Patch hardcoded paths for Arch Linux Qt

Partially addresses https://github.com/probonopd/linuxdeployqt/issues/98

linuxdeployqt/main.cpp

@@ -63,9 +63,11 @@ int main(int argc, char **argv)
         qDebug() << "It deploys the Qt instance that qmake on the $PATH points to,";
         qDebug() << "so make sure that it is the correct one.";
         qDebug() << "";
-        qDebug() << "Plugins related to a Qt library are copied in with the";
+        qDebug() << "Plugins related to a Qt library are copied in with the library.";
-        qDebug() << "library. The accessibility, image formats, and text codec";
+        /* TODO: To be implemented
+        qDebug() << "The accessibility, image formats, and text codec";
         qDebug() << "plugins are always copied, unless \"-no-plugins\" is specified.";
+        */
         qDebug() << "";
         qDebug() << "See the \"Deploying Applications on Linux\" topic in the";
         qDebug() << "documentation for more information about deployment on Linux.";

shared/shared.cpp

@@ -643,6 +643,59 @@ bool patchQtCore(const QString &path, const QString &variable, const QString &va
     return true;
 }
 
+/* Replace searchString string with replacementString string, filling with 0x00s
+ * replacementString must not be longer than searchString */
+
+bool patchString(const QString &path, const QString &searchString, const QString &replacementString)
+{
+    if(replacementString.length() > searchString.length()){
+        LogWarning() << QString::fromLatin1("%1 is longer than %2").arg(
+                    replacementString, searchString);
+        return false;
+    }
+    QFile file(path);
+    if (!file.open(QIODevice::ReadWrite)) {
+        LogWarning() << QString::fromLatin1("Unable to patch %1: %2").arg(
+                    QDir::toNativeSeparators(path), file.errorString());
+        return false;
+    }
+    QByteArray content = file.readAll();
+
+    if (content.isEmpty()) {
+        LogWarning() << QString::fromLatin1("Unable to patch %1: Could not read file content").arg(
+                    QDir::toNativeSeparators(path));
+        return false;
+    }
+
+    QByteArray searchStringQByteArray = searchString.toLatin1().data();
+
+    int startPos = content.indexOf(searchStringQByteArray);
+    if (startPos != -1) {
+        LogNormal() << QString::fromLatin1(
+                    "Patching %2 in %1 to '%3'").arg(QDir::toNativeSeparators(path), searchString, replacementString);
+    }
+    int endPos = content.indexOf(char(0), startPos);
+    if (endPos == -1) {
+        LogWarning() << QString::fromLatin1("Unable to patch %1: Internal error").arg(
+                    QDir::toNativeSeparators(path));
+        return false;
+    }
+
+    QByteArray replacement = QByteArray(endPos - startPos, char(0));
+    QByteArray replacementBegin = replacementString.toLatin1().data();
+    replacement.prepend(replacementBegin);
+    replacement.truncate(endPos - startPos);
+
+    content.replace(startPos, endPos - startPos, replacement);
+
+    if (!file.seek(0) || (file.write(content) != content.size())) {
+        LogWarning() << QString::fromLatin1("Unable to patch %1: Could not write to file").arg(
+                    QDir::toNativeSeparators(path));
+        return false;
+    }
+    return true;
+}
+
 void changeIdentification(const QString &id, const QString &binaryPath)
 {
     LogDebug() << "Using patchelf:";
@@ -652,7 +705,7 @@ void changeIdentification(const QString &id, const QString &binaryPath)
 
     // qt_prfxpath:
     if (binaryPath.contains("libQt5Core")) {
-        LogDebug() << "libQt5Core detected, patching its qt_* strings";
+        LogDebug() << "libQt5Core detected, patching its hardcoded strings";
 
         /* https://codereview.qt-project.org/gitweb?p=qt/qttools.git;a=blob_plain;f=src/windeployqt/utils.cpp;h=e89496ea1f371ed86f6937284c1c801daf576572;hb=7be81b804da102b374c2089aac38353a0383c254
          * Search for "qt_prfxpath=<xxx>" in a path, and replace it with "qt_prfxpath=." or "qt_prfxpath=.." */
@@ -680,7 +733,21 @@ void changeIdentification(const QString &id, const QString &binaryPath)
         patchQtCore(binaryPath, "qt_hpfxpath", ".");
         patchQtCore(binaryPath, "qt_hbinpath", "bin");
         patchQtCore(binaryPath, "qt_hdatpath", ".");
-	patchQtCore(binaryPath, "qt_stngpath", "."); // e.g., /opt/qt53/etc/xdg; does it load Trolltech.conf from there?
+        patchQtCore(binaryPath, "qt_stngpath", "."); // e.g., /opt/qt53/etc/xdg; does it load Trolltech.conf from there?
+
+        /* Qt on Arch Linux comes with more hardcoded paths
+         * https://github.com/probonopd/linuxdeployqt/issues/98 */
+
+        patchString(binaryPath, "lib/qt/libexec", "libexec");
+        patchString(binaryPath, "lib/qt/plugins", "plugins");
+        patchString(binaryPath, "lib/qt/imports", "imports");
+        patchString(binaryPath, "lib/qt/qml", "qml");
+        patchString(binaryPath, "lib/qt", "");
+        patchString(binaryPath, "share/doc/qt", "doc");
+        patchString(binaryPath, "include/qt", "include");
+        patchString(binaryPath, "share/qt", "");
+        patchString(binaryPath, "share/qt/translations", "translations");
+        patchString(binaryPath, "share/doc/qt/examples", "examples");
     }
 
 }