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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include "Dalvik.h"
     18 #include "alloc/HeapTable.h"
     19 #include "alloc/HeapInternal.h"
     20 
     21 #include <limits.h> // for INT_MAX
     22 
     23 static const int kLargeHeapRefTableNElems = 1024;
     24 static const int  kFinalizableRefDefault = 128;
     25 
     26 void dvmHeapHeapTableFree(void *ptr)
     27 {
     28     free(ptr);
     29 }
     30 
     31 #define heapRefTableIsFull(refs) \
     32     dvmIsReferenceTableFull(refs)
     33 
     34 bool dvmHeapInitHeapRefTable(HeapRefTable *refs)
     35 {
     36     memset(refs, 0, sizeof(*refs));
     37     return dvmInitReferenceTable(refs, kFinalizableRefDefault, INT_MAX);
     38 }
     39 
     40 /* Frees the array inside the HeapRefTable, not the HeapRefTable itself.
     41  */
     42 void dvmHeapFreeHeapRefTable(HeapRefTable *refs)
     43 {
     44     dvmClearReferenceTable(refs);
     45 }
     46 
     47 /*
     48  * Large, non-contiguous reference tables
     49  */
     50 
     51 bool dvmHeapAddRefToLargeTable(LargeHeapRefTable **tableP, Object *ref)
     52 {
     53     LargeHeapRefTable *table;
     54 
     55     assert(tableP != NULL);
     56     assert(ref != NULL);
     57 
     58     /* Make sure that a table with a free slot is
     59      * at the head of the list.
     60      */
     61     if (*tableP != NULL) {
     62         table = *tableP;
     63         LargeHeapRefTable *prevTable;
     64 
     65         /* Find an empty slot for this reference.
     66          */
     67         prevTable = NULL;
     68         while (table != NULL && heapRefTableIsFull(&table->refs)) {
     69             prevTable = table;
     70             table = table->next;
     71         }
     72         if (table != NULL) {
     73             if (prevTable != NULL) {
     74                 /* Move the table to the head of the list.
     75                  */
     76                 prevTable->next = table->next;
     77                 table->next = *tableP;
     78                 *tableP = table;
     79             }
     80             /* else it's already at the head. */
     81 
     82             goto insert;
     83         }
     84         /* else all tables are already full;
     85          * fall through to the alloc case.
     86          */
     87     }
     88 
     89     /* Allocate a new table.
     90      */
     91     table = calloc(1, sizeof(LargeHeapRefTable));
     92     if (table == NULL) {
     93         LOGE_HEAP("Can't allocate a new large ref table\n");
     94         return false;
     95     }
     96     if (!dvmInitReferenceTable(&table->refs,
     97                                kLargeHeapRefTableNElems,
     98                                INT_MAX)) {
     99         LOGE_HEAP("Can't initialize a new large ref table\n");
    100         dvmHeapHeapTableFree(table);
    101         return false;
    102     }
    103 
    104     /* Stick it at the head.
    105      */
    106     table->next = *tableP;
    107     *tableP = table;
    108 
    109 insert:
    110     /* Insert the reference.
    111      */
    112     assert(table == *tableP);
    113     assert(table != NULL);
    114     assert(!heapRefTableIsFull(&table->refs));
    115     *table->refs.nextEntry++ = ref;
    116 
    117     return true;
    118 }
    119 
    120 bool dvmHeapAddTableToLargeTable(LargeHeapRefTable **tableP, HeapRefTable *refs)
    121 {
    122     LargeHeapRefTable *table;
    123 
    124     /* Allocate a node.
    125      */
    126     table = calloc(1, sizeof(LargeHeapRefTable));
    127     if (table == NULL) {
    128         LOGE_HEAP("Can't allocate a new large ref table\n");
    129         return false;
    130     }
    131     table->refs = *refs;
    132 
    133     /* Insert the table into the list.
    134      */
    135     table->next = *tableP;
    136     *tableP = table;
    137 
    138     return true;
    139 }
    140 
    141 /* Frees everything associated with the LargeHeapRefTable.
    142  */
    143 void dvmHeapFreeLargeTable(LargeHeapRefTable *table)
    144 {
    145     while (table != NULL) {
    146         LargeHeapRefTable *next = table->next;
    147         dvmHeapFreeHeapRefTable(&table->refs);
    148         dvmHeapHeapTableFree(table);
    149         table = next;
    150     }
    151 }
    152 
    153 Object *dvmHeapGetNextObjectFromLargeTable(LargeHeapRefTable **pTable)
    154 {
    155     LargeHeapRefTable *table;
    156     Object *obj;
    157 
    158     assert(pTable != NULL);
    159 
    160     obj = NULL;
    161     table = *pTable;
    162     if (table != NULL) {
    163         HeapRefTable *refs = &table->refs;
    164 
    165         /* We should never have an empty table node in the list.
    166          */
    167         assert(dvmReferenceTableEntries(refs) != 0);
    168 
    169         /* Remove and return the last entry in the list.
    170          */
    171         obj = *--refs->nextEntry;
    172 
    173         /* If this was the last entry in the table node,
    174          * free it and patch up the list.
    175          */
    176         if (refs->nextEntry == refs->table) {
    177             *pTable = table->next;
    178             dvmClearReferenceTable(refs);
    179             dvmHeapHeapTableFree(table);
    180         }
    181     }
    182 
    183     return obj;
    184 }
    185 
    186 void dvmHeapMarkLargeTableRefs(LargeHeapRefTable *table)
    187 {
    188     while (table != NULL) {
    189         Object **ref, **lastRef;
    190 
    191         ref = table->refs.table;
    192         lastRef = table->refs.nextEntry;
    193         while (ref < lastRef) {
    194             dvmMarkObjectNonNull(*ref++);
    195         }
    196         table = table->next;
    197     }
    198 }
    199