Git: Introduce MergeTool support

Change-Id: I906c3c692d9f4819bdf2a1489c42ae04f292894d
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/git/mergetool.cpp

@@ -0,0 +1,232 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 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 "gitclient.h"
+#include "gitplugin.h"
+#include "mergetool.h"
+
+#include <QMessageBox>
+#include <QProcess>
+#include <QPushButton>
+#include <QRegExp>
+
+namespace Git {
+namespace Internal {
+
+MergeTool::MergeTool(QObject *parent) :
+    QObject(parent),
+    m_process(0)
+{
+}
+
+MergeTool::~MergeTool()
+{
+    delete m_process;
+}
+
+bool MergeTool::start(const QString &workingDirectory, const QStringList &files)
+{
+    QStringList arguments;
+    arguments << QLatin1String("mergetool") << QLatin1String("-y");
+    GitClient *client = GitPlugin::instance()->gitClient();
+    if (!files.isEmpty()) {
+        if (client->gitVersion() < 0x010708) {
+            QMessageBox::warning(0, tr("Error"), tr("Files input for mergetool requires git >= 1.7.8"));
+            return false;
+        }
+        arguments << files;
+    }
+    m_process = new QProcess(this);
+    m_process->setWorkingDirectory(workingDirectory);
+    m_process->start(QLatin1String("git"), arguments);
+    if (m_process->waitForStarted()) {
+        connect(m_process, SIGNAL(finished(int)), this, SLOT(done()));
+        connect(m_process, SIGNAL(readyRead()), this, SLOT(readData()));
+    }
+    else {
+        delete m_process;
+        m_process = 0;
+        return false;
+    }
+    return true;
+}
+
+MergeTool::FileState MergeTool::waitAndReadStatus(QString &extraInfo)
+{
+    QByteArray state;
+    if (m_process->canReadLine() || (m_process->waitForReadyRead(500) && m_process->canReadLine())) {
+        state = m_process->readLine().trimmed();
+        // "  {local}: modified file"
+        // "  {remote}: deleted"
+        if (!state.isEmpty()) {
+            state = state.mid(state.indexOf(':') + 2);
+            if (state == "deleted")
+                return DeletedState;
+            if (state.startsWith("modified"))
+                return ModifiedState;
+            if (state.startsWith("created"))
+                return CreatedState;
+            QByteArray submodulePrefix("submodule commit ");
+            // "  {local}: submodule commit <hash>"
+            if (state.startsWith(submodulePrefix)) {
+                extraInfo = QString::fromLocal8Bit(state.mid(submodulePrefix.size()));
+                return SubmoduleState;
+            }
+            // "  {local}: a symbolic link -> 'foo.cpp'"
+            QByteArray symlinkPrefix("a symbolic link -> '");
+            if (state.startsWith(symlinkPrefix)) {
+                extraInfo = QString::fromLocal8Bit(state.mid(symlinkPrefix.size()));
+                extraInfo.chop(1); // remove last quote
+                return SymbolicLinkState;
+            }
+        }
+    }
+    return UnknownState;
+}
+
+static MergeTool::MergeType mergeType(const QByteArray &type)
+{
+    if (type == "Normal")
+        return MergeTool::NormalMerge;
+    if (type == "Deleted")
+        return MergeTool::DeletedMerge;
+    if (type == "Submodule")
+        return MergeTool::SubmoduleMerge;
+    else
+        return MergeTool::SymbolicLinkMerge;
+}
+
+QString MergeTool::mergeTypeName()
+{
+    switch (m_mergeType) {
+    case NormalMerge: return tr("Normal");
+    case SubmoduleMerge: return tr("Submodule");
+    case DeletedMerge: return tr("Deleted");
+    case SymbolicLinkMerge: return tr("Symbolic link");
+    }
+    return QString();
+}
+
+QString MergeTool::stateName(MergeTool::FileState state, const QString &extraInfo)
+{
+    switch (state) {
+    case ModifiedState: return tr("Modified");
+    case CreatedState: return tr("Created");
+    case DeletedState: return tr("Deleted");
+    case SubmoduleState: return tr("Submodule commit %1").arg(extraInfo);
+    case SymbolicLinkState: return tr("Symbolic link -> %1").arg(extraInfo);
+    default: break;
+    }
+    return QString();
+}
+
+void MergeTool::chooseAction()
+{
+    m_merging = (m_mergeType == NormalMerge);
+    if (m_merging)
+        return;
+    QMessageBox msgBox;
+    msgBox.setWindowTitle(tr("Merge Conflict"));
+    msgBox.setIcon(QMessageBox::Question);
+    msgBox.setStandardButtons(QMessageBox::Abort);
+    msgBox.setText(tr("%1 merge conflict for '%2'\nLocal: %3\nRemote: %4")
+                   .arg(mergeTypeName())
+                   .arg(m_fileName)
+                   .arg(stateName(m_localState, m_localInfo))
+                   .arg(stateName(m_remoteState, m_remoteInfo))
+                   );
+    switch (m_mergeType) {
+    case SubmoduleMerge:
+    case SymbolicLinkMerge:
+        addButton(&msgBox, tr("&Local"), 'l');
+        addButton(&msgBox, tr("&Remote"), 'r');
+        break;
+    case DeletedMerge:
+        if (m_localState == CreatedState || m_remoteState == CreatedState)
+            addButton(&msgBox, tr("&Created"), 'c');
+        else
+            addButton(&msgBox, tr("&Modified"), 'm');
+        addButton(&msgBox, tr("&Deleted"), 'd');
+        break;
+    default:
+        break;
+    }
+
+    msgBox.exec();
+    QByteArray ba;
+    QVariant key;
+    QAbstractButton *button = msgBox.clickedButton();
+    if (button)
+        key = button->property("key");
+    // either the message box was closed without clicking anything, or abort was clicked
+    if (!key.isValid())
+        key = QVariant(QLatin1Char('a')); // abort
+    ba.append(key.toChar().toLatin1());
+    ba.append('\n');
+    m_process->write(ba);
+}
+
+void MergeTool::addButton(QMessageBox *msgBox, const QString &text, char key)
+{
+    msgBox->addButton(text, QMessageBox::AcceptRole)->setProperty("key", key);
+}
+
+void MergeTool::readData()
+{
+    while (m_process->bytesAvailable()) {
+        QByteArray line = m_process->canReadLine() ? m_process->readLine() : m_process->readAllStandardOutput();
+        // {Normal|Deleted|Submodule|Symbolic link} merge conflict for 'foo.cpp'
+        int index = line.indexOf(" merge conflict for ");
+        if (index != -1) {
+            m_mergeType = mergeType(line.left(index));
+            int quote = line.indexOf('\'');
+            m_fileName = QString::fromLocal8Bit(line.mid(quote + 1, line.lastIndexOf('\'') - quote - 1));
+            m_localState = waitAndReadStatus(m_localInfo);
+            m_remoteState = waitAndReadStatus(m_remoteInfo);
+            chooseAction();
+        } else if (m_merging && line.startsWith("Continue merging")) {
+            if (QMessageBox::question(0, tr("Continue Merging"),
+                                      tr("Continue merging other unresolved paths?"),
+                                      QMessageBox::Yes, QMessageBox::No) == QMessageBox::Yes) {
+                m_process->write("y\n");
+            } else {
+                m_process->write("n\n");
+            }
+        }
+    }
+}
+
+void MergeTool::done()
+{
+    QMessageBox::information(0, tr("Done"), tr("Merge done"));
+    deleteLater();
+}
+
+} // namespace Internal
+} // namespace Git