SQLite4  Check-in [b81bc323b9]

*/
struct TreeKey {
  int nKey;                       /* Size of pKey in bytes */
  int nValue;                     /* Size of pValue. Or negative. */
  u8 flags;                       /* Various LSM_XXX flags */
};

#define TKV_KEY(p) ((void *)&(p)[1])
#define TKV_VAL(p) ((void *)(((u8 *)&(p)[1]) + (p)->nKey))

/*
** A single tree node. A node structure may contain up to 3 key/value
** pairs. Internal (non-leaf) nodes have up to 4 children.
**
** TODO: Update the format of this to be more compact. Get it working
** first though...

  assert( p==pNode || rc!=LSM_OK );
}
#else
# define assertIsWorkingChild(w,x,y,z)
#endif

/* Values for the third argument to treeShmkey(). */
#define TKV_LOADKEY  1
#define TKV_LOADVAL  2

static TreeKey *treeShmkey(
  lsm_db *pDb,                    /* Database handle */
  u32 iPtr,                       /* Shmptr to TreeKey struct */
  int eLoad,                      /* Either zero or a TREEKEY_LOADXXX value */
  TreeBlob *pBlob,                /* Used if dynamic memory is required */
  int *pRc                        /* IN/OUT: Error code */
){
  TreeKey *pRet;

  assert( eLoad==TKV_LOADKEY || eLoad==TKV_LOADVAL );
  pRet = (TreeKey *)treeShmptr(pDb, iPtr, pRc);
  if( pRet ){
    int nReq;                     /* Bytes of space required at pRet */
    int nAvail;                   /* Bytes of space available at pRet */

    nReq = sizeof(TreeKey) + pRet->nKey;
    if( eLoad==TKV_LOADVAL && pRet->nValue>0 ){
      nReq += pRet->nValue;
    }
    assert( LSM_SHM_CHUNK_SIZE==(1<<15) );
    nAvail = LSM_SHM_CHUNK_SIZE - (iPtr & (LSM_SHM_CHUNK_SIZE-1));

    if( nAvail<nReq ){
      if( tblobGrow(pDb, pBlob, nReq, pRc)==0 ){

    /* Append the nIndent bytes of space to string s. */
    lsmStringInit(&s, pDb->pEnv);

    /* Append each key to string s. */
    for(i=0; i<3; i++){
      u32 iPtr = pNode->aiKeyPtr[i];
      if( iPtr ){
        TreeKey *pKey = treeShmkey(pDb, pNode->aiKeyPtr[i],TKV_LOADKEY, &b,&rc);
        strAppendFlags(&s, pKey->flags);
        lsmAppendStrBlob(&s, TKV_KEY(pKey), pKey->nKey);
        lsmStringAppend(&s, "     ", -1);
      }
    }

    printf("% 6d %.*sleaf%.*s: %s\n", 
        iNode, nPath, zPath, 20-nPath-4, zSpace, s.z
    );
    lsmStringClear(&s);
  }else{
    for(i=0; i<4 && nHeight>0; i++){
      u32 iPtr = getChildPtr(pNode, pDb->treehdr.root.iTransId, i);
      zPath[nPath] = i+'0';
      zPath[nPath+1] = '/';

      if( iPtr ){
        dump_node_contents(pDb, iPtr, zPath, nPath+2, nHeight-1);
      }
      if( i!=3 && pNode->aiKeyPtr[i] ){
        TreeKey *pKey = treeShmkey(pDb, pNode->aiKeyPtr[i], TKV_LOADKEY,&b,&rc);
        lsmStringInit(&s, pDb->pEnv);
        strAppendFlags(&s, pKey->flags);
        lsmAppendStrBlob(&s, TKV_KEY(pKey), pKey->nKey);
        printf("% 6d %.*s%.*s: %s\n", 
            iNode, nPath+1, zPath, 20-nPath-1, zSpace, s.z);
        lsmStringClear(&s);
      }
    }
  }

/*
** Return a pointer to the mapping of the TreeKey object that the cursor
** is pointing to. 
*/
static TreeKey *csrGetKey(TreeCursor *pCsr, TreeBlob *pBlob, int *pRc){
  TreeKey *pRet = (TreeKey *)treeShmkey(pCsr->pDb,
      pCsr->apTreeNode[pCsr->iNode]->aiKeyPtr[pCsr->aiCell[pCsr->iNode]], 
      TKV_LOADVAL, pBlob, pRc
  );
  assert( pRet==0 || assertFlagsOk(pRet->flags) );
  return pRet;
}

/*
** Save the current position of tree cursor pCsr.

*/
static int treeCursorRestore(TreeCursor *pCsr, int *pRes){
  int rc = LSM_OK;
  if( pCsr->pSave ){
    TreeKey *pKey = pCsr->pSave;
    pCsr->pSave = 0;
    if( pRes ){
      rc = lsmTreeCursorSeek(pCsr, TKV_KEY(pKey), pKey->nKey, pRes);
    }
  }
  return rc;
}

/*
** Allocate nByte bytes of space within the *-shm file. If successful, 

        goto insert_entry_out;
      }
    }

    if( res==0 && (flags & (LSM_END_DELETE|LSM_START_DELETE)) ){
      if( pRes->flags & LSM_INSERT ){
        nVal = pRes->nValue;
        pVal = TKV_VAL(pRes);
      }
      flags = flags | pRes->flags;
    }

    if( flags & (LSM_INSERT|LSM_POINT_DELETE) ){
      if( (res<0 && (pRes->flags & LSM_START_DELETE))
       || (res>0 && (pRes->flags & LSM_END_DELETE)) 

        lsmTreeCursorNext(&csr);
        assert( csr.iNode==(p->nHeight-1) );

        iKey = csr.apTreeNode[csr.iNode]->aiKeyPtr[csr.aiCell[csr.iNode]];
        lsmTreeCursorPrev(&csr);

        treeOverwriteKey(db, &csr, iKey, &rc);
        pKey = treeShmkey(db, iKey, TKV_LOADKEY, &blob, &rc);
        if( pKey ){
          rc = lsmTreeCursorSeek(&csr, TKV_KEY(pKey), pKey->nKey, &res);
        }
        if( rc==LSM_OK ){
          assert( res==0 && csr.iNode==iNode );
          rc = lsmTreeCursorNext(&csr);
          if( rc==LSM_OK ){
            rc = treeDeleteEntry(db, &csr, 0);
          }

static int treeCsrCompare(TreeCursor *pCsr, void *pKey, int nKey){
  TreeKey *p;
  int cmp = 0;
  int rc = LSM_OK;
  assert( pCsr->iNode>=0 );
  p = csrGetKey(pCsr, &pCsr->blob, &rc);
  if( p ){
    cmp = pCsr->pDb->xCmp(TKV_KEY(p), p->nKey, pKey, nKey);
  }
  return cmp;
}
#endif


/*

      pNode = (TreeNode *)treeShmptr(pDb, iNodePtr, &rc);
      iNode++;
      pCsr->apTreeNode[iNode] = pNode;

      /* Compare (pKey/nKey) with the key in the middle slot of B-tree node
      ** pNode. The middle slot is never empty. If the comparison is a match,
      ** then the search is finished. Break out of the loop. */
      pTreeKey = treeShmkey(pDb, pNode->aiKeyPtr[1], TKV_LOADKEY, &b, &rc);
      if( rc!=LSM_OK ) break;
      res = xCmp((void *)&pTreeKey[1], pTreeKey->nKey, pKey, nKey);
      if( res==0 ){
        pCsr->aiCell[iNode] = 1;
        break;
      }

      /* Based on the results of the previous comparison, compare (pKey/nKey)
      ** to either the left or right key of the B-tree node, if such a key
      ** exists. */
      iTest = (res>0 ? 0 : 2);
      pTreeKey = treeShmkey(pDb, pNode->aiKeyPtr[iTest], TKV_LOADKEY, &b, &rc);
      if( rc ) break;
      if( pTreeKey==0 ){
        iTest = 1;
      }else{
        res = xCmp((void *)&pTreeKey[1], pTreeKey->nKey, pKey, nKey);
        if( res==0 ){
          pCsr->aiCell[iNode] = iTest;

      if( iCell<3 && pCsr->apTreeNode[pCsr->iNode]->aiKeyPtr[iCell] ) break;
    }
  }

#ifndef NDEBUG
  if( pCsr->iNode>=0 ){
    TreeKey *pK2 = csrGetKey(pCsr, &pCsr->blob, &rc);
    assert( rc || pDb->xCmp(TKV_KEY(pK2),pK2->nKey,TKV_KEY(pK1),pK1->nKey)>=0 );
  }
  tblobFree(pDb, &key1);
#endif

  return rc;
}

    }while( (--pCsr->iNode)>=0 );
    pCsr->aiCell[pCsr->iNode] = iCell;
  }

#ifndef NDEBUG
  if( pCsr->iNode>=0 ){
    TreeKey *pK2 = csrGetKey(pCsr, &pCsr->blob, &rc);
    assert( rc || pDb->xCmp(TKV_KEY(pK2), pK2->nKey, TKV_KEY(pK1), pK1->nKey)<0 );
  }
  tblobFree(pDb, &key1);
#endif

  return rc;
}

  rc = treeCursorRestore(pCsr, &res);
  if( res==0 ){
    TreeKey *pTreeKey = csrGetKey(pCsr, &pCsr->blob, &rc);
    if( rc==LSM_OK ){
      if( pTreeKey->flags & LSM_INSERT ){
        *pnVal = pTreeKey->nValue;
        *ppVal = TKV_VAL(pTreeKey);
      }else{
        *ppVal = 0;
        *pnVal = -1;
      }
    }
  }else{
    *ppVal = 0;

  }

  tblobFree(csr.pDb, &csr.blob);

  return nEntry;
}
#endif