SVN: Add method to find SVN version and use it in svnDiff

We want to enforce the internal diff if possible, but that option
is only in 1.7 and later.

Task-number: QTCREATORBUG-9425
Change-Id: If89f0a7eedae51a04a5f1c40d48287a6425f7a12
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/subversion/subversionplugin.cpp

@@ -572,7 +572,9 @@ void SubversionPlugin::svnDiff(const Subversion::Internal::SubversionDiffParamet
                              QFileInfo(p.files.front()).fileName() : p.diffName;
 
     QStringList args(QLatin1String("diff"));
-    args.append(QLatin1String("--internal-diff"));
+    Version v = svnVersion();
+    if (v.majorVersion >= 1 && v.minorVersion >= 7) // --internal-diff is new in v1.7.0
+        args.append(QLatin1String("--internal-diff"));
     args.append(p.arguments);
     args << p.files;
 
@@ -1110,6 +1112,32 @@ QStringList SubversionPlugin::addAuthenticationOptions(const QStringList &args,
     return rc;
 }
 
+SubversionPlugin::Version SubversionPlugin::svnVersion()
+{
+    if (m_svnVersionBinary != m_settings.binaryPath()) {
+        QStringList args;
+        args << QLatin1String("--version") << QLatin1String("-q");
+        const Utils::SynchronousProcessResponse response =
+                VcsBase::VcsBasePlugin::runVcs(QDir().absolutePath(), m_settings.binaryPath(),
+                                               args, m_settings.timeOutMs(), 0);
+        if (response.result == Utils::SynchronousProcessResponse::Finished &&
+                response.exitCode == 0) {
+            m_svnVersionBinary = m_settings.binaryPath();
+            m_svnVersion = response.stdOut.trimmed();
+        } else {
+            m_svnVersionBinary.clear();
+            m_svnVersion.clear();
+        }
+    }
+
+    SubversionPlugin::Version v;
+    if (::sscanf(m_svnVersion.toLatin1().constData(), "%d.%d.%d",
+           &v.majorVersion, &v.minorVersion, &v.patchVersion) != 3)
+        v.majorVersion = v.minorVersion = v.patchVersion = -1;
+
+    return v;
+}
+
 SubversionResponse SubversionPlugin::runSvn(const QString &workingDir,
                           const QString &userName, const QString &password,
                           const QStringList &arguments, int timeOut,

src/plugins/subversion/subversionplugin.h

@@ -106,6 +106,15 @@ public:
                                                 const QString &userName = QString(),
                                                 const QString &password = QString());
 
+    class Version {
+    public:
+        int majorVersion;
+        int minorVersion;
+        int patchVersion;
+    };
+
+    Version svnVersion();
+
 public slots:
     void vcsAnnotate(const QString &workingDir, const QString &file,
                      const QString &revision = QString(), int lineNumber = -1);
@@ -204,6 +213,9 @@ private:
     QAction *m_menuAction;
     bool    m_submitActionTriggered;
 
+    QString m_svnVersionBinary;
+    QString m_svnVersion;
+
     static SubversionPlugin *m_subversionPluginInstance;
 };