95 lines
3.1 KiB
C++
95 lines
3.1 KiB
C++
/* This file is part of Clementine.
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Copyright 2012, David Sansome <me@davidsansome.com>
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Clementine is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Clementine is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with Clementine. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef PLAYLISTFILTERPARSER_H
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#define PLAYLISTFILTERPARSER_H
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#include <QMap>
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#include <QModelIndex>
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#include <QSet>
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#include <QString>
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class QAbstractItemModel;
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// structure for filter parse tree
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class FilterTree {
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public:
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virtual ~FilterTree() {}
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virtual bool accept(int row, const QModelIndex& parent,
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const QAbstractItemModel* const model) const = 0;
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enum FilterType { Nop = 0, Or, And, Not, Column, Term };
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virtual FilterType type() = 0;
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};
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// trivial filter that accepts *anything*
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class NopFilter : public FilterTree {
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public:
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virtual bool accept(int row, const QModelIndex& parent,
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const QAbstractItemModel* const model) const {
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return true;
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}
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virtual FilterType type() { return Nop; }
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};
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// A utility class to parse search filter strings into a decision tree
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// that can decide whether a playlist entry matches the filter.
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//
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// Here's a grammar describing the filters we expect:
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// expr ::= or-group
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// or-group ::= and-group ('OR' and-group)*
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// and-group ::= sexpr ('AND' sexpr)*
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// sexpr ::= sterm | '-' sexpr | '(' or-group ')'
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// sterm ::= col ':' sstring | sstring
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// sstring ::= prefix? string
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// string ::= [^:-()" ]+ | '"' [^"]+ '"'
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// prefix ::= '=' | '<' | '>' | '<=' | '>='
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// col ::= "title" | "artist" | ...
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class FilterParser {
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public:
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FilterParser(const QString& filter, const QMap<QString, int>& columns,
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const QSet<int>& numerical_cols);
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FilterTree* parse();
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private:
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void advance();
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FilterTree* parseOrGroup();
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FilterTree* parseAndGroup();
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// check if iter is at the start of 'AND'
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// if so, step over it and return true
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// it not, return false and leave iter where it was
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bool checkAnd();
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// check if iter is at the start of 'OR'
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bool checkOr(bool step_over = true);
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FilterTree* parseSearchExpression();
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FilterTree* parseSearchTerm();
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FilterTree* createSearchTermTreeNode(const QString& col,
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const QString& prefix,
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const QString& search) const;
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int parseTime(const QString& time_str) const;
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QString::const_iterator iter_;
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QString::const_iterator end_;
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QString buf_;
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const QString filterstring_;
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const QMap<QString, int> columns_;
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const QSet<int> numerical_columns_;
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};
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#endif // PLAYLISTFILTERPARSER_H
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