Refactor KConfigXT

Summary:
The current KConfigXT compiler is in a sad state:
It's a massive file with loads of global variables that handle state, the generator is done within the main() function and it seems to have grown organically. There are no classes to separate logic / state / generation, what exists is code that generates code from a xml / ini pair, but it's hard to even discover what a bit of code is doing. The code istyle is C++ / Java from the nineties, which is not bad per see but it also uses quite a few things that are going to be deprecated in Qt 6 so I'm also taking the time make the code more streamlined with newer code style (no iterators, lambdas, auto usage, etc).

The code that generates the files simplly pushes strings to a text stream, and it's hard to figure out when something starts or something ends: for instance, the code that generates the Constructor has more than sixty lines of code englobing some nested if - for - if - for constructs.

Currently the code is "done" - there's one bug that I still need to find & fix regarding Translations, but the rest seems sane.
The current testcode generates incorrect *whitespaces* regarding the old code (there's some parts that I feel that it's important to fix before merging, but overall, the whitespace changes are not bad and easier to handle, old code had a hand-counted amount of spaces before each line, new code has a function whitespace() that adds the current-and-correct amount of whitespaces based on indentation level that you start by startScope() and ends with endScope(). rest of the code still needs to be ported to it.

I plan to fix the testcases whitespace by manually adding them, I'v fougth with the code for a while and added a few hacks there but I don't want to make the code hackish again.

New code is not perfect by any means, but is a good step in the right direction.

This code tries to Separate the compiler code into many different files / classes to be more obvious what's happening, and each class also has many helper methods to minimize copypaste.

  -     CodeGenerator: Has base code for the header and source files that can be shared
  -     HeaderGenerator: Logic for generating the header file
  -     SourceGenerator: Logic for generating the source file
  -     KcfgParser: Logic for parsing the kcfg file and extracting the information from the Xml file
  -     CommonStructs: a header that contains the structs that are currently used everywhere.
  -     KConfigParameters: (was CfgConfig - ConfigConfig, wat) - Has information passed via the kcfgc file
  -     kcfg_compiler - will be renamed to main - start the other classes and generates the files.

This code here currently has the begining of this separation, with the CodeGenerator and the HeaderGenerator in a ~good~ state, but unfinished.

Test Plan:
- Run the test cases,
- Compare the diffs generated by the testcases and fix in the code the errors / differences
- Run and compare real kde source with the new and old generators to look for errors

Reviewers: #frameworks, ervin, bport, dfaure

Reviewed By: dfaure

Subscribers: davidre, bcooksley, cgiboudeaux, kossebau, bport, ngraham, kde-frameworks-devel

Tags: #frameworks

Differential Revision: https://phabricator.kde.org/D26202

1 files changed, 83 insertions, 0 deletions

diff --git a/src/kconfig_compiler/KConfigXmlParser.h b/src/kconfig_compiler/KConfigXmlParser.h
new file mode 100644
index 00000000..5dbd2745
--- /dev/null
+++ b/src/kconfig_compiler/KConfigXmlParser.h
@@ -0,0 +1,83 @@
+/* This file is part of the KDE libraries
+    Copyright (c) 2003 Cornelius Schumacher <schumacher@kde.org>
+    Copyright (c) 2003 Waldo Bastian <bastian@kde.org>
+    Copyright (c) 2003 Zack Rusin <zack@kde.org>
+    Copyright (c) 2006 Michaël Larouche <michael.larouche@kdemail.net>
+    Copyright (c) 2008 Allen Winter <winter@kde.org>
+    Copyright (C) 2020 Tomaz Cananbrava (tcanabrava@kde.org)
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public License
+    along with this library; see the file COPYING.LIB.  If not, write to
+    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+    Boston, MA 02110-1301, USA.
+*/
+
+#ifndef KCONFIGXMLPARSER_H
+#define KCONFIGXMLPARSER_H
+
+#include <QDomDocument>
+#include <QString>
+#include <QRegularExpression>
+
+#include "KConfigCommonStructs.h"
+#include "KConfigParameters.h"
+
+/* This parses the contents of a Xml file into a ParseResult Structure,
+ * It also fails hard:
+ * If start() succeeds, you can use the result,
+ * if start() fails, the program aborts with an error message so there's
+ * no possibility of generating incorrect code information.
+ */
+class KConfigXmlParser
+{
+public:
+    KConfigXmlParser(const KConfigParameters &cfg, const QString &inputFileName);
+
+    // Start the parser and reads the contents of the inputFileName into the ParseResult Structure
+    void start();
+
+    // Get the result of the parse
+    ParseResult getParseResult() const;
+
+private:
+    // creates a `somethingChanged` signal for every property
+    void createChangedSignal(CfgEntry &readEntry);
+
+    void validateNameAndKey(CfgEntry &readEntry, const QDomElement &element);
+
+    // TODO: Use std::optional and CfgEntry (without heap allocation) for this function
+    // *or* fail hard if the parse fails.
+    CfgEntry *parseEntry(const QString &group, const QDomElement &element);
+
+    // Steps
+    void readIncludeTag(const QDomElement &element);
+    void readGroupTag(const QDomElement &element);
+    void readKcfgfileTag(const QDomElement &element);
+    void readSignalTag(const QDomElement &element);
+
+    // Those are the Entries in the Xml, that represent a parameter within the <group> </group> tag.
+    void readParameterFromEntry(CfgEntry &entry, const QDomElement &element);
+    bool hasDefaultCode(CfgEntry &entry, const QDomElement &element);
+    void readChoicesFromEntry(CfgEntry &entry, const QDomElement &element);
+    void readGroupElements(CfgEntry &entry, const QDomElement &element);
+    void readParamDefaultValues(CfgEntry &entry, const QDomElement &element);
+
+private:
+    ParseResult mParseResult;
+    KConfigParameters cfg;
+    QString mInputFileName;
+    QStringList mAllNames;
+    QRegularExpression mValidNameRegexp;
+};
+
+#endif