Added PythonEditor plugin

Contains lexical highlighter, indenter and file wizard.
Icon loaded from theme, if possible.
Class wizard will be added later since it needs to extend libUtils.

Change-Id: If723867c01e9be83371424e406d116805c88c2b0
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/pythoneditor/tools/pythonindenter.cpp

@@ -0,0 +1,129 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#include "pythonindenter.h"
+#include "lexical/pythonscanner.h"
+
+#include <texteditor/tabsettings.h>
+
+#include <QSet>
+
+namespace PythonEditor {
+
+// Tab size hardcoded as PEP8 style guide requires, but can be moved to settings
+static const int TAB_SIZE = 4;
+
+PythonIndenter::PythonIndenter()
+{
+    m_jumpKeywords << QLatin1String("return")
+                   << QLatin1String("yield")
+                   << QLatin1String("break")
+                   << QLatin1String("continue")
+                   << QLatin1String("raise")
+                   << QLatin1String("pass");
+}
+
+PythonIndenter::~PythonIndenter()
+{
+}
+
+/**
+ * @brief Does given character change indentation level?
+ * @param ch Any value
+ * @return True if character increases indentation level at the next line
+ */
+bool PythonIndenter::isElectricCharacter(const QChar &ch) const
+{
+    return (ch == QLatin1Char(':'));
+}
+
+/**
+ * @brief Indents one block (i.e. one line) of code
+ * @param doc Unused
+ * @param block Block that represents line
+ * @param typedChar Unused
+ * @param tabSettings An IDE tabulation settings
+ *
+ * Usually this method called once when you begin new line of code by pressing
+ * Enter. If Indenter reimplements indent() method, than indentBlock() may be
+ * called in other cases.
+ */
+void PythonIndenter::indentBlock(QTextDocument *document,
+                                 const QTextBlock &block,
+                                 const QChar &typedChar,
+                                 const TextEditor::TabSettings &settings)
+{
+    Q_UNUSED(document);
+    Q_UNUSED(typedChar);
+    QTextBlock previousBlock = block.previous();
+    if (previousBlock.isValid()) {
+        QString previousLine = previousBlock.text();
+        int indentation = settings.indentationColumn(previousLine);
+
+        if (isElectricLine(previousLine))
+            indentation += TAB_SIZE;
+        else
+            indentation = qMax<int>(0, indentation + getIndentDiff(previousLine));
+
+        settings.indentLine(block, indentation);
+    } else {
+        // First line in whole document
+        settings.indentLine(block, 0);
+    }
+}
+
+/// @return True if electric character is last non-space character at given string
+bool PythonIndenter::isElectricLine(const QString &line) const
+{
+    if (line.isEmpty())
+        return false;
+
+    // trim spaces in 'if True:  '
+    int index = line.length() - 1;
+    while ((index > 0) && line[index].isSpace())
+        --index;
+
+    return isElectricCharacter(line[index]);
+}
+
+/// @return negative indent diff if previous line breaks control flow branch
+int PythonIndenter::getIndentDiff(const QString &previousLine) const
+{
+    Internal::Scanner sc(previousLine.constData(), previousLine.length());
+    forever {
+        Internal::FormatToken tk = sc.read();
+        if ((tk.format() == Internal::Format_Keyword) && m_jumpKeywords.contains(sc.value(tk)))
+            return -TAB_SIZE;
+        if (tk.format() != Internal::Format_Whitespace)
+            break;
+    }
+    return 0;
+}
+
+} // namespace PythonEditor