最近在移植第三方SKIA图形库.发现有内存泄露.简述如下.
SKIA源代码有内存泄露的解决办法.
1) 源码SkMemory_stdlib.cpp中将函数 static SkMutex& get_block_mutex() 修改如下:
static SkMutex& get_block_mutex() {
//fixed by warpo. ADD 35-40.
static SkMutex gbm;
static SkMutex* gBlockMutex = &gbm;
if (NULL == gBlockMutex ) {
gBlockMutex = new SkMutex;
}
return *gBlockMutex;
//原始代码如下:
//static SkMutex* gBlockMutex;
//if (NULL == gBlockMutex) {
// gBlockMutex = new SkMutex;
//}
//return *gBlockMutex;
}
该错是new SkMutex之后未释放内存.
2).源码SkGlyphCache.cpp中的内存泄露.
为SkGlyphCache类增加一个静态函数,然后在程序结束时调用即可:
size_t SkGlyphCache::freeGlyphCache_Globals(/*SkGlyphCache_Globals* globals, size_t bytesNeeded*/)
{
SkGlyphCache_Globals& globals = FIND_GC_GLOBALS();
globals.validate();
size_t bytesFreed = 0;
int count = 0;
// don't do any "small" purges
//size_t minToPurge = globals.fTotalMemoryUsed >> 2;
//if (bytesNeeded < minToPurge)
// bytesNeeded = minToPurge;
SkGlyphCache* cache = FindTail(globals.fHead);
while (cache != NULL ) {
SkGlyphCache* prev = cache->fPrev;
bytesFreed += cache->fMemoryUsed;
#ifdef USE_CACHE_HASH
unsigned index = desc_to_hashindex(cache->fDesc);
if (cache == globals.fHash[index]) {
globals.fHash[index] = NULL;
}
#endif
cache->detach(&globals.fHead);
SkDELETE(cache);
cache = prev;
count += 1;
}
SkASSERT(bytesFreed <= globals.fTotalMemoryUsed);
globals.fTotalMemoryUsed -= bytesFreed;
globals.validate();
#ifdef SPEW_PURGE_STATUS
if (count) {
SkDebugf("purging %dK from font cache [%d entries]\n",
(int)(bytesFreed >> 10), count);
}
#endif
return bytesFreed;
}
在WIN平台下(其它平台未验证)引起该内存泄露的原因是SKIA使用的字体缓存机制,当绘制文字时都会new一些缓存,其中globals是全局静态的一个保存字体缓存数据的结构,但笔者使用源码时发现未释放.所以需要手动调用释放.
3). 需要手动调用类的SkTypefaceCache的purge方法清空缓存.该问题也是由于NEW后未释放造成的.具体流程不详说.可以自己跟踪调试.
转自：http://topic.csdn.net/u/20110914/18/776eed8d-77d5-4d49-b935-978d695746cc.html