Initial commit

Signed-off-by: Mavridis Philippe <mavridisf@gmail.com>

1 files changed, 505 insertions, 0 deletions

diff --git a/src/sqlite/update.c b/src/sqlite/update.c
new file mode 100644
index 0000000..47bfe13
--- /dev/null
+++ b/src/sqlite/update.c
@@ -0,0 +1,505 @@
+/*
+** 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.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** to handle UPDATE statements.
+**
+** $Id: update.c,v 1.1.1.1 2006/02/03 20:35:11 hoganrobert Exp $
+*/
+#include "sqliteInt.h"
+
+/*
+** The most recently coded instruction was an OP_Column to retrieve column
+** 'i' of table pTab. This routine sets the P3 parameter of the 
+** OP_Column to the default value, if any.
+**
+** The default value of a column is specified by a DEFAULT clause in the 
+** column definition. This was either supplied by the user when the table
+** was created, or added later to the table definition by an ALTER TABLE
+** command. If the latter, then the row-records in the table btree on disk
+** may not contain a value for the column and the default value, taken
+** from the P3 parameter of the OP_Column instruction, is returned instead.
+** If the former, then all row-records are guaranteed to include a value
+** for the column and the P3 value is not required.
+**
+** Column definitions created by an ALTER TABLE command may only have 
+** literal default values specified: a number, null or a string. (If a more
+** complicated default expression value was provided, it is evaluated 
+** when the ALTER TABLE is executed and one of the literal values written
+** into the sqlite_master table.)
+**
+** Therefore, the P3 parameter is only required if the default value for
+** the column is a literal number, string or null. The sqlite3ValueFromExpr()
+** function is capable of transforming these types of expressions into
+** sqlite3_value objects.
+*/
+void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
+  if( pTab && !pTab->pSelect ){
+    sqlite3_value *pValue;
+    u8 enc = sqlite3VdbeDb(v)->enc;
+    Column *pCol = &pTab->aCol[i];
+    sqlite3ValueFromExpr(pCol->pDflt, enc, pCol->affinity, &pValue);
+    sqlite3VdbeChangeP3(v, -1, (const char *)pValue, P3_MEM);
+  }
+}
+
+/*
+** Process an UPDATE statement.
+**
+**   UPDATE OR IGNORE table_wxyz SET a=b, c=d WHERE e<5 AND f NOT NULL;
+**          \_______/ \________/     \______/       \________________/
+*            onError   pTabList      pChanges             pWhere
+*/
+void sqlite3Update(
+  Parse *pParse,         /* The parser context */
+  SrcList *pTabList,     /* The table in which we should change things */
+  ExprList *pChanges,    /* Things to be changed */
+  Expr *pWhere,          /* The WHERE clause.  May be null */
+  int onError            /* How to handle constraint errors */
+){
+  int i, j;              /* Loop counters */
+  Table *pTab;           /* The table to be updated */
+  int addr = 0;          /* VDBE instruction address of the start of the loop */
+  WhereInfo *pWInfo;     /* Information about the WHERE clause */
+  Vdbe *v;               /* The virtual database engine */
+  Index *pIdx;           /* For looping over indices */
+  int nIdx;              /* Number of indices that need updating */
+  int nIdxTotal;         /* Total number of indices */
+  int iCur;              /* VDBE Cursor number of pTab */
+  sqlite3 *db;           /* The database structure */
+  Index **apIdx = 0;     /* An array of indices that need updating too */
+  char *aIdxUsed = 0;    /* aIdxUsed[i]==1 if the i-th index is used */
+  int *aXRef = 0;        /* aXRef[i] is the index in pChanges->a[] of the
+                         ** an expression for the i-th column of the table.
+                         ** aXRef[i]==-1 if the i-th column is not changed. */
+  int chngRowid;         /* True if the record number is being changed */
+  Expr *pRowidExpr = 0;  /* Expression defining the new record number */
+  int openAll = 0;       /* True if all indices need to be opened */
+  AuthContext sContext;  /* The authorization context */
+  NameContext sNC;       /* The name-context to resolve expressions in */
+
+#ifndef SQLITE_OMIT_TRIGGER
+  int isView;                  /* Trying to update a view */
+  int triggers_exist = 0;      /* True if any row triggers exist */
+#endif
+
+  int newIdx      = -1;  /* index of trigger "new" temp table       */
+  int oldIdx      = -1;  /* index of trigger "old" temp table       */
+
+  sContext.pParse = 0;
+  if( pParse->nErr || sqlite3_malloc_failed ) goto update_cleanup;
+  db = pParse->db;
+  assert( pTabList->nSrc==1 );
+
+  /* Locate the table which we want to update. 
+  */
+  pTab = sqlite3SrcListLookup(pParse, pTabList);
+  if( pTab==0 ) goto update_cleanup;
+
+  /* Figure out if we have any triggers and if the table being
+  ** updated is a view
+  */
+#ifndef SQLITE_OMIT_TRIGGER
+  triggers_exist = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges);
+  isView = pTab->pSelect!=0;
+#else
+# define triggers_exist 0
+# define isView 0
+#endif
+#ifdef SQLITE_OMIT_VIEW
+# undef isView
+# define isView 0
+#endif
+
+  if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){
+    goto update_cleanup;
+  }
+  if( isView ){
+    if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+      goto update_cleanup;
+    }
+  }
+  aXRef = sqliteMallocRaw( sizeof(int) * pTab->nCol );
+  if( aXRef==0 ) goto update_cleanup;
+  for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;
+
+  /* If there are FOR EACH ROW triggers, allocate cursors for the
+  ** special OLD and NEW tables
+  */
+  if( triggers_exist ){
+    newIdx = pParse->nTab++;
+    oldIdx = pParse->nTab++;
+  }
+
+  /* Allocate a cursors for the main database table and for all indices.
+  ** The index cursors might not be used, but if they are used they
+  ** need to occur right after the database cursor.  So go ahead and
+  ** allocate enough space, just in case.
+  */
+  pTabList->a[0].iCursor = iCur = pParse->nTab++;
+  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+    pParse->nTab++;
+  }
+
+  /* Initialize the name-context */
+  memset(&sNC, 0, sizeof(sNC));
+  sNC.pParse = pParse;
+  sNC.pSrcList = pTabList;
+
+  /* Resolve the column names in all the expressions of the
+  ** of the UPDATE statement.  Also find the column index
+  ** for each column to be updated in the pChanges array.  For each
+  ** column to be updated, make sure we have authorization to change
+  ** that column.
+  */
+  chngRowid = 0;
+  for(i=0; i<pChanges->nExpr; i++){
+    if( sqlite3ExprResolveNames(&sNC, pChanges->a[i].pExpr) ){
+      goto update_cleanup;
+    }
+    for(j=0; j<pTab->nCol; j++){
+      if( sqlite3StrICmp(pTab->aCol[j].zName, pChanges->a[i].zName)==0 ){
+        if( j==pTab->iPKey ){
+          chngRowid = 1;
+          pRowidExpr = pChanges->a[i].pExpr;
+        }
+        aXRef[j] = i;
+        break;
+      }
+    }
+    if( j>=pTab->nCol ){
+      if( sqlite3IsRowid(pChanges->a[i].zName) ){
+        chngRowid = 1;
+        pRowidExpr = pChanges->a[i].pExpr;
+      }else{
+        sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zName);
+        goto update_cleanup;
+      }
+    }
+#ifndef SQLITE_OMIT_AUTHORIZATION
+    {
+      int rc;
+      rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName,
+                           pTab->aCol[j].zName, db->aDb[pTab->iDb].zName);
+      if( rc==SQLITE_DENY ){
+        goto update_cleanup;
+      }else if( rc==SQLITE_IGNORE ){
+        aXRef[j] = -1;
+      }
+    }
+#endif
+  }
+
+  /* Allocate memory for the array apIdx[] and fill it with pointers to every
+  ** index that needs to be updated.  Indices only need updating if their
+  ** key includes one of the columns named in pChanges or if the record
+  ** number of the original table entry is changing.
+  */
+  for(nIdx=nIdxTotal=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdxTotal++){
+    if( chngRowid ){
+      i = 0;
+    }else {
+      for(i=0; i<pIdx->nColumn; i++){
+        if( aXRef[pIdx->aiColumn[i]]>=0 ) break;
+      }
+    }
+    if( i<pIdx->nColumn ) nIdx++;
+  }
+  if( nIdxTotal>0 ){
+    apIdx = sqliteMallocRaw( sizeof(Index*) * nIdx + nIdxTotal );
+    if( apIdx==0 ) goto update_cleanup;
+    aIdxUsed = (char*)&apIdx[nIdx];
+  }
+  for(nIdx=j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
+    if( chngRowid ){
+      i = 0;
+    }else{
+      for(i=0; i<pIdx->nColumn; i++){
+        if( aXRef[pIdx->aiColumn[i]]>=0 ) break;
+      }
+    }
+    if( i<pIdx->nColumn ){
+      if( sqlite3CheckIndexCollSeq(pParse, pIdx) ) goto update_cleanup;
+      apIdx[nIdx++] = pIdx;
+      aIdxUsed[j] = 1;
+    }else{
+      aIdxUsed[j] = 0;
+    }
+  }
+
+  /* Resolve the column names in all the expressions in the
+  ** WHERE clause.
+  */
+  if( sqlite3ExprResolveNames(&sNC, pWhere) ){
+    goto update_cleanup;
+  }
+
+  /* Start the view context
+  */
+  if( isView ){
+    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
+  }
+
+  /* Begin generating code.
+  */
+  v = sqlite3GetVdbe(pParse);
+  if( v==0 ) goto update_cleanup;
+  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
+  sqlite3BeginWriteOperation(pParse, 1, pTab->iDb);
+
+  /* If we are trying to update a view, construct that view into
+  ** a temporary table.
+  */
+  if( isView ){
+    Select *pView;
+    pView = sqlite3SelectDup(pTab->pSelect);
+    sqlite3Select(pParse, pView, SRT_TempTable, iCur, 0, 0, 0, 0);
+    sqlite3SelectDelete(pView);
+  }
+
+  /* Begin the database scan
+  */
+  pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0);
+  if( pWInfo==0 ) goto update_cleanup;
+
+  /* Remember the index of every item to be updated.
+  */
+  sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0);
+  sqlite3VdbeAddOp(v, OP_ListWrite, 0, 0);
+
+  /* End the database scan loop.
+  */
+  sqlite3WhereEnd(pWInfo);
+
+  /* Initialize the count of updated rows
+  */
+  if( db->flags & SQLITE_CountRows && !pParse->trigStack ){
+    sqlite3VdbeAddOp(v, OP_Integer, 0, 0);
+  }
+
+  if( triggers_exist ){
+    /* Create pseudo-tables for NEW and OLD
+    */
+    sqlite3VdbeAddOp(v, OP_OpenPseudo, oldIdx, 0);
+    sqlite3VdbeAddOp(v, OP_SetNumColumns, oldIdx, pTab->nCol);
+    sqlite3VdbeAddOp(v, OP_OpenPseudo, newIdx, 0);
+    sqlite3VdbeAddOp(v, OP_SetNumColumns, newIdx, pTab->nCol);
+
+    /* The top of the update loop for when there are triggers.
+    */
+    sqlite3VdbeAddOp(v, OP_ListRewind, 0, 0);
+    addr = sqlite3VdbeAddOp(v, OP_ListRead, 0, 0);
+
+    if( !isView ){
+      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
+      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
+      /* Open a cursor and make it point to the record that is
+      ** being updated.
+      */
+      sqlite3OpenTableForReading(v, iCur, pTab);
+    }
+    sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
+
+    /* Generate the OLD table
+    */
+    sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0);
+    sqlite3VdbeAddOp(v, OP_RowData, iCur, 0);
+    sqlite3VdbeAddOp(v, OP_Insert, oldIdx, 0);
+
+    /* Generate the NEW table
+    */
+    if( chngRowid ){
+      sqlite3ExprCodeAndCache(pParse, pRowidExpr);
+    }else{
+      sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0);
+    }
+    for(i=0; i<pTab->nCol; i++){
+      if( i==pTab->iPKey ){
+        sqlite3VdbeAddOp(v, OP_Null, 0, 0);
+        continue;
+      }
+      j = aXRef[i];
+      if( j<0 ){
+        sqlite3VdbeAddOp(v, OP_Column, iCur, i);
+        sqlite3ColumnDefault(v, pTab, i);
+      }else{
+        sqlite3ExprCodeAndCache(pParse, pChanges->a[j].pExpr);
+      }
+    }
+    sqlite3VdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0);
+    if( !isView ){
+      sqlite3TableAffinityStr(v, pTab);
+    }
+    if( pParse->nErr ) goto update_cleanup;
+    sqlite3VdbeAddOp(v, OP_Insert, newIdx, 0);
+    if( !isView ){
+      sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
+    }
+
+    /* Fire the BEFORE and INSTEAD OF triggers
+    */
+    if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_BEFORE, pTab,
+          newIdx, oldIdx, onError, addr) ){
+      goto update_cleanup;
+    }
+  }
+
+  if( !isView ){
+    /* 
+    ** Open every index that needs updating.  Note that if any
+    ** index could potentially invoke a REPLACE conflict resolution 
+    ** action, then we need to open all indices because we might need
+    ** to be deleting some records.
+    */
+    sqlite3VdbeAddOp(v, OP_Integer, pTab->iDb, 0);
+    sqlite3VdbeAddOp(v, OP_OpenWrite, iCur, pTab->tnum);
+    sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, pTab->nCol);
+    if( onError==OE_Replace ){
+      openAll = 1;
+    }else{
+      openAll = 0;
+      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+        if( pIdx->onError==OE_Replace ){
+          openAll = 1;
+          break;
+        }
+      }
+    }
+    for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
+      if( openAll || aIdxUsed[i] ){
+        sqlite3VdbeAddOp(v, OP_Integer, pIdx->iDb, 0);
+        sqlite3VdbeOp3(v, OP_OpenWrite, iCur+i+1, pIdx->tnum,
+                       (char*)&pIdx->keyInfo, P3_KEYINFO);
+        assert( pParse->nTab>iCur+i+1 );
+      }
+    }
+
+    /* Loop over every record that needs updating.  We have to load
+    ** the old data for each record to be updated because some columns
+    ** might not change and we will need to copy the old value.
+    ** Also, the old data is needed to delete the old index entires.
+    ** So make the cursor point at the old record.
+    */
+    if( !triggers_exist ){
+      sqlite3VdbeAddOp(v, OP_ListRewind, 0, 0);
+      addr = sqlite3VdbeAddOp(v, OP_ListRead, 0, 0);
+      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
+    }
+    sqlite3VdbeAddOp(v, OP_NotExists, iCur, addr);
+
+    /* If the record number will change, push the record number as it
+    ** will be after the update. (The old record number is currently
+    ** on top of the stack.)
+    */
+    if( chngRowid ){
+      sqlite3ExprCode(pParse, pRowidExpr);
+      sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
+    }
+
+    /* Compute new data for this record.  
+    */
+    for(i=0; i<pTab->nCol; i++){
+      if( i==pTab->iPKey ){
+        sqlite3VdbeAddOp(v, OP_Null, 0, 0);
+        continue;
+      }
+      j = aXRef[i];
+      if( j<0 ){
+        sqlite3VdbeAddOp(v, OP_Column, iCur, i);
+        sqlite3ColumnDefault(v, pTab, i);
+      }else{
+        sqlite3ExprCode(pParse, pChanges->a[j].pExpr);
+      }
+    }
+
+    /* Do constraint checks
+    */
+    sqlite3GenerateConstraintChecks(pParse, pTab, iCur, aIdxUsed, chngRowid, 1,
+                                   onError, addr);
+
+    /* Delete the old indices for the current record.
+    */
+    sqlite3GenerateRowIndexDelete(db, v, pTab, iCur, aIdxUsed);
+
+    /* If changing the record number, delete the old record.
+    */
+    if( chngRowid ){
+      sqlite3VdbeAddOp(v, OP_Delete, iCur, 0);
+    }
+
+    /* Create the new index entries and the new record.
+    */
+    sqlite3CompleteInsertion(pParse, pTab, iCur, aIdxUsed, chngRowid, 1, -1);
+  }
+
+  /* Increment the row counter 
+  */
+  if( db->flags & SQLITE_CountRows && !pParse->trigStack){
+    sqlite3VdbeAddOp(v, OP_AddImm, 1, 0);
+  }
+
+  /* If there are triggers, close all the cursors after each iteration
+  ** through the loop.  The fire the after triggers.
+  */
+  if( triggers_exist ){
+    if( !isView ){
+      for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
+        if( openAll || aIdxUsed[i] )
+          sqlite3VdbeAddOp(v, OP_Close, iCur+i+1, 0);
+      }
+      sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
+    }
+    if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_AFTER, pTab, 
+          newIdx, oldIdx, onError, addr) ){
+      goto update_cleanup;
+    }
+  }
+
+  /* Repeat the above with the next record to be updated, until
+  ** all record selected by the WHERE clause have been updated.
+  */
+  sqlite3VdbeAddOp(v, OP_Goto, 0, addr);
+  sqlite3VdbeChangeP2(v, addr, sqlite3VdbeCurrentAddr(v));
+  sqlite3VdbeAddOp(v, OP_ListReset, 0, 0);
+
+  /* Close all tables if there were no FOR EACH ROW triggers */
+  if( !triggers_exist ){
+    for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
+      if( openAll || aIdxUsed[i] ){
+        sqlite3VdbeAddOp(v, OP_Close, iCur+i+1, 0);
+      }
+    }
+    sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
+  }else{
+    sqlite3VdbeAddOp(v, OP_Close, newIdx, 0);
+    sqlite3VdbeAddOp(v, OP_Close, oldIdx, 0);
+  }
+
+  /*
+  ** Return the number of rows that were changed. If this routine is 
+  ** generating code because of a call to sqlite3NestedParse(), do not
+  ** invoke the callback function.
+  */
+  if( db->flags & SQLITE_CountRows && !pParse->trigStack && pParse->nested==0 ){
+    sqlite3VdbeAddOp(v, OP_Callback, 1, 0);
+    sqlite3VdbeSetNumCols(v, 1);
+    sqlite3VdbeSetColName(v, 0, "rows updated", P3_STATIC);
+  }
+
+update_cleanup:
+  sqlite3AuthContextPop(&sContext);
+  sqliteFree(apIdx);
+  sqliteFree(aXRef);
+  sqlite3SrcListDelete(pTabList);
+  sqlite3ExprListDelete(pChanges);
+  sqlite3ExprDelete(pWhere);
+  return;
+}