// Copyright (c) 1998-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// SQL parser

// 

//

#include "UQ_STD.H"

// class TSqlParser

const TInt KSqlError = -1;

TSqlParser::TSqlParser(const TDesC& aSql)

	: iSql(aSql)

	{

	NextToken();		// parse the first token

	}

TSqlTokenType TSqlParser::NextToken()

	{

	return iSql.NextToken(iToken);

	}

CSqlSearchCondition* TSqlParser::SqlError()

	{

	if (!Error())

		iToken.SetError(KErrArgument);

	return 0;

	}

TSqlTokenType TSqlParser::SqlErrorL()

//

// Report a SQL syntax error

//

	{

	return TSqlTokenType(__LEAVE_IF_ERROR(KErrArgument));

	}

TSqlTokenType TSqlParser::Parse(TSqlKeyword aKeyword)

//

// look for requested keyword, skip to the next token if found

// return the next token if found, else ESqlNoToken (==0)

//

	{

	return TSqlLexer::IsKeyword(aKeyword,iToken) ? NextToken() : ESqlNoToken;

	}

TSqlTokenType TSqlParser::ParseL(TSqlTokenType aToken)

//

// parse the desired token

//

	{

	return iToken!=aToken ? SqlErrorL() : NextToken();

	}

TSqlTokenType TSqlParser::ParseL(TSqlKeyword aKeyword)

//

// parse the desired keyword

//

	{

	TSqlTokenType t=Parse(aKeyword);

	return t==ESqlNoToken ? SqlErrorL() : t;

	}

TSqlKeyword TSqlParser::Keyword()

//

// parse a keyword

//

	{

	TSqlKeyword k=TSqlLexer::Keyword(iToken);

	if (k!=ESqlNotKeyword)

		NextToken();

	return k;

	}

TSqlTokenType TSqlParser::RightBracketL()

//

// parse a right bracket, and fail if not found

//

	{

	return ParseL(ESqlRightBracket);

	}

void TSqlParser::EndL()

//

// Check that the SQL has been fully parsed

//

	{

	if (iToken!=ESqlEos)

		SqlErrorL();

	}

TSqlTokenType TSqlParser::IdentifierL(TPtrC& aIdentifier)

//

// parse an identifer, fail if not found

//

	{

	if (iToken!=ESqlIdentifier)

		return SqlErrorL();

	const TText* p=iToken.Literal().Ptr();

	TInt len=iToken.Literal().End()-p;

	aIdentifier.Set(p,len);

	return NextToken();

	}

TPtrC TSqlParser::IdentifierL()

//

// parse an identifer, fail if not found

//

	{

	if (iToken!=ESqlIdentifier)

		SqlErrorL();

	return iToken.Literal().DesC();

	}

TSqlTokenType TSqlParser::ColumnNameL(RSqlColumnList& aList)

//

// Parse a column-identifier

//

	{

	__LEAVE_IF_ERROR(aList.Append(IdentifierL()));

	return NextToken();

	}

TSqlTokenType TSqlParser::ColumnListL(RSqlColumnList& aList)

//

// Parse a column-identifier-comma-list

//

	{

	for (;;)

		{

		TSqlTokenType t=ColumnNameL(aList);

		if (t!=ESqlComma)

			return t;

		NextToken();

		}

	}

TSqlTokenType TSqlParser::AddColumnSpecL(TDbCol& aDef)

//

// Parse an add-column-spec

//

	{

	aDef.iAttributes=0;

	aDef.iName=IdentifierL();

	NextToken();

//

	TDbColType type;

	switch (Keyword())

		{

	case ESqlKeyword_bit:

		type=EDbColBit;

		break;

	case ESqlKeyword_tinyint:

		type=EDbColInt8;

		break;

	case ESqlKeyword_smallint:

		type=EDbColInt16;

		break;

	case ESqlKeyword_integer:

		type=EDbColInt32;

		break;

	case ESqlKeyword_counter:

		aDef.iAttributes=aDef.EAutoIncrement;

		type=EDbColUint32;

		break;

	case ESqlKeyword_bigint:

		type=EDbColInt64;

		break;

	case ESqlKeyword_real:

		type=EDbColReal32;

		break;

	case ESqlKeyword_double:

	//Return value is intentionaly not checked. Parse() checks for  

	//an optional SQL keyword and calls internal checks. 

	//coverity[check_return]

	//coverity[unchecked_value]

		Parse(ESqlKeyword_precision);

		// fall through

	case ESqlKeyword_float:

		type=EDbColReal64;

		break;

	case ESqlKeyword_date:

	case ESqlKeyword_time:

	case ESqlKeyword_timestamp:

		type=EDbColDateTime;

		break;

	case ESqlKeyword_char:

	case ESqlKeyword_varchar:

		type=EDbColText;

		break;

	case ESqlKeyword_binary:

	case ESqlKeyword_varbinary:

		type=EDbColBinary;

		break;

	case ESqlKeyword_unsigned:	// unsigned tinyint, smallint or integer

		switch (Keyword())

			{

		case ESqlKeyword_tinyint:

			type=EDbColUint8;

			break;

		case ESqlKeyword_smallint:

			type=EDbColUint16;

			break;

		case ESqlKeyword_integer:

			type=EDbColUint32;

			break;

		default:

			return SqlErrorL();

			};

		break;

	case ESqlKeyword_long:		// varchar or varbinary

		switch (Keyword())

			{

		case ESqlKeyword_varchar:

			type=EDbColLongText;

			break;

		case ESqlKeyword_varbinary:

			type=EDbColLongBinary;

			break;

		default:

			return SqlErrorL();

			};

		break;

	default:

		return SqlErrorL();

		}

	aDef.iType=type;

//

// get any optional length

	aDef.iMaxLength=KDbUndefinedLength;

	TSqlTokenType t=iToken.Type();

	switch (type)

		{

	case EDbColText:

	case EDbColBinary:

		if (t==ESqlLeftBracket)

			{

			if (NextToken()==ESqlLiteralInt)

				{

				iToken.Literal().ToInt32L();

				aDef.iMaxLength=iToken.Literal().Int32();

				NextToken();

				t=RightBracketL();

				}

			else

				return SqlErrorL();

			}

		break;

	default:

		break;

		}

	return t;

	}

CSqlSearchCondition* TSqlParser::SearchCondition(TInt aNot)

//

// Parse a search-condition

//

	{

	CSqlSearchCondition* left=BooleanTerm(aNot);

	if (left==0 || Parse(ESqlKeyword_or)==ESqlNoToken)

		return left;

	return CSqlMultiNode::New(aNot ? CSqlMultiNode::EAnd : CSqlMultiNode::EOr,left,SearchCondition(aNot));

	}

CSqlSearchCondition* TSqlParser::BooleanTerm(TInt aNot)

//

// Parse a boolean-term

//

	{

	CSqlSearchCondition* left=BooleanFactor(aNot);

	if (left==0 || Parse(ESqlKeyword_and)==ESqlNoToken)

		return left;

	return CSqlMultiNode::New(aNot ? CSqlMultiNode::EOr : CSqlMultiNode::EAnd,left,BooleanTerm(aNot));

	}

CSqlSearchCondition* TSqlParser::BooleanFactor(TInt aNot)

//

// Parse a boolean-factor

//

	{

	while (Parse(ESqlKeyword_not))

		aNot=~aNot;

	return BooleanPrimary(aNot);

	}

CSqlSearchCondition* TSqlParser::BooleanPrimary(TInt aNot)

//

// Parse a boolean-factor

//

	{

	// brackets only allowed in this element, so this ordering is valid

	if (iToken!=ESqlLeftBracket)

		return Predicate(aNot);

	// bracketed search condition

	NextToken();

	CSqlSearchCondition* node=SearchCondition(aNot);

	if (!node)

		return node;

	if (iToken==ESqlRightBracket)

		{

		NextToken();

		return node;

		}

	delete node;

	return SqlError();

	}

CSqlSearchCondition* TSqlParser::Predicate(TInt aNot)

//

// Parse predicate

// On null return, error will already be set

//

	{

	if (iToken!=ESqlIdentifier)	// column name

		return SqlError();

	TPtrC column(iToken.Literal().DesC());

	TSqlTokenType t=NextToken();

	if (t==ESqlIdentifier)

		{	// like-predicate or null-predicate

		switch (Keyword())

			{

		case ESqlKeyword_is:	// IS [NOT] NULL

			if (Parse(ESqlKeyword_not))

				aNot=~aNot;

			if (Parse(ESqlKeyword_null)==ESqlNoToken)

				return SqlError();

			return new CSqlNullPredicate(aNot ? CSqlNullPredicate::EIsNotNull : CSqlNullPredicate::EIsNull,column);

		case ESqlKeyword_not:	// NOT LIKE

			if (Parse(ESqlKeyword_like)==ESqlNoToken)

				return SqlError();

			aNot=~aNot;

			// drop through to Like

		case ESqlKeyword_like:	// LIKE

			{

			if (iToken!=ESqlLiteralText)

				return SqlError();

			//Following code is for the implementation of limited-ESCAPE-clause 

			const TText *next = iSql.Next(); 		//remember thecurrent position in the SQL statement

			RSqlLiteral pattern = iToken.Literal(); //this is the LIKE pattern, remember it, because the next keyword might be ESCAPE

			NextToken(); // Searching for ESCAPE keyword

			if (Keyword() == ESqlKeyword_escape)

				{

				if (pattern.DesC().Length() <= 0 || pattern.DesC().Length() > (KMaxSegmentLength + 2 ))

					return SqlError();

				TPtrC escapeChar(iToken.Literal().DesC());

				if (escapeChar.Length() <= 0)

					return SqlError();

				TChar escchar = escapeChar[0];

				TText newPattern[KMaxSegmentLength + 2]; // '*' can come as first and last char

				TInt count = PatternFilter(pattern.DesC(),escchar, newPattern);//remove the escape characters from the pattern and store it in "newPattern" variable

				if (count <=0 )

					return SqlError();

				iToken.Literal().SetText(newPattern,(newPattern + count));

				// copy the text to RSqlLiteral as "newPattern" is stack based variable and will go out of scope

				if (iToken.Literal().CopyText() != KErrNone)

					{

					return SqlError();

					}

				CSqlSearchCondition* node = new CSqlLikePredicate(aNot ? CSqlLikePredicate::ENotLike : CSqlLikePredicate::ELike,column,iToken.Literal());

				//cleanup iToken.Literal(), because if there is another LIKE predicate, the allocated by CopyText() buffer will

				//be shared between two RSqlLiteral instances and RSqlLiteral::Close() call will crash. 

				//RSqlLiteral::RSqlLiteral() will set the "iBuffer" data member to NULL.

				iToken.Literal() = RSqlLiteral();

				if (node)

					{

					NextToken();

					node->iIsEscape = ETrue;

					}

				return node;						

				}

			else

				{

				//Set to the previous node

				iSql.Set(next);

				CSqlSearchCondition* node = new CSqlLikePredicate(aNot ? CSqlLikePredicate::ENotLike : CSqlLikePredicate::ELike,column,pattern);

				if(node)

					NextToken();

				return node;

				}

			}

		default:

			return SqlError();

			}

		}

	// Comparison predicate...

	CSqlSearchCondition::TType op;

	switch (t)

		{

	case ESqlGreaterEqual:

		aNot=~aNot;

		// drop through to less

	case ESqlLess:

		op=aNot ? CSqlSearchCondition::EGreaterEqual : CSqlSearchCondition::ELess;

		break;

	case ESqlGreater:

		aNot=~aNot;

		// drop through to less equal

	case ESqlLessEqual:

		op=aNot ? CSqlSearchCondition::EGreater: CSqlSearchCondition::ELessEqual;

		break;

	case ESqlNotEqual:

		aNot=~aNot;

		// drop through to equal

	case ESqlEqual:

		op=aNot ? CSqlSearchCondition::ENotEqual : CSqlSearchCondition::EEqual;

		break;

	default:

		return SqlError();

		}

	t=NextToken();

	if (t!=ESqlLiteralInt && t!=ESqlLiteralReal && t!=ESqlLiteralTime && t!=ESqlLiteralText)

		return SqlError();

	CSqlSearchCondition* node=new CSqlCompPredicate(op,column,iToken.Literal());

	if (node)

		NextToken();

	return node;

	}

CSqlSearchCondition* TSqlParser::SearchConditionL()

//

// Parse a search-condition

//

	{

	CSqlSearchCondition* sc=SearchCondition(0);

	if (!sc)

		{

		__LEAVE_IF_ERROR(Error());	// syntax error

		User::LeaveNoMemory();		// otherwise a OOM error

		}

	return sc;

	}

void TSqlParser::SortSpecificationL(CDbKey& aKey)

//

// Parse a sort-specification

//

	{

	for (;;)

		{

		TDbKeyCol col(IdentifierL());

		NextToken();

		if (Parse(ESqlKeyword_desc))

			col.iOrder=col.EDesc;

		else

			{

			//Return value is intentionaly not checked. Parse() checks for  

			//an optional SQL keyword and calls internal checks. 

			//coverity[check_return]

			//coverity[unchecked_value]

			Parse(ESqlKeyword_asc);

			col.iOrder=col.EAsc;

			}

		aKey.AddL(col);

		if (iToken!=ESqlComma)

			break;

		NextToken();

		}

	}

CSqlQuery* TSqlParser::QueryLC()

//

// Generate a CSqlQuery

//

	{

	CSqlQuery* query=new(ELeave) CSqlQuery;

	CleanupStack::PushL(query);

	if (ParseL(ESqlKeyword_select)==ESqlAsterisk)

		NextToken();

	else

		ColumnListL(query->iColumns);

	ParseL(ESqlKeyword_from);

	IdentifierL(query->iTable);

	if (Parse(ESqlKeyword_where))

		query->iSearchCondition=SearchConditionL();

	if (Parse(ESqlKeyword_order))

		{

		ParseL(ESqlKeyword_by);

		SortSpecificationL(query->SortSpecificationL());

		}

	EndL();

	return query;

	}

CSqlSearchCondition* TSqlParser::SearchConditionLC()

//

// Parse a standalone search-condition

//

	{

	CSqlSearchCondition* sc=SearchConditionL();

	CleanupStack::PushL(sc);

	EndL();

	return sc;

	}

CSqlDDLStatement* TSqlParser::CreateTableLC()

//

// Parse a CREATE TABLE statement

//

	{

	CSqlCreateTableStatement* statement=new(ELeave) CSqlCreateTableStatement;

	CleanupStack::PushL(statement);

	IdentifierL(statement->iName);

	ParseL(ESqlLeftBracket);

	TDbCol def;

	for (;;)

		{

		AddColumnSpecL(def);

		if (Parse(ESqlKeyword_not))

			{

			ParseL(ESqlKeyword_null);

			def.iAttributes|=TDbCol::ENotNull;

			}

		statement->iColumns.AddL(def);

		if (iToken!=ESqlComma)

			break;

		NextToken();

		}

	RightBracketL();

	return statement;

	}

CSqlDDLStatement* TSqlParser::DropTableLC()

//

// Parse a DROP TABLE statement

//

	{

	CSqlDropTableStatement* statement=new(ELeave) CSqlDropTableStatement;

	CleanupStack::PushL(statement);

	IdentifierL(statement->iName);

	return statement;

	}

CSqlDDLStatement* TSqlParser::AlterTableLC()

//

// Parse a CREATE TABLE statement

//

	{

	CSqlAlterTableStatement* statement=new(ELeave) CSqlAlterTableStatement;

	CleanupStack::PushL(statement);

	IdentifierL(statement->iName);

	TSqlTokenType t=Parse(ESqlKeyword_add);

	if (t!=ESqlNoToken)

		{

		TDbCol def;

		if (t==ESqlLeftBracket)

			{

			NextToken();

			for (;;)

				{

				t=AddColumnSpecL(def);

				statement->iAdd.AddL(def);

				if (t!=ESqlComma)

					break;

				NextToken();

				}

			RightBracketL();

			}

		else

			{

			AddColumnSpecL(def);

			statement->iAdd.AddL(def);

			}

		}

	t=Parse(ESqlKeyword_drop);

	if (t!=ESqlNoToken)

		{

		if (t!=ESqlLeftBracket)

			ColumnNameL(statement->iDrop);

		else

			{

			NextToken();

			ColumnListL(statement->iDrop);

			RightBracketL();

			}

		}

	return statement;

	}

CSqlDDLStatement* TSqlParser::CreateIndexLC(TBool aUnique)

//

// Parse a CREATE INDEX statement

//

	{

	CSqlCreateIndexStatement* statement=new(ELeave) CSqlCreateIndexStatement;

	CleanupStack::PushL(statement);

	if (aUnique)

		statement->iKey.MakeUnique();

	IdentifierL(statement->iName);

	ParseL(ESqlKeyword_on);

	IdentifierL(statement->iTable);

	ParseL(ESqlLeftBracket);

	SortSpecificationL(statement->iKey);

	RightBracketL();

	return statement;

	}

CSqlDDLStatement* TSqlParser::DropIndexLC()

//

// Parse a DROP INDEX statement

//

	{

	CSqlDropIndexStatement* statement=new(ELeave) CSqlDropIndexStatement;

	CleanupStack::PushL(statement);

	IdentifierL(statement->iName);

	ParseL(ESqlKeyword_from);

	IdentifierL(statement->iTable);

	return statement;

	}

CSqlDDLStatement* TSqlParser::DDLStatementLC()

	{

	CSqlDDLStatement* statement;

	if (Parse(ESqlKeyword_create))

		{

		if (Parse(ESqlKeyword_table))

			statement=CreateTableLC();

		else

			{

			TSqlTokenType unique=Parse(ESqlKeyword_unique);

			ParseL(ESqlKeyword_index);

			statement=CreateIndexLC(unique);

			}

		}

	else if (Parse(ESqlKeyword_drop))

		{

		if (Parse(ESqlKeyword_table))

			statement=DropTableLC();

		else

			{

			ParseL(ESqlKeyword_index);

			statement=DropIndexLC();

			}

		}

	else

		{

		ParseL(ESqlKeyword_alter);

		ParseL(ESqlKeyword_table);

		statement=AlterTableLC();

		}

	EndL();

	return statement;

	}

TSqlTokenType TSqlParser::ColumnValueL(CSqlValues& aValues)

//

// parse a column-value and add to aValues

//

	{

	switch (iToken.Type())

		{

	case ESqlLiteralInt:

	case ESqlLiteralReal:

	case ESqlLiteralTime:

	case ESqlLiteralText:

		aValues.AddL(iToken.Literal());

		return NextToken();

	case ESqlIdentifier:	// NULL

		{

		TSqlTokenType t=ParseL(ESqlKeyword_null);

		aValues.AddL(RSqlLiteral());		// default c'ted RSqlLiteral is null

		return t;

		}

	default:	// SQL error

		return SqlErrorL();

		}

	}

CSqlDMLStatement* TSqlParser::InsertStatementLC()

//

// parse an insert-statement

//

	{

	ParseL(ESqlKeyword_into);

	CSqlInsertStatement* statement=CSqlInsertStatement::NewLC();

	if (IdentifierL(statement->iQuery.iTable)==ESqlLeftBracket)

		{

		NextToken();

		ColumnListL(statement->iQuery.iColumns);

		RightBracketL();

		}

	ParseL(ESqlKeyword_values);

	ParseL(ESqlLeftBracket);

	CSqlValues& values=statement->ValuesL();

	while (ColumnValueL(values)==ESqlComma)

		NextToken();

	RightBracketL();

	return statement;

	}

CSqlDMLStatement* TSqlParser::UpdateStatementLC()

//

// parse an update-statement

//

	{

	CSqlModifyStatement* statement=CSqlModifyStatement::NewLC();

	IdentifierL(statement->iQuery.iTable);

	ParseL(ESqlKeyword_set);

	CSqlValues& values=statement->ValuesL();

	for (;;)

		{

		ColumnNameL(statement->iQuery.iColumns);

		ParseL(ESqlEqual);

		if (ColumnValueL(values)!=ESqlComma)

			break;

		NextToken();

		}

	if (Parse(ESqlKeyword_where))

		statement->iQuery.iSearchCondition=SearchConditionL();

	return statement;

	}

CSqlDMLStatement* TSqlParser::DeleteStatementLC()

//

// parse a delete-statement

//

	{

	ParseL(ESqlKeyword_from);

	CSqlModifyStatement* statement=CSqlModifyStatement::NewLC();

	IdentifierL(statement->iQuery.iTable);

	if (Parse(ESqlKeyword_where))

		statement->iQuery.iSearchCondition=SearchConditionL();

	return statement;

	}

CSqlDMLStatement* TSqlParser::DMLStatementLC()

	{

	CSqlDMLStatement* statement;

	if (Parse(ESqlKeyword_insert))

		statement=InsertStatementLC();

	else if (Parse(ESqlKeyword_update))

		statement=UpdateStatementLC();

	else 

		{

		ParseL(ESqlKeyword_delete);

		statement=DeleteStatementLC();

		}

	EndL();

	return statement;

	}

Sql::TStatementType TSqlParser::Type()

	{

	TSqlKeyword k=TSqlLexer::Keyword(iToken);

	if (k==ESqlKeyword_create || k==ESqlKeyword_alter || k==ESqlKeyword_drop)

		return Sql::EDDL;

	if (k==ESqlKeyword_insert || k==ESqlKeyword_update || k==ESqlKeyword_delete)

		return Sql::EDML;

	return Sql::ENone;

	}

TInt TSqlParser::PatternFilter(const TDesC& aPattern,const TChar aEscape,TText *aNewPatternBuffer )

	{

	TInt length = aPattern.Length();

	TInt count =0;

	// Ensure that the pattern begins and ends with an '*'

	if ((length < 2) || (aPattern[0] != KMatchAny || aPattern[length-1] != KMatchAny))

 		{

 		return KSqlError;	

 		}	

	for (TInt i = 1 ; i< length -1 ;++i)

		{

		if (aPattern[i]== (TUint)aEscape) 

			{

			if ((aPattern[i + 1] == KMatchAny) || (aPattern[i + 1] == KMatchOne) || (aPattern[i + 1] == (TUint)aEscape))

				{

				i++;

				aNewPatternBuffer[count++] = aPattern[i];

				}

			else

				{

				return KSqlError;  

				}

			}

		else

			{

			if ((aPattern[i] == KMatchAny || aPattern[i] == KMatchOne)  )

				{

				return KSqlError;

				}

			else

				{

				aNewPatternBuffer[count++] = aPattern[i];

				}

			}					

		}

	return count;

	}