forked from qt-creator/qt-creator
634 lines
19 KiB
C++
634 lines
19 KiB
C++
/**************************************************************************
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**
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** This file is part of Qt Creator
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**
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** Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
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**
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** Contact: Nokia Corporation (qt-info@nokia.com)
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**
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** Commercial Usage
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**
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** Licensees holding valid Qt Commercial licenses may use this file in
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** accordance with the Qt Commercial License Agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and Nokia.
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**
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** GNU Lesser General Public License Usage
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**
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** General Public License version 2.1 as published by the Free Software
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** Foundation and appearing in the file LICENSE.LGPL included in the
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** packaging of this file. Please review the following information to
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** ensure the GNU Lesser General Public License version 2.1 requirements
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** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
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**
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** If you are unsure which license is appropriate for your use, please
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** contact the sales department at http://qt.nokia.com/contact.
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**
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**************************************************************************/
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/*
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This file is a self-contained interactive indenter for Qt Script.
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The general problem of indenting a program is ill posed. On
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the one hand, an indenter has to analyze programs written in a
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free-form formal language that is best described in terms of
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tokens, not characters, not lines. On the other hand, indentation
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applies to lines and white space characters matter, and otherwise
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the programs to indent are formally invalid in general, as they
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are begin edited.
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The approach taken here works line by line. We receive a program
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consisting of N lines or more, and we want to compute the
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indentation appropriate for the Nth line. Lines beyond the Nth
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lines are of no concern to us, so for simplicity we pretend the
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program has exactly N lines and we call the Nth line the "bottom
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line". Typically, we have to indent the bottom line when it's
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still empty, so we concentrate our analysis on the N - 1 lines
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that precede.
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By inspecting the (N - 1)-th line, the (N - 2)-th line, ...
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backwards, we determine the kind of the bottom line and indent it
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accordingly.
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* The bottom line is a comment line. See
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bottomLineStartsInCComment() and
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indentWhenBottomLineStartsInCComment().
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* The bottom line is a continuation line. See isContinuationLine()
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and indentForContinuationLine().
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* The bottom line is a standalone line. See
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indentForStandaloneLine().
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Certain tokens that influence the indentation, notably braces,
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are looked for in the lines. This is done by simple string
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comparison, without a real tokenizer. Confusing constructs such
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as comments and string literals are removed beforehand.
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*/
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#include <qmljs/qmljsindenter.h>
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#include <qmljs/qmljsscanner.h>
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#include <QtDebug>
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using namespace QmlJS;
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/*
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Saves and restores the state of the global linizer. This enables
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backtracking.
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Identical to the defines in qmljslineinfo.cpp
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*/
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#define YY_SAVE() LinizerState savedState = yyLinizerState
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#define YY_RESTORE() yyLinizerState = savedState
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QmlJSIndenter::QmlJSIndenter()
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: caseOrDefault(QRegExp(QLatin1String(
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"\\s*(?:"
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"case\\b[^:]+|"
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"default)"
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"\\s*:.*")))
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{
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/*
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The indenter supports a few parameters:
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* ppHardwareTabSize is the size of a '\t' in your favorite editor.
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* ppIndentSize is the size of an indentation, or software tab
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size.
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* ppContinuationIndentSize is the extra indent for a continuation
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line, when there is nothing to align against on the previous
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line.
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* ppCommentOffset is the indentation within a C-style comment,
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when it cannot be picked up.
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*/
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ppHardwareTabSize = 8;
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ppIndentSize = 4;
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ppContinuationIndentSize = 8;
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ppCommentOffset = 2;
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}
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QmlJSIndenter::~QmlJSIndenter()
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{
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}
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void QmlJSIndenter::setTabSize(int size)
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{
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ppHardwareTabSize = size;
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}
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void QmlJSIndenter::setIndentSize(int size)
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{
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ppIndentSize = size;
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ppContinuationIndentSize = 2 * size;
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}
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/*
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Returns true if string t is made only of white space; otherwise
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returns false.
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*/
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bool QmlJSIndenter::isOnlyWhiteSpace(const QString &t) const
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{
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return firstNonWhiteSpace(t).isNull();
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}
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/*
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Assuming string t is a line, returns the column number of a given
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index. Column numbers and index are identical for strings that don't
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contain '\t's.
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*/
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int QmlJSIndenter::columnForIndex(const QString &t, int index) const
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{
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int col = 0;
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if (index > t.length())
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index = t.length();
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for (int i = 0; i < index; i++) {
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if (t.at(i) == QLatin1Char('\t')) {
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col = ((col / ppHardwareTabSize) + 1) * ppHardwareTabSize;
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} else {
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col++;
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}
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}
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return col;
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}
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/*
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Returns the indentation size of string t.
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*/
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int QmlJSIndenter::indentOfLine(const QString &t) const
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{
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return columnForIndex(t, t.indexOf(firstNonWhiteSpace(t)));
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}
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/*
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Replaces t[k] by ch, unless t[k] is '\t'. Tab characters are better
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left alone since they break the "index equals column" rule. No
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provisions are taken against '\n' or '\r', which shouldn't occur in
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t anyway.
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*/
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void QmlJSIndenter::eraseChar(QString &t, int k, QChar ch) const
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{
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if (t.at(k) != QLatin1Char('\t'))
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t[k] = ch;
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}
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/*
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Returns '(' if the last parenthesis is opening, ')' if it is
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closing, and QChar() if there are no parentheses in t.
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*/
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QChar QmlJSIndenter::lastParen() const
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{
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for (int index = yyLinizerState.tokens.size() - 1; index != -1; --index) {
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const Token &token = yyLinizerState.tokens.at(index);
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if (token.is(Token::LeftParenthesis))
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return QChar('(');
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else if (token.is(Token::RightParenthesis))
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return QChar(')');
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}
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return QChar();
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}
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/*
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Returns true if typedIn the same as okayCh or is null; otherwise
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returns false.
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*/
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bool QmlJSIndenter::okay(QChar typedIn, QChar okayCh) const
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{
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return typedIn == QChar() || typedIn == okayCh;
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}
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/*
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Returns the recommended indent for the bottom line of yyProgram
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assuming that it starts in a C-style comment, a condition that is
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tested elsewhere.
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Essentially, we're trying to align against some text on the
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previous line.
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*/
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int QmlJSIndenter::indentWhenBottomLineStartsInMultiLineComment()
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{
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QTextBlock block = yyProgram.lastBlock().previous();
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QString blockText;
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for (; block.isValid(); block = block.previous()) {
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blockText = block.text();
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if (! isOnlyWhiteSpace(blockText))
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break;
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}
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return indentOfLine(blockText);
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}
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/*
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Returns the recommended indent for the bottom line of yyProgram,
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assuming it's a continuation line.
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We're trying to align the continuation line against some parenthesis
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or other bracked left opened on a previous line, or some interesting
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operator such as '='.
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*/
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int QmlJSIndenter::indentForContinuationLine()
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{
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int braceDepth = 0;
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int delimDepth = 0;
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bool leftBraceFollowed = *yyLeftBraceFollows;
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for (int i = 0; i < SmallRoof; i++) {
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int hook = -1;
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int j = yyLine->length();
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while (j > 0 && hook < 0) {
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j--;
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QChar ch = yyLine->at(j);
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switch (ch.unicode()) {
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case ')':
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delimDepth++;
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break;
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case ']':
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braceDepth++;
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break;
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case '}':
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braceDepth++;
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break;
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case '(':
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delimDepth--;
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/*
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An unclosed delimiter is a good place to align at,
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at least for some styles (including Qt's).
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*/
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if (delimDepth == -1)
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hook = j;
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break;
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case '[':
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braceDepth--;
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/*
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An unclosed delimiter is a good place to align at,
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at least for some styles (including Qt's).
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*/
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if (braceDepth == -1)
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hook = j;
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break;
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case '{':
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braceDepth--;
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/*
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A left brace followed by other stuff on the same
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line is typically for an enum or an initializer.
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Such a brace must be treated just like the other
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delimiters.
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*/
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if (braceDepth == -1) {
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if (j < yyLine->length() - 1) {
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hook = j;
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} else {
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return 0; // shouldn't happen
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}
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}
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break;
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case '=':
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/*
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An equal sign is a very natural alignment hook
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because it's usually the operator with the lowest
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precedence in statements it appears in. Case in
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point:
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int x = 1 +
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2;
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However, we have to beware of constructs such as
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default arguments and explicit enum constant
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values:
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void foo(int x = 0,
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int y = 0);
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And not
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void foo(int x = 0,
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int y = 0);
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These constructs are caracterized by a ',' at the
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end of the unfinished lines or by unbalanced
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parentheses.
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*/
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Q_ASSERT(j - 1 >= 0);
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if (QString::fromLatin1("!=<>").indexOf(yyLine->at(j - 1)) == -1 &&
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j + 1 < yyLine->length() && yyLine->at(j + 1) != '=') {
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if (braceDepth == 0 && delimDepth == 0 &&
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j < yyLine->length() - 1 &&
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!yyLine->endsWith(QLatin1Char(',')) &&
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(yyLine->contains(QLatin1Char('(')) == yyLine->contains(QLatin1Char(')'))))
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hook = j;
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}
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}
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}
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if (hook >= 0) {
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/*
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Yes, we have a delimiter or an operator to align
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against! We don't really align against it, but rather
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against the following token, if any. In this example,
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the following token is "11":
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int x = (11 +
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2);
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If there is no such token, we use a continuation indent:
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static QRegExp foo(QString(
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"foo foo foo foo foo foo foo foo foo"));
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*/
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hook++;
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while (hook < yyLine->length()) {
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if (!yyLine->at(hook).isSpace())
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return columnForIndex(*yyLine, hook);
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hook++;
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}
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return indentOfLine(*yyLine) + ppContinuationIndentSize;
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}
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if (braceDepth != 0)
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break;
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/*
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The line's delimiters are balanced. It looks like a
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continuation line or something.
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*/
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if (delimDepth == 0) {
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if (leftBraceFollowed) {
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/*
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We have
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int main()
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{
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or
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Bar::Bar()
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: Foo(x)
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{
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The "{" should be flush left.
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*/
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if (!isContinuationLine())
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return indentOfLine(*yyLine);
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} else if (isContinuationLine() || yyLine->endsWith(QLatin1String(","))) {
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/*
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We have
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x = a +
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b +
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c;
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or
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int t[] = {
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1, 2, 3,
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4, 5, 6
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The "c;" should fall right under the "b +", and the
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"4, 5, 6" right under the "1, 2, 3,".
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*/
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return indentOfLine(*yyLine);
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} else {
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/*
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We have
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stream << 1 +
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2;
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We could, but we don't, try to analyze which
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operator has precedence over which and so on, to
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obtain the excellent result
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stream << 1 +
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2;
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We do have a special trick above for the assignment
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operator above, though.
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*/
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return indentOfLine(*yyLine) + ppContinuationIndentSize;
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}
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}
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if (!readLine())
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break;
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}
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return 0;
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}
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/*
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Returns the recommended indent for the bottom line of yyProgram if
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that line is standalone (or should be indented likewise).
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Indenting a standalone line is tricky, mostly because of braceless
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control statements. Grossly, we are looking backwards for a special
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line, a "hook line", that we can use as a starting point to indent,
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and then modify the indentation level according to the braces met
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along the way to that hook.
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Let's consider a few examples. In all cases, we want to indent the
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bottom line.
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Example 1:
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x = 1;
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y = 2;
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The hook line is "x = 1;". We met 0 opening braces and 0 closing
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braces. Therefore, "y = 2;" inherits the indent of "x = 1;".
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Example 2:
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if (x) {
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y;
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The hook line is "if (x) {". No matter what precedes it, "y;" has
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to be indented one level deeper than the hook line, since we met one
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opening brace along the way.
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Example 3:
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if (a)
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while (b) {
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c;
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}
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d;
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To indent "d;" correctly, we have to go as far as the "if (a)".
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Compare with
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if (a) {
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while (b) {
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c;
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}
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d;
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Still, we're striving to go back as little as possible to
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accommodate people with irregular indentation schemes. A hook line
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near at hand is much more reliable than a remote one.
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*/
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int QmlJSIndenter::indentForStandaloneLine()
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{
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for (int i = 0; i < SmallRoof; i++) {
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if (!*yyLeftBraceFollows) {
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YY_SAVE();
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if (matchBracelessControlStatement()) {
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/*
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The situation is this, and we want to indent "z;":
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if (x &&
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y)
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z;
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yyLine is "if (x &&".
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*/
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return indentOfLine(*yyLine) + ppIndentSize;
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}
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YY_RESTORE();
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}
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if (yyLine->endsWith(QLatin1Char(';')) || yyLine->contains(QLatin1Char('{'))) {
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/*
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The situation is possibly this, and we want to indent
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"z;":
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while (x)
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y;
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z;
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We return the indent of "while (x)". In place of "y;",
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any arbitrarily complex compound statement can appear.
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*/
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if (*yyBraceDepth > 0) {
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do {
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if (!readLine())
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break;
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} while (*yyBraceDepth > 0);
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}
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LinizerState hookState;
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while (isContinuationLine())
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readLine();
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hookState = yyLinizerState;
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readLine();
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if (*yyBraceDepth <= 0) {
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do {
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if (!matchBracelessControlStatement())
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break;
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hookState = yyLinizerState;
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} while (readLine());
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}
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yyLinizerState = hookState;
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while (isContinuationLine())
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readLine();
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int indentChange = - *yyBraceDepth;
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if (caseOrDefault.exactMatch(*yyLine))
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++indentChange;
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/*
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Never trust lines containing only '{' or '}', as some
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people (Richard M. Stallman) format them weirdly.
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*/
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if (yyLine->trimmed().length() > 1)
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return indentOfLine(*yyLine) + indentChange * ppIndentSize;
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}
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if (!readLine())
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return -*yyBraceDepth * ppIndentSize;
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}
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return 0;
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}
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/*
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Returns the recommended indent for the bottom line of program.
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Unless null, typedIn stores the character of yyProgram that
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triggered reindentation.
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This function works better if typedIn is set properly; it is
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slightly more conservative if typedIn is completely wild, and
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slighly more liberal if typedIn is always null. The user might be
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annoyed by the liberal behavior.
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*/
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int QmlJSIndenter::indentForBottomLine(QTextBlock begin, QTextBlock end, QChar typedIn)
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{
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if (begin == end)
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return 0;
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const QTextBlock last = end.previous();
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initialize(begin, last);
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QString bottomLine = last.text();
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QChar firstCh = firstNonWhiteSpace(bottomLine);
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int indent = 0;
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if (bottomLineStartsInMultilineComment()) {
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/*
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The bottom line starts in a C-style comment. Indent it
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smartly, unless the user has already played around with it,
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in which case it's better to leave her stuff alone.
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*/
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if (isOnlyWhiteSpace(bottomLine)) {
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indent = indentWhenBottomLineStartsInMultiLineComment();
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} else {
|
|
indent = indentOfLine(bottomLine);
|
|
}
|
|
} else {
|
|
if (isUnfinishedLine()) {
|
|
indent = indentForContinuationLine();
|
|
} else {
|
|
indent = indentForStandaloneLine();
|
|
}
|
|
|
|
if ((okay(typedIn, QLatin1Char('}')) && firstCh == QLatin1Char('}'))
|
|
|| (okay(typedIn, QLatin1Char(']')) && firstCh == QLatin1Char(']'))) {
|
|
/*
|
|
A closing brace is one level more to the left than the
|
|
code it follows.
|
|
*/
|
|
indent -= ppIndentSize;
|
|
} else if (okay(typedIn, QLatin1Char(':'))) {
|
|
if (caseOrDefault.exactMatch(bottomLine)) {
|
|
/*
|
|
Move a case label (or the ':' in front of a
|
|
constructor initialization list) one level to the
|
|
left, but only if the user did not play around with
|
|
it yet. Some users have exotic tastes in the
|
|
matter, and most users probably are not patient
|
|
enough to wait for the final ':' to format their
|
|
code properly.
|
|
|
|
We don't attempt the same for goto labels, as the
|
|
user is probably the middle of "foo::bar". (Who
|
|
uses goto, anyway?)
|
|
*/
|
|
if (indentOfLine(bottomLine) <= indent)
|
|
indent -= ppIndentSize;
|
|
else
|
|
indent = indentOfLine(bottomLine);
|
|
}
|
|
}
|
|
}
|
|
|
|
return qMax(0, indent);
|
|
}
|
|
|