zero after calling the destructor");
     }
   }
   finally
   {
-    for (let [prop, value] of this.cleanupValues)
+    for (let [prop, value] of this.initialValues)
       obj[prop] = value;
 
-    // Mark object as first free spot
-    let oldFreeBufferIndex = this.firstFree.bufferIndex;
-    let oldFreeByteOffset = this.firstFree.byteOffset;
-    this.firstFree.bufferIndex = obj.bufferIndex;
-    this.firstFree.byteOffset = obj.byteOffset;
-    this.firstFree.targetBufferIndex = oldFreeBufferIndex;
-    this.firstFree.targetByteOffset = oldFreeByteOffset;
+    dealloc(this.firstFree, obj.bufferIndex, obj.byteOffset);
   }
 }
 
 function createGetter(offset)
 {
   offset = offset | 0;
 
   let views = Array.prototype.slice.call(arguments, 1);
   let reference = new Reference(types, views);
-  return function()
+  return function(bufferIndex, byteOffset)
   {
-    reference.bufferIndex = this.bufferIndex | 0;
-    reference.byteOffset = (this.byteOffset | 0) + offset;
+    reference.bufferIndex = bufferIndex | 0;
+    reference.byteOffset = (byteOffset | 0) + offset;
     return fromReference(reference);
   };
 }
 
 function createSetter(typeId, offset)
 {
   typeId = typeId | 0;
   offset = offset | 0;
 
   let views = Array.prototype.slice.call(arguments, 2);
   let reference = new Reference(types, views);
-  return function(value)
+  return function(bufferIndex, byteOffset, value)
   {
     if (value && !isInstance(typeId, value))
       throw new Error("Incompatible type");
 
-    reference.bufferIndex = this.bufferIndex | 0;
-    reference.byteOffset = (this.byteOffset | 0) + offset;
+    reference.bufferIndex = bufferIndex | 0;
+    reference.byteOffset = (byteOffset | 0) + offset;
 
     if ((this._state | 0) > STATE_UNINITIALIZED)
     {
       let oldValue = fromReference(reference);
       if (oldValue)
         oldValue.release();
     }
 
@@ -236,22 +198,31 @@ function extend(parentTypeInfo, typeDesc
       if (name in methods)
         type = createSubclassMethod(type, methods[name].value);
       methods[name] = fixedPropertyDescriptor(type);
     }
     else
       throw new Error("Unrecognized type " + type + " given for property " + name);
   }
 
+  // Combine inherited watchers with the ones specified for this object
+  let watchers = parentTypeInfo && parentTypeInfo.watchers;
+  if (meta.watch)
+  {
+    watchers = Object.create(watchers);
+    for (let key in meta.watch)
+      watchers[key] = meta.watch[key];
+  }
+
   let proto = {};
   let buffers = [];
   let viewTypes = [];
   let views = [];
-  let cleanupValues = [];
-  let byteLength = defineProperties(proto, properties, viewTypes, views, 0, cleanupValues);
+  let initialValues = [];
+  let byteLength = defineProperties(proto, properties, viewTypes, views, 0, watchers, initialValues);
   Object.defineProperties(proto, methods);
 
   // Round up to be a multiple of the maximal property size
   byteLength = ((byteLength - 1) | (maxReferenceLength - 1)) + 1;
 
   // We need to be able to store a typed reference in the object's buffer
   byteLength = Math.max(byteLength, TypedReference.byteLength) | 0;
   let typedReferenceViews = getViewsForType(TypedReference, viewTypes, views);
@@ -279,37 +250,39 @@ function extend(parentTypeInfo, typeDesc
   let typeId = types.length | 0;
   let typeInfo = {
     byteLength: byteLength,
     bufferSize: "bufferSize" in meta ? Math.max(meta.bufferSize | 0, 2) : 128,
     firstFree: new TypedReference(typeId, typedReferenceViews),
     proto: proto,
     properties: properties,
     methods: methods,
+    watchers: watchers,
     buffers: buffers,
     viewTypes: viewTypes,
     views: views,
-    cleanupValues: cleanupValues,
+    initialValues: initialValues,
     typeId: typeId,
     parentTypeInfo: parentTypeInfo,
     constructor: constructor,
     destructor: destructor
   };
 
   let result = create.bind(typeInfo);
   Object.defineProperties(result, {
     byteLength: fixedPropertyDescriptor(byteLength),
 
     referenceLength: fixedPropertyDescriptor(Reference.byteLength),
     viewTypes: fixedPropertyDescriptor(Reference.viewTypes),
-    cleanupValue: fixedPropertyDescriptor(null),
+    initialValue: fixedPropertyDescriptor(null),
 
     typeId: fixedPropertyDescriptor(typeId),
     extend: fixedPropertyDescriptor(extend.bind(null, typeInfo)),
     isInstance: fixedPropertyDescriptor(isInstance.bind(null, typeId)),
+    Array: fixedPropertyDescriptor(createArrayType.bind(null, result)),
 
     createGetter: fixedPropertyDescriptor(createGetter),
     createSetter: fixedPropertyDescriptor(createSetter.bind(null, typeId))
   });
   types.push(typeInfo);
   return result;
 }