[sql] Import reference version of SQLite 3.10.2.

third_party/sqlite/sqlite-src-3100200/src/update.c

 /*
 ** 2001 September 15
 **
 ** 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.
 **
@@ skipping 116 matching lines @@
   Trigger *pTrigger;     /* List of triggers on pTab, if required */
   int tmask;             /* Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
 #endif
   int newmask;           /* Mask of NEW.* columns accessed by BEFORE triggers */
   int iEph = 0;          /* Ephemeral table holding all primary key values */
   int nKey = 0;          /* Number of elements in regKey for WITHOUT ROWID */
   int aiCurOnePass[2];   /* The write cursors opened by WHERE_ONEPASS */
 
   /* Register Allocations */
   int regRowCount = 0;   /* A count of rows changed */
-  int regOldRowid;       /* The old rowid */
-  int regNewRowid;       /* The new rowid */
-  int regNew;            /* Content of the NEW.* table in triggers */
+  int regOldRowid = 0;   /* The old rowid */
+  int regNewRowid = 0;   /* The new rowid */
+  int regNew = 0;        /* Content of the NEW.* table in triggers */
   int regOld = 0;        /* Content of OLD.* table in triggers */
   int regRowSet = 0;     /* Rowset of rows to be updated */
   int regKey = 0;        /* composite PRIMARY KEY value */
 
   memset(&sContext, 0, sizeof(sContext));
   db = pParse->db;
   if( pParse->nErr || db->mallocFailed ){
     goto update_cleanup;
   }
   assert( pTabList->nSrc==1 );
@@ skipping 106 matching lines @@
         aXRef[j] = -1;
       }
     }
 #endif
   }
   assert( (chngRowid & chngPk)==0 );
   assert( chngRowid==0 || chngRowid==1 );
   assert( chngPk==0 || chngPk==1 );
   chngKey = chngRowid + chngPk;
 
-  /* The SET expressions are not actually used inside the WHERE loop.
-  ** So reset the colUsed mask
+  /* The SET expressions are not actually used inside the WHERE loop.  
+  ** So reset the colUsed mask. Unless this is a virtual table. In that
+  ** case, set all bits of the colUsed mask (to ensure that the virtual
+  ** table implementation makes all columns available).
   */
-  pTabList->a[0].colUsed = 0;
+  pTabList->a[0].colUsed = IsVirtual(pTab) ? (Bitmask)-1 : 0;
 
   hasFK = sqlite3FkRequired(pParse, pTab, aXRef, chngKey);
 
   /* There is one entry in the aRegIdx[] array for each index on the table
   ** being updated.  Fill in aRegIdx[] with a register number that will hold
-  ** the key for accessing each index.  
+  ** the key for accessing each index.
+  **
+  ** FIXME:  Be smarter about omitting indexes that use expressions.
   */
   for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
     int reg;
     if( chngKey || hasFK || pIdx->pPartIdxWhere || pIdx==pPk ){
       reg = ++pParse->nMem;
     }else{
       reg = 0;
       for(i=0; i<pIdx->nKeyCol; i++){
-        if( aXRef[pIdx->aiColumn[i]]>=0 ){
+        i16 iIdxCol = pIdx->aiColumn[i];
+        if( iIdxCol<0 || aXRef[iIdxCol]>=0 ){
           reg = ++pParse->nMem;
           break;
         }
       }
     }
     if( reg==0 ) aToOpen[j+1] = 0;
     aRegIdx[j] = reg;
   }
 
   /* Begin generating code. */
   v = sqlite3GetVdbe(pParse);
   if( v==0 ) goto update_cleanup;
   if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
   sqlite3BeginWriteOperation(pParse, 1, iDb);
 
-#ifndef SQLITE_OMIT_VIRTUALTABLE
-  /* Virtual tables must be handled separately */
-  if( IsVirtual(pTab) ){
-    updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
-                       pWhere, onError);
-    pWhere = 0;
-    pTabList = 0;
-    goto update_cleanup;
-  }
-#endif
-
   /* Allocate required registers. */
-  regRowSet = ++pParse->nMem;
-  regOldRowid = regNewRowid = ++pParse->nMem;
-  if( chngPk || pTrigger || hasFK ){
-    regOld = pParse->nMem + 1;
+  if( !IsVirtual(pTab) ){
+    regRowSet = ++pParse->nMem;
+    regOldRowid = regNewRowid = ++pParse->nMem;
+    if( chngPk || pTrigger || hasFK ){
+      regOld = pParse->nMem + 1;
+      pParse->nMem += pTab->nCol;
+    }
+    if( chngKey || pTrigger || hasFK ){
+      regNewRowid = ++pParse->nMem;
+    }
+    regNew = pParse->nMem + 1;
     pParse->nMem += pTab->nCol;
   }
-  if( chngKey || pTrigger || hasFK ){
-    regNewRowid = ++pParse->nMem;
-  }
-  regNew = pParse->nMem + 1;
-  pParse->nMem += pTab->nCol;
 
   /* Start the view context. */
   if( isView ){
     sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
   }
 
   /* If we are trying to update a view, realize that view into
   ** an ephemeral table.
   */
 #if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
   if( isView ){
     sqlite3MaterializeView(pParse, pTab, pWhere, iDataCur);
   }
 #endif
 
   /* Resolve the column names in all the expressions in the
   ** WHERE clause.
   */
   if( sqlite3ResolveExprNames(&sNC, pWhere) ){
     goto update_cleanup;
   }
 
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+  /* Virtual tables must be handled separately */
+  if( IsVirtual(pTab) ){
+    updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
+                       pWhere, onError);
+    goto update_cleanup;
+  }
+#endif
+
   /* Begin the database scan
   */
   if( HasRowid(pTab) ){
     sqlite3VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldRowid);
     pWInfo = sqlite3WhereBegin(
         pParse, pTabList, pWhere, 0, 0, WHERE_ONEPASS_DESIRED, iIdxCur
     );
     if( pWInfo==0 ) goto update_cleanup;
     okOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
   
@@ skipping 19 matching lines @@
     regKey = ++pParse->nMem;
     iEph = pParse->nTab++;
     sqlite3VdbeAddOp2(v, OP_Null, 0, iPk);
     addrOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEph, nPk);
     sqlite3VdbeSetP4KeyInfo(pParse, pPk);
     pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0, 
                                WHERE_ONEPASS_DESIRED, iIdxCur);
     if( pWInfo==0 ) goto update_cleanup;
     okOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
     for(i=0; i<nPk; i++){
+      assert( pPk->aiColumn[i]>=0 );
       sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, pPk->aiColumn[i],
                                       iPk+i);
     }
     if( okOnePass ){
       sqlite3VdbeChangeToNoop(v, addrOpen);
       nKey = nPk;
       regKey = iPk;
     }else{
       sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, regKey,
-                        sqlite3IndexAffinityStr(v, pPk), nPk);
+                        sqlite3IndexAffinityStr(db, pPk), nPk);
       sqlite3VdbeAddOp2(v, OP_IdxInsert, iEph, regKey);
     }
     sqlite3WhereEnd(pWInfo);
   }
 
   /* Initialize the count of updated rows
   */
   if( (db->flags & SQLITE_CountRows) && !pParse->pTriggerTab ){
     regRowCount = ++pParse->nMem;
     sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
@@ skipping 14 matching lines @@
         if( pIdx->onError==OE_Replace ){
           memset(aToOpen, 1, nIdx+1);
           break;
         }
       }
     }
     if( okOnePass ){
       if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iBaseCur] = 0;
       if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iBaseCur] = 0;
     }
-    sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, iBaseCur, aToOpen,
+    sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, iBaseCur, aToOpen,
                                0, 0);
   }
 
   /* Top of the update loop */
   if( okOnePass ){
     if( aToOpen[iDataCur-iBaseCur] && !isView ){
       assert( pPk );
       sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelBreak, regKey, nKey);
       VdbeCoverageNeverTaken(v);
     }
@@ skipping 57 matching lines @@
   ** registers associated with columns that are (a) not modified by
   ** this UPDATE statement and (b) not accessed by new.* references. The
   ** values for registers not modified by the UPDATE must be reloaded from 
   ** the database after the BEFORE triggers are fired anyway (as the trigger 
   ** may have modified them). So not loading those that are not going to
   ** be used eliminates some redundant opcodes.
   */
   newmask = sqlite3TriggerColmask(
       pParse, pTrigger, pChanges, 1, TRIGGER_BEFORE, pTab, onError
   );
-  /*sqlite3VdbeAddOp3(v, OP_Null, 0, regNew, regNew+pTab->nCol-1);*/
   for(i=0; i<pTab->nCol; i++){
     if( i==pTab->iPKey ){
       sqlite3VdbeAddOp2(v, OP_Null, 0, regNew+i);
     }else{
       j = aXRef[i];
       if( j>=0 ){
         sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regNew+i);
       }else if( 0==(tmask&TRIGGER_BEFORE) || i>31 || (newmask & MASKBIT32(i)) ){
         /* This branch loads the value of a column that will not be changed 
         ** into a register. This is done if there are no BEFORE triggers, or
         ** if there are one or more BEFORE triggers that use this value via
         ** a new.* reference in a trigger program.
         */
         testcase( i==31 );
         testcase( i==32 );
-        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, regNew+i);
+        sqlite3ExprCodeGetColumnToReg(pParse, pTab, i, iDataCur, regNew+i);
       }else{
         sqlite3VdbeAddOp2(v, OP_Null, 0, regNew+i);
       }
     }
   }
 
   /* Fire any BEFORE UPDATE triggers. This happens before constraints are
   ** verified. One could argue that this is wrong.
   */
   if( tmask&TRIGGER_BEFORE ){
@@ skipping 21 matching lines @@
     ** registers in case this has happened.
     */
     for(i=0; i<pTab->nCol; i++){
       if( aXRef[i]<0 && i!=pTab->iPKey ){
         sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, regNew+i);
       }
     }
   }
 
   if( !isView ){
-    int j1 = 0;           /* Address of jump instruction */
+    int addr1 = 0;        /* Address of jump instruction */
     int bReplace = 0;     /* True if REPLACE conflict resolution might happen */
 
     /* Do constraint checks. */
     assert( regOldRowid>0 );
     sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
         regNewRowid, regOldRowid, chngKey, onError, labelContinue, &bReplace);
 
     /* Do FK constraint checks. */
     if( hasFK ){
       sqlite3FkCheck(pParse, pTab, regOldRowid, 0, aXRef, chngKey);
     }
 
     /* Delete the index entries associated with the current record.  */
     if( bReplace || chngKey ){
       if( pPk ){
-        j1 = sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, 0, regKey, nKey);
+        addr1 = sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, 0, regKey, nKey);
       }else{
-        j1 = sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, 0, regOldRowid);
+        addr1 = sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, 0, regOldRowid);
       }
       VdbeCoverageNeverTaken(v);
     }
-    sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur, aRegIdx);
+    sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur, aRegIdx, -1);
   
     /* If changing the record number, delete the old record.  */
     if( hasFK || chngKey || pPk!=0 ){
       sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, 0);
     }
     if( bReplace || chngKey ){
-      sqlite3VdbeJumpHere(v, j1);
+      sqlite3VdbeJumpHere(v, addr1);
     }
 
     if( hasFK ){
       sqlite3FkCheck(pParse, pTab, 0, regNewRowid, aXRef, chngKey);
     }
   
     /* Insert the new index entries and the new record. */
     sqlite3CompleteInsertion(pParse, pTab, iDataCur, iIdxCur,
                              regNewRowid, aRegIdx, 1, 0, 0);
 
@@ skipping 16 matching lines @@
 
   /* Repeat the above with the next record to be updated, until
   ** all record selected by the WHERE clause have been updated.
   */
   if( okOnePass ){
     /* Nothing to do at end-of-loop for a single-pass */
   }else if( pPk ){
     sqlite3VdbeResolveLabel(v, labelContinue);
     sqlite3VdbeAddOp2(v, OP_Next, iEph, addrTop); VdbeCoverage(v);
   }else{
-    sqlite3VdbeAddOp2(v, OP_Goto, 0, labelContinue);
+    sqlite3VdbeGoto(v, labelContinue);
   }
   sqlite3VdbeResolveLabel(v, labelBreak);
 
   /* Close all tables */
   for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
     assert( aRegIdx );
     if( aToOpen[i+1] ){
       sqlite3VdbeAddOp2(v, OP_Close, iIdxCur+i, 0);
     }
   }
@@ skipping 33 matching lines @@
  #undef isView
 #endif
 #ifdef pTrigger
  #undef pTrigger
 #endif
 
 #ifndef SQLITE_OMIT_VIRTUALTABLE
 /*
 ** Generate code for an UPDATE of a virtual table.
 **
-** The strategy is that we create an ephemeral table that contains
+** There are two possible strategies - the default and the special 
+** "onepass" strategy. Onepass is only used if the virtual table 
+** implementation indicates that pWhere may match at most one row.
+**
+** The default strategy is to create an ephemeral table that contains
 ** for each row to be changed:
 **
 **   (A)  The original rowid of that row.
-**   (B)  The revised rowid for the row. (note1)
+**   (B)  The revised rowid for the row.
 **   (C)  The content of every column in the row.
 **
-** Then we loop over this ephemeral table and for each row in
-** the ephemeral table call VUpdate.
+** Then loop through the contents of this ephemeral table executing a
+** VUpdate for each row. When finished, drop the ephemeral table.
 **
-** When finished, drop the ephemeral table.
-**
-** (note1) Actually, if we know in advance that (A) is always the same
-** as (B) we only store (A), then duplicate (A) when pulling
-** it out of the ephemeral table before calling VUpdate.
+** The "onepass" strategy does not use an ephemeral table. Instead, it
+** stores the same values (A, B and C above) in a register array and
+** makes a single invocation of VUpdate.
 */
 static void updateVirtualTable(
   Parse *pParse,       /* The parsing context */
   SrcList *pSrc,       /* The virtual table to be modified */
   Table *pTab,         /* The virtual table */
   ExprList *pChanges,  /* The columns to change in the UPDATE statement */
   Expr *pRowid,        /* Expression used to recompute the rowid */
   int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
   Expr *pWhere,        /* WHERE clause of the UPDATE statement */
   int onError          /* ON CONFLICT strategy */
 ){
   Vdbe *v = pParse->pVdbe;  /* Virtual machine under construction */
-  ExprList *pEList = 0;     /* The result set of the SELECT statement */
-  Select *pSelect = 0;      /* The SELECT statement */
-  Expr *pExpr;              /* Temporary expression */
   int ephemTab;             /* Table holding the result of the SELECT */
   int i;                    /* Loop counter */
-  int addr;                 /* Address of top of loop */
-  int iReg;                 /* First register in set passed to OP_VUpdate */
   sqlite3 *db = pParse->db; /* Database connection */
   const char *pVTab = (const char*)sqlite3GetVTable(db, pTab);
-  SelectDest dest;
+  WhereInfo *pWInfo;
+  int nArg = 2 + pTab->nCol;      /* Number of arguments to VUpdate */
+  int regArg;                     /* First register in VUpdate arg array */
+  int regRec;                     /* Register in which to assemble record */
+  int regRowid;                   /* Register for ephem table rowid */
+  int iCsr = pSrc->a[0].iCursor;  /* Cursor used for virtual table scan */
+  int aDummy[2];                  /* Unused arg for sqlite3WhereOkOnePass() */
+  int bOnePass;                   /* True to use onepass strategy */
+  int addr;                       /* Address of OP_OpenEphemeral */
 
-  /* Construct the SELECT statement that will find the new values for
-  ** all updated rows. 
-  */
-  pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ID, "_rowid_"));
+  /* Allocate nArg registers to martial the arguments to VUpdate. Then
+  ** create and open the ephemeral table in which the records created from
+  ** these arguments will be temporarily stored. */
+  assert( v );
+  ephemTab = pParse->nTab++;
+  addr= sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, nArg);
+  regArg = pParse->nMem + 1;
+  pParse->nMem += nArg;
+  regRec = ++pParse->nMem;
+  regRowid = ++pParse->nMem;
+
+  /* Start scanning the virtual table */
+  pWInfo = sqlite3WhereBegin(pParse, pSrc, pWhere, 0,0,WHERE_ONEPASS_DESIRED,0);
+  if( pWInfo==0 ) return;
+
+  /* Populate the argument registers. */
+  sqlite3VdbeAddOp2(v, OP_Rowid, iCsr, regArg);
   if( pRowid ){
-    pEList = sqlite3ExprListAppend(pParse, pEList,
-                                   sqlite3ExprDup(db, pRowid, 0));
+    sqlite3ExprCode(pParse, pRowid, regArg+1);
+  }else{
+    sqlite3VdbeAddOp2(v, OP_Rowid, iCsr, regArg+1);
   }
-  assert( pTab->iPKey<0 );
   for(i=0; i<pTab->nCol; i++){
     if( aXRef[i]>=0 ){
-      pExpr = sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr, 0);
+      sqlite3ExprCode(pParse, pChanges->a[aXRef[i]].pExpr, regArg+2+i);
     }else{
-      pExpr = sqlite3Expr(db, TK_ID, pTab->aCol[i].zName);
+      sqlite3VdbeAddOp3(v, OP_VColumn, iCsr, i, regArg+2+i);
     }
-    pEList = sqlite3ExprListAppend(pParse, pEList, pExpr);
   }
-  pSelect = sqlite3SelectNew(pParse, pEList, pSrc, pWhere, 0, 0, 0, 0, 0, 0);
-  
-  /* Create the ephemeral table into which the update results will
-  ** be stored.
-  */
-  assert( v );
-  ephemTab = pParse->nTab++;
-  sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0));
-  sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
 
-  /* fill the ephemeral table 
-  */
-  sqlite3SelectDestInit(&dest, SRT_Table, ephemTab);
-  sqlite3Select(pParse, pSelect, &dest);
+  bOnePass = sqlite3WhereOkOnePass(pWInfo, aDummy);
 
-  /* Generate code to scan the ephemeral table and call VUpdate. */
-  iReg = ++pParse->nMem;
-  pParse->nMem += pTab->nCol+1;
-  addr = sqlite3VdbeAddOp2(v, OP_Rewind, ephemTab, 0); VdbeCoverage(v);
-  sqlite3VdbeAddOp3(v, OP_Column,  ephemTab, 0, iReg);
-  sqlite3VdbeAddOp3(v, OP_Column, ephemTab, (pRowid?1:0), iReg+1);
-  for(i=0; i<pTab->nCol; i++){
-    sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i+1+(pRowid!=0), iReg+2+i);
+  if( bOnePass ){
+    /* If using the onepass strategy, no-op out the OP_OpenEphemeral coded
+    ** above. Also, if this is a top-level parse (not a trigger), clear the
+    ** multi-write flag so that the VM does not open a statement journal */
+    sqlite3VdbeChangeToNoop(v, addr);
+    if( sqlite3IsToplevel(pParse) ){
+      pParse->isMultiWrite = 0;
+    }
+  }else{
+    /* Create a record from the argument register contents and insert it into
+    ** the ephemeral table. */
+    sqlite3VdbeAddOp3(v, OP_MakeRecord, regArg, nArg, regRec);
+    sqlite3VdbeAddOp2(v, OP_NewRowid, ephemTab, regRowid);
+    sqlite3VdbeAddOp3(v, OP_Insert, ephemTab, regRec, regRowid);
+  }
+
+
+  if( bOnePass==0 ){
+    /* End the virtual table scan */
+    sqlite3WhereEnd(pWInfo);
+
+    /* Begin scannning through the ephemeral table. */
+    addr = sqlite3VdbeAddOp1(v, OP_Rewind, ephemTab); VdbeCoverage(v);
+
+    /* Extract arguments from the current row of the ephemeral table and 
+    ** invoke the VUpdate method.  */
+    for(i=0; i<nArg; i++){
+      sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i, regArg+i);
+    }
   }
   sqlite3VtabMakeWritable(pParse, pTab);
-  sqlite3VdbeAddOp4(v, OP_VUpdate, 0, pTab->nCol+2, iReg, pVTab, P4_VTAB);
+  sqlite3VdbeAddOp4(v, OP_VUpdate, 0, nArg, regArg, pVTab, P4_VTAB);
   sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
   sqlite3MayAbort(pParse);
-  sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr+1); VdbeCoverage(v);
-  sqlite3VdbeJumpHere(v, addr);
-  sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
 
-  /* Cleanup */
-  sqlite3SelectDelete(db, pSelect);  
+  /* End of the ephemeral table scan. Or, if using the onepass strategy,
+  ** jump to here if the scan visited zero rows. */
+  if( bOnePass==0 ){
+    sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr+1); VdbeCoverage(v);
+    sqlite3VdbeJumpHere(v, addr);
+    sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
+  }else{
+    sqlite3WhereEnd(pWInfo);
+  }
 }
 #endif /* SQLITE_OMIT_VIRTUALTABLE */