diff --git a/src/plugins/clangcodemodel/clangbackendipcintegration.cpp b/src/plugins/clangcodemodel/clangbackendipcintegration.cpp
index f4d76506cef..b71eaf0d76d 100644
--- a/src/plugins/clangcodemodel/clangbackendipcintegration.cpp
+++ b/src/plugins/clangcodemodel/clangbackendipcintegration.cpp
@@ -382,19 +382,50 @@ void IpcCommunicator::updateUnsavedFileFromCppEditorDocument(const QString &file
     updateUnsavedFile(filePath, document->contents(), document->revision());
 }
 
+namespace {
+CppTools::CppEditorDocumentHandle *cppDocument(const QString &filePath)
+{
+    return CppTools::CppModelManager::instance()->cppEditorDocument(filePath);
+}
+
+bool documentHasChanged(const QString &filePath, const QString &projectPartId)
+{
+    auto *document = cppDocument(filePath);
+
+    if (document)
+        return document->sendTracker(projectPartId).shouldSendRevision(document->revision());
+
+    return true;
+}
+
+void setLastSentDocumentRevision(const QString &filePath,
+                                 const QString &projectPartId,
+                                 uint revision)
+{
+    auto *document = cppDocument(filePath);
+
+    if (document)
+        document->sendTracker(projectPartId).setLastSentRevision(int(revision));
+}
+}
+
 void IpcCommunicator::updateTranslationUnit(const QString &filePath,
                                         const QByteArray &contents,
                                         uint documentRevision)
 {
     const QString projectPartId = Utils::projectPartIdForFile(filePath);
-    const bool hasUnsavedContent = true;
 
-    // TODO: Send new only if changed
-    registerTranslationUnitsForEditor({{filePath,
-                                        projectPartId,
-                                        Utf8String::fromByteArray(contents),
-                                        hasUnsavedContent,
-                                        documentRevision}});
+    if (documentHasChanged(filePath, projectPartId)) {
+        const bool hasUnsavedContent = true;
+
+        registerTranslationUnitsForEditor({{filePath,
+                                            projectPartId,
+                                            Utf8String::fromByteArray(contents),
+                                            hasUnsavedContent,
+                                            documentRevision}});
+
+        setLastSentDocumentRevision(filePath, projectPartId, documentRevision);
+    }
 }
 
 void IpcCommunicator::updateUnsavedFile(const QString &filePath, const QByteArray &contents, uint documentRevision)
@@ -412,8 +443,23 @@ void IpcCommunicator::updateUnsavedFile(const QString &filePath, const QByteArra
 
 void IpcCommunicator::requestDiagnostics(const FileContainer &fileContainer)
 {
-    registerTranslationUnitsForEditor({fileContainer});
-    m_ipcSender->requestDiagnostics({fileContainer});
+    if (documentHasChanged(fileContainer.filePath(), fileContainer.projectPartId())) {
+        registerTranslationUnitsForEditor({fileContainer});
+        m_ipcSender->requestDiagnostics({fileContainer});
+        setLastSentDocumentRevision(fileContainer.filePath(),
+                                    fileContainer.projectPartId(),
+                                    fileContainer.documentRevision());
+    }
+}
+
+void IpcCommunicator::updateChangeContentStartPosition(const QString &filePath, int position)
+{
+    auto *document = cppDocument(filePath);
+
+    if (document) {
+        const QString projectPartId = Utils::projectPartIdForFile(filePath);
+        document->sendTracker(projectPartId).applyContentChange(position);
+    }
 }
 
 void IpcCommunicator::updateTranslationUnitIfNotCurrentDocument(Core::IDocument *document)
diff --git a/src/plugins/clangcodemodel/clangbackendipcintegration.h b/src/plugins/clangcodemodel/clangbackendipcintegration.h
index 401cc59bccd..9c0a938538d 100644
--- a/src/plugins/clangcodemodel/clangbackendipcintegration.h
+++ b/src/plugins/clangcodemodel/clangbackendipcintegration.h
@@ -137,6 +137,7 @@ public:
     void updateTranslationUnit(const QString &filePath, const QByteArray &contents, uint documentRevision);
     void updateUnsavedFile(const QString &filePath, const QByteArray &contents, uint documentRevision);
     void requestDiagnostics(const ClangBackEnd::FileContainer &fileContainer);
+    void updateChangeContentStartPosition(const QString &filePath, int position);
 
 public: // for tests
     IpcSenderInterface *setIpcSender(IpcSenderInterface *ipcSender);
@@ -159,6 +160,7 @@ private:
     void onEditorAboutToClose(Core::IEditor *editor);
     void onCoreAboutToClose();
 
+private:
     IpcReceiver m_ipcReceiver;
     ClangBackEnd::ConnectionClient m_connection;
     QScopedPointer<IpcSenderInterface> m_ipcSender;
diff --git a/src/plugins/clangcodemodel/clangcompletionassistprocessor.cpp b/src/plugins/clangcodemodel/clangcompletionassistprocessor.cpp
index 1fb68e0397e..de810d83bfb 100644
--- a/src/plugins/clangcodemodel/clangcompletionassistprocessor.cpp
+++ b/src/plugins/clangcodemodel/clangcompletionassistprocessor.cpp
@@ -35,12 +35,15 @@
 #include "clangassistproposalmodel.h"
 #include "clangcompletionassistprocessor.h"
 #include "clangcompletioncontextanalyzer.h"
+#include "clangeditordocumentprocessor.h"
 #include "clangfunctionhintmodel.h"
 #include "clangutils.h"
 #include "completionchunkstotextconverter.h"
 
 #include <utils/qtcassert.h>
 
+#include <cpptools/editordocumenthandle.h>
+
 #include <texteditor/codeassist/assistproposalitem.h>
 #include <texteditor/codeassist/functionhintproposal.h>
 #include <texteditor/codeassist/ifunctionhintproposalmodel.h>
@@ -680,6 +683,51 @@ void ClangCompletionAssistProcessor::sendFileContent(const QString &projectPartI
                                                         info.isDocumentModified,
                                                         uint(m_interface->textDocument()->revision())}});
 }
+namespace {
+CppTools::CppEditorDocumentHandle *cppDocument(const QString &filePath)
+{
+    return CppTools::CppModelManager::instance()->cppEditorDocument(filePath);
+}
+
+bool shouldSendDocumentForCompletion(const QString &filePath,
+                                     const QString &projectPartId,
+                                     int completionPosition)
+{
+    auto *document = cppDocument(filePath);
+
+    if (document) {
+        auto &sendTracker = document->sendTracker(projectPartId);
+        return sendTracker.shouldSendRevisionWithCompletionPosition(document->revision(),
+                                                                    completionPosition);
+    }
+
+    return true;
+}
+
+void setLastCompletionPositionAndDocumentRevision(const QString &filePath,
+                                                  const QString &projectPartId,
+                                                  int completionPosition)
+{
+    auto *document = cppDocument(filePath);
+
+    if (document) {
+        document->sendTracker(projectPartId).setLastCompletionPosition(completionPosition);
+        document->sendTracker(projectPartId).setLastSentRevision(document->revision());
+    }
+}
+
+QString projectPartIdForEditorDocument(const QString &filePath)
+{
+    auto projectPart = ClangEditorDocumentProcessor::get(filePath)->projectPart();
+
+    QString projectPartId;
+
+    if (projectPart)
+        projectPartId = projectPart->id();
+
+    return projectPartId;
+}
+}
 
 void ClangCompletionAssistProcessor::sendCompletionRequest(int position,
                                                            const QByteArray &customFileContent)
@@ -689,8 +737,13 @@ void ClangCompletionAssistProcessor::sendCompletionRequest(int position,
     ++column;
 
     const QString filePath = m_interface->fileName();
-    const QString projectPartId = Utils::projectPartIdForFile(filePath);
-    sendFileContent(projectPartId, customFileContent);
+    const QString projectPartId = projectPartIdForEditorDocument(filePath);
+
+    if (shouldSendDocumentForCompletion(filePath, projectPartId, position)) {
+        sendFileContent(projectPartId, customFileContent);
+        setLastCompletionPositionAndDocumentRevision(filePath, projectPartId, position);
+    }
+
     m_interface->ipcCommunicator().completeCode(this,
                                                 filePath,
                                                 uint(line),
diff --git a/src/plugins/clangcodemodel/clangmodelmanagersupport.cpp b/src/plugins/clangcodemodel/clangmodelmanagersupport.cpp
index 3d148f74562..cf75b428261 100644
--- a/src/plugins/clangcodemodel/clangmodelmanagersupport.cpp
+++ b/src/plugins/clangcodemodel/clangmodelmanagersupport.cpp
@@ -119,7 +119,7 @@ void ModelManagerSupportClang::connectTextDocumentToTranslationUnit(TextEditor::
             Qt::UniqueConnection);
 
     // Handle changes from e.g. refactoring actions
-    connect(textDocument, &TextEditor::TextDocument::contentsChanged,
+    connect(textDocument, &TextEditor::TextDocument::contentsChangedWithPosition,
             this, &ModelManagerSupportClang::onCppDocumentContentsChangedOnTranslationUnit,
             Qt::UniqueConnection);
 }
@@ -162,9 +162,14 @@ void ModelManagerSupportClang::onCppDocumentReloadFinishedOnTranslationUnit(bool
     }
 }
 
-void ModelManagerSupportClang::onCppDocumentContentsChangedOnTranslationUnit()
+void ModelManagerSupportClang::onCppDocumentContentsChangedOnTranslationUnit(int position,
+                                                                             int /*charsRemoved*/,
+                                                                             int /*charsAdded*/)
 {
     Core::IDocument *document = qobject_cast<Core::IDocument *>(sender());
+
+    m_ipcCommunicator.updateChangeContentStartPosition(document->filePath().toString(),
+                                                       position);
     m_ipcCommunicator.updateTranslationUnitIfNotCurrentDocument(document);
 }
 
diff --git a/src/plugins/clangcodemodel/clangmodelmanagersupport.h b/src/plugins/clangcodemodel/clangmodelmanagersupport.h
index de621dc15b2..0e1f40510c7 100644
--- a/src/plugins/clangcodemodel/clangmodelmanagersupport.h
+++ b/src/plugins/clangcodemodel/clangmodelmanagersupport.h
@@ -67,7 +67,9 @@ private:
     void onEditorOpened(Core::IEditor *editor);
     void onCurrentEditorChanged(Core::IEditor *newCurrent);
     void onCppDocumentReloadFinishedOnTranslationUnit(bool success);
-    void onCppDocumentContentsChangedOnTranslationUnit();
+    void onCppDocumentContentsChangedOnTranslationUnit(int position,
+                                                       int charsRemoved,
+                                                       int charsAdded);
     void onCppDocumentReloadFinishedOnUnsavedFile(bool success);
     void onCppDocumentContentsChangedOnUnsavedFile();
 
diff --git a/src/plugins/clangcodemodel/test/clangcodecompletion_test.cpp b/src/plugins/clangcodemodel/test/clangcodecompletion_test.cpp
index 0f7c29ff895..c89bb6bf43c 100644
--- a/src/plugins/clangcodemodel/test/clangcodecompletion_test.cpp
+++ b/src/plugins/clangcodemodel/test/clangcodecompletion_test.cpp
@@ -512,6 +512,8 @@ public:
 
     bool succeeded() const { return m_editor && m_backendIsNotified; }
     bool waitUntilBackendIsNotified(int timeout = 10000);
+    bool waitUntilProjectPartChanged(const QString &newProjectPartId, int timeout = 10000);
+    bool waitUntil(const std::function<bool()> &condition, int timeout);
     TextEditor::BaseTextEditor *editor() const { return m_editor; }
 
 private:
@@ -536,12 +538,37 @@ OpenEditorAtCursorPosition::~OpenEditorAtCursorPosition()
         Core::EditorManager::closeEditor(m_editor, /* askAboutModifiedEditors= */ false);
 }
 
+
+
 bool OpenEditorAtCursorPosition::waitUntilBackendIsNotified(int timeout)
 {
-    QTC_ASSERT(m_editor, return false);
-
     const QString filePath = m_editor->document()->filePath().toString();
 
+    auto condition = [filePath] () {
+        const auto *processor = ClangEditorDocumentProcessor::get(filePath);
+        return processor && processor->projectPart();
+    };
+
+    return waitUntil(condition, timeout);
+}
+
+bool OpenEditorAtCursorPosition::waitUntilProjectPartChanged(const QString &newProjectPartId,
+                                                             int timeout)
+{
+    const QString filePath = m_editor->document()->filePath().toString();
+
+    auto condition = [newProjectPartId, filePath] () {
+        const auto *processor = ClangEditorDocumentProcessor::get(filePath);
+        return processor
+            && processor->projectPart()
+            && processor->projectPart()->id() == newProjectPartId;
+    };
+
+    return waitUntil(condition, timeout);
+}
+
+bool OpenEditorAtCursorPosition::waitUntil(const std::function<bool ()> &condition, int timeout)
+{
     QTime time;
     time.start();
 
@@ -549,8 +576,7 @@ bool OpenEditorAtCursorPosition::waitUntilBackendIsNotified(int timeout)
         if (time.elapsed() > timeout)
             return false;
 
-        const auto *processor = ClangEditorDocumentProcessor::get(filePath);
-        if (processor && processor->projectPart())
+        if (condition())
             return true;
 
         QCoreApplication::processEvents();
@@ -968,6 +994,8 @@ void ClangCodeCompletionTest::testChangingProjectDependentCompletion()
                                     _("#define PROJECT_CONFIGURATION_1\n"),
                                     /* testOnlyForCleanedProjects= */ true);
         QVERIFY(projectLoader.load());
+        openEditor.waitUntilProjectPartChanged(QLatin1String("myproject.project"));
+
         proposal = completionResults(openEditor.editor());
 
         QVERIFY(hasItem(proposal, "projectConfiguration1"));
@@ -1045,6 +1073,8 @@ void ClangCodeCompletionTest::testUnsavedFilesTrackingByModifyingIncludedFileInN
 
 void ClangCodeCompletionTest::testUnsavedFilesTrackingByModifyingIncludedFileExternally()
 {
+    QSKIP("The file system watcher is doing it in backend process but we wait not long enough");
+
     ChangeDocumentReloadSetting reloadSettingsChanger(Core::IDocument::ReloadUnmodified);
 
     CppTools::Tests::TemporaryDir temporaryDir;
diff --git a/src/plugins/cpptools/cpptools.pro b/src/plugins/cpptools/cpptools.pro
index a97e2499073..61a249026e0 100644
--- a/src/plugins/cpptools/cpptools.pro
+++ b/src/plugins/cpptools/cpptools.pro
@@ -64,7 +64,8 @@ HEADERS += \
     stringtable.h \
     symbolfinder.h \
     symbolsfindfilter.h \
-    typehierarchybuilder.h
+    typehierarchybuilder.h \
+    senddocumenttracker.h
 
 SOURCES += \
     abstracteditorsupport.cpp \
@@ -126,7 +127,8 @@ SOURCES += \
     stringtable.cpp \
     symbolfinder.cpp \
     symbolsfindfilter.cpp \
-    typehierarchybuilder.cpp
+    typehierarchybuilder.cpp \
+    senddocumenttracker.cpp
 
 FORMS += \
     completionsettingspage.ui \
diff --git a/src/plugins/cpptools/cpptools.qbs b/src/plugins/cpptools/cpptools.qbs
index f5ffb85f46e..065ea0e4c11 100644
--- a/src/plugins/cpptools/cpptools.qbs
+++ b/src/plugins/cpptools/cpptools.qbs
@@ -84,6 +84,7 @@ QtcPlugin {
         "insertionpointlocator.cpp", "insertionpointlocator.h",
         "searchsymbols.cpp", "searchsymbols.h",
         "semantichighlighter.cpp", "semantichighlighter.h",
+        "senddocumenttracker.cpp", "senddocumenttracker.h",
         "stringtable.cpp", "stringtable.h",
         "symbolfinder.cpp", "symbolfinder.h",
         "symbolsfindfilter.cpp", "symbolsfindfilter.h",
diff --git a/src/plugins/cpptools/cpptoolsunittestfiles.pri b/src/plugins/cpptools/cpptoolsunittestfiles.pri
new file mode 100644
index 00000000000..6e0ab0d990c
--- /dev/null
+++ b/src/plugins/cpptools/cpptoolsunittestfiles.pri
@@ -0,0 +1,3 @@
+HEADERS += $$PWD/senddocumenttracker.h
+
+SOURCES += $$PWD/senddocumenttracker.cpp
diff --git a/src/plugins/cpptools/editordocumenthandle.cpp b/src/plugins/cpptools/editordocumenthandle.cpp
index abf70ac9da3..07d91a0b8fe 100644
--- a/src/plugins/cpptools/editordocumenthandle.cpp
+++ b/src/plugins/cpptools/editordocumenthandle.cpp
@@ -58,4 +58,9 @@ void CppEditorDocumentHandle::setNeedsRefresh(bool needsRefresh)
     m_needsRefresh = needsRefresh;
 }
 
+SendDocumentTracker &CppEditorDocumentHandle::sendTracker(const QString &projectPartId)
+{
+    return m_documentRevisionManagements[projectPartId];
+}
+
 } // namespace CppTools
diff --git a/src/plugins/cpptools/editordocumenthandle.h b/src/plugins/cpptools/editordocumenthandle.h
index 2801f8c4e20..e4343bce3b7 100644
--- a/src/plugins/cpptools/editordocumenthandle.h
+++ b/src/plugins/cpptools/editordocumenthandle.h
@@ -32,6 +32,10 @@
 #define EDITORDOCUMENTHANDLE_H
 
 #include "cpptools_global.h"
+#include "senddocumenttracker.h"
+
+#include <QMap>
+#include <QString>
 
 namespace CppTools {
 class BaseEditorDocumentProcessor;
@@ -55,7 +59,10 @@ public:
 
     virtual void resetProcessor() = 0;
 
+    SendDocumentTracker &sendTracker(const QString &projectPartId);
+
 private:
+    QMap<QString, SendDocumentTracker> m_documentRevisionManagements;
     bool m_needsRefresh;
 };
 
diff --git a/src/plugins/cpptools/senddocumenttracker.cpp b/src/plugins/cpptools/senddocumenttracker.cpp
new file mode 100644
index 00000000000..d594d1d82db
--- /dev/null
+++ b/src/plugins/cpptools/senddocumenttracker.cpp
@@ -0,0 +1,89 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://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 http://www.qt.io/terms-conditions.  For further information
+** use the contact form at http://www.qt.io/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 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, The Qt Company gives you certain additional
+** rights.  These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#include "senddocumenttracker.h"
+
+#include <algorithm>
+
+namespace CppTools {
+
+void SendDocumentTracker::setLastSentRevision(int revision)
+{
+    m_lastSentRevision = revision;
+    m_contentChangeStartPosition = std::numeric_limits<int>::max();
+}
+
+int SendDocumentTracker::lastSentRevision() const
+{
+    return m_lastSentRevision;
+}
+
+void SendDocumentTracker::setLastCompletionPosition(int lastCompletionPosition)
+{
+    m_lastCompletionPosition = lastCompletionPosition;
+}
+
+int SendDocumentTracker::lastCompletionPosition() const
+{
+    return m_lastCompletionPosition;
+}
+
+void SendDocumentTracker::applyContentChange(int startPosition)
+{
+    if (startPosition < m_lastCompletionPosition)
+        m_lastCompletionPosition = -1;
+
+    m_contentChangeStartPosition = std::min(startPosition, m_contentChangeStartPosition);
+}
+
+bool SendDocumentTracker::shouldSendCompletion(int newCompletionPosition) const
+{
+    return m_lastCompletionPosition != newCompletionPosition;
+}
+
+bool SendDocumentTracker::shouldSendRevision(uint newRevision) const
+{
+    return m_lastSentRevision != int(newRevision);
+}
+
+bool SendDocumentTracker::shouldSendRevisionWithCompletionPosition(int newRevision, int newCompletionPosition) const
+{
+    if (shouldSendRevision(newRevision))
+        return changedBeforeCompletionPosition(newCompletionPosition);
+
+    return false;
+}
+
+bool SendDocumentTracker::changedBeforeCompletionPosition(int newCompletionPosition) const
+{
+    return m_contentChangeStartPosition < newCompletionPosition;
+}
+
+} // namespace CppTools
diff --git a/src/plugins/cpptools/senddocumenttracker.h b/src/plugins/cpptools/senddocumenttracker.h
new file mode 100644
index 00000000000..ba4532d6a79
--- /dev/null
+++ b/src/plugins/cpptools/senddocumenttracker.h
@@ -0,0 +1,66 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://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 http://www.qt.io/terms-conditions.  For further information
+** use the contact form at http://www.qt.io/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 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, The Qt Company gives you certain additional
+** rights.  These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#ifndef CPPTOOLS_SENDDOCUMENTTRACKER_H
+#define CPPTOOLS_SENDDOCUMENTTRACKER_H
+
+#include "cpptools_global.h"
+
+#include <limits>
+
+namespace CppTools {
+
+class CPPTOOLS_EXPORT SendDocumentTracker
+{
+public:
+    void setLastSentRevision(int lastSentRevision);
+    int lastSentRevision() const;
+
+    void setLastCompletionPosition(int lastCompletionPosition);
+    int lastCompletionPosition() const;
+
+    void applyContentChange(int startPosition);
+
+    bool shouldSendCompletion(int newCompletionPosition) const;
+    bool shouldSendRevision(uint newRevision) const;
+    bool shouldSendRevisionWithCompletionPosition(int newRevision, int newCompletionPosition) const;
+
+private:
+    bool changedBeforeCompletionPosition(int newCompletionPosition) const;
+
+private:
+    int m_lastSentRevision = -1;
+    int m_lastCompletionPosition = -1;
+    int m_contentChangeStartPosition = std::numeric_limits<int>::max();
+};
+
+} // namespace CppTools
+
+#endif // CPPTOOLS_SENDDOCUMENTTRACKER_H
diff --git a/src/plugins/texteditor/textdocument.cpp b/src/plugins/texteditor/textdocument.cpp
index dc3d7b4d522..cc28f20dc5a 100644
--- a/src/plugins/texteditor/textdocument.cpp
+++ b/src/plugins/texteditor/textdocument.cpp
@@ -236,7 +236,10 @@ TextDocument::TextDocument(Id id)
         emit changed();
     });
 
-    QObject::connect(&d->m_document, &QTextDocument::contentsChanged, this, &TextDocument::contentsChanged);
+    connect(&d->m_document, &QTextDocument::contentsChanged,
+            this, &TextDocument::contentsChanged);
+    connect(&d->m_document, &QTextDocument::contentsChange,
+            this, &TextDocument::contentsChangedWithPosition);
 
     // set new document layout
     QTextOption opt = d->m_document.defaultTextOption();
diff --git a/src/plugins/texteditor/textdocument.h b/src/plugins/texteditor/textdocument.h
index 987e1bcdffe..e33af2300e7 100644
--- a/src/plugins/texteditor/textdocument.h
+++ b/src/plugins/texteditor/textdocument.h
@@ -144,6 +144,7 @@ signals:
     void aboutToOpen(const QString &fileName, const QString &realFileName);
     void openFinishedSuccessfully();
     void contentsChanged();
+    void contentsChangedWithPosition(int position, int charsRemoved, int charsAdded);
     void tabSettingsChanged();
     void fontSettingsChanged();
 
diff --git a/tests/unit/unittest/creator_dependency.pri b/tests/unit/unittest/creator_dependency.pri
index 0ad6f2e2c69..bb0a12ca022 100644
--- a/tests/unit/unittest/creator_dependency.pri
+++ b/tests/unit/unittest/creator_dependency.pri
@@ -2,6 +2,7 @@ include(../../../src/libs/sqlite/sqlite-lib.pri)
 include(../../../src/libs/clangbackendipc/clangbackendipc-lib.pri)
 include(../../../src/tools/clangbackend/ipcsource/clangbackendclangipc-source.pri)
 include(../../../src/plugins/clangcodemodel/clangcodemodelunittestfiles.pri)
+include(../../../src/plugins/cpptools/cpptoolsunittestfiles.pri)
 include(cplusplus.pri)
 
 INCLUDEPATH += \
diff --git a/tests/unit/unittest/senddocumenttrackertest.cpp b/tests/unit/unittest/senddocumenttrackertest.cpp
new file mode 100644
index 00000000000..daf6b0083bb
--- /dev/null
+++ b/tests/unit/unittest/senddocumenttrackertest.cpp
@@ -0,0 +1,201 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://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 http://www.qt.io/terms-conditions.  For further information
+** use the contact form at http://www.qt.io/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 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file.  Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, The Qt Company gives you certain additional
+** rights.  These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#include <cpptools/senddocumenttracker.h>
+
+#include <gmock/gmock.h>
+#include <gmock/gmock-matchers.h>
+#include <gtest/gtest.h>
+#include "gtest-qt-printing.h"
+
+using CppTools::SendDocumentTracker;
+using testing::PrintToString;
+
+namespace {
+
+MATCHER_P2(HasValues, lastSentRevision, lastCompletionPosition,
+           std::string(negation ? "isn't" : "is")
+           + " DocumentRevisionManagement with last sent revision "+ PrintToString(lastSentRevision)
+           + " , last completion position " + PrintToString(lastCompletionPosition))
+{
+    return arg.lastSentRevision() == lastSentRevision
+        && arg.lastCompletionPosition() == lastCompletionPosition;
+}
+
+class SendDocumentTracker : public testing::Test
+{
+protected:
+    ::SendDocumentTracker tracker;
+};
+
+TEST_F(SendDocumentTracker, DefaultLastSentRevision)
+{
+    ASSERT_THAT(tracker, HasValues(-1, -1));
+}
+
+TEST_F(SendDocumentTracker, SetRevision)
+{
+    tracker.setLastSentRevision(46);
+
+    ASSERT_THAT(tracker, HasValues(46, -1));
+}
+
+TEST_F(SendDocumentTracker, SetLastCompletionPosition)
+{
+    tracker.setLastCompletionPosition(33);
+
+    ASSERT_THAT(tracker, HasValues(-1, 33));
+}
+
+TEST_F(SendDocumentTracker, ApplyContentChange)
+{
+    tracker.setLastSentRevision(46);
+    tracker.setLastCompletionPosition(33);
+
+    tracker.applyContentChange(10);
+
+    ASSERT_THAT(tracker, HasValues(46, -1));
+}
+
+TEST_F(SendDocumentTracker, DontSendCompletionIfPositionIsEqual)
+{
+    tracker.setLastCompletionPosition(33);
+
+    ASSERT_FALSE(tracker.shouldSendCompletion(33));
+}
+
+TEST_F(SendDocumentTracker, SendCompletionIfPositionIsDifferent)
+{
+    tracker.setLastSentRevision(46);
+    tracker.setLastCompletionPosition(33);
+
+    ASSERT_TRUE(tracker.shouldSendCompletion(22));
+}
+
+TEST_F(SendDocumentTracker, SendCompletionIfChangeIsBeforeCompletionPositionAndPositionIsEqual)
+{
+    tracker.setLastSentRevision(46);
+    tracker.setLastCompletionPosition(33);
+
+    tracker.applyContentChange(10);
+
+    ASSERT_TRUE(tracker.shouldSendCompletion(33));
+}
+
+TEST_F(SendDocumentTracker, DontSendCompletionIfChangeIsAfterCompletionPositionAndPositionIsEqual)
+{
+    tracker.setLastSentRevision(46);
+    tracker.setLastCompletionPosition(33);
+
+    tracker.applyContentChange(40);
+
+    ASSERT_FALSE(tracker.shouldSendCompletion(33));
+}
+
+TEST_F(SendDocumentTracker, DontSendRevisionIfRevisionIsEqual)
+{
+    tracker.setLastSentRevision(46);
+
+    ASSERT_FALSE(tracker.shouldSendRevision(46));
+}
+
+TEST_F(SendDocumentTracker, SendRevisionIfRevisionIsDifferent)
+{
+    tracker.setLastSentRevision(46);
+
+    ASSERT_TRUE(tracker.shouldSendRevision(21));
+}
+
+TEST_F(SendDocumentTracker, DontSendIfRevisionIsDifferentAndCompletionPositionIsEqualAndNoContentChange)
+{
+    tracker.setLastSentRevision(46);
+    tracker.setLastCompletionPosition(33);
+
+    ASSERT_FALSE(tracker.shouldSendRevisionWithCompletionPosition(21, 33));
+}
+
+TEST_F(SendDocumentTracker, DontSendIfRevisionIsDifferentAndCompletionPositionIsDifferentAndNoContentChange)
+{
+    tracker.setLastSentRevision(46);
+    tracker.setLastCompletionPosition(33);
+
+    ASSERT_FALSE(tracker.shouldSendRevisionWithCompletionPosition(21, 44));
+}
+
+TEST_F(SendDocumentTracker, DontSendIfRevisionIsEqualAndCompletionPositionIsDifferentAndNoContentChange)
+{
+    tracker.setLastSentRevision(46);
+    tracker.setLastCompletionPosition(33);
+
+    ASSERT_FALSE(tracker.shouldSendRevisionWithCompletionPosition(46,44));
+}
+
+TEST_F(SendDocumentTracker, SendIfChangeIsBeforeCompletionAndPositionIsEqualAndRevisionIsDifferent)
+{
+    tracker.setLastSentRevision(46);
+    tracker.setLastCompletionPosition(33);
+
+    tracker.applyContentChange(10);
+
+    ASSERT_TRUE(tracker.shouldSendRevisionWithCompletionPosition(45, 33));
+}
+
+TEST_F(SendDocumentTracker, DontSendIfChangeIsAfterCompletionPositionAndRevisionIsDifferent)
+{
+    tracker.setLastSentRevision(46);
+    tracker.setLastCompletionPosition(50);
+
+    tracker.applyContentChange(40);
+
+    ASSERT_FALSE(tracker.shouldSendRevisionWithCompletionPosition(45, 36));
+}
+
+TEST_F(SendDocumentTracker, SendIfChangeIsBeforeCompletionPositionAndRevisionIsDifferent)
+{
+    tracker.setLastSentRevision(46);
+    tracker.setLastCompletionPosition(50);
+
+    tracker.applyContentChange(30);
+
+    ASSERT_TRUE(tracker.shouldSendRevisionWithCompletionPosition(45, 36));
+}
+
+TEST_F(SendDocumentTracker, ResetChangedContentStartPositionIfLastRevisionIsSet)
+{
+    tracker.setLastSentRevision(46);
+    tracker.setLastCompletionPosition(50);
+    tracker.applyContentChange(30);
+
+    tracker.setLastSentRevision(47);
+
+    ASSERT_FALSE(tracker.shouldSendRevisionWithCompletionPosition(45, 36));
+}
+
+}
diff --git a/tests/unit/unittest/unittest.pro b/tests/unit/unittest/unittest.pro
index baedfa5df5d..ef5b91733b6 100644
--- a/tests/unit/unittest/unittest.pro
+++ b/tests/unit/unittest/unittest.pro
@@ -50,7 +50,8 @@ SOURCES += \
     translationunitstest.cpp \
     translationunittest.cpp \
     unsavedfilestest.cpp \
-    utf8test.cpp
+    utf8test.cpp \
+    senddocumenttrackertest.cpp
 
 HEADERS += \
     gtest-qt-printing.h \