asherkin@263: /* vim: set ts=4 sw=4 tw=99 et:
asherkin@263:  *
asherkin@263:  * Copyright (C) 2012 David Anderson
asherkin@263:  *
asherkin@263:  * This file is part of SourcePawn.
asherkin@263:  *
asherkin@263:  * SourcePawn is free software: you can redistribute it and/or modify it under
asherkin@263:  * the terms of the GNU General Public License as published by the Free
asherkin@263:  * Software Foundation, either version 3 of the License, or (at your option)
asherkin@263:  * any later version.
asherkin@263:  * 
asherkin@263:  * SourcePawn is distributed in the hope that it will be useful, but WITHOUT ANY
asherkin@263:  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
asherkin@263:  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
asherkin@263:  *
asherkin@263:  * You should have received a copy of the GNU General Public License along with
asherkin@263:  * SourcePawn. If not, see http://www.gnu.org/licenses/.
asherkin@263:  */
asherkin@263: #ifndef _include_jc_root_scopes_h_
asherkin@263: #define _include_jc_root_scopes_h_
asherkin@263: 
asherkin@263: #include "../include/keima.h"
asherkin@263: #include "Objects.h"
asherkin@263: #include "VirtualObjectVisitor.h"
asherkin@263: 
asherkin@263: namespace ke {
asherkin@263: 
asherkin@263: class RootScope;
asherkin@263: 
asherkin@263: // A RootScopeManager is essentially a specialized PoolAllocator that can
asherkin@263: // only allocate Object ** entries. It is used to allow huge, temporary
asherkin@263: // heap data structures like ASTs to hold safe references to objects. When
asherkin@263: // the data structures is no longer needed, all of the roots are removed
asherkin@263: // at once.
asherkin@263: class RootScopeManager
asherkin@263: {
asherkin@263:     static const size_t kObjectsPerBlock = 4096;
asherkin@263: 
asherkin@263:     struct Block {
asherkin@263:         Object *objects[kObjectsPerBlock];
asherkin@263:         Object **cur;
asherkin@263:         Object **end;
asherkin@263:         Block *prev;
asherkin@263: 
asherkin@263:         Block(Block *prev)
asherkin@263:           : cur(objects),
asherkin@263:             end(objects + kObjectsPerBlock),
asherkin@263:             prev(prev)
asherkin@263:         {
asherkin@263:         }
asherkin@263:     };
asherkin@263: 
asherkin@263:   private:
asherkin@263:     bool grow();
asherkin@263:     void unwindSlow(Object **position);
asherkin@263: 
asherkin@263:   public:
asherkin@263:     RootScopeManager();
asherkin@263:     ~RootScopeManager();
asherkin@263: 
asherkin@263:     Object **position() const {
asherkin@263:         return blocks_->cur;
asherkin@263:     }
asherkin@263: 
asherkin@263:     void unwind(Object **position) {
asherkin@263:         if (position >= blocks_->cur && position <= blocks_->end) {
asherkin@263:             blocks_->cur = position;
asherkin@263:             return;
asherkin@263:         }
asherkin@263:         unwindSlow(position);
asherkin@263:     }
asherkin@263: 
asherkin@263:     Object **make(Object *obj) {
asherkin@263:         assert(scope_);
asherkin@263:         if (blocks_->cur + 1 > blocks_->end) {
asherkin@263:             if (!grow())
asherkin@263:                 return NULL;
asherkin@263:         }
asherkin@263:         Object **ptr = blocks_->cur;
asherkin@263:         blocks_->cur++;
asherkin@263:         *ptr = obj;
asherkin@263:         return ptr;
asherkin@263:     }
asherkin@263: 
asherkin@263:     Ke::HandleScope **scope() {
asherkin@263:         return &scope_;
asherkin@263:     }
asherkin@263: 
asherkin@263:     void accept(VirtualObjectVisitor *visitor);
asherkin@263: 
asherkin@263:   private:
asherkin@263:     Block *blocks_;
asherkin@263:     Block first_;
asherkin@263:     Ke::HandleScope *scope_;
asherkin@263: };
asherkin@263: 
asherkin@263: class RootScope : public Ke::HandleScope
asherkin@263: {
asherkin@263:   public:
asherkin@263:     // These are implemented in Zone.h.
asherkin@263:     inline RootScope(Zone *zone);
asherkin@263: };
asherkin@263: 
asherkin@263: }
asherkin@263: 
asherkin@263: #endif // _include_jc_root_scope_h_