ClangFormat: Synchronize with C++ code style settings

And remove UI for default code style settings because
it does not affect anything when ClangFormat plugin is
enabled.

Change-Id: Ie348b7d2691b09ea2b4868da987f2a27347ea0f3
Reviewed-by: Marco Bubke <marco.bubke@qt.io>

src/plugins/clangformat/clangformatutils.cpp

@@ -0,0 +1,179 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 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.
+**
+****************************************************************************/
+
+#include "clangformatutils.h"
+
+#include <coreplugin/icore.h>
+#include <cpptools/cppcodestylesettings.h>
+#include <texteditor/tabsettings.h>
+#include <projectexplorer/project.h>
+#include <projectexplorer/session.h>
+
+using namespace clang;
+using namespace format;
+using namespace llvm;
+using namespace CppTools;
+using namespace ProjectExplorer;
+using namespace TextEditor;
+
+namespace ClangFormat {
+
+static void applyTabSettings(clang::format::FormatStyle &style, const TabSettings &settings)
+{
+    style.IndentWidth = static_cast<unsigned>(settings.m_indentSize);
+    style.TabWidth = static_cast<unsigned>(settings.m_tabSize);
+
+    if (settings.m_tabPolicy == TabSettings::TabsOnlyTabPolicy)
+        style.UseTab = FormatStyle::UT_Always;
+    else if (settings.m_tabPolicy == TabSettings::SpacesOnlyTabPolicy)
+        style.UseTab = FormatStyle::UT_Never;
+    else
+        style.UseTab = FormatStyle::UT_ForContinuationAndIndentation;
+
+    if (settings.m_continuationAlignBehavior == TabSettings::NoContinuationAlign) {
+        style.ContinuationIndentWidth = 0;
+        style.AlignAfterOpenBracket = FormatStyle::BAS_DontAlign;
+    } else {
+        style.ContinuationIndentWidth = style.IndentWidth;
+        style.AlignAfterOpenBracket = FormatStyle::BAS_Align;
+    }
+}
+
+static void applyCppCodeStyleSettings(clang::format::FormatStyle &style,
+                                      const CppCodeStyleSettings &settings)
+{
+    style.IndentCaseLabels = settings.indentSwitchLabels;
+    style.AlignOperands = settings.alignAssignments;
+    style.NamespaceIndentation = FormatStyle::NI_None;
+    if (settings.indentNamespaceBody)
+        style.NamespaceIndentation = FormatStyle::NI_All;
+
+    style.BraceWrapping.IndentBraces = false;
+    if (settings.indentBlockBraces) {
+        if (settings.indentClassBraces && settings.indentEnumBraces
+                && settings.indentNamespaceBraces && settings.indentFunctionBraces) {
+            style.BraceWrapping.IndentBraces = true;
+        } else {
+            style.BreakBeforeBraces = FormatStyle::BS_GNU;
+        }
+    }
+
+    if (settings.bindStarToIdentifier || settings.bindStarToRightSpecifier)
+        style.PointerAlignment = FormatStyle::PAS_Right;
+    else
+        style.PointerAlignment = FormatStyle::PAS_Left;
+
+    style.AccessModifierOffset = settings.indentAccessSpecifiers
+            ? 0
+            : - static_cast<int>(style.IndentWidth);
+}
+
+static Utils::FileName projectStylePath()
+{
+    const Project *project = SessionManager::startupProject();
+    if (project)
+        return project->projectDirectory();
+
+    return Utils::FileName();
+}
+
+static Utils::FileName globalStylePath()
+{
+    return Utils::FileName::fromString(Core::ICore::userResourcePath());
+}
+
+Utils::FileName currentStyleConfigPath()
+{
+    Utils::FileName path = projectStylePath();
+    if (!path.isEmpty())
+        return path;
+
+    return globalStylePath();
+}
+
+static clang::format::FormatStyle constructStyle(bool isGlobal)
+{
+    FormatStyle style = getLLVMStyle();
+    const CppCodeStyleSettings codeStyleSettings = isGlobal
+            ? CppCodeStyleSettings::currentGlobalCodeStyle()
+            : CppCodeStyleSettings::currentProjectCodeStyle();
+    const TabSettings tabSettings = isGlobal
+            ? CppCodeStyleSettings::currentGlobalTabSettings()
+            : CppCodeStyleSettings::currentProjectTabSettings();
+
+    applyTabSettings(style, tabSettings);
+    applyCppCodeStyleSettings(style, codeStyleSettings);
+
+    return style;
+}
+
+void createStyleFileIfNeeded(Utils::FileName styleConfigPath, bool isGlobal)
+{
+    const QString configFile = styleConfigPath.appendPath(".clang-format").toString();
+    if (QFile::exists(configFile))
+        return;
+
+    std::fstream newStyleFile(configFile.toStdString(), std::fstream::out);
+    if (newStyleFile.is_open()) {
+        newStyleFile << clang::format::configurationAsText(constructStyle(isGlobal));
+        newStyleFile.close();
+    }
+}
+
+static clang::format::FormatStyle currentStyle(bool isGlobal)
+{
+    Utils::FileName styleConfigPath = isGlobal ? globalStylePath() : projectStylePath();
+    createStyleFileIfNeeded(styleConfigPath, isGlobal);
+
+    Expected<FormatStyle> style = format::getStyle(
+                "file", styleConfigPath.appendPath("test.cpp").toString().toStdString(), "LLVM");
+    if (style)
+        return *style;
+
+    handleAllErrors(style.takeError(), [](const ErrorInfoBase &) {
+        // do nothing
+    });
+
+    return constructStyle(isGlobal);
+}
+
+clang::format::FormatStyle currentProjectStyle()
+{
+    return currentStyle(false);
+}
+
+clang::format::FormatStyle currentGlobalStyle()
+{
+    return currentStyle(true);
+}
+
+clang::format::FormatStyle currentStyle()
+{
+    const bool isGlobal = (CppCodeStyleSettings::currentProjectCodeStyle()
+                           == CppCodeStyleSettings::currentGlobalCodeStyle());
+    return currentStyle(isGlobal);
+}
+
+}