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/pythonhighlighter.cpp

@@ -0,0 +1,185 @@
+/****************************************************************************
+**
+** 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.
+**
+****************************************************************************/
+
+/**
+ * @brief The Highlighter class pre-highlights Python source using simple scanner.
+ *
+ * Highlighter doesn't highlight user types (classes and enumerations), syntax
+ * and semantic errors, unnecessary code, etc. It's implements only
+ * basic highlight mechanism.
+ *
+ * Main highlight procedure is highlightBlock().
+ */
+
+#include "pythonhighlighter.h"
+#include "lexical/pythonscanner.h"
+
+#include <texteditor/basetextdocumentlayout.h>
+#include <texteditor/basetextdocument.h>
+#include <texteditor/fontsettings.h>
+#include <texteditor/texteditorconstants.h>
+
+namespace PythonEditor {
+
+using namespace PythonEditor::Internal;
+
+/**
+ * @class PyEditor::Highlighter
+ * @brief Handles incremental lexical highlighting, but not semantic
+ *
+ * Incremental lexical highlighting works every time when any character typed
+ * or some text inserted (i.e. copied & pasted).
+ * Each line keeps associated scanner state - integer number. This state is the
+ * scanner context for next line. For example, 3 quotes begin a multiline
+ * string, and each line up to next 3 quotes has state 'MultiLineString'.
+ *
+ * @code
+ *  def __init__:               # Normal
+ *      self.__doc__ = """      # MultiLineString (next line is inside)
+ *                     banana   # MultiLineString
+ *                     """      # Normal
+ * @endcode
+ */
+
+/// @return List that maps enum Format values to TextEditor plugin formats
+QVector<TextEditor::TextStyle> initFormatCategories()
+{
+    QVector<TextEditor::TextStyle> categories(Format_FormatsAmount);
+    categories[Format_Number] = TextEditor::C_NUMBER;
+    categories[Format_String] = TextEditor::C_STRING;
+    categories[Format_Keyword] = TextEditor::C_KEYWORD;
+    categories[Format_Type] = TextEditor::C_TYPE;
+    categories[Format_ClassField] = TextEditor::C_FIELD;
+    categories[Format_MagicAttr] = TextEditor::C_JS_SCOPE_VAR;
+    categories[Format_Operator] = TextEditor::C_OPERATOR;
+    categories[Format_Comment] = TextEditor::C_COMMENT;
+    categories[Format_Doxygen] = TextEditor::C_DOXYGEN_COMMENT;
+    categories[Format_Whitespace] = TextEditor::C_VISUAL_WHITESPACE;
+    categories[Format_Identifier] = TextEditor::C_TEXT;
+    categories[Format_ImportedModule] = TextEditor::C_STRING;
+
+    return categories;
+}
+
+/// New instance created when opening any document in editor
+PythonHighlighter::PythonHighlighter(TextEditor::BaseTextDocument *parent) :
+    TextEditor::SyntaxHighlighter(parent)
+{
+}
+
+/// Instance destroyed when one of documents closed from editor
+PythonHighlighter::~PythonHighlighter()
+{
+}
+
+/**
+  QtCreator has own fonts&color settings. Highlighter wants get access to
+  this settings before highlightBlock() called first time.
+  Settings provided by PyEditor::EditorWidget class.
+  */
+void PythonHighlighter::setFontSettings(const TextEditor::FontSettings &fs)
+{
+    QVector<TextEditor::TextStyle> categories = initFormatCategories();
+    m_formats = fs.toTextCharFormats(categories);
+    rehighlight();
+}
+
+/**
+ * @brief Highlighter::highlightBlock highlights single line of Python code
+ * @param text is single line without EOLN symbol. Access to all block data
+ * can be obtained through inherited currentBlock() method.
+ *
+ * This method receives state (int number) from previously highlighted block,
+ * scans block using received state and sets initial highlighting for current
+ * block. At the end, it saves internal state in current block.
+ */
+void PythonHighlighter::highlightBlock(const QString &text)
+{
+    int initialState = previousBlockState();
+    if (initialState == -1)
+        initialState = 0;
+    setCurrentBlockState(highlightLine(text, initialState));
+}
+
+/**
+ * @return True if this keyword is acceptable at start of import line
+ */
+static inline
+bool isImportKeyword(const QString &keyword)
+{
+    return (keyword == QLatin1String("import")
+            || keyword == QLatin1String("from"));
+}
+
+/**
+ * @brief Highlight line of code, returns new block state
+ * @param text Source code to highlight
+ * @param initialState Initial state of scanner, retrieved from previous block
+ * @return Final state of scanner, should be saved with current block
+ */
+int PythonHighlighter::highlightLine(const QString &text, int initialState)
+{
+    Scanner scanner(text.constData(), text.size());
+    scanner.setState(initialState);
+
+    FormatToken tk;
+    bool hasOnlyWhitespace = true;
+    while ((tk = scanner.read()).format() != Format_EndOfBlock) {
+        Format format = tk.format();
+        if (format == Format_Keyword) {
+            QString value = scanner.value(tk);
+            if (isImportKeyword(value) && hasOnlyWhitespace) {
+                setFormat(tk.begin(), tk.length(), m_formats[format]);
+                highlightImport(scanner);
+                break;
+            }
+        }
+
+        setFormat(tk.begin(), tk.length(), m_formats[format]);
+        if (format != Format_Whitespace)
+            hasOnlyWhitespace = false;
+    }
+    return scanner.state();
+}
+
+/**
+ * @brief Highlights rest of line as import directive
+ */
+void PythonHighlighter::highlightImport(Scanner &scanner)
+{
+    FormatToken tk;
+    while ((tk = scanner.read()).format() != Format_EndOfBlock) {
+        Format format = tk.format();
+        if (tk.format() == Format_Identifier)
+            format = Format_ImportedModule;
+        setFormat(tk.begin(), tk.length(), m_formats[format]);
+    }
+}
+
+} // namespace PythonEditor