support for id-based translations

unlike in an earlier attempt, ids are textual this time.

the developer is able to provide a template for the string. when lupdate
and lrelease are integrated into the build process, this makes it
possible to avoid a round-trip to a dedicated string designer during the
early development stage.

Requirement-id: QT-435

11 files changed, 267 insertions, 17 deletions

diff --git a/doc/src/snippets/code/src_corelib_global_qglobal.cpp b/doc/src/snippets/code/src_corelib_global_qglobal.cpp
index 287181a..50052c3 100644
--- a/doc/src/snippets/code/src_corelib_global_qglobal.cpp
+++ b/doc/src/snippets/code/src_corelib_global_qglobal.cpp
@@ -358,6 +358,30 @@ QString global_greeting(int type)
 //! [36]
 
 
+//! [qttrid]
+    //% "%n fooish bar(s) found.\n"
+    //% "Do you want to continue?"
+    QString text = qtTrId("qtn_foo_bar", n);
+//! [qttrid]
+
+
+//! [qttrid_noop]
+static const char * const ids[] = {
+    //% "This is the first text."
+    QT_TRID_NOOP("qtn_1st_text"),
+    //% "This is the second text."
+    QT_TRID_NOOP("qtn_2nd_text"),
+    0
+};
+
+void TheClass::addLabels()
+{
+    for (int i = 0; ids[i]; ++i)
+        new QLabel(qtTrId(ids[i]), this);
+}
+//! [qttrid_noop]
+
+
 //! [37]
 qWarning("%s: %s", qPrintable(key), qPrintable(value));
 //! [37]
diff --git a/src/corelib/global/qglobal.cpp b/src/corelib/global/qglobal.cpp
index f7a97e1..ad4868d 100644
--- a/src/corelib/global/qglobal.cpp
+++ b/src/corelib/global/qglobal.cpp
@@ -2459,6 +2459,62 @@ int qrand()
 */
 
 /*!
+    \fn QString qtTrId(const char *id, int n = -1)
+    \relates <QtGlobal>
+    \reentrant
+    \since 4.6
+
+    Returns a translated string identified by \a id.
+    If no matching string is found, the id itself is returned. This
+    should not happen under normal conditions.
+
+    If \a n >= 0, all occurrences of \c %n in the resulting string
+    are replaced with a decimal representation of \a n. In addition,
+    depending on \a n's value, the translation text may vary.
+
+    Meta data and comments can be passed as documented for QObject::tr().
+    In addition, it is possible to supply a source string template like that:
+
+    \tt{//% <C string>}
+
+    or
+
+    \tt{\begincomment% <C string> \endcomment}
+
+    Example:
+
+    \snippet doc/src/snippets/code/src_corelib_global_qglobal.cpp qttrid
+
+    Creating QM files suitable for use with this function requires passing
+    the \c -idbased option to the \c lrelease tool.
+
+    \warning This method is reentrant only if all translators are
+    installed \e before calling this method. Installing or removing
+    translators while performing translations is not supported. Doing
+    so will probably result in crashes or other undesirable behavior.
+
+    \sa QObject::tr(), QCoreApplication::translate(), {Internationalization with Qt}
+*/
+
+/*!
+    \macro QT_TRID_NOOP(id)
+    \relates <QtGlobal>
+    \since 4.6
+
+    Marks \a id for dynamic translation.
+    The only purpose of this macro is to provide an anchor for attaching
+    meta data like to qtTrId().
+
+    The macro expands to \a id.
+
+    Example:
+
+    \snippet doc/src/snippets/code/src_corelib_global_qglobal.cpp qttrid_noop
+
+    \sa qtTrId(), {Internationalization with Qt}
+*/
+
+/*!
     \macro QT_POINTER_SIZE
     \relates <QtGlobal>
 
diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index a522bcf..a139a55 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -2198,6 +2198,18 @@ inline const QForeachContainer<T> *qForeachContainer(const QForeachContainerBase
 #define QT_TRANSLATE_NOOP_UTF8(scope, x) (x)
 #define QT_TRANSLATE_NOOP3(scope, x, comment) {x, comment}
 #define QT_TRANSLATE_NOOP3_UTF8(scope, x, comment) {x, comment}
+
+#ifndef QT_NO_TRANSLATION // ### This should enclose the NOOPs above
+
+// Defined in qcoreapplication.cpp
+// The better name qTrId() is reserved for an upcoming function which would
+// return a much more powerful QStringFormatter instead of a QString.
+Q_CORE_EXPORT QString qtTrId(const char *id, int n = -1);
+
+#define QT_TRID_NOOP(id) id
+
+#endif // QT_NO_TRANSLATION
+
 #define QDOC_PROPERTY(text)
 
 /*
diff --git a/src/corelib/kernel/qcoreapplication.cpp b/src/corelib/kernel/qcoreapplication.cpp
index e2708c3..054be70 100644
--- a/src/corelib/kernel/qcoreapplication.cpp
+++ b/src/corelib/kernel/qcoreapplication.cpp
@@ -1675,6 +1675,12 @@ QString QCoreApplication::translate(const char *context, const char *sourceText,
     return result;
 }
 
+// Declared in qglobal.h
+QString qtTrId(const char *id, int n)
+{
+    return QCoreApplication::translate(0, id, 0, QCoreApplication::UnicodeUTF8, n);
+}
+
 bool QCoreApplicationPrivate::isTranslatorInstalled(QTranslator *translator)
 {
     return QCoreApplication::self
diff --git a/tests/auto/linguist/lrelease/tst_lrelease.cpp b/tests/auto/linguist/lrelease/tst_lrelease.cpp
index 512987d..ff90b3c 100644
--- a/tests/auto/linguist/lrelease/tst_lrelease.cpp
+++ b/tests/auto/linguist/lrelease/tst_lrelease.cpp
@@ -55,6 +55,7 @@ private slots:
     void translate();
     void mixedcodecs();
     void compressed();
+    void idbased();
     void dupes();
 
 private:
@@ -191,6 +192,18 @@ void tst_lrelease::compressed()
 
 }
 
+void tst_lrelease::idbased()
+{
+    QVERIFY(!QProcess::execute("lrelease -idbased testdata/idbased.ts"));
+
+    QTranslator translator;
+    QVERIFY(translator.load("testdata/idbased.qm"));
+    qApp->installTranslator(&translator);
+
+    QCOMPARE(qtTrId("test_id"), QString::fromAscii("This is a test string."));
+    QCOMPARE(qtTrId("untranslated_id"), QString::fromAscii("This has no translation."));
+}
+
 void tst_lrelease::dupes()
 {
     QProcess proc;
diff --git a/tests/auto/linguist/lupdate/testdata/good/parsecpp/main.cpp b/tests/auto/linguist/lupdate/testdata/good/parsecpp/main.cpp
index 9fb43fe..735e4cd 100644
--- a/tests/auto/linguist/lupdate/testdata/good/parsecpp/main.cpp
+++ b/tests/auto/linguist/lupdate/testdata/good/parsecpp/main.cpp
@@ -175,3 +175,15 @@ class TestingTake17 : QObject {
         tr("even more cool");
     }
 };
+
+
+
+
+//: again an extra comment, this time for id-based NOOP
+//% "This is supposed\tto be quoted \" newline\n"
+//% "backslashed \\ stuff."
+QT_TRID_NOOP("this_a_id")
+
+//~ some thing
+//% "This needs to be here. Really."
+QString test = qtTrId("this_another_id", n);
diff --git a/tests/auto/linguist/lupdate/testdata/good/parsecpp/project.ts.result b/tests/auto/linguist/lupdate/testdata/good/parsecpp/project.ts.result
index 5bd7525..97d3bce 100644
--- a/tests/auto/linguist/lupdate/testdata/good/parsecpp/project.ts.result
+++ b/tests/auto/linguist/lupdate/testdata/good/parsecpp/project.ts.result
@@ -2,6 +2,24 @@
 <!DOCTYPE TS>
 <TS version="2.0">
 <context>
+    <name></name>
+    <message id="this_a_id">
+        <location filename="main.cpp" line="185"/>
+        <source>This is supposed	to be quoted &quot; newline
+backslashed \ stuff.</source>
+        <extracomment>again an extra comment, this time for id-based NOOP</extracomment>
+        <translation type="unfinished"></translation>
+    </message>
+    <message id="this_another_id" numerus="yes">
+        <location filename="main.cpp" line="189"/>
+        <source>This needs to be here. Really.</source>
+        <translation type="unfinished">
+            <numerusform></numerusform>
+        </translation>
+        <extra-some>thing</extra-some>
+    </message>
+</context>
+<context>
     <name>Dialog2</name>
     <message numerus="yes">
         <location filename="main.cpp" line="29"/>
diff --git a/tools/linguist/lrelease/main.cpp b/tools/linguist/lrelease/main.cpp
index 86b7866..5fbecac 100644
--- a/tools/linguist/lrelease/main.cpp
+++ b/tools/linguist/lrelease/main.cpp
@@ -70,6 +70,8 @@ static void printUsage()
         "format into the 'compiled' .qm format used by QTranslator objects.\n\n"
         "Options:\n"
         "    -help  Display this information and exit\n"
+        "    -idbased\n"
+        "           Use IDs instead of source strings for message keying\n"
         "    -compress\n"
         "           Compress the .qm files\n"
         "    -nounfinished\n"
@@ -99,7 +101,7 @@ static bool loadTsFile(Translator &tor, const QString &tsFileName, bool /* verbo
 
 static bool releaseTranslator(Translator &tor, const QString &qmFileName,
     bool verbose, bool ignoreUnfinished,
-    bool removeIdentical, TranslatorSaveMode mode)
+    bool removeIdentical, bool idBased, TranslatorSaveMode mode)
 {
     Translator::reportDuplicates(tor.resolveDuplicates(), qmFileName, verbose);
 
@@ -121,6 +123,7 @@ static bool releaseTranslator(Translator &tor, const QString &qmFileName,
     ConversionData cd;
     cd.m_verbose = verbose;
     cd.m_ignoreUnfinished = ignoreUnfinished;
+    cd.m_idBased = idBased;
     cd.m_saveMode = mode;
     bool ok = tor.release(&file, cd);
     file.close();
@@ -136,7 +139,7 @@ static bool releaseTranslator(Translator &tor, const QString &qmFileName,
 }
 
 static bool releaseTsFile(const QString& tsFileName, bool verbose,
-    bool ignoreUnfinished, bool removeIdentical, TranslatorSaveMode mode)
+    bool ignoreUnfinished, bool removeIdentical, bool idBased, TranslatorSaveMode mode)
 {
     Translator tor;
     if (!loadTsFile(tor, tsFileName, verbose))
@@ -151,7 +154,7 @@ static bool releaseTsFile(const QString& tsFileName, bool verbose,
     }
     qmFileName += QLatin1String(".qm");
 
-    return releaseTranslator(tor, qmFileName, verbose, ignoreUnfinished, removeIdentical, mode);
+    return releaseTranslator(tor, qmFileName, verbose, ignoreUnfinished, removeIdentical, idBased, mode);
 }
 
 int main(int argc, char **argv)
@@ -164,6 +167,7 @@ int main(int argc, char **argv)
 
     bool verbose = true; // the default is true starting with Qt 4.2
     bool ignoreUnfinished = false;
+    bool idBased = false;
     // the default mode is SaveEverything starting with Qt 4.2
     TranslatorSaveMode mode = SaveEverything;
     bool removeIdentical = false;
@@ -175,6 +179,9 @@ int main(int argc, char **argv)
         if (args[i] == QLatin1String("-compress")) {
             mode = SaveStripped;
             continue;
+        } else if (args[i] == QLatin1String("-idbased")) {
+            idBased = true;
+            continue;
         } else if (args[i] == QLatin1String("-nocompress")) {
             mode = SaveEverything;
             continue;
@@ -232,7 +239,7 @@ int main(int argc, char **argv)
                              qPrintable(args[i]));
                 } else {
                     foreach (const QString &trans, translations)
-                        if (!releaseTsFile(trans, verbose, ignoreUnfinished, removeIdentical, mode))
+                        if (!releaseTsFile(trans, verbose, ignoreUnfinished, removeIdentical, idBased, mode))
                             return 1;
                 }
             } else {
@@ -243,7 +250,7 @@ int main(int argc, char **argv)
             }
         } else {
             if (outputFile.isEmpty()) {
-                if (!releaseTsFile(args[i], verbose, ignoreUnfinished, removeIdentical, mode))
+                if (!releaseTsFile(args[i], verbose, ignoreUnfinished, removeIdentical, idBased, mode))
                     return 1;
             } else {
                 if (!loadTsFile(tor, args[i], verbose))
@@ -254,7 +261,7 @@ int main(int argc, char **argv)
 
     if (!outputFile.isEmpty())
         return releaseTranslator(tor, outputFile, verbose, ignoreUnfinished,
-                                 removeIdentical, mode) ? 0 : 1;
+                                 removeIdentical, idBased, mode) ? 0 : 1;
 
     return 0;
 }
diff --git a/tools/linguist/lupdate/cpp.cpp b/tools/linguist/lupdate/cpp.cpp
index 35b41d4..58e094b 100644
--- a/tools/linguist/lupdate/cpp.cpp
+++ b/tools/linguist/lupdate/cpp.cpp
@@ -199,7 +199,7 @@ private:
 
     enum {
         Tok_Eof, Tok_class, Tok_friend, Tok_namespace, Tok_using, Tok_return,
-        Tok_tr = 10, Tok_trUtf8, Tok_translate, Tok_translateUtf8,
+        Tok_tr = 10, Tok_trUtf8, Tok_translate, Tok_translateUtf8, Tok_trid,
         Tok_Q_OBJECT = 20, Tok_Q_DECLARE_TR_FUNCTIONS,
         Tok_Ident, Tok_Comment, Tok_String, Tok_Arrow, Tok_Colon, Tok_ColonColon,
         Tok_Equals,
@@ -553,6 +553,8 @@ uint CppParser::getToken()
                     return Tok_Q_DECLARE_TR_FUNCTIONS;
                 if (yyIdent == QLatin1String("QT_TR_NOOP"))
                     return Tok_tr;
+                if (yyIdent == QLatin1String("QT_TRID_NOOP"))
+                    return Tok_trid;
                 if (yyIdent == QLatin1String("QT_TRANSLATE_NOOP"))
                     return Tok_translate;
                 if (yyIdent == QLatin1String("QT_TRANSLATE_NOOP3"))
@@ -588,6 +590,10 @@ uint CppParser::getToken()
                 if (yyIdent == QLatin1String("namespace"))
                     return Tok_namespace;
                 break;
+            case 'q':
+                if (yyIdent == QLatin1String("qtTrId"))
+                    return Tok_trid;
+                break;
             case 'r':
                 if (yyIdent == QLatin1String("return"))
                     return Tok_return;
@@ -1328,6 +1334,7 @@ void CppParser::parseInternal(ConversionData &cd, QSet<QString> &inclusions)
     QString comment;
     QString extracomment;
     QString msgid;
+    QString sourcetext;
     TranslatorMessage::ExtraData extra;
     QString prefix;
 #ifdef DIAGNOSE_RETRANSLATABILITY
@@ -1514,6 +1521,9 @@ void CppParser::parseInternal(ConversionData &cd, QSet<QString> &inclusions)
         case Tok_trUtf8:
             if (!results->tor)
                 goto case_default;
+            if (!sourcetext.isEmpty())
+                qWarning("%s:%d: //%% cannot be used with tr() / QT_TR_NOOP(). Ignoring\n",
+                         qPrintable(yyFileName), yyLineNo);
             utf8 = (yyTok == Tok_trUtf8);
             line = yyLineNo;
             yyTok = getToken();
@@ -1611,6 +1621,9 @@ void CppParser::parseInternal(ConversionData &cd, QSet<QString> &inclusions)
         case Tok_translate:
             if (!results->tor)
                 goto case_default;
+            if (!sourcetext.isEmpty())
+                qWarning("%s:%d: //%% cannot be used with translate() / QT_TRANSLATE_NOOP(). Ignoring\n",
+                         qPrintable(yyFileName), yyLineNo);
             utf8 = (yyTok == Tok_translateUtf8);
             line = yyLineNo;
             yyTok = getToken();
@@ -1660,6 +1673,27 @@ void CppParser::parseInternal(ConversionData &cd, QSet<QString> &inclusions)
             msgid.clear();
             extra.clear();
             break;
+        case Tok_trid:
+            if (!results->tor)
+                goto case_default;
+            if (!sourcetext.isEmpty()) {
+                if (!msgid.isEmpty())
+                    qWarning("%s:%d: //= cannot be used with qtTrId() / QT_TRID_NOOP(). Ignoring\n",
+                             qPrintable(yyFileName), yyLineNo);
+                //utf8 = false; // Maybe use //%% or something like that
+                line = yyLineNo;
+                yyTok = getToken();
+                if (match(Tok_LeftParen) && matchString(&msgid) && !msgid.isEmpty()) {
+                    bool plural = match(Tok_Comma);
+                    recordMessage(line, QString(), sourcetext, QString(), extracomment,
+                                  msgid, extra, false, plural);
+                }
+                sourcetext.clear();
+            }
+            extracomment.clear();
+            msgid.clear();
+            extra.clear();
+            break;
         case Tok_Q_DECLARE_TR_FUNCTIONS:
         case Tok_Q_OBJECT:
             namespaces.last()->hasTrFunctions = true;
@@ -1689,6 +1723,40 @@ void CppParser::parseInternal(ConversionData &cd, QSet<QString> &inclusions)
                 int k = yyComment.indexOf(QLatin1Char(' '));
                 if (k > -1)
                     extra.insert(yyComment.left(k), yyComment.mid(k + 1).trimmed());
+            } else if (yyComment.startsWith(QLatin1Char('%'))) {
+                int p = 1, c;
+                forever {
+                    if (p >= yyComment.length())
+                        break;
+                    c = yyComment.unicode()[p++].unicode();
+                    if (isspace(c))
+                        continue;
+                    if (c != '"') {
+                        qWarning("%s:%d: Unexpected character in meta string\n",
+                                 qPrintable(yyFileName), yyLineNo);
+                        break;
+                    }
+                    forever {
+                        if (p >= yyComment.length()) {
+                          whoops:
+                            qWarning("%s:%d: Unterminated meta string\n",
+                                     qPrintable(yyFileName), yyLineNo);
+                            break;
+                        }
+                        c = yyComment.unicode()[p++].unicode();
+                        if (c == '"')
+                            break;
+                        if (c == '\\') {
+                            if (p >= yyComment.length())
+                                goto whoops;
+                            c = yyComment.unicode()[p++].unicode();
+                            if (c == '\n')
+                                goto whoops;
+                            sourcetext.append(QLatin1Char('\\'));
+                        }
+                        sourcetext.append(c);
+                    }
+                }
             } else {
                 comment = yyComment.simplified();
                 if (comment.startsWith(QLatin1String(MagicComment))) {
diff --git a/tools/linguist/shared/qm.cpp b/tools/linguist/shared/qm.cpp
index ec61cb6..05d8e12 100644
--- a/tools/linguist/shared/qm.cpp
+++ b/tools/linguist/shared/qm.cpp
@@ -173,6 +173,7 @@ public:
     bool save(QIODevice *iod);
 
     void insert(const TranslatorMessage &msg, bool forceComment);
+    void insertIdBased(const TranslatorMessage &message);
 
     void squeeze(TranslatorSaveMode mode);
 
@@ -436,6 +437,16 @@ void Releaser::insert(const TranslatorMessage &message, bool forceComment)
         insertInternal(message, forceComment, false);
 }
 
+void Releaser::insertIdBased(const TranslatorMessage &message)
+{
+    QStringList tlns = message.translations();
+    for (int i = 0; i < tlns.size(); ++i)
+        if (tlns.at(i).isEmpty())
+            tlns[i] = message.sourceText();
+    ByteTranslatorMessage bmsg("", originalBytes(message.id(), false), "", tlns);
+    m_messages.insert(bmsg, 0);
+}
+
 void Releaser::setNumerusRules(const QByteArray &rules)
 {
     m_numerusRules = rules;
@@ -689,11 +700,17 @@ static bool saveQM(const Translator &translator, QIODevice &dev, ConversionData
     int finished = 0;
     int unfinished = 0;
     int untranslated = 0;
+    int missingIds = 0;
+    int droppedData = 0;
 
     for (int i = 0; i != translator.messageCount(); ++i) {
         const TranslatorMessage &msg = translator.message(i);
         TranslatorMessage::Type typ = msg.type();
         if (typ != TranslatorMessage::Obsolete) {
+            if (cd.m_idBased && msg.id().isEmpty()) {
+                ++missingIds;
+                continue;
+            }
             if (typ == TranslatorMessage::Unfinished) {
                 if (msg.translation().isEmpty()) {
                     ++untranslated;
@@ -706,19 +723,34 @@ static bool saveQM(const Translator &translator, QIODevice &dev, ConversionData
             } else {
                 ++finished;
             }
-            // Drop the comment in (context, sourceText, comment),
-            // unless the context is empty,
-            // unless (context, sourceText, "") already exists or
-            // unless we already dropped the comment of (context,
-            // sourceText, comment0).
-            bool forceComment =
-                    msg.comment().isEmpty()
-                    || msg.context().isEmpty()
-                    || translator.contains(msg.context(), msg.sourceText(), QString());
-            releaser.insert(msg, forceComment);
+            if (cd.m_idBased) {
+                if (!msg.context().isEmpty() || !msg.comment().isEmpty())
+                    ++droppedData;
+                releaser.insertIdBased(msg);
+            } else {
+                // Drop the comment in (context, sourceText, comment),
+                // unless the context is empty,
+                // unless (context, sourceText, "") already exists or
+                // unless we already dropped the comment of (context,
+                // sourceText, comment0).
+                bool forceComment =
+                        msg.comment().isEmpty()
+                        || msg.context().isEmpty()
+                        || translator.contains(msg.context(), msg.sourceText(), QString());
+                releaser.insert(msg, forceComment);
+            }
         }
     }
 
+    if (missingIds)
+        cd.appendError(QCoreApplication::translate("LRelease",
+            "Dropped %n message(s) which had no ID.", 0,
+            QCoreApplication::CodecForTr, missingIds));
+    if (droppedData)
+        cd.appendError(QCoreApplication::translate("LRelease",
+            "Excess context/disambiguation dropped from %n message(s).", 0,
+            QCoreApplication::CodecForTr, droppedData));
+
     releaser.squeeze(cd.m_saveMode);
     bool saved = releaser.save(&dev);
     if (saved && cd.isVerbose()) {
diff --git a/tools/linguist/shared/translator.h b/tools/linguist/shared/translator.h
index ac824f3..fb17fd1 100644
--- a/tools/linguist/shared/translator.h
+++ b/tools/linguist/shared/translator.h
@@ -65,6 +65,7 @@ public:
         m_ignoreUnfinished(false),
         m_sortContexts(false),
         m_noUiLines(false),
+        m_idBased(false),
         m_saveMode(SaveEverything)
     {}
 
@@ -97,6 +98,7 @@ public:
     bool m_ignoreUnfinished;
     bool m_sortContexts;
     bool m_noUiLines;
+    bool m_idBased;
     TranslatorSaveMode m_saveMode;
 };