Fix for bug 3244 - new feed not removed from cleanupstack when parsing OPML
/*** 2007 October 14**** The author disclaims copyright to this source code. In place of** a legal notice, here is a blessing:**** May you do good and not evil.** May you find forgiveness for yourself and forgive others.** May you share freely, never taking more than you give.***************************************************************************** This file contains the C functions that implement a memory** allocation subsystem for use by SQLite. **** This version of the memory allocation subsystem omits all** use of malloc(). All dynamically allocatable memory is** contained in a static array, mem.aPool[]. The size of this** fixed memory pool is SQLITE_MEMORY_SIZE bytes.**** This version of the memory allocation subsystem is used if** and only if SQLITE_MEMORY_SIZE is defined.**** $Id: mem3.cpp 1282 2008-11-13 09:31:33Z LarsPson $*//*** This version of the memory allocator is used only when ** SQLITE_MEMORY_SIZE is defined.*/#if defined(SQLITE_MEMORY_SIZE)#include "sqliteInt.h"#ifdef SQLITE_MEMDEBUG# error cannot define both SQLITE_MEMDEBUG and SQLITE_MEMORY_SIZE#endif/*** Maximum size (in Mem3Blocks) of a "small" chunk.*/#define MX_SMALL 10/*** Number of freelist hash slots*/#define N_HASH 61/*** A memory allocation (also called a "chunk") consists of two or ** more blocks where each block is 8 bytes. The first 8 bytes are ** a header that is not returned to the user.**** A chunk is two or more blocks that is either checked out or** free. The first block has format u.hdr. u.hdr.size is the** size of the allocation in blocks if the allocation is free.** If the allocation is checked out, u.hdr.size is the negative** of the size. Similarly, u.hdr.prevSize is the size of the** immediately previous allocation.**** We often identify a chunk by its index in mem.aPool[]. When** this is done, the chunk index refers to the second block of** the chunk. In this way, the first chunk has an index of 1.** A chunk index of 0 means "no such chunk" and is the equivalent** of a NULL pointer.**** The second block of free chunks is of the form u.list. The** two fields form a double-linked list of chunks of related sizes.** Pointers to the head of the list are stored in mem.aiSmall[] ** for smaller chunks and mem.aiHash[] for larger chunks.**** The second block of a chunk is user data if the chunk is checked ** out.*/typedef struct Mem3Block Mem3Block;struct Mem3Block { union { struct { int prevSize; /* Size of previous chunk in Mem3Block elements */ int size; /* Size of current chunk in Mem3Block elements */ } hdr; struct { int next; /* Index in mem.aPool[] of next free chunk */ int prev; /* Index in mem.aPool[] of previous free chunk */ } list; } u;};/*** All of the static variables used by this module are collected** into a single structure named "mem". This is to keep the** static variables organized and to reduce namespace pollution** when this module is combined with other in the amalgamation.*/static struct { /* ** True if we are evaluating an out-of-memory callback. */ int alarmBusy; /* ** Mutex to control access to the memory allocation subsystem. */ sqlite3_mutex *mutex; /* ** The minimum amount of free space that we have seen. */ int mnMaster; /* ** iMaster is the index of the master chunk. Most new allocations ** occur off of this chunk. szMaster is the size (in Mem3Blocks) ** of the current master. iMaster is 0 if there is not master chunk. ** The master chunk is not in either the aiHash[] or aiSmall[]. */ int iMaster; int szMaster; /* ** Array of lists of free blocks according to the block size ** for smaller chunks, or a hash on the block size for larger ** chunks. */ int aiSmall[MX_SMALL-1]; /* For sizes 2 through MX_SMALL, inclusive */ int aiHash[N_HASH]; /* For sizes MX_SMALL+1 and larger */ /* ** Memory available for allocation */ Mem3Block aPool[SQLITE_MEMORY_SIZE/sizeof(Mem3Block)+2];} mem;/*** Unlink the chunk at mem.aPool[i] from list it is currently** on. *pRoot is the list that i is a member of.*/static void memsys3UnlinkFromList(int i, int *pRoot){ int next = mem.aPool[i].u.list.next; int prev = mem.aPool[i].u.list.prev; assert( sqlite3_mutex_held(mem.mutex) ); if( prev==0 ){ *pRoot = next; }else{ mem.aPool[prev].u.list.next = next; } if( next ){ mem.aPool[next].u.list.prev = prev; } mem.aPool[i].u.list.next = 0; mem.aPool[i].u.list.prev = 0;}/*** Unlink the chunk at index i from ** whatever list is currently a member of.*/static void memsys3Unlink(int i){ int size, hash; assert( sqlite3_mutex_held(mem.mutex) ); size = mem.aPool[i-1].u.hdr.size; assert( size==mem.aPool[i+size-1].u.hdr.prevSize ); assert( size>=2 ); if( size <= MX_SMALL ){ memsys3UnlinkFromList(i, &mem.aiSmall[size-2]); }else{ hash = size % N_HASH; memsys3UnlinkFromList(i, &mem.aiHash[hash]); }}/*** Link the chunk at mem.aPool[i] so that is on the list rooted** at *pRoot.*/static void memsys3LinkIntoList(int i, int *pRoot){ assert( sqlite3_mutex_held(mem.mutex) ); mem.aPool[i].u.list.next = *pRoot; mem.aPool[i].u.list.prev = 0; if( *pRoot ){ mem.aPool[*pRoot].u.list.prev = i; } *pRoot = i;}/*** Link the chunk at index i into either the appropriate** small chunk list, or into the large chunk hash table.*/static void memsys3Link(int i){ int size, hash; assert( sqlite3_mutex_held(mem.mutex) ); size = mem.aPool[i-1].u.hdr.size; assert( size==mem.aPool[i+size-1].u.hdr.prevSize ); assert( size>=2 ); if( size <= MX_SMALL ){ memsys3LinkIntoList(i, &mem.aiSmall[size-2]); }else{ hash = size % N_HASH; memsys3LinkIntoList(i, &mem.aiHash[hash]); }}/*** Enter the mutex mem.mutex. Allocate it if it is not already allocated.**** Also: Initialize the memory allocation subsystem the first time** this routine is called.*/static void memsys3Enter(void){ if( mem.mutex==0 ){ mem.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_MEM); mem.aPool[0].u.hdr.size = SQLITE_MEMORY_SIZE/8; mem.aPool[SQLITE_MEMORY_SIZE/8].u.hdr.prevSize = SQLITE_MEMORY_SIZE/8; mem.iMaster = 1; mem.szMaster = SQLITE_MEMORY_SIZE/8; mem.mnMaster = mem.szMaster; } sqlite3_mutex_enter(mem.mutex);}/*** Return the amount of memory currently checked out.*/sqlite3_int64 sqlite3_memory_used(void){ sqlite3_int64 n; memsys3Enter(); n = SQLITE_MEMORY_SIZE - mem.szMaster*8; sqlite3_mutex_leave(mem.mutex); return n;}/*** Return the maximum amount of memory that has ever been** checked out since either the beginning of this process** or since the most recent reset.*/sqlite3_int64 sqlite3_memory_highwater(int resetFlag){ sqlite3_int64 n; memsys3Enter(); n = SQLITE_MEMORY_SIZE - mem.mnMaster*8; if( resetFlag ){ mem.mnMaster = mem.szMaster; } sqlite3_mutex_leave(mem.mutex); return n;}/*** Change the alarm callback.**** This is a no-op for the static memory allocator. The purpose** of the memory alarm is to support sqlite3_soft_heap_limit().** But with this memory allocator, the soft_heap_limit is really** a hard limit that is fixed at SQLITE_MEMORY_SIZE.*/int sqlite3_memory_alarm( void(*xCallback)(void *pArg, sqlite3_int64 used,int N), void *pArg, sqlite3_int64 iThreshold){ return SQLITE_OK;}/*** Called when we are unable to satisfy an allocation of nBytes.*/static void memsys3OutOfMemory(int nByte){ if( !mem.alarmBusy ){ mem.alarmBusy = 1; assert( sqlite3_mutex_held(mem.mutex) ); sqlite3_mutex_leave(mem.mutex); sqlite3_release_memory(nByte); sqlite3_mutex_enter(mem.mutex); mem.alarmBusy = 0; }}/*** Return the size of an outstanding allocation, in bytes. The** size returned omits the 8-byte header overhead. This only** works for chunks that are currently checked out.*/static int memsys3Size(void *p){ Mem3Block *pBlock = (Mem3Block*)p; assert( pBlock[-1].u.hdr.size<0 ); return (-1-pBlock[-1].u.hdr.size)*8;}/*** Chunk i is a free chunk that has been unlinked. Adjust its ** size parameters for check-out and return a pointer to the ** user portion of the chunk.*/static void *memsys3Checkout(int i, int nBlock){ assert( sqlite3_mutex_held(mem.mutex) ); assert( mem.aPool[i-1].u.hdr.size==nBlock ); assert( mem.aPool[i+nBlock-1].u.hdr.prevSize==nBlock ); mem.aPool[i-1].u.hdr.size = -nBlock; mem.aPool[i+nBlock-1].u.hdr.prevSize = -nBlock; return &mem.aPool[i];}/*** Carve a piece off of the end of the mem.iMaster free chunk.** Return a pointer to the new allocation. Or, if the master chunk** is not large enough, return 0.*/static void *memsys3FromMaster(int nBlock){ assert( sqlite3_mutex_held(mem.mutex) ); assert( mem.szMaster>=nBlock ); if( nBlock>=mem.szMaster-1 ){ /* Use the entire master */ void *p = memsys3Checkout(mem.iMaster, mem.szMaster); mem.iMaster = 0; mem.szMaster = 0; mem.mnMaster = 0; return p; }else{ /* Split the master block. Return the tail. */ int newi; newi = mem.iMaster + mem.szMaster - nBlock; assert( newi > mem.iMaster+1 ); mem.aPool[mem.iMaster+mem.szMaster-1].u.hdr.prevSize = -nBlock; mem.aPool[newi-1].u.hdr.size = -nBlock; mem.szMaster -= nBlock; mem.aPool[newi-1].u.hdr.prevSize = mem.szMaster; mem.aPool[mem.iMaster-1].u.hdr.size = mem.szMaster; if( mem.szMaster < mem.mnMaster ){ mem.mnMaster = mem.szMaster; } return (void*)&mem.aPool[newi]; }}/*** *pRoot is the head of a list of free chunks of the same size** or same size hash. In other words, *pRoot is an entry in either** mem.aiSmall[] or mem.aiHash[]. **** This routine examines all entries on the given list and tries** to coalesce each entries with adjacent free chunks. **** If it sees a chunk that is larger than mem.iMaster, it replaces ** the current mem.iMaster with the new larger chunk. In order for** this mem.iMaster replacement to work, the master chunk must be** linked into the hash tables. That is not the normal state of** affairs, of course. The calling routine must link the master** chunk before invoking this routine, then must unlink the (possibly** changed) master chunk once this routine has finished.*/static void memsys3Merge(int *pRoot){ int iNext, prev, size, i; assert( sqlite3_mutex_held(mem.mutex) ); for(i=*pRoot; i>0; i=iNext){ iNext = mem.aPool[i].u.list.next; size = mem.aPool[i-1].u.hdr.size; assert( size>0 ); if( mem.aPool[i-1].u.hdr.prevSize>0 ){ memsys3UnlinkFromList(i, pRoot); prev = i - mem.aPool[i-1].u.hdr.prevSize; assert( prev>=0 ); if( prev==iNext ){ iNext = mem.aPool[prev].u.list.next; } memsys3Unlink(prev); size = i + size - prev; mem.aPool[prev-1].u.hdr.size = size; mem.aPool[prev+size-1].u.hdr.prevSize = size; memsys3Link(prev); i = prev; } if( size>mem.szMaster ){ mem.iMaster = i; mem.szMaster = size; } }}/*** Return a block of memory of at least nBytes in size.** Return NULL if unable.*/static void *memsys3Malloc(int nByte){ int i; int nBlock; int toFree; assert( sqlite3_mutex_held(mem.mutex) ); assert( sizeof(Mem3Block)==8 ); if( nByte<=0 ){ nBlock = 2; }else{ nBlock = (nByte + 15)/8; } assert( nBlock >= 2 ); /* STEP 1: ** Look for an entry of the correct size in either the small ** chunk table or in the large chunk hash table. This is ** successful most of the time (about 9 times out of 10). */ if( nBlock <= MX_SMALL ){ i = mem.aiSmall[nBlock-2]; if( i>0 ){ memsys3UnlinkFromList(i, &mem.aiSmall[nBlock-2]); return memsys3Checkout(i, nBlock); } }else{ int hash = nBlock % N_HASH; for(i=mem.aiHash[hash]; i>0; i=mem.aPool[i].u.list.next){ if( mem.aPool[i-1].u.hdr.size==nBlock ){ memsys3UnlinkFromList(i, &mem.aiHash[hash]); return memsys3Checkout(i, nBlock); } } } /* STEP 2: ** Try to satisfy the allocation by carving a piece off of the end ** of the master chunk. This step usually works if step 1 fails. */ if( mem.szMaster>=nBlock ){ return memsys3FromMaster(nBlock); } /* STEP 3: ** Loop through the entire memory pool. Coalesce adjacent free ** chunks. Recompute the master chunk as the largest free chunk. ** Then try again to satisfy the allocation by carving a piece off ** of the end of the master chunk. This step happens very ** rarely (we hope!) */ for(toFree=nBlock*16; toFree<SQLITE_MEMORY_SIZE*2; toFree *= 2){ memsys3OutOfMemory(toFree); if( mem.iMaster ){ memsys3Link(mem.iMaster); mem.iMaster = 0; mem.szMaster = 0; } for(i=0; i<N_HASH; i++){ memsys3Merge(&mem.aiHash[i]); } for(i=0; i<MX_SMALL-1; i++){ memsys3Merge(&mem.aiSmall[i]); } if( mem.szMaster ){ memsys3Unlink(mem.iMaster); if( mem.szMaster>=nBlock ){ return memsys3FromMaster(nBlock); } } } /* If none of the above worked, then we fail. */ return 0;}/*** Free an outstanding memory allocation.*/void memsys3Free(void *pOld){ Mem3Block *p = (Mem3Block*)pOld; int i; int size; assert( sqlite3_mutex_held(mem.mutex) ); assert( p>mem.aPool && p<&mem.aPool[SQLITE_MEMORY_SIZE/8] ); i = p - mem.aPool; size = -mem.aPool[i-1].u.hdr.size; assert( size>=2 ); assert( mem.aPool[i+size-1].u.hdr.prevSize==-size ); mem.aPool[i-1].u.hdr.size = size; mem.aPool[i+size-1].u.hdr.prevSize = size; memsys3Link(i); /* Try to expand the master using the newly freed chunk */ if( mem.iMaster ){ while( mem.aPool[mem.iMaster-1].u.hdr.prevSize>0 ){ size = mem.aPool[mem.iMaster-1].u.hdr.prevSize; mem.iMaster -= size; mem.szMaster += size; memsys3Unlink(mem.iMaster); mem.aPool[mem.iMaster-1].u.hdr.size = mem.szMaster; mem.aPool[mem.iMaster+mem.szMaster-1].u.hdr.prevSize = mem.szMaster; } while( mem.aPool[mem.iMaster+mem.szMaster-1].u.hdr.size>0 ){ memsys3Unlink(mem.iMaster+mem.szMaster); mem.szMaster += mem.aPool[mem.iMaster+mem.szMaster-1].u.hdr.size; mem.aPool[mem.iMaster-1].u.hdr.size = mem.szMaster; mem.aPool[mem.iMaster+mem.szMaster-1].u.hdr.prevSize = mem.szMaster; } }}/*** Allocate nBytes of memory*/void *sqlite3_malloc(int nBytes){ sqlite3_int64 *p = 0; if( nBytes>0 ){ memsys3Enter(); p = memsys3Malloc(nBytes); sqlite3_mutex_leave(mem.mutex); } return (void*)p; }/*** Free memory.*/void sqlite3_free(void *pPrior){ if( pPrior==0 ){ return; } assert( mem.mutex!=0 ); sqlite3_mutex_enter(mem.mutex); memsys3Free(pPrior); sqlite3_mutex_leave(mem.mutex); }/*** Change the size of an existing memory allocation*/void *sqlite3_realloc(void *pPrior, int nBytes){ int nOld; void *p; if( pPrior==0 ){ return sqlite3_malloc(nBytes); } if( nBytes<=0 ){ sqlite3_free(pPrior); return 0; } assert( mem.mutex!=0 ); nOld = memsys3Size(pPrior); if( nBytes<=nOld && nBytes>=nOld-128 ){ return pPrior; } sqlite3_mutex_enter(mem.mutex); p = memsys3Malloc(nBytes); if( p ){ if( nOld<nBytes ){ memcpy(p, pPrior, nOld); }else{ memcpy(p, pPrior, nBytes); } memsys3Free(pPrior); } sqlite3_mutex_leave(mem.mutex); return p;}/*** Open the file indicated and write a log of all unfreed memory ** allocations into that log.*/void sqlite3_memdebug_dump(const char *zFilename){#ifdef SQLITE_DEBUG FILE *out; int i, j, size; if( zFilename==0 || zFilename[0]==0 ){ out = stdout; }else{ out = fopen(zFilename, "w"); if( out==0 ){ fprintf(stderr, "** Unable to output memory debug output log: %s **\n", zFilename); return; } } memsys3Enter(); fprintf(out, "CHUNKS:\n"); for(i=1; i<=SQLITE_MEMORY_SIZE/8; i+=size){ size = mem.aPool[i-1].u.hdr.size; if( size>=-1 && size<=1 ){ fprintf(out, "%p size error\n", &mem.aPool[i]); assert( 0 ); break; } if( mem.aPool[i+(size<0?-size:size)-1].u.hdr.prevSize!=size ){ fprintf(out, "%p tail size does not match\n", &mem.aPool[i]); assert( 0 ); break; } if( size<0 ){ size = -size; fprintf(out, "%p %6d bytes checked out\n", &mem.aPool[i], size*8-8); }else{ fprintf(out, "%p %6d bytes free%s\n", &mem.aPool[i], size*8-8, i==mem.iMaster ? " **master**" : ""); } } for(i=0; i<MX_SMALL-1; i++){ if( mem.aiSmall[i]==0 ) continue; fprintf(out, "small(%2d):", i); for(j = mem.aiSmall[i]; j>0; j=mem.aPool[j].u.list.next){ fprintf(out, " %p(%d)", &mem.aPool[j], mem.aPool[j-1].u.hdr.size*8-8); } fprintf(out, "\n"); } for(i=0; i<N_HASH; i++){ if( mem.aiHash[i]==0 ) continue; fprintf(out, "hash(%2d):", i); for(j = mem.aiHash[i]; j>0; j=mem.aPool[j].u.list.next){ fprintf(out, " %p(%d)", &mem.aPool[j], mem.aPool[j-1].u.hdr.size*8-8); } fprintf(out, "\n"); } fprintf(out, "master=%d\n", mem.iMaster); fprintf(out, "nowUsed=%d\n", SQLITE_MEMORY_SIZE - mem.szMaster*8); fprintf(out, "mxUsed=%d\n", SQLITE_MEMORY_SIZE - mem.mnMaster*8); sqlite3_mutex_leave(mem.mutex); if( out==stdout ){ fflush(stdout); }else{ fclose(out); }#endif}#endif /* !SQLITE_MEMORY_SIZE */