PythonEditor: Modernize/Streamline

Remove virtual, add override, add = delete, remove QLatin1*,
flatten filesystem hierarchy, remove unneeded 'inline',
use initializer list, etc.

Change-Id: I0a95d806d73ca1a33cfd1ba85c2664d9ebc32690
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/pythoneditor/pythonhighlighter.cpp

@@ -0,0 +1,153 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** 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 The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+/**
+ * @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 "pythonscanner.h"
+
+#include <texteditor/textdocument.h>
+#include <texteditor/texteditorconstants.h>
+
+namespace PythonEditor {
+namespace Internal {
+
+/**
+ * @class PythonEditor::Internal::PythonHighlighter
+ * @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
+ */
+
+PythonHighlighter::PythonHighlighter()
+{
+    static const QVector<TextEditor::TextStyle> categories = {
+        TextEditor::C_NUMBER,
+        TextEditor::C_STRING,
+        TextEditor::C_KEYWORD,
+        TextEditor::C_TYPE,
+        TextEditor::C_FIELD,
+        TextEditor::C_JS_SCOPE_VAR,
+        TextEditor::C_OPERATOR,
+        TextEditor::C_COMMENT,
+        TextEditor::C_DOXYGEN_COMMENT,
+        TextEditor::C_TEXT,
+        TextEditor::C_VISUAL_WHITESPACE,
+        TextEditor::C_STRING
+    };
+    setTextFormatCategories(categories);
+}
+
+/**
+ * @brief PythonHighlighter::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() function.
+ *
+ * This function 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 bool isImportKeyword(const QString &keyword)
+{
+    return keyword == "import" || keyword == "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(), formatForCategory(format));
+                highlightImport(scanner);
+                break;
+            }
+        }
+
+        setFormat(tk.begin(), tk.length(), formatForCategory(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(), formatForCategory(format));
+    }
+}
+
+} // namespace Internal
+} // namespace PythonEditor