looqs/shared/qssquery.cpp
Albert S 404f05b89f Refactor search queries: Introduced QSSQuery
Purpose is to seperate certain logic from SQLite and generalize it more.
Even though we only have Sqlite atm, in general the database layers
must be stupid as possible, while QSSQuery should do most of the hard work.

Fixes in Tokenizer logic.
Switched to C++17.
2019-08-18 00:25:21 +02:00

293 regels
8.1 KiB
C++

#include <QStack>
#include <QRegularExpression>
#include <QSqlQuery>
#include <QSqlError>
#include <QStringList>
#include <QDebug>
#include <optional>
#include <algorithm>
#include "qssquery.h"
const QVector<Token> &QSSQuery::getTokens() const
{
return tokens;
}
const QVector<SortCondition> &QSSQuery::getSortConditions() const
{
return sortConditions;
}
QueryType QSSQuery::getQueryType()
{
return static_cast<QueryType>(tokensMask & COMBINED);
}
bool QSSQuery::checkParanthesis(QString expression)
{
QStack<QChar> open;
QStack<QChar> close;
for(QChar &c : expression)
{
if(c == '(')
{
open.push(c);
}
if(c == ')')
{
close.push(c);
}
}
if(open.size() != close.size())
{
return false;
}
while(!open.empty() && !close.empty())
{
QChar o = open.pop();
QChar c = close.pop();
if(o != '(' && c != ')' )
{
return false;
}
}
return true;
}
std::optional<QueryField> fromString(QString fieldString)
{
if(fieldString == "path" || fieldString == "file.path")
{
return FILE_PATH;
}
else if(fieldString == "mtime" || fieldString == "file.mtime")
{
return FILE_MTIME;
}
else if(fieldString == "size" || fieldString == "file.size")
{
return FILE_SIZE;
}
else if(fieldString == "content.text")
{
return CONTENT_TEXT;
}
else if(fieldString == "content.page" || fieldString == "page")
{
return CONTENT_TEXT_PAGE;
}
return { };
}
//sort:(mtime desc, page asc)
QVector<SortCondition> createSortConditions(QString sortExpression)
{
QVector<SortCondition> result;
QStringList splitted_inner = sortExpression.split(",");
for(int i = 0; i < splitted_inner.length(); i++)
{
QStringList splitted = splitted_inner[i].split(" ");
if(splitted.length() < 1 || splitted.length() > 2)
{
throw QSSGeneralException("sort specifier must have format [field] (asc|desc)");
}
QString field = splitted[0];
auto queryField = fromString(field);
if(!queryField)
{
throw QSSGeneralException("Unknown sort field supplied");
}
SortOrder order;
if(splitted.length() == 2)
{
QString orderstr = splitted[1];
if(orderstr.compare("asc", Qt::CaseInsensitive) == 0)
{
order = ASC;
}
else if(orderstr.compare("desc", Qt::CaseInsensitive) == 0)
{
order = DESC;
}
else
{
throw QSSGeneralException("Unknown order specifier: " + order);
}
}
else
{
order = ASC;
}
SortCondition condition;
condition.field = queryField.value();
condition.order = order;
result.append(condition);
}
return result;
}
void QSSQuery::addToken(Token t)
{
tokens.append(t);
tokensMask |= t.type;
}
/* Builds the query from the supplied expression
*
* AND is the default boolean operator, when the user does not provide any
* thus, "Downloads zip" becomes essentailly "path.contains:(Downloads) AND path.contains:(zip)"
*
* TODO: It's a bit ugly still*/
QSSQuery QSSQuery::build(QString expression)
{
if(!checkParanthesis(expression))
{
throw QSSGeneralException("Invalid paranthesis");
}
QSSQuery result;
//TODO: merge lonewords
QRegularExpression rx("((?<filtername>(\\.|\\w)+):(?<args>\\((?<innerargs>[^\\)]+)\\)|([\\w,])+)|(?<boolean>AND|OR)|(?<negation>!)|(?<bracket>\\(|\\))|(?<loneword>\\w+))");
QRegularExpressionMatchIterator i = rx.globalMatch(expression);
auto previousWasBool = [&result]{ return ! result.tokens.empty() && ( (result.tokens.last().type & BOOL) == BOOL); };
auto previousWas = [&result](TokenType t) { return ! result.tokens.empty() && ( result.tokens.last().type == t); };
while(i.hasNext())
{
QRegularExpressionMatch m = i.next();
QString boolean = m.captured("boolean");
QString negation = m.captured("negation");
QString filtername = m.captured("filtername");
QString bracket = m.captured("bracket");
QString loneword = m.captured("loneword");
if(boolean != "")
{
if(previousWasBool())
{
throw QSSGeneralException("Can't have two booleans following each other");
}
if(previousWas(NEGATION))
{
throw QSSGeneralException("Can't have a negation preceeding a boolean");
}
if(boolean == "AND")
{
result.addToken(Token(BOOL_AND));
}
else if(boolean == "OR")
{
result.addToken(Token(BOOL_OR));
}
}
if(negation != "")
{
if(previousWas(NEGATION))
{
throw QSSGeneralException("Can't have two negations following each other");
}
if(!previousWasBool())
{
result.addToken(Token(BOOL_AND)); //Implicit and, our default operation
}
result.addToken(Token(NEGATION));
}
if(!result.tokens.isEmpty() && !previousWasBool() && !previousWas(NEGATION) && !previousWas(BRACKET_OPEN) && bracket != ")")
{
//the current token isn't a negation, isn't a boolean. Thus, implicit AND is required
result.addToken(Token(BOOL_AND));
}
if(bracket != "")
{
if(bracket == "(")
{
result.addToken(Token(BRACKET_OPEN));
}
else
{
result.addToken(Token(BRACKET_CLOSE));
}
}
if(loneword != "")
{
result.addToken(Token(FILTER_PATH_CONTAINS, loneword));
}
if(filtername != "")
{
TokenType tokenType;
QString value = m.captured("innerargs");
if(value == "")
{
value = m.captured("args");
}
if(filtername == "path.contains")
{
tokenType = FILTER_PATH_CONTAINS;
}
else if(filtername == "path.starts")
{
tokenType = FILTER_PATH_STARTS;
}
else if(filtername == "path.ends")
{
tokenType = FILTER_PATH_ENDS;
}
else if(filtername == "file.size" || filtername == "size")
{
tokenType = FILTER_PATH_SIZE;
}
else if(filtername == "c" || filtername == "contains")
{
tokenType = FILTER_CONTENT_CONTAINS;
}
else if(filtername == "page" || filtername == "content.page")
{
tokenType = FILTER_CONTENT_PAGE;
}
else if(filtername == "sort") //TODO: given this is not really a "filter", this feels slightly misplaced here
{
if(!result.sortConditions.empty())
{
throw QSSGeneralException("Two sort statements are illegal");
}
result.sortConditions = createSortConditions(value);
continue;
}
else
{
throw QSSGeneralException("Unknown filter provided!");
}
result.addToken(Token(tokenType, value));
}
}
bool contentsearch = result.getTokensMask() & FILTER_CONTENT == FILTER_CONTENT;
bool sortsForContent = std::any_of(result.sortConditions.begin(), result.sortConditions.end(), [](SortCondition c){ return c.field == CONTENT_TEXT; });
if(!contentsearch && sortsForContent)
{
throw QSSGeneralException("We cannot sort by text if we don't search for it");
}
return result;
}