/***** 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.*****************************************************************************/#include "sqliteInt.h"/*** Delete a linked list of TriggerStep structures.*/void sqliteDeleteTriggerStep(TriggerStep *pTriggerStep){  while( pTriggerStep ){    TriggerStep * pTmp = pTriggerStep;    pTriggerStep = pTriggerStep->pNext;    if( pTmp->target.dyn ) sqliteFree((char*)pTmp->target.z);    sqliteExprDelete(pTmp->pWhere);    sqliteExprListDelete(pTmp->pExprList);    sqliteSelectDelete(pTmp->pSelect);    sqliteIdListDelete(pTmp->pIdList);    sqliteFree(pTmp);  }}/*** This is called by the parser when it sees a CREATE TRIGGER statement** up to the point of the BEGIN before the trigger actions.  A Trigger** structure is generated based on the information available and stored** in pParse->pNewTrigger.  After the trigger actions have been parsed, the** sqliteFinishTrigger() function is called to complete the trigger** construction process.*/void sqliteBeginTrigger(  Parse *pParse,      /* The parse context of the CREATE TRIGGER statement */  Token *pName,       /* The name of the trigger */  int tr_tm,          /* One of TK_BEFORE, TK_AFTER, TK_INSTEAD */  int op,             /* One of TK_INSERT, TK_UPDATE, TK_DELETE */  IdList *pColumns,   /* column list if this is an UPDATE OF trigger */  SrcList *pTableName,/* The name of the table/view the trigger applies to */  int foreach,        /* One of TK_ROW or TK_STATEMENT */  Expr *pWhen,        /* WHEN clause */  int isTemp          /* True if the TEMPORARY keyword is present */){  Trigger *nt;  Table   *tab;  char *zName = 0;        /* Name of the trigger */  sqlite *db = pParse->db;  int iDb;                /* When database to store the trigger in */  DbFixer sFix;  /* Check that:   ** 1. the trigger name does not already exist.  ** 2. the table (or view) does exist in the same database as the trigger.  ** 3. that we are not trying to create a trigger on the sqlite_master table  ** 4. That we are not trying to create an INSTEAD OF trigger on a table.  ** 5. That we are not trying to create a BEFORE or AFTER trigger on a view.  */  if( sqlite_malloc_failed ) goto trigger_cleanup;  assert( pTableName->nSrc==1 );  if( db->init.busy   && sqliteFixInit(&sFix, pParse, db->init.iDb, "trigger", pName)   && sqliteFixSrcList(&sFix, pTableName)  ){    goto trigger_cleanup;  }  tab = sqliteSrcListLookup(pParse, pTableName);  if( !tab ){    goto trigger_cleanup;  }  iDb = isTemp ? 1 : tab->iDb;  if( iDb>=2 && !db->init.busy ){    sqliteErrorMsg(pParse, "triggers may not be added to auxiliary "       "database %s", db->aDb[tab->iDb].zName);    goto trigger_cleanup;  }  zName = sqliteStrNDup(pName->z, pName->n);  sqliteDequote(zName);  if( sqliteHashFind(&(db->aDb[iDb].trigHash), zName,pName->n+1) ){    sqliteErrorMsg(pParse, "trigger %T already exists", pName);    goto trigger_cleanup;  }  if( sqliteStrNICmp(tab->zName, "sqlite_", 7)==0 ){    sqliteErrorMsg(pParse, "cannot create trigger on system table");    pParse->nErr++;    goto trigger_cleanup;  }  if( tab->pSelect && tr_tm != TK_INSTEAD ){    sqliteErrorMsg(pParse, "cannot create %s trigger on view: %S",         (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0);    goto trigger_cleanup;  }  if( !tab->pSelect && tr_tm == TK_INSTEAD ){    sqliteErrorMsg(pParse, "cannot create INSTEAD OF"        " trigger on table: %S", pTableName, 0);    goto trigger_cleanup;  }#ifndef SQLITE_OMIT_AUTHORIZATION  {    int code = SQLITE_CREATE_TRIGGER;    const char *zDb = db->aDb[tab->iDb].zName;    const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb;    if( tab->iDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;    if( sqliteAuthCheck(pParse, code, zName, tab->zName, zDbTrig) ){      goto trigger_cleanup;    }    if( sqliteAuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(tab->iDb), 0, zDb)){      goto trigger_cleanup;    }  }#endif  /* INSTEAD OF triggers can only appear on views and BEGIN triggers  ** cannot appear on views.  So we might as well translate every  ** INSTEAD OF trigger into a BEFORE trigger.  It simplifies code  ** elsewhere.  */  if (tr_tm == TK_INSTEAD){    tr_tm = TK_BEFORE;  }  /* Build the Trigger object */  nt = (Trigger*)sqliteMalloc(sizeof(Trigger));  if( nt==0 ) goto trigger_cleanup;  nt->name = zName;  zName = 0;  nt->table = sqliteStrDup(pTableName->a[0].zName);  if( sqlite_malloc_failed ) goto trigger_cleanup;  nt->iDb = iDb;  nt->iTabDb = tab->iDb;  nt->op = op;  nt->tr_tm = tr_tm;  nt->pWhen = sqliteExprDup(pWhen);  nt->pColumns = sqliteIdListDup(pColumns);  nt->foreach = foreach;  sqliteTokenCopy(&nt->nameToken,pName);  assert( pParse->pNewTrigger==0 );  pParse->pNewTrigger = nt;trigger_cleanup:  sqliteFree(zName);  sqliteSrcListDelete(pTableName);  sqliteIdListDelete(pColumns);  sqliteExprDelete(pWhen);}/*** This routine is called after all of the trigger actions have been parsed** in order to complete the process of building the trigger.*/void sqliteFinishTrigger(  Parse *pParse,          /* Parser context */  TriggerStep *pStepList, /* The triggered program */  Token *pAll             /* Token that describes the complete CREATE TRIGGER */){  Trigger *nt = 0;          /* The trigger whose construction is finishing up */  sqlite *db = pParse->db;  /* The database */  DbFixer sFix;  if( pParse->nErr || pParse->pNewTrigger==0 ) goto triggerfinish_cleanup;  nt = pParse->pNewTrigger;  pParse->pNewTrigger = 0;  nt->step_list = pStepList;  while( pStepList ){    pStepList->pTrig = nt;    pStepList = pStepList->pNext;  }  if( sqliteFixInit(&sFix, pParse, nt->iDb, "trigger", &nt->nameToken)           && sqliteFixTriggerStep(&sFix, nt->step_list) ){    goto triggerfinish_cleanup;  }  /* if we are not initializing, and this trigger is not on a TEMP table,   ** build the sqlite_master entry  */  if( !db->init.busy ){    static VdbeOpList insertTrig[] = {      { OP_NewRecno,   0, 0,  0          },      { OP_String,     0, 0,  "trigger"  },      { OP_String,     0, 0,  0          },  /* 2: trigger name */      { OP_String,     0, 0,  0          },  /* 3: table name */      { OP_Integer,    0, 0,  0          },      { OP_String,     0, 0,  0          },  /* 5: SQL */      { OP_MakeRecord, 5, 0,  0          },      { OP_PutIntKey,  0, 0,  0          },    };    int addr;    Vdbe *v;    /* Make an entry in the sqlite_master table */    v = sqliteGetVdbe(pParse);    if( v==0 ) goto triggerfinish_cleanup;    sqliteBeginWriteOperation(pParse, 0, 0);    sqliteOpenMasterTable(v, nt->iDb);    addr = sqliteVdbeAddOpList(v, ArraySize(insertTrig), insertTrig);    sqliteVdbeChangeP3(v, addr+2, nt->name, 0);     sqliteVdbeChangeP3(v, addr+3, nt->table, 0);     sqliteVdbeChangeP3(v, addr+5, pAll->z, pAll->n);    if( nt->iDb==0 ){      sqliteChangeCookie(db, v);    }    sqliteVdbeAddOp(v, OP_Close, 0, 0);    sqliteEndWriteOperation(pParse);  }  if( !pParse->explain ){    Table *pTab;    sqliteHashInsert(&db->aDb[nt->iDb].trigHash,                      nt->name, strlen(nt->name)+1, nt);    pTab = sqliteLocateTable(pParse, nt->table, db->aDb[nt->iTabDb].zName);    assert( pTab!=0 );    nt->pNext = pTab->pTrigger;    pTab->pTrigger = nt;    nt = 0;  }triggerfinish_cleanup:  sqliteDeleteTrigger(nt);  sqliteDeleteTrigger(pParse->pNewTrigger);  pParse->pNewTrigger = 0;  sqliteDeleteTriggerStep(pStepList);}/*** Make a copy of all components of the given trigger step.  This has** the effect of copying all Expr.token.z values into memory obtained** from sqliteMalloc().  As initially created, the Expr.token.z values** all point to the input string that was fed to the parser.  But that** string is ephemeral - it will go away as soon as the sqlite_exec()** call that started the parser exits.  This routine makes a persistent** copy of all the Expr.token.z strings so that the TriggerStep structure** will be valid even after the sqlite_exec() call returns.*/static void sqlitePersistTriggerStep(TriggerStep *p){  if( p->target.z ){    p->target.z = sqliteStrNDup(p->target.z, p->target.n);    p->target.dyn = 1;  }  if( p->pSelect ){    Select *pNew = sqliteSelectDup(p->pSelect);    sqliteSelectDelete(p->pSelect);    p->pSelect = pNew;  }  if( p->pWhere ){    Expr *pNew = sqliteExprDup(p->pWhere);    sqliteExprDelete(p->pWhere);    p->pWhere = pNew;  }  if( p->pExprList ){    ExprList *pNew = sqliteExprListDup(p->pExprList);    sqliteExprListDelete(p->pExprList);    p->pExprList = pNew;  }  if( p->pIdList ){    IdList *pNew = sqliteIdListDup(p->pIdList);    sqliteIdListDelete(p->pIdList);    p->pIdList = pNew;  }}/*** Turn a SELECT statement (that the pSelect parameter points to) into** a trigger step.  Return a pointer to a TriggerStep structure.**** The parser calls this routine when it finds a SELECT statement in** body of a TRIGGER.  */TriggerStep *sqliteTriggerSelectStep(Select *pSelect){  TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));  if( pTriggerStep==0 ) return 0;  pTriggerStep->op = TK_SELECT;  pTriggerStep->pSelect = pSelect;  pTriggerStep->orconf = OE_Default;  sqlitePersistTriggerStep(pTriggerStep);  return pTriggerStep;}/*** Build a trigger step out of an INSERT statement.  Return a pointer** to the new trigger step.**** The parser calls this routine when it sees an INSERT inside the** body of a trigger.*/TriggerStep *sqliteTriggerInsertStep(  Token *pTableName,  /* Name of the table into which we insert */  IdList *pColumn,    /* List of columns in pTableName to insert into */  ExprList *pEList,   /* The VALUE clause: a list of values to be inserted */  Select *pSelect,    /* A SELECT statement that supplies values */  int orconf          /* The conflict algorithm (OE_Abort, OE_Replace, etc.) */){  TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));  if( pTriggerStep==0 ) return 0;  assert(pEList == 0 || pSelect == 0);  assert(pEList != 0 || pSelect != 0);  pTriggerStep->op = TK_INSERT;  pTriggerStep->pSelect = pSelect;  pTriggerStep->target  = *pTableName;  pTriggerStep->pIdList = pColumn;  pTriggerStep->pExprList = pEList;  pTriggerStep->orconf = orconf;  sqlitePersistTriggerStep(pTriggerStep);  return pTriggerStep;}/*** Construct a trigger step that implements an UPDATE statement and return** a pointer to that trigger step.  The parser calls this routine when it** sees an UPDATE statement inside the body of a CREATE TRIGGER.*/TriggerStep *sqliteTriggerUpdateStep(  Token *pTableName,   /* Name of the table to be updated */  ExprList *pEList,    /* The SET clause: list of column and new values */  Expr *pWhere,        /* The WHERE clause */  int orconf           /* The conflict algorithm. (OE_Abort, OE_Ignore, etc) */){  TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));  if( pTriggerStep==0 ) return 0;  pTriggerStep->op = TK_UPDATE;  pTriggerStep->target  = *pTableName;  pTriggerStep->pExprList = pEList;  pTriggerStep->pWhere = pWhere;  pTriggerStep->orconf = orconf;  sqlitePersistTriggerStep(pTriggerStep);  return pTriggerStep;}/*** Construct a trigger step that implements a DELETE statement and return** a pointer to that trigger step.  The parser calls this routine when it** sees a DELETE statement inside the body of a CREATE TRIGGER.*/TriggerStep *sqliteTriggerDeleteStep(Token *pTableName, Expr *pWhere){  TriggerStep *pTriggerStep = sqliteMalloc(sizeof(TriggerStep));  if( pTriggerStep==0 ) return 0;  pTriggerStep->op = TK_DELETE;  pTriggerStep->target  = *pTableName;  pTriggerStep->pWhere = pWhere;  pTriggerStep->orconf = OE_Default;  sqlitePersistTriggerStep(pTriggerStep);  return pTriggerStep;}/* ** Recursively delete a Trigger structure*/void sqliteDeleteTrigger(Trigger *pTrigger){  if( pTrigger==0 ) return;  sqliteDeleteTriggerStep(pTrigger->step_list);  sqliteFree(pTrigger->name);  sqliteFree(pTrigger->table);  sqliteExprDelete(pTrigger->pWhen);  sqliteIdListDelete(pTrigger->pColumns);  if( pTrigger->nameToken.dyn ) sqliteFree((char*)pTrigger->nameToken.z);  sqliteFree(pTrigger);}/* * This function is called to drop a trigger from the database schema.  * * This may be called directly from the parser and therefore identifies * the trigger by name.  The sqliteDropTriggerPtr() routine does the * same job as this routine except it take a spointer to the trigger * instead of the trigger name. * * Note that this function does not delete the trigger entirely. Instead it