Copy the KDE 3.5 branch to branches/trinity for new KDE 3.5 features.

BUG:215923


git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/kdelibs@1054174 283d02a7-25f6-0310-bc7c-ecb5cbfe19da

1 files changed, 312 insertions, 0 deletions

diff --git a/kjs/collector.cpp b/kjs/collector.cpp
new file mode 100644
index 000000000..62d594329
--- /dev/null
+++ b/kjs/collector.cpp
@@ -0,0 +1,312 @@
+// -*- c-basic-offset: 2 -*-
+/*
+ *  This file is part of the KDE libraries
+ *  Copyright (C) 2003 Apple Computer, Inc.
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#include "collector.h"
+
+#include "value.h"
+#include "internal.h"
+
+#ifndef MAX
+#define MAX(a,b) ((a) > (b) ? (a) : (b))
+#endif
+
+namespace KJS {
+
+// tunable parameters
+const int MINIMUM_CELL_SIZE = 56;
+const int BLOCK_SIZE = (8 * 4096);
+const int SPARE_EMPTY_BLOCKS = 2;
+const int MIN_ARRAY_SIZE = 14;
+const int GROWTH_FACTOR = 2;
+const int LOW_WATER_FACTOR = 4;
+const int ALLOCATIONS_PER_COLLECTION = 1000;
+
+// derived constants
+const int CELL_ARRAY_LENGTH = (MINIMUM_CELL_SIZE / sizeof(double)) + (MINIMUM_CELL_SIZE % sizeof(double) != 0 ? sizeof(double) : 0);
+const int CELL_SIZE = CELL_ARRAY_LENGTH * sizeof(double);
+const int CELLS_PER_BLOCK = ((BLOCK_SIZE * 8 - sizeof(int) * 8 - sizeof(void *) * 8) / (CELL_SIZE * 8));
+
+
+
+struct CollectorCell {
+  double memory[CELL_ARRAY_LENGTH];
+};
+
+
+struct CollectorBlock {
+  CollectorCell cells[CELLS_PER_BLOCK];
+  int usedCells;
+  CollectorCell *freeList;
+};
+
+struct CollectorHeap {
+  CollectorBlock **blocks;
+  int numBlocks;
+  int usedBlocks;
+  int firstBlockWithPossibleSpace;
+
+  CollectorCell **oversizeCells;
+  int numOversizeCells;
+  int usedOversizeCells;
+
+  int numLiveObjects;
+  int numAllocationsSinceLastCollect;
+};
+
+static CollectorHeap heap = {NULL, 0, 0, 0, NULL, 0, 0, 0, 0};
+
+bool Collector::memoryFull = false;
+
+void* Collector::allocate(size_t s)
+{
+  if (s == 0)
+    return 0L;
+
+  // collect if needed
+  if (++heap.numAllocationsSinceLastCollect >= ALLOCATIONS_PER_COLLECTION) {
+    collect();
+  }
+
+  if (s > (unsigned)CELL_SIZE) {
+    // oversize allocator
+    if (heap.usedOversizeCells == heap.numOversizeCells) {
+      heap.numOversizeCells = MAX(MIN_ARRAY_SIZE, heap.numOversizeCells * GROWTH_FACTOR);
+      heap.oversizeCells = (CollectorCell **)realloc(heap.oversizeCells, heap.numOversizeCells * sizeof(CollectorCell *));
+    }
+
+    void *newCell = malloc(s);
+    heap.oversizeCells[heap.usedOversizeCells] = (CollectorCell *)newCell;
+    heap.usedOversizeCells++;
+    heap.numLiveObjects++;
+
+    ((ValueImp *)(newCell))->_flags = 0;
+    return newCell;
+  }
+
+  // slab allocator
+
+  CollectorBlock *targetBlock = NULL;
+
+  int i;
+  for (i = heap.firstBlockWithPossibleSpace; i < heap.usedBlocks; i++) {
+    if (heap.blocks[i]->usedCells < CELLS_PER_BLOCK) {
+      targetBlock = heap.blocks[i];
+      break;
+    }
+  }
+
+  heap.firstBlockWithPossibleSpace = i;
+
+  if (targetBlock == NULL) {
+    // didn't find one, need to allocate a new block
+
+    if (heap.usedBlocks == heap.numBlocks) {
+      heap.numBlocks = MAX(MIN_ARRAY_SIZE, heap.numBlocks * GROWTH_FACTOR);
+      heap.blocks = (CollectorBlock **)realloc(heap.blocks, heap.numBlocks * sizeof(CollectorBlock *));
+    }
+
+    targetBlock = (CollectorBlock *)calloc(1, sizeof(CollectorBlock));
+    targetBlock->freeList = targetBlock->cells;
+    heap.blocks[heap.usedBlocks] = targetBlock;
+    heap.usedBlocks++;
+  }
+
+  // find a free spot in the block and detach it from the free list
+  CollectorCell *newCell = targetBlock->freeList;
+
+  ValueImp *imp = (ValueImp*)newCell;
+  if (imp->_vd != NULL) {
+    targetBlock->freeList = (CollectorCell*)(imp->_vd);
+  } else if (targetBlock->usedCells == (CELLS_PER_BLOCK - 1)) {
+    // last cell in this block
+    targetBlock->freeList = NULL;
+  } else {
+    // all next pointers are initially 0, meaning "next cell"
+    targetBlock->freeList = newCell + 1;
+  }
+
+  targetBlock->usedCells++;
+  heap.numLiveObjects++;
+
+  ((ValueImp *)(newCell))->_flags = 0;
+  return (void *)(newCell);
+}
+
+bool Collector::collect()
+{
+  bool deleted = false;
+
+  // MARK: first mark all referenced objects recursively
+  // starting out from the set of root objects
+  if (InterpreterImp::s_hook) {
+    InterpreterImp *scr = InterpreterImp::s_hook;
+    do {
+      //fprintf( stderr, "Collector marking interpreter %p\n",(void*)scr);
+      scr->mark();
+      scr = scr->next;
+    } while (scr != InterpreterImp::s_hook);
+  }
+
+  // mark any other objects that we wouldn't delete anyway
+  for (int block = 0; block < heap.usedBlocks; block++) {
+
+    int minimumCellsToProcess = heap.blocks[block]->usedCells;
+    CollectorBlock *curBlock = heap.blocks[block];
+
+    for (int cell = 0; cell < CELLS_PER_BLOCK; cell++) {
+      if (minimumCellsToProcess < cell) {
+	goto skip_block_mark;
+      }
+
+      ValueImp *imp = (ValueImp *)(curBlock->cells + cell);
+
+      if (!(imp->_flags & ValueImp::VI_DESTRUCTED)) {
+
+	if ((imp->_flags & (ValueImp::VI_CREATED|ValueImp::VI_MARKED)) == ValueImp::VI_CREATED &&
+	    ((imp->_flags & ValueImp::VI_GCALLOWED) == 0 || imp->refcount != 0)) {
+	  imp->mark();
+	}
+      } else {
+	minimumCellsToProcess++;
+      }
+    }
+  skip_block_mark: ;
+  }
+
+  for (int cell = 0; cell < heap.usedOversizeCells; cell++) {
+    ValueImp *imp = (ValueImp *)heap.oversizeCells[cell];
+    if ((imp->_flags & (ValueImp::VI_CREATED|ValueImp::VI_MARKED)) == ValueImp::VI_CREATED &&
+	((imp->_flags & ValueImp::VI_GCALLOWED) == 0 || imp->refcount != 0)) {
+      imp->mark();
+    }
+  }
+
+  // SWEEP: delete everything with a zero refcount (garbage) and unmark everything else
+
+  int emptyBlocks = 0;
+
+  for (int block = 0; block < heap.usedBlocks; block++) {
+    CollectorBlock *curBlock = heap.blocks[block];
+
+    int minimumCellsToProcess = curBlock->usedCells;
+
+    for (int cell = 0; cell < CELLS_PER_BLOCK; cell++) {
+      if (minimumCellsToProcess < cell) {
+	goto skip_block_sweep;
+      }
+
+      ValueImp *imp = (ValueImp *)(curBlock->cells + cell);
+
+      if (!(imp->_flags & ValueImp::VI_DESTRUCTED)) {
+	if (!imp->refcount && imp->_flags == (ValueImp::VI_GCALLOWED | ValueImp::VI_CREATED)) {
+	  //fprintf( stderr, "Collector::deleting ValueImp %p (%s)\n", (void*)imp, typeid(*imp).name());
+	  // emulate destructing part of 'operator delete()'
+	  imp->~ValueImp();
+	  curBlock->usedCells--;
+	  heap.numLiveObjects--;
+	  deleted = true;
+
+	  // put it on the free list
+	  imp->_vd = (ValueImpPrivate*)curBlock->freeList;
+	  curBlock->freeList = (CollectorCell *)imp;
+
+	} else {
+	  imp->_flags &= ~ValueImp::VI_MARKED;
+	}
+      } else {
+	minimumCellsToProcess++;
+      }
+    }
+
+  skip_block_sweep:
+
+    if (heap.blocks[block]->usedCells == 0) {
+      emptyBlocks++;
+      if (emptyBlocks > SPARE_EMPTY_BLOCKS) {
+#ifndef DEBUG_COLLECTOR
+	free(heap.blocks[block]);
+#endif
+	// swap with the last block so we compact as we go
+	heap.blocks[block] = heap.blocks[heap.usedBlocks - 1];
+	heap.usedBlocks--;
+	block--; // Don't move forward a step in this case
+
+	if (heap.numBlocks > MIN_ARRAY_SIZE && heap.usedBlocks < heap.numBlocks / LOW_WATER_FACTOR) {
+	  heap.numBlocks = heap.numBlocks / GROWTH_FACTOR;
+	  heap.blocks = (CollectorBlock **)realloc(heap.blocks, heap.numBlocks * sizeof(CollectorBlock *));
+	}
+      }
+    }
+  }
+
+  if (deleted) {
+    heap.firstBlockWithPossibleSpace = 0;
+  }
+
+  int cell = 0;
+  while (cell < heap.usedOversizeCells) {
+    ValueImp *imp = (ValueImp *)heap.oversizeCells[cell];
+
+    if (!imp->refcount &&
+	imp->_flags == (ValueImp::VI_GCALLOWED | ValueImp::VI_CREATED)) {
+
+      imp->~ValueImp();
+#ifndef DEBUG_COLLECTOR
+      free((void *)imp);
+#endif
+
+      // swap with the last oversize cell so we compact as we go
+      heap.oversizeCells[cell] = heap.oversizeCells[heap.usedOversizeCells - 1];
+
+      heap.usedOversizeCells--;
+      deleted = true;
+      heap.numLiveObjects--;
+
+      if (heap.numOversizeCells > MIN_ARRAY_SIZE && heap.usedOversizeCells < heap.numOversizeCells / LOW_WATER_FACTOR) {
+	heap.numOversizeCells = heap.numOversizeCells / GROWTH_FACTOR;
+	heap.oversizeCells = (CollectorCell **)realloc(heap.oversizeCells, heap.numOversizeCells * sizeof(CollectorCell *));
+      }
+
+    } else {
+      imp->_flags &= ~ValueImp::VI_MARKED;
+      cell++;
+    }
+  }
+
+  heap.numAllocationsSinceLastCollect = 0;
+
+  memoryFull = (heap.numLiveObjects >= KJS_MEM_LIMIT);
+
+  return deleted;
+}
+
+int Collector::size()
+{
+  return heap.numLiveObjects;
+}
+
+#ifdef KJS_DEBUG_MEM
+void Collector::finalCheck()
+{
+}
+#endif
+
+} // namespace KJS