rcc: Add -d option to output a Makefile-syntax depfile

The -d option makes rcc output a dependency file with the specified
file name.

The resulting dependency file is useful for make or ninja based build
systems.

[ChangeLog][Tools][rcc] Added -d option to generate a dependency file.

Fixes: QTBUG-45460
Change-Id: I495ade50f8d9865d4c00dce9373b2b6d1a6c8f2f
Reviewed-by: Jörg Bornemann <joerg.bornemann@qt.io>

src/tools/rcc/main.cpp

@@ -99,6 +99,37 @@ int createProject(const QString &outFileName)
     return 0;
 }
 
+// Escapes a path for use in a Depfile (Makefile syntax)
+QString makefileEscape(const QString &filepath)
+{
+    // Always use forward slashes
+    QString result = QDir::cleanPath(filepath);
+    // Spaces are escaped with a backslash
+    result.replace(QLatin1Char(' '), QLatin1String("\\ "));
+    // Pipes are escaped with a backslash
+    result.replace(QLatin1Char('|'), QLatin1String("\\|"));
+    // Dollars are escaped with a dollar
+    result.replace(QLatin1Char('$'), QLatin1String("$$"));
+
+    return result;
+}
+
+void writeDepFile(QIODevice &iodev, const QStringList &depsList, const QString &targetName)
+{
+    QTextStream out(&iodev);
+    out << qPrintable(makefileEscape(targetName));
+    out << QLatin1Char(':');
+
+    // Write depfile
+    for (int i = 0; i < depsList.size(); ++i) {
+        out << QLatin1Char(' ');
+
+        out << qPrintable(makefileEscape(depsList.at(i)));
+    }
+
+    out << QLatin1Char('\n');
+}
+
 int runRcc(int argc, char *argv[])
 {
     QCoreApplication app(argc, argv);
@@ -176,6 +207,10 @@ int runRcc(int argc, char *argv[])
                                  QStringLiteral("Only output a mapping of resource paths to file system paths defined in the .qrc file, do not generate code."));
     parser.addOption(mapOption);
 
+    QCommandLineOption depFileOption(QStringList{QStringLiteral("d"), QStringLiteral("depfile")},
+                                     QStringLiteral("Write a depfile with the .qrc dependencies to <file>."), QStringLiteral("file"));
+    parser.addOption(depFileOption);
+
     QCommandLineOption projectOption(QStringLiteral("project"), QStringLiteral("Output a resource file containing all files from the current directory."));
     parser.addOption(projectOption);
 
@@ -266,6 +301,7 @@ int runRcc(int argc, char *argv[])
 
     QString outFilename = parser.value(outputOption);
     QString tempFilename = parser.value(tempOption);
+    QString depFilename = parser.value(depFileOption);
 
     if (projectRequested) {
         return createProject(outFilename);
@@ -352,6 +388,28 @@ int runRcc(int argc, char *argv[])
         return 0;
     }
 
+    // Write depfile
+    if (!depFilename.isEmpty()) {
+        QFile depout;
+        depout.setFileName(depFilename);
+
+        if (outFilename.isEmpty() || outFilename == QLatin1String("-")) {
+            const QString msg = QString::fromUtf8("Unable to write depfile when outputting to stdout!\n");
+            errorDevice.write(msg.toUtf8());
+            return 1;
+        }
+
+        if (!depout.open(QIODevice::WriteOnly | QIODevice::Text)) {
+            const QString msg = QString::fromUtf8("Unable to open depfile %1 for writing: %2\n")
+                    .arg(depout.fileName(), depout.errorString());
+            errorDevice.write(msg.toUtf8());
+            return 1;
+        }
+
+        writeDepFile(depout, library.dataFiles(), outFilename);
+        depout.close();
+    }
+
     QFile temp;
     if (!tempFilename.isEmpty()) {
         temp.setFileName(tempFilename);

tests/auto/tools/rcc/data/depfile/simple.d.expected

@@ -0,0 +1 @@
+simple.qrc.cpp: ../images/images/circle.png ../images/images/square.png

tests/auto/tools/rcc/data/depfile/simple.qrc

@@ -0,0 +1,6 @@
+<!DOCTYPE RCC><RCC version="1.0">
+<qresource>
+   <file>../images/images/circle.png</file>
+   <file>../images/images/square.png</file>
+</qresource>
+</RCC>

tests/auto/tools/rcc/data/depfile/specialchar$file.txt

@@ -0,0 +1 @@
+ABC

tests/auto/tools/rcc/data/depfile/specialchar.d.expected

@@ -0,0 +1 @@
+specialchar.qrc.cpp: specialchar$$file.txt ../images/images/subdir/triangle.png

tests/auto/tools/rcc/data/depfile/specialchar.qrc

@@ -0,0 +1,6 @@
+<!DOCTYPE RCC><RCC version="1.0">
+<qresource>
+   <file>../images/images/subdir/triangle.png</file>
+   <file>specialchar$file.txt</file>
+</qresource>
+</RCC>

tests/auto/tools/rcc/tst_rcc.cpp

@@ -89,6 +89,9 @@ private slots:
     void readback_data();
     void readback();
 
+    void depFileGeneration_data();
+    void depFileGeneration();
+
     void python();
 
     void cleanupTestCase();
@@ -416,6 +419,49 @@ void tst_rcc::readback()
     QCOMPARE(resourceData, fileSystemData);
 }
 
+void tst_rcc::depFileGeneration_data()
+{
+    QTest::addColumn<QString>("qrcfile");
+    QTest::addColumn<QString>("depfile");
+    QTest::addColumn<QString>("expected");
+
+    QTest::newRow("simple") << "simple.qrc" << "simple.d" << "simple.d.expected";
+    QTest::newRow("specialchar") << "specialchar.qrc" << "specialchar.d" << "specialchar.d.expected";
+}
+
+void tst_rcc::depFileGeneration()
+{
+    QFETCH(QString, qrcfile);
+    QFETCH(QString, depfile);
+    QFETCH(QString, expected);
+    const QString directory = m_dataPath + QLatin1String("/depfile");
+
+    QProcess process;
+    process.setWorkingDirectory(directory);
+    process.start(m_rcc, { "-d", depfile, "-o", qrcfile + ".cpp", qrcfile });
+    QVERIFY2(process.waitForStarted(), msgProcessStartFailed(process).constData());
+    if (!process.waitForFinished()) {
+        process.kill();
+        QFAIL(msgProcessTimeout(process).constData());
+    }
+    QVERIFY2(process.exitStatus() == QProcess::NormalExit,
+             msgProcessCrashed(process).constData());
+    QVERIFY2(process.exitCode() == 0,
+             msgProcessFailed(process).constData());
+
+    QFile depFileOutput(directory + QLatin1String("/") + depfile);
+    QVERIFY(depFileOutput.open(QIODevice::ReadOnly | QIODevice::Text));
+    QByteArray depFileData = depFileOutput.readAll();
+    depFileOutput.close();
+
+    QFile depFileExpected(directory + QLatin1String("/") + expected);
+    QVERIFY(depFileExpected.open(QIODevice::ReadOnly | QIODevice::Text));
+    QByteArray expectedData = depFileExpected.readAll();
+    depFileExpected.close();
+
+    QCOMPARE(depFileData, expectedData);
+}
+
 void tst_rcc::python()
 {
     const QString path = m_dataPath + QLatin1String("/sizes");
@@ -450,6 +496,8 @@ void tst_rcc::cleanupTestCase()
 {
     QDir dataDir(m_dataPath + QLatin1String("/binary"));
     QFileInfoList entries = dataDir.entryInfoList(QStringList() << QLatin1String("*.rcc"));
+    QDir dataDepDir(m_dataPath + QLatin1String("/depfile"));
+    entries += dataDepDir.entryInfoList({QLatin1String("*.d"), QLatin1String("*.qrc.cpp")});
     foreach (const QFileInfo &entry, entries)
         QFile::remove(entry.absoluteFilePath());
 }