CppEditor: Improve finding position for new includes

...by detecting include groups (separated by new lines, include types
and same dir prefix).

Task-number: QTCREATORBUG-9317
Change-Id: I73e80fdc715104901cb2d4f5b15b4cab5d04d305
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/plugins/cppeditor/cppeditorplugin.h

@@ -162,14 +162,28 @@ private slots:
 
     void test_quickfix_InsertDeclFromDef();
 
+    void test_quickfix_AddIncludeForUndefinedIdentifier_detectIncludeGroupsByNewLines();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_detectIncludeGroupsByIncludeDir();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_detectIncludeGroupsByIncludeType();
     void test_quickfix_AddIncludeForUndefinedIdentifier_normal();
     void test_quickfix_AddIncludeForUndefinedIdentifier_ignoremoc();
     void test_quickfix_AddIncludeForUndefinedIdentifier_sortingTop();
     void test_quickfix_AddIncludeForUndefinedIdentifier_sortingMiddle();
     void test_quickfix_AddIncludeForUndefinedIdentifier_sortingBottom();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_appendToUnsorted();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_firstLocalIncludeAtFront();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_firstGlobalIncludeAtBack();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_preferGroupWithLongerMatchingPrefix();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_newGroupIfOnlyDifferentIncludeDirs();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_mixedDirsSorted();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_mixedDirsUnsorted();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_mixedIncludeTypes1();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_mixedIncludeTypes2();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_mixedIncludeTypes3();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_mixedIncludeTypes4();
     void test_quickfix_AddIncludeForUndefinedIdentifier_noinclude();
-    void test_quickfix_AddIncludeForUndefinedIdentifier_noincludeComment01();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_veryFirstIncludeCppStyleCommentOnTop();
-    void test_quickfix_AddIncludeForUndefinedIdentifier_noincludeComment02();
+    void test_quickfix_AddIncludeForUndefinedIdentifier_veryFirstIncludeCStyleCommentOnTop();
 
     void test_quickfix_MoveFuncDefOutside_MemberFuncToCpp();
     void test_quickfix_MoveFuncDefOutside_MemberFuncOutside();

src/plugins/cppeditor/cppquickfixes.cpp

@@ -40,6 +40,7 @@
 #include <cpptools/cpppointerdeclarationformatter.h>
 #include <cpptools/cpptoolsconstants.h>
 #include <cpptools/cpptoolsreuse.h>
+#include <cpptools/includeutils.h>
 #include <cpptools/insertionpointlocator.h>
 #include <cpptools/symbolfinder.h>
 
@@ -182,6 +183,37 @@ Class *isMemberFunction(const LookupContext &context, Function *function)
     return 0;
 }
 
+// Given include is e.g. "afile.h" or <afile.h> (quotes/angle brackets included!).
+void insertNewIncludeDirective(const QString &include, CppRefactoringFilePtr file)
+{
+    // Find optimal position
+    using namespace IncludeUtils;
+    LineForNewIncludeDirective finder(file->document(), file->cppDocument()->includes(),
+                                      LineForNewIncludeDirective::IgnoreMocIncludes,
+                                      LineForNewIncludeDirective::AutoDetect);
+    unsigned newLinesToPrepend = 0;
+    unsigned newLinesToAppend = 0;
+    const int insertLine = finder(include, &newLinesToPrepend, &newLinesToAppend);
+    QTC_ASSERT(insertLine >= 1, return);
+    const int insertPosition = file->position(insertLine, 1);
+    QTC_ASSERT(insertPosition >= 0, return);
+
+    // Construct text to insert
+    const QString includeLine = QLatin1String("#include ") + include + QLatin1Char('\n');
+    QString prependedNewLines, appendedNewLines;
+    while (newLinesToAppend--)
+        appendedNewLines += QLatin1String("\n");
+    while (newLinesToPrepend--)
+        prependedNewLines += QLatin1String("\n");
+    const QString textToInsert = prependedNewLines + includeLine + appendedNewLines;
+
+    // Insert
+    ChangeSet changes;
+    changes.insert(insertPosition, textToInsert);
+    file->setChangeSet(changes);
+    file->apply();
+}
+
 } // anonymous namespace
 
 namespace {
@@ -1479,24 +1511,8 @@ public:
             if (best.isEmpty())
                 best = headerFile;
 
-            int pos = currentFile->startOf(1);
+            const QString include = QString::fromLatin1("<%1>").arg(QFileInfo(best).fileName());
-
+            insertNewIncludeDirective(include, currentFile);
-            unsigned currentLine = currentFile->cursor().blockNumber() + 1;
-            unsigned bestLine = 0;
-            foreach (const Document::Include &incl,
-                     assistInterface()->semanticInfo().doc->includes()) {
-                if (incl.line() < currentLine)
-                    bestLine = incl.line();
-            }
-
-            if (bestLine)
-                pos = currentFile->document()->findBlockByNumber(bestLine).position();
-
-            ChangeSet changes;
-            changes.insert(pos, QLatin1String("#include <")
-                           + QFileInfo(best).fileName() + QLatin1String(">\n"));
-            currentFile->setChangeSet(changes);
-            currentFile->apply();
         }
     }
 
@@ -1731,108 +1747,21 @@ void ConvertToCamelCase::match(const CppQuickFixInterface &interface, QuickFixOp
     }
 }
 
-namespace {
+AddIncludeForUndefinedIdentifierOp::AddIncludeForUndefinedIdentifierOp(
-
+        const CppQuickFixInterface &interface, int priority, const QString &include)
-class AddIncludeForUndefinedIdentifierOp: public CppQuickFixOperation
+    : CppQuickFixOperation(interface, priority)
+    , m_include(include)
 {
-public:
+    setDescription(QApplication::translate("CppTools::QuickFix", "Add #include %1").arg(m_include));
-    AddIncludeForUndefinedIdentifierOp(const CppQuickFixInterface &interface, int priority,
+}
-                                       const QString &include)
-        : CppQuickFixOperation(interface, priority)
-        , m_include(include)
-    {
-        setDescription(QApplication::translate("CppTools::QuickFix",
-                                               "Add #include %1").arg(m_include));
-    }
 
-    void perform()
+void AddIncludeForUndefinedIdentifierOp::perform()
-    {
+{
-        CppRefactoringChanges refactoring(snapshot());
+    CppRefactoringChanges refactoring(snapshot());
-        CppRefactoringFilePtr file = refactoring.file(fileName());
+    CppRefactoringFilePtr file = refactoring.file(fileName());
 
-        QList<Document::Include> includes = file->cppDocument()->includes();
+    insertNewIncludeDirective(m_include, file);
-        if (!includes.isEmpty()) {
+}
-            QHash<QString, unsigned> includePositions;
-            foreach (const Document::Include &include, includes) {
-                const QString fileName = include.unresolvedFileName();
-                if (fileName.endsWith(QLatin1String(".moc")))
-                    continue;
-                includePositions.insert(fileName, include.line());
-            }
-
-            if (!includePositions.isEmpty()) {
-                const QString include = m_include.mid(1, m_include.length() - 2);
-                QList<QString> keys = includePositions.keys();
-                keys << include;
-                qSort(keys);
-                const int pos = keys.indexOf(include);
-
-                ChangeSet changes;
-                if (pos + 1 != keys.count()) {
-                    const int insertPos = qMax(0, file->position(
-                                                   includePositions.value(keys.at(pos + 1)), 1));
-                    changes.insert(insertPos,
-                                   QLatin1String("#include ") + m_include + QLatin1String("\n"));
-
-                } else {
-                    const int insertPos = qMax(0, file->position(includePositions.value(
-                                                                     keys.at(pos - 1)) + 1, 1) - 1);
-                    changes.insert(insertPos, QLatin1String("\n#include ") + m_include);
-                }
-                file->setChangeSet(changes);
-                file->apply();
-                return;
-            }
-        }
-
-        // No includes or no matching include, find possible first/multi line comment
-        int insertPos = 0;
-        QTextBlock block = file->document()->firstBlock();
-        while (block.isValid()) {
-            const QString trimmedText = block.text().trimmed();
-
-            // Only skip the first comment!
-            if (trimmedText.startsWith(QLatin1String("/*"))) {
-                do {
-                    const int pos = block.text().indexOf(QLatin1String("*/"));
-                    if (pos > -1) {
-                        insertPos = block.position() + pos + 2;
-                        break;
-                    }
-                    block = block.next();
-                } while (block.isValid());
-                break;
-            } else if (trimmedText.startsWith(QLatin1String("//"))) {
-                block = block.next();
-                while (block.isValid()) {
-                    if (!block.text().trimmed().startsWith(QLatin1String("//"))) {
-                        insertPos = block.position() - 1;
-                        break;
-                    }
-                    block = block.next();
-                }
-                break;
-            }
-
-            if (!trimmedText.isEmpty())
-                break;
-            block = block.next();
-        }
-
-        ChangeSet changes;
-        if (insertPos != 0)
-            changes.insert(insertPos, QLatin1String("\n\n#include ") + m_include);
-        else
-            changes.insert(insertPos, QString::fromLatin1("#include %1\n\n").arg(m_include));
-        file->setChangeSet(changes);
-        file->apply();
-    }
-
-private:
-    QString m_include;
-};
-
-} // anonymous namespace
 
 void AddIncludeForUndefinedIdentifier::match(const CppQuickFixInterface &interface,
                                              QuickFixOperations &result)

src/plugins/cppeditor/cppquickfixes.h

@@ -71,6 +71,18 @@ public:
     void match(const CppQuickFixInterface &interface, QuickFixOperations &result);
 };
 
+// Exposed for tests
+class AddIncludeForUndefinedIdentifierOp: public CppQuickFixOperation
+{
+public:
+    AddIncludeForUndefinedIdentifierOp(const CppQuickFixInterface &interface, int priority,
+                                       const QString &include);
+    void perform();
+
+private:
+    QString m_include;
+};
+
 /*!
   Can be triggered on a class forward declaration to add the matching #include.
 
@@ -493,6 +505,7 @@ public:
 
 /*!
  Insert (pure) virtual functions of a base class.
+ Exposed for tests.
  */
 class InsertVirtualMethodsDialog : public QDialog
 {

src/plugins/cpptools/cppmodelmanager.h

@@ -124,6 +124,12 @@ public:
         return m_includePaths;
     }
 
+    // Use this *only* for auto tests
+    void setIncludePaths(const QStringList &includePaths)
+    {
+        m_includePaths = includePaths;
+    }
+
     QStringList frameworkPaths()
     {
         ensureUpdated();

src/plugins/cpptools/cpptools.pro

@@ -45,7 +45,8 @@ HEADERS += completionsettingspage.h \
     builtinindexingsupport.h \
     cpppointerdeclarationformatter.h \
     cppprojectfile.h \
-    cpppreprocessor.h
+    cpppreprocessor.h \
+    includeutils.h
 
 SOURCES += completionsettingspage.cpp \
     cppclassesfilter.cpp \
@@ -89,7 +90,8 @@ SOURCES += completionsettingspage.cpp \
     builtinindexingsupport.cpp \
     cpppointerdeclarationformatter.cpp \
     cppprojectfile.cpp \
-    cpppreprocessor.cpp
+    cpppreprocessor.cpp \
+    includeutils.cpp
 
 FORMS += completionsettingspage.ui \
     cppfilesettingspage.ui \

src/plugins/cpptools/cpptools.qbs

@@ -107,7 +107,9 @@ QtcPlugin {
         "builtinindexingsupport.cpp",
         "builtinindexingsupport.h",
         "cpppreprocessor.cpp",
-        "cpppreprocessor.h"
+        "cpppreprocessor.h",
+        "includeutils.cpp",
+        "includeutils.h"
     ]
 
     Group {

src/plugins/cpptools/includeutils.cpp

@@ -0,0 +1,495 @@
+/****************************************************************************
+**
+** 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 "includeutils.h"
+
+#include <cplusplus/pp-engine.h>
+#include <cplusplus/PreprocessorClient.h>
+#include <cplusplus/PreprocessorEnvironment.h>
+
+#include <utils/stringutils.h>
+
+#include <QDir>
+#include <QFileInfo>
+#include <QStringList>
+#include <QTextBlock>
+#include <QTextDocument>
+
+using namespace CPlusPlus;
+using namespace CppTools;
+using namespace CppTools::IncludeUtils;
+using namespace Utils;
+
+static bool includeLineLessThan(const Include &left, const Include &right)
+{ return left.line() < right.line(); }
+
+static bool includeFileNamelessThen(const Include & left, const Include & right)
+{ return left.unresolvedFileName() < right.unresolvedFileName(); }
+
+LineForNewIncludeDirective::LineForNewIncludeDirective(const QTextDocument *textDocument,
+                                                       QList<Document::Include> includes,
+                                                       MocIncludeMode mocIncludeMode,
+                                                       IncludeStyle includeStyle)
+    : m_textDocument(textDocument)
+    , m_includeStyle(includeStyle)
+{
+    // Ignore *.moc includes if requested
+    if (mocIncludeMode == IgnoreMocIncludes) {
+        foreach (const Document::Include &include, includes) {
+            if (!include.unresolvedFileName().endsWith(QLatin1String(".moc")))
+                m_includes << include;
+        }
+    } else {
+        m_includes = includes;
+    }
+
+    // TODO: Remove this filter loop once FastPreprocessor::sourceNeeded does not add
+    // extra includes anymore.
+    for (int i = m_includes.count() - 1; i >= 0; --i) {
+        if (!QFileInfo(m_includes.at(i).resolvedFileName()).isAbsolute())
+            m_includes.removeAt(i);
+    }
+
+    // Detect include style
+    if (m_includeStyle == AutoDetect) {
+        unsigned timesIncludeStyleChanged = 0;
+        if (m_includes.isEmpty() || m_includes.size() == 1) {
+            m_includeStyle = LocalBeforeGlobal; // Fallback
+        } else {
+            for (int i = 1, size = m_includes.size(); i < size; ++i) {
+                if (m_includes.at(i - 1).type() != m_includes.at(i).type()) {
+                    if (++timesIncludeStyleChanged > 1)
+                        break;
+                }
+            }
+            if (timesIncludeStyleChanged == 1) {
+                m_includeStyle = m_includes.first().type() == Client::IncludeLocal
+                    ? LocalBeforeGlobal
+                    : GlobalBeforeLocal;
+            } else {
+                m_includeStyle = LocalBeforeGlobal; // Fallback
+            }
+        }
+    }
+}
+
+int LineForNewIncludeDirective::operator()(const QString &newIncludeFileName,
+                                           unsigned *newLinesToPrepend,
+                                           unsigned *newLinesToAppend)
+{
+    if (newLinesToPrepend)
+        *newLinesToPrepend = false;
+    if (newLinesToAppend)
+        *newLinesToAppend = false;
+
+    const QString pureIncludeFileName = newIncludeFileName.mid(1, newIncludeFileName.length() - 2);
+    const CPlusPlus::Client::IncludeType newIncludeType =
+        newIncludeFileName.startsWith(QLatin1Char('"')) ? Client::IncludeLocal
+                                                        : Client::IncludeGlobal;
+
+    // Handle no includes
+    if (m_includes.empty()) {
+        unsigned insertLine = 0;
+
+        QTextBlock block = m_textDocument->firstBlock();
+        while (block.isValid()) {
+            const QString trimmedText = block.text().trimmed();
+
+            // Only skip the first comment!
+            if (trimmedText.startsWith(QLatin1String("/*"))) {
+                do {
+                    const int pos = block.text().indexOf(QLatin1String("*/"));
+                    if (pos > -1) {
+                        insertLine = block.blockNumber() + 2;
+                        break;
+                    }
+                    block = block.next();
+                } while (block.isValid());
+                break;
+            } else if (trimmedText.startsWith(QLatin1String("//"))) {
+                block = block.next();
+                while (block.isValid()) {
+                    if (!block.text().trimmed().startsWith(QLatin1String("//"))) {
+                        insertLine = block.blockNumber() + 1;
+                        break;
+                    }
+                    block = block.next();
+                }
+                break;
+            }
+
+            if (!trimmedText.isEmpty())
+                break;
+            block = block.next();
+        }
+
+        if (insertLine == 0) {
+            if (newLinesToAppend)
+                *newLinesToAppend += 1;
+            insertLine = 1;
+        } else {
+            if (newLinesToPrepend)
+                *newLinesToPrepend = 1;
+        }
+        return insertLine;
+    }
+
+    typedef QList<IncludeGroup> IncludeGroups;
+
+    const IncludeGroups groupsNewline = IncludeGroup::detectIncludeGroupsByNewLines(m_includes);
+    const bool includeAtTop
+        = (newIncludeType == Client::IncludeLocal && m_includeStyle == LocalBeforeGlobal)
+            || (newIncludeType == Client::IncludeGlobal && m_includeStyle == GlobalBeforeLocal);
+    IncludeGroup bestGroup = includeAtTop ? groupsNewline.first() : groupsNewline.last();
+
+    IncludeGroups groupsMatchingIncludeType = getGroupsByIncludeType(groupsNewline, newIncludeType);
+    if (groupsMatchingIncludeType.isEmpty()) {
+        const IncludeGroups groupsMixedIncludeType
+            = IncludeGroup::filterMixedIncludeGroups(groupsNewline);
+        // case: The new include goes into an own include group
+        if (groupsMixedIncludeType.isEmpty()) {
+            return includeAtTop
+                ? IncludeGroup::lineForPrependedIncludeGroup(groupsNewline, newLinesToAppend)
+                : IncludeGroup::lineForAppendedIncludeGroup(groupsNewline, newLinesToPrepend);
+        // case: add to mixed group
+        } else {
+            const IncludeGroup bestMixedGroup = groupsMixedIncludeType.last(); // TODO: flaterize
+            const IncludeGroups groupsIncludeType
+                = IncludeGroup::detectIncludeGroupsByIncludeType(bestMixedGroup.includes());
+            groupsMatchingIncludeType = getGroupsByIncludeType(groupsIncludeType, newIncludeType);
+            // Avoid extra new lines for include groups which are not separated by new lines
+            newLinesToPrepend = 0;
+            newLinesToAppend = 0;
+        }
+    }
+
+    IncludeGroups groupsSameIncludeDir;
+    IncludeGroups groupsMixedIncludeDirs;
+    foreach (const IncludeGroup &group, groupsMatchingIncludeType) {
+        if (group.hasCommonIncludeDir())
+            groupsSameIncludeDir << group;
+        else
+            groupsMixedIncludeDirs << group;
+    }
+
+    IncludeGroups groupsMatchingIncludeDir;
+    foreach (const IncludeGroup &group, groupsSameIncludeDir) {
+        if (group.commonIncludeDir() == IncludeGroup::includeDir(pureIncludeFileName))
+            groupsMatchingIncludeDir << group;
+    }
+
+    // case: There are groups with a matching include dir, insert the new include
+    //       at the best position of the best group
+    if (!groupsMatchingIncludeDir.isEmpty()) {
+        // The group with the longest common matching prefix is the best group
+        int longestPrefixSoFar = 0;
+        foreach (const IncludeGroup &group, groupsMatchingIncludeDir) {
+            const int groupPrefixLength = group.commonPrefix().length();
+            if (groupPrefixLength >= longestPrefixSoFar) {
+                bestGroup = group;
+                longestPrefixSoFar = groupPrefixLength;
+            }
+        }
+    } else {
+        // case: The new include goes into an own include group
+        if (groupsMixedIncludeDirs.isEmpty()) {
+            if (includeAtTop) {
+                return groupsSameIncludeDir.isEmpty()
+                    ? IncludeGroup::lineForPrependedIncludeGroup(groupsNewline, newLinesToAppend)
+                    : IncludeGroup::lineForAppendedIncludeGroup(groupsSameIncludeDir, newLinesToPrepend);
+            } else {
+                return IncludeGroup::lineForAppendedIncludeGroup(groupsNewline, newLinesToPrepend);
+            }
+        // case: The new include is inserted at the best position of the best
+        //       group with mixed include dirs
+        } else {
+            IncludeGroups groupsIncludeDir;
+            foreach (const IncludeGroup &group, groupsMixedIncludeDirs) {
+                groupsIncludeDir.append(
+                            IncludeGroup::detectIncludeGroupsByIncludeDir(group.includes()));
+            }
+            IncludeGroup localBestIncludeGroup = IncludeGroup(QList<Include>());
+            foreach (const IncludeGroup &group, groupsIncludeDir) {
+                if (group.commonIncludeDir() == IncludeGroup::includeDir(pureIncludeFileName))
+                    localBestIncludeGroup = group;
+            }
+            if (!localBestIncludeGroup.isEmpty()) {
+                bestGroup = localBestIncludeGroup;
+            } else {
+                bestGroup = groupsMixedIncludeDirs.last();
+            }
+        }
+    }
+
+    return bestGroup.lineForNewInclude(pureIncludeFileName, newIncludeType);
+}
+
+QList<IncludeGroup> LineForNewIncludeDirective::getGroupsByIncludeType(
+        const QList<IncludeGroup> &groups, IncludeType includeType)
+{
+    return includeType == Client::IncludeLocal
+        ? IncludeGroup::filterIncludeGroups(groups, Client::IncludeLocal)
+        : IncludeGroup::filterIncludeGroups(groups, Client::IncludeGlobal);
+}
+
+/// includes will be modified!
+QList<IncludeGroup> IncludeGroup::detectIncludeGroupsByNewLines(QList<Document::Include> &includes)
+{
+    // Sort by line
+    qSort(includes.begin(), includes.end(), includeLineLessThan);
+
+    // Create groups
+    QList<IncludeGroup> result;
+    unsigned lastLine = 0;
+    QList<Include> currentIncludes;
+    bool isFirst = true;
+    foreach (const Include &include, includes) {
+        // First include...
+        if (isFirst) {
+            isFirst = false;
+            currentIncludes << include;
+        }
+        // Include belongs to current group
+        else if (lastLine + 1 == include.line()) {
+            currentIncludes << include;
+        }
+        // Include is member of new group
+        else {
+            result << IncludeGroup(currentIncludes);
+            currentIncludes.clear();
+            currentIncludes << include;
+        }
+
+        lastLine = include.line();
+    }
+
+    if (!currentIncludes.isEmpty())
+        result << IncludeGroup(currentIncludes);
+
+    return result;
+}
+
+QList<IncludeGroup> IncludeGroup::detectIncludeGroupsByIncludeDir(const QList<Include> &includes)
+{
+    // Create sub groups
+    QList<IncludeGroup> result;
+    QString lastDir;
+    QList<Include> currentIncludes;
+    bool isFirst = true;
+    foreach (const Include &include, includes) {
+        const QString currentDirPrefix = includeDir(include.unresolvedFileName());
+
+        // First include...
+        if (isFirst) {
+            isFirst = false;
+            currentIncludes << include;
+        }
+        // Include belongs to current group
+        else if (lastDir == currentDirPrefix) {
+            currentIncludes << include;
+        }
+        // Include is member of new group
+        else {
+            result << IncludeGroup(currentIncludes);
+            currentIncludes.clear();
+            currentIncludes << include;
+        }
+
+        lastDir = currentDirPrefix;
+    }
+
+    if (!currentIncludes.isEmpty())
+        result << IncludeGroup(currentIncludes);
+
+    return result;
+}
+
+QList<IncludeGroup> IncludeGroup::detectIncludeGroupsByIncludeType(const QList<Include> &includes)
+{
+    // Create sub groups
+    QList<IncludeGroup> result;
+    CPlusPlus::Client::IncludeType lastIncludeType;
+    QList<Include> currentIncludes;
+    bool isFirst = true;
+    foreach (const Include &include, includes) {
+        const CPlusPlus::Client::IncludeType currentIncludeType = include.type();
+
+        // First include...
+        if (isFirst) {
+            isFirst = false;
+            currentIncludes << include;
+        }
+        // Include belongs to current group
+        else if (lastIncludeType == currentIncludeType) {
+            currentIncludes << include;
+        }
+        // Include is member of new group
+        else {
+            result << IncludeGroup(currentIncludes);
+            currentIncludes.clear();
+            currentIncludes << include;
+        }
+
+        lastIncludeType = currentIncludeType;
+    }
+
+    if (!currentIncludes.isEmpty())
+        result << IncludeGroup(currentIncludes);
+
+    return result;
+}
+
+QString IncludeGroup::includeDir(const QString &include)
+{
+    QString dirPrefix = QFileInfo(include).dir().path();
+    if (dirPrefix == QLatin1String("."))
+        return QString();
+    dirPrefix.append(QLatin1Char('/'));
+    return dirPrefix;
+}
+
+/// returns groups that solely contains includes of the given include type
+QList<IncludeGroup> IncludeGroup::filterIncludeGroups(const QList<IncludeGroup> &groups,
+                                                      Client::IncludeType includeType)
+{
+    QList<IncludeGroup> result;
+    foreach (const IncludeGroup &group, groups) {
+        if (group.hasOnlyIncludesOfType(includeType))
+            result << group;
+    }
+    return result;
+}
+
+/// returns groups that contains includes with local and globale include type
+QList<IncludeGroup> IncludeGroup::filterMixedIncludeGroups(const QList<IncludeGroup> &groups)
+{
+    QList<IncludeGroup> result;
+    foreach (const IncludeGroup &group, groups) {
+        if (!group.hasOnlyIncludesOfType(Client::IncludeLocal)
+            && !group.hasOnlyIncludesOfType(Client::IncludeGlobal)) {
+            result << group;
+        }
+    }
+    return result;
+}
+
+bool IncludeGroup::hasOnlyIncludesOfType(Client::IncludeType includeType) const
+{
+    foreach (const Include &include, m_includes) {
+        if (include.type() != includeType)
+            return false;
+    }
+    return true;
+}
+
+bool IncludeGroup::isSorted() const
+{
+    const QStringList names = filesNames();
+    if (names.isEmpty() || names.size() == 1)
+        return true;
+    for (int i = 1, total = names.size(); i < total; ++i) {
+        if (names.at(i) < names.at(i - 1))
+            return false;
+    }
+    return true;
+}
+
+int IncludeGroup::lineForNewInclude(const QString &newIncludeFileName,
+                                    Client::IncludeType newIncludeType) const
+{
+    if (m_includes.empty())
+        return -1;
+
+    if (isSorted()) {
+        const Include newInclude(newIncludeFileName, QString(), -1, newIncludeType);
+        const QList<Include>::const_iterator it = std::lower_bound(m_includes.begin(),
+            m_includes.end(), newInclude, includeFileNamelessThen);
+        if (it == m_includes.end())
+            return m_includes.last().line() + 1;
+        else
+            return (*it).line();
+    } else {
+        return m_includes.last().line() + 1;
+    }
+
+    return -1;
+}
+
+QStringList IncludeGroup::filesNames() const
+{
+    QStringList names;
+    foreach (const Include &include, m_includes)
+        names << include.unresolvedFileName();
+    return names;
+}
+
+QString IncludeGroup::commonPrefix() const
+{
+    const QStringList files = filesNames();
+    if (files.size() <= 1)
+        return QString(); // no prefix for single item groups
+    return Utils::commonPrefix(files);
+}
+
+QString IncludeGroup::commonIncludeDir() const
+{
+    if (m_includes.isEmpty())
+        return QString();
+    return includeDir(m_includes.first().unresolvedFileName());
+}
+
+bool IncludeGroup::hasCommonIncludeDir() const
+{
+    if (m_includes.isEmpty())
+        return false;
+
+    const QString candidate = includeDir(m_includes.first().unresolvedFileName());
+    for (int i = 1, size = m_includes.size(); i < size; ++i) {
+        if (includeDir(m_includes.at(i).unresolvedFileName()) != candidate)
+            return false;
+    }
+    return true;
+}
+
+int IncludeGroup::lineForAppendedIncludeGroup(const QList<IncludeGroup> &groups,
+                                              unsigned *newLinesToPrepend)
+{
+    if (newLinesToPrepend)
+        *newLinesToPrepend += 1;
+    return groups.last().last().line() + 1;
+}
+
+int IncludeGroup::lineForPrependedIncludeGroup(const QList<IncludeGroup> &groups,
+                                               unsigned *newLinesToAppend)
+{
+    if (newLinesToAppend)
+        *newLinesToAppend += 1;
+    return groups.first().first().line();
+}

src/plugins/cpptools/includeutils.h

@@ -0,0 +1,121 @@
+/****************************************************************************
+**
+** 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.
+**
+****************************************************************************/
+
+
+#ifndef INCLUDEUTILS_H
+#define INCLUDEUTILS_H
+
+#include "cpptools_global.h"
+
+#include <cplusplus/CppDocument.h>
+#include <cplusplus/PreprocessorClient.h>
+
+#include <QList>
+#include <QString>
+
+QT_FORWARD_DECLARE_CLASS(QStringList)
+QT_FORWARD_DECLARE_CLASS(QTextDocument)
+
+namespace CppTools {
+namespace IncludeUtils {
+
+typedef CPlusPlus::Document::Include Include;
+typedef CPlusPlus::Client::IncludeType IncludeType;
+
+class CPPTOOLS_EXPORT IncludeGroup
+{
+public:
+    static QList<IncludeGroup> detectIncludeGroupsByNewLines(QList<Include> &includes);
+    static QList<IncludeGroup> detectIncludeGroupsByIncludeDir(const QList<Include> &includes);
+    static QList<IncludeGroup> detectIncludeGroupsByIncludeType(const QList<Include> &includes);
+
+    static int lineForAppendedIncludeGroup(const QList<IncludeGroup> &groups,
+                                           unsigned *newLinesToPrepend);
+    static int lineForPrependedIncludeGroup(const QList<IncludeGroup> &groups,
+                                            unsigned *newLinesToAppend);
+
+    static QList<IncludeGroup> filterMixedIncludeGroups(const QList<IncludeGroup> &groups);
+    static QList<IncludeGroup> filterIncludeGroups(const QList<IncludeGroup> &groups,
+                                                   CPlusPlus::Client::IncludeType includeType);
+
+    static QString includeDir(const QString &include);
+
+public:
+    IncludeGroup(const QList<Include> &includes) : m_includes(includes) {}
+
+    QList<Include> includes() const { return m_includes; }
+    Include first() const { return m_includes.first(); }
+    Include last() const { return m_includes.last(); }
+    int size() const { return m_includes.size(); }
+    bool isEmpty() const { return m_includes.isEmpty(); }
+
+    QString commonPrefix() const;
+    QString commonIncludeDir() const; /// only valid if hasCommonDir() == true
+    bool hasCommonIncludeDir() const;
+    bool hasOnlyIncludesOfType(CPlusPlus::Client::IncludeType includeType) const;
+    bool isSorted() const; /// name-wise
+
+    int lineForNewInclude(const QString &newIncludeFileName,
+                          CPlusPlus::Client::IncludeType newIncludeType) const;
+
+private:
+    QStringList filesNames() const;
+
+    QList<Include> m_includes;
+};
+
+class CPPTOOLS_EXPORT LineForNewIncludeDirective
+{
+public:
+    enum MocIncludeMode { RespectMocIncludes, IgnoreMocIncludes };
+    enum IncludeStyle { LocalBeforeGlobal, GlobalBeforeLocal, AutoDetect };
+
+    LineForNewIncludeDirective(const QTextDocument *textDocument,
+                               QList<Include> includes,
+                               MocIncludeMode mocIncludeMode = IgnoreMocIncludes,
+                               IncludeStyle includeStyle = AutoDetect);
+
+    /// Returns the line (1-based) at which the include directive should be inserted.
+    /// On error, -1 is returned.
+    int operator()(const QString &newIncludeFileName, unsigned *newLinesToPrepend = 0,
+                   unsigned *newLinesToAppend = 0);
+
+private:
+    QList<IncludeGroup> getGroupsByIncludeType(const QList<IncludeGroup> &groups,
+                                               IncludeType includeType);
+
+    const QTextDocument *m_textDocument;
+    IncludeStyle m_includeStyle;
+    QList<Include> m_includes;
+};
+
+} // namespace IncludeUtils
+} // namespace CppTools
+
+#endif // INCLUDEUTILS_H

tests/auto/cplusplus/preprocessor/data/include-data/global/QDebug

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/global/QDir

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/global/QString

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/global/except

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/global/global.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/global/iostream

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/global/lib/file.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/global/lib/fileother.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/global/otherlib/file.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/global/otherlib/fileother.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/global/string

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/global/utils/file.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/a.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/b.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/file.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/fileother.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/header.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/lib/file.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/lib/fileother.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/otherlib/file.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/otherlib/fileother.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/prefixa.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/prefixb.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/prefixc.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/stuff

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/utils/utils.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/y.h

@@ -0,0 +1 @@
+// comment

tests/auto/cplusplus/preprocessor/data/include-data/local/z.h

@@ -0,0 +1 @@
+// comment