add generic macro expansion classes & functions to Utils

AbstractMacroExpander (any macros), AbstractQtcMacroExpander (%{var}
style macros, which is a hybrid of printf format specifiers and unix
environment expansions) and expandMacros() for the actual string
manipulation.

src/libs/utils/stringutils.cpp

@@ -119,4 +119,42 @@ QTCREATOR_UTILS_EXPORT QString withTildeHomePath(const QString &path)
     return outPath;
 }
 
+int AbstractQtcMacroExpander::findMacro(const QString &str, int *pos, QString *ret)
+{
+    forever {
+        int openPos = str.indexOf(QLatin1String("%{"), *pos);
+        if (openPos < 0)
+            return 0;
+        int varPos = openPos + 2;
+        int closePos = str.indexOf(QLatin1Char('}'), varPos);
+        if (closePos < 0)
+            return 0;
+        int varLen = closePos - varPos;
+        if (resolveMacro(str.mid(varPos, varLen), ret)) {
+            *pos = openPos;
+            return varLen + 3;
+        }
+        // An actual expansion may be nested into a "false" one,
+        // so we continue right after the last %{.
+        *pos = varPos;
+    }
+}
+
+QTCREATOR_UTILS_EXPORT void expandMacros(QString *str, AbstractMacroExpander *mx)
+{
+    QString rsts;
+
+    for (int pos = 0; int len = mx->findMacro(*str, &pos, &rsts); ) {
+        str->replace(pos, len, rsts);
+        pos += rsts.length();
+    }
+}
+
+QTCREATOR_UTILS_EXPORT QString expandMacros(const QString &str, AbstractMacroExpander *mx)
+{
+    QString ret = str;
+    expandMacros(&ret, mx);
+    return ret;
+}
+
 } // namespace Utils

src/libs/utils/stringutils.h

@@ -55,6 +55,30 @@ QTCREATOR_UTILS_EXPORT QString commonPath(const QStringList &files);
 // If path is not sub of home path, or when running on Windows, returns the input
 QTCREATOR_UTILS_EXPORT QString withTildeHomePath(const QString &path);
 
+class QTCREATOR_UTILS_EXPORT AbstractMacroExpander {
+public:
+    // Not const, as it may change the state of the expander.
+    //! Find an expando to replace and provide a replacement string.
+    //! \param str The string to scan
+    //! \param pos Position to start scan on input, found position on output
+    //! \param ret Replacement string on output
+    //! \return Length of string part to replace, zero if no (further) matches found
+    virtual int findMacro(const QString &str, int *pos, QString *ret) = 0;
+};
+
+class QTCREATOR_UTILS_EXPORT AbstractQtcMacroExpander : public AbstractMacroExpander {
+public:
+    virtual int findMacro(const QString &str, int *pos, QString *ret);
+    //! Provide a replacement string for an expando
+    //! \param name The name of the expando
+    //! \param ret Replacement string on output
+    //! \return True if the expando was found
+    virtual bool resolveMacro(const QString &name, QString *ret) = 0;
+};
+
+QTCREATOR_UTILS_EXPORT void expandMacros(QString *str, AbstractMacroExpander *mx);
+QTCREATOR_UTILS_EXPORT QString expandMacros(const QString &str, AbstractMacroExpander *mx);
+
 } // namespace Utils
 
 #endif // SETTINGSTUTILS_H

tests/auto/utils_stringutils/tst_stringutils.cpp

@@ -33,13 +33,30 @@
 
 //TESTED_COMPONENT=src/libs/utils
 
+class TestMacroExpander : public Utils::AbstractQtcMacroExpander
+{
+public:
+    virtual bool resolveMacro(const QString &name, QString *ret)
+    {
+        if (name == QLatin1String("a")) {
+            *ret = QLatin1String("hi");
+            return true;
+        }
+        return false;
+    }
+};
+
 class tst_StringUtils : public QObject
 {
     Q_OBJECT
 
 private slots:
     void testWithTildeHomePath();
+    void testMacroExpander_data();
+    void testMacroExpander();
 
+private:
+    TestMacroExpander mx;
 };
 
 void tst_StringUtils::testWithTildeHomePath()
@@ -73,6 +90,39 @@ void tst_StringUtils::testWithTildeHomePath()
 #endif
 }
 
+void tst_StringUtils::testMacroExpander_data()
+
+{
+    QTest::addColumn<QString>("in");
+    QTest::addColumn<QString>("out");
+
+    static const struct {
+        const char * const in;
+        const char * const out;
+    } vals[] = {
+        { "text", "text" },
+        { "%{a}", "hi" },
+        { "pre%{a}", "prehi" },
+        { "%{a}post", "hipost" },
+        { "pre%{a}post", "prehipost" },
+        { "%{a}%{a}", "hihi" },
+        { "%{a}text%{a}", "hitexthi" },
+    };
+
+    for (unsigned i = 0; i < sizeof(vals)/sizeof(vals[0]); i++)
+        QTest::newRow(vals[i].in) << QString::fromLatin1(vals[i].in)
+                                  << QString::fromLatin1(vals[i].out);
+}
+
+void tst_StringUtils::testMacroExpander()
+{
+    QFETCH(QString, in);
+    QFETCH(QString, out);
+
+    Utils::expandMacros(&in, &mx);
+    QCOMPARE(in, out);
+}
+
 QTEST_MAIN(tst_StringUtils)
 
 #include "tst_stringutils.moc"