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Diffstat (limited to 'comm/mailnews/search/public/nsMsgSearchBoolExpression.h')
| -rw-r--r-- | comm/mailnews/search/public/nsMsgSearchBoolExpression.h | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/comm/mailnews/search/public/nsMsgSearchBoolExpression.h b/comm/mailnews/search/public/nsMsgSearchBoolExpression.h new file mode 100644 index 0000000000..1eefd81fcc --- /dev/null +++ b/comm/mailnews/search/public/nsMsgSearchBoolExpression.h @@ -0,0 +1,110 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "nsMsgSearchCore.h" + +#ifndef __nsMsgSearchBoolExpression_h +# define __nsMsgSearchBoolExpression_h + +//----------------------------------------------------------------------------- +// nsMsgSearchBoolExpression is a class added to provide AND/OR terms in search +// queries. +// A nsMsgSearchBoolExpression contains either a search term or two +// nsMsgSearchBoolExpressions and +// a boolean operator. +// I (mscott) am placing it here for now.... +//----------------------------------------------------------------------------- + +/* CBoolExpression --> encapsulates one or more search terms by internally + representing the search terms and their boolean operators as a binary + expression tree. Each node in the tree consists of either + (1) a boolean operator and two nsMsgSearchBoolExpressions or + (2) if the node is a leaf node then it contains a search term. + With each search term that is part of the expression we may also keep + a character string. The character + string is used to store the IMAP/NNTP encoding of the search term. This + makes generating a search encoding (for online) easier. + + For IMAP/NNTP: nsMsgSearchBoolExpression has/assumes knowledge about how + AND and OR search terms are combined according to IMAP4 and NNTP protocol. + That is the only piece of IMAP/NNTP knowledge it is aware of. + + Order of Evaluation: Okay, the way in which the boolean expression tree + is put together directly effects the order of evaluation. We currently + support left to right evaluation. + Supporting other order of evaluations involves adding new internal add + term methods. + */ + +class nsMsgSearchBoolExpression { + public: + // create a leaf node expression + explicit nsMsgSearchBoolExpression(nsIMsgSearchTerm* aNewTerm, + char* aEncodingString = NULL); + + // create a non-leaf node expression containing 2 expressions + // and a boolean operator + nsMsgSearchBoolExpression(nsMsgSearchBoolExpression*, + nsMsgSearchBoolExpression*, + nsMsgSearchBooleanOperator boolOp); + + nsMsgSearchBoolExpression(); + ~nsMsgSearchBoolExpression(); // recursively destroys all sub + // expressions as well + + // accessors + + // Offline + static nsMsgSearchBoolExpression* AddSearchTerm( + nsMsgSearchBoolExpression* aOrigExpr, nsIMsgSearchTerm* aNewTerm, + char* aEncodingStr); // IMAP/NNTP + static nsMsgSearchBoolExpression* AddExpressionTree( + nsMsgSearchBoolExpression* aOrigExpr, + nsMsgSearchBoolExpression* aExpression, bool aBoolOp); + + // parses the expression tree and all + // expressions underneath this node to + // determine if the end result is true or false. + bool OfflineEvaluate(nsIMsgDBHdr* msgToMatch, const char* defaultCharset, + nsIMsgSearchScopeTerm* scope, nsIMsgDatabase* db, + const nsACString& headers, bool Filtering); + + // assuming the expression is for online + // searches, determine the length of the + // resulting IMAP/NNTP encoding string + int32_t CalcEncodeStrSize(); + + // fills pre-allocated + // memory in buffer with + // the IMAP/NNTP encoding for the expression + void GenerateEncodeStr(nsCString* buffer); + + // if we are not a leaf node, then we have two other expressions + // and a boolean operator + nsMsgSearchBoolExpression* m_leftChild; + nsMsgSearchBoolExpression* m_rightChild; + nsMsgSearchBooleanOperator m_boolOp; + + protected: + // if we are a leaf node, all we have is a search term + + nsIMsgSearchTerm* m_term; + + // store IMAP/NNTP encoding for the search term if applicable + nsCString m_encodingStr; + + // internal methods + + // the idea is to separate the public interface for adding terms to + // the expression tree from the order of evaluation which influences + // how we internally construct the tree. Right now, we are supporting + // left to right evaluation so the tree is constructed to represent + // that by calling leftToRightAddTerm. If future forms of evaluation + // need to be supported, add new methods here for proper tree construction. + nsMsgSearchBoolExpression* leftToRightAddTerm(nsIMsgSearchTerm* newTerm, + char* encodingStr); +}; + +#endif |