/***** 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"#ifndef SQLITE_OMIT_TRIGGER/*** Delete a linked list of TriggerStep structures.*/void sqlite3DeleteTriggerStep(TriggerStep *pTriggerStep){  while( pTriggerStep ){    TriggerStep * pTmp = pTriggerStep;    pTriggerStep = pTriggerStep->pNext;    if( pTmp->target.dyn ) sqliteFree((char*)pTmp->target.z);    sqlite3ExprDelete(pTmp->pWhere);    sqlite3ExprListDelete(pTmp->pExprList);    sqlite3SelectDelete(pTmp->pSelect);    sqlite3IdListDelete(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** sqlite3FinishTrigger() function is called to complete the trigger** construction process.*/void sqlite3BeginTrigger(  Parse *pParse,      /* The parse context of the CREATE TRIGGER statement */  Token *pName1,      /* The name of the trigger */  Token *pName2,      /* 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 *pTrigger = 0;  Table *pTab;  char *zName = 0;        /* Name of the trigger */  sqlite3 *db = pParse->db;  int iDb;                /* The database to store the trigger in */  Token *pName;           /* The unqualified db name */  DbFixer sFix;  if( isTemp ){    /* If TEMP was specified, then the trigger name may not be qualified. */    if( pName2 && pName2->n>0 ){      sqlite3ErrorMsg(pParse, "temporary trigger may not have qualified name");      goto trigger_cleanup;    }    iDb = 1;    pName = pName1;  }else{    /* Figure out the db that the the trigger will be created in */    iDb = sqlite3TwoPartName(pParse, pName1, pName2, &pName);    if( iDb<0 ){      goto trigger_cleanup;    }  }  /* If the trigger name was unqualified, and the table is a temp table,  ** then set iDb to 1 to create the trigger in the temporary database.  ** If sqlite3SrcListLookup() returns 0, indicating the table does not  ** exist, the error is caught by the block below.  */  if( !pTableName || sqlite3_malloc_failed ) goto trigger_cleanup;  pTab = sqlite3SrcListLookup(pParse, pTableName);  if( pName2->n==0 && pTab && pTab->iDb==1 ){    iDb = 1;  }  /* Ensure the table name matches database name and that the table exists */  if( sqlite3_malloc_failed ) goto trigger_cleanup;  assert( pTableName->nSrc==1 );  if( sqlite3FixInit(&sFix, pParse, iDb, "trigger", pName) &&       sqlite3FixSrcList(&sFix, pTableName) ){    goto trigger_cleanup;  }  pTab = sqlite3SrcListLookup(pParse, pTableName);  if( !pTab ){    /* The table does not exist. */    goto trigger_cleanup;  }  /* Check that the trigger name is not reserved and that no trigger of the  ** specified name exists */  zName = sqlite3NameFromToken(pName);  if( !zName || SQLITE_OK!=sqlite3CheckObjectName(pParse, zName) ){    goto trigger_cleanup;  }  if( sqlite3HashFind(&(db->aDb[iDb].trigHash), zName,pName->n+1) ){    sqlite3ErrorMsg(pParse, "trigger %T already exists", pName);    goto trigger_cleanup;  }  /* Do not create a trigger on a system table */  if( sqlite3StrNICmp(pTab->zName, "sqlite_", 7)==0 ){    sqlite3ErrorMsg(pParse, "cannot create trigger on system table");    pParse->nErr++;    goto trigger_cleanup;  }  /* INSTEAD of triggers are only for views and views only support INSTEAD  ** of triggers.  */  if( pTab->pSelect && tr_tm!=TK_INSTEAD ){    sqlite3ErrorMsg(pParse, "cannot create %s trigger on view: %S",         (tr_tm == TK_BEFORE)?"BEFORE":"AFTER", pTableName, 0);    goto trigger_cleanup;  }  if( !pTab->pSelect && tr_tm==TK_INSTEAD ){    sqlite3ErrorMsg(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[pTab->iDb].zName;    const char *zDbTrig = isTemp ? db->aDb[1].zName : zDb;    if( pTab->iDb==1 || isTemp ) code = SQLITE_CREATE_TEMP_TRIGGER;    if( sqlite3AuthCheck(pParse, code, zName, pTab->zName, zDbTrig) ){      goto trigger_cleanup;    }    if( sqlite3AuthCheck(pParse, SQLITE_INSERT, SCHEMA_TABLE(pTab->iDb),0,zDb)){      goto trigger_cleanup;    }  }#endif  /* INSTEAD OF triggers can only appear on views and BEFORE 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 */  pTrigger = (Trigger*)sqliteMalloc(sizeof(Trigger));  if( pTrigger==0 ) goto trigger_cleanup;  pTrigger->name = zName;  zName = 0;  pTrigger->table = sqliteStrDup(pTableName->a[0].zName);  pTrigger->iDb = iDb;  pTrigger->iTabDb = pTab->iDb;  pTrigger->op = op;  pTrigger->tr_tm = tr_tm==TK_BEFORE ? TRIGGER_BEFORE : TRIGGER_AFTER;  pTrigger->pWhen = sqlite3ExprDup(pWhen);  pTrigger->pColumns = sqlite3IdListDup(pColumns);  pTrigger->foreach = foreach;  sqlite3TokenCopy(&pTrigger->nameToken,pName);  assert( pParse->pNewTrigger==0 );  pParse->pNewTrigger = pTrigger;trigger_cleanup:  sqliteFree(zName);  sqlite3SrcListDelete(pTableName);  sqlite3IdListDelete(pColumns);  sqlite3ExprDelete(pWhen);  if( !pParse->pNewTrigger ){    sqlite3DeleteTrigger(pTrigger);  }else{    assert( pParse->pNewTrigger==pTrigger );  }}/*** This routine is called after all of the trigger actions have been parsed** in order to complete the process of building the trigger.*/void sqlite3FinishTrigger(  Parse *pParse,          /* Parser context */  TriggerStep *pStepList, /* The triggered program */  Token *pAll             /* Token that describes the complete CREATE TRIGGER */){  Trigger *pTrig = 0;     /* The trigger whose construction is finishing up */  sqlite3 *db = pParse->db;  /* The database */  DbFixer sFix;  pTrig = pParse->pNewTrigger;  pParse->pNewTrigger = 0;  if( pParse->nErr || pTrig==0 ) goto triggerfinish_cleanup;  pTrig->step_list = pStepList;  while( pStepList ){    pStepList->pTrig = pTrig;    pStepList = pStepList->pNext;  }  if( sqlite3FixInit(&sFix, pParse, pTrig->iDb, "trigger", &pTrig->nameToken)           && sqlite3FixTriggerStep(&sFix, pTrig->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 const VdbeOpList insertTrig[] = {      { OP_NewRowid,   0, 0,  0          },      { OP_String8,    0, 0,  "trigger"  },      { OP_String8,    0, 0,  0          },  /* 2: trigger name */      { OP_String8,    0, 0,  0          },  /* 3: table name */      { OP_Integer,    0, 0,  0          },      { OP_String8,    0, 0,  "CREATE TRIGGER "},      { OP_String8,    0, 0,  0          },  /* 6: SQL */      { OP_Concat,     0, 0,  0          },       { OP_MakeRecord, 5, 0,  "tttit"    },      { OP_Insert,     0, 0,  0          },    };    int addr;    Vdbe *v;    /* Make an entry in the sqlite_master table */    v = sqlite3GetVdbe(pParse);    if( v==0 ) goto triggerfinish_cleanup;    sqlite3BeginWriteOperation(pParse, 0, pTrig->iDb);    sqlite3OpenMasterTable(v, pTrig->iDb);    addr = sqlite3VdbeAddOpList(v, ArraySize(insertTrig), insertTrig);    sqlite3VdbeChangeP3(v, addr+2, pTrig->name, 0);     sqlite3VdbeChangeP3(v, addr+3, pTrig->table, 0);     sqlite3VdbeChangeP3(v, addr+6, pAll->z, pAll->n);    sqlite3ChangeCookie(db, v, pTrig->iDb);    sqlite3VdbeAddOp(v, OP_Close, 0, 0);    sqlite3VdbeOp3(v, OP_ParseSchema, pTrig->iDb, 0,        sqlite3MPrintf("type='trigger' AND name='%q'", pTrig->name), P3_DYNAMIC);  }  if( db->init.busy ){    Table *pTab;    Trigger *pDel;    pDel = sqlite3HashInsert(&db->aDb[pTrig->iDb].trigHash,                      pTrig->name, strlen(pTrig->name)+1, pTrig);    if( pDel ){      assert( sqlite3_malloc_failed && pDel==pTrig );      goto triggerfinish_cleanup;    }    pTab = sqlite3LocateTable(pParse,pTrig->table,db->aDb[pTrig->iTabDb].zName);    assert( pTab!=0 );    pTrig->pNext = pTab->pTrigger;    pTab->pTrigger = pTrig;    pTrig = 0;  }triggerfinish_cleanup:  sqlite3DeleteTrigger(pTrig);  assert( !pParse->pNewTrigger );  sqlite3DeleteTriggerStep(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 sqlite3_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 sqlite3_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 = sqlite3SelectDup(p->pSelect);    sqlite3SelectDelete(p->pSelect);    p->pSelect = pNew;  }  if( p->pWhere ){    Expr *pNew = sqlite3ExprDup(p->pWhere);    sqlite3ExprDelete(p->pWhere);    p->pWhere = pNew;  }  if( p->pExprList ){    ExprList *pNew = sqlite3ExprListDup(p->pExprList);    sqlite3ExprListDelete(p->pExprList);    p->pExprList = pNew;  }  if( p->pIdList ){    IdList *pNew = sqlite3IdListDup(p->pIdList);    sqlite3IdListDelete(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 *sqlite3TriggerSelectStep(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 *sqlite3TriggerInsertStep(  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));  assert(pEList == 0 || pSelect == 0);  assert(pEList != 0 || pSelect != 0);  if( pTriggerStep ){    pTriggerStep->op = TK_INSERT;    pTriggerStep->pSelect = pSelect;    pTriggerStep->target  = *pTableName;    pTriggerStep->pIdList = pColumn;    pTriggerStep->pExprList = pEList;    pTriggerStep->orconf = orconf;    sqlitePersistTriggerStep(pTriggerStep);  }else{    sqlite3IdListDelete(pColumn);    sqlite3ExprListDelete(pEList);    sqlite3SelectDup(pSelect);  }  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 *sqlite3TriggerUpdateStep(  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 *sqlite3TriggerDeleteStep(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;}