QMimeDatabase: fix detection of pattern conflict in different prefixes

Installing a second mimetype with *.txt as glob had a different
effect depending on whether it was installed into the same prefix
or a different prefix as the one where text/plain is installed.

Change-Id: I7f54b8efe22f620eb57257745c48fe5402c87626
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit 1b39e61a775d70ee96287e9f0e418cb5741e6638)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/corelib/mimetypes/qmimeprovider.cpp

@@ -213,22 +213,25 @@ void QMimeBinaryProvider::addFileNameMatches(const QString &fileName, QMimeGlobM
         return;
     Q_ASSERT(m_cacheFile);
     const QString lowerFileName = fileName.toLower();
+    int numMatches = 0;
     // Check literals (e.g. "Makefile")
-    matchGlobList(result, m_cacheFile.get(), m_cacheFile->getUint32(PosLiteralListOffset),
+    numMatches = matchGlobList(result, m_cacheFile.get(),
-                  fileName);
+                               m_cacheFile->getUint32(PosLiteralListOffset), fileName);
     // Check the very common *.txt cases with the suffix tree
-    if (result.m_matchingMimeTypes.isEmpty()) {
+    if (numMatches == 0) {
         const int reverseSuffixTreeOffset = m_cacheFile->getUint32(PosReverseSuffixTreeOffset);
         const int numRoots = m_cacheFile->getUint32(reverseSuffixTreeOffset);
         const int firstRootOffset = m_cacheFile->getUint32(reverseSuffixTreeOffset + 4);
-        matchSuffixTree(result, m_cacheFile.get(), numRoots, firstRootOffset, lowerFileName,
+        if (matchSuffixTree(result, m_cacheFile.get(), numRoots, firstRootOffset, lowerFileName,
-                        lowerFileName.size() - 1, false);
+                            lowerFileName.size() - 1, false)) {
-        if (result.m_matchingMimeTypes.isEmpty())
+            ++numMatches;
-            matchSuffixTree(result, m_cacheFile.get(), numRoots, firstRootOffset, fileName,
+        } else if (matchSuffixTree(result, m_cacheFile.get(), numRoots, firstRootOffset, fileName,
-                            fileName.size() - 1, true);
+                                   fileName.size() - 1, true)) {
+            ++numMatches;
+        }
     }
     // Check complex globs (e.g. "callgrind.out[0-9]*" or "README*")
-    if (result.m_matchingMimeTypes.isEmpty())
+    if (numMatches == 0)
         matchGlobList(result, m_cacheFile.get(), m_cacheFile->getUint32(PosGlobListOffset),
                       fileName);
 }
@@ -244,8 +247,10 @@ void QMimeBinaryProvider::excludeMimeTypeGlobs(const QStringList &toExclude)
         appendIfNew(m_mimeTypesWithExcludedGlobs, mt);
 }
 
-void QMimeBinaryProvider::matchGlobList(QMimeGlobMatchResult &result, CacheFile *cacheFile, int off, const QString &fileName)
+int QMimeBinaryProvider::matchGlobList(QMimeGlobMatchResult &result, CacheFile *cacheFile, int off,
+                                       const QString &fileName)
 {
+    int numMatches = 0;
     const int numGlobs = cacheFile->getUint32(off);
     //qDebug() << "Loading" << numGlobs << "globs from" << cacheFile->file.fileName() << "at offset" << cacheFile->globListOffset;
     for (int i = 0; i < numGlobs; ++i) {
@@ -263,9 +268,12 @@ void QMimeBinaryProvider::matchGlobList(QMimeGlobMatchResult &result, CacheFile
             continue;
 
         QMimeGlobPattern glob(pattern, QString() /*unused*/, weight, qtCaseSensitive);
-        if (glob.matchFileName(fileName))
+        if (glob.matchFileName(fileName)) {
             result.addMatch(QLatin1StringView(mimeType), weight, pattern);
+            ++numMatches;
+        }
     }
+    return numMatches;
 }
 
 bool QMimeBinaryProvider::matchSuffixTree(QMimeGlobMatchResult &result,

src/corelib/mimetypes/qmimeprovider_p.h

@@ -111,7 +111,8 @@ public:
 private:
     struct CacheFile;
 
-    void matchGlobList(QMimeGlobMatchResult &result, CacheFile *cacheFile, int offset, const QString &fileName);
+    int matchGlobList(QMimeGlobMatchResult &result, CacheFile *cacheFile, int offset,
+                      const QString &fileName);
     bool matchSuffixTree(QMimeGlobMatchResult &result, CacheFile *cacheFile, int numEntries,
                          int firstOffset, const QString &fileName, qsizetype charPos,
                          bool caseSensitiveCheck);

tests/auto/corelib/mimetypes/qmimedatabase/qmimedatabase-cache/CMakeLists.txt

@@ -32,6 +32,7 @@ set(testdata_resource_files
     "../qml-again.xml"
     "../test.qml"
     "../text-x-objcsrc.xml"
+    "../text-plain-subclass.xml"
     "../yast2-metapackage-handler-mimetypes.xml"
 )
 

tests/auto/corelib/mimetypes/qmimedatabase/qmimedatabase-xml/CMakeLists.txt

@@ -32,6 +32,7 @@ set(testdata_resource_files
     "../qml-again.xml"
     "../test.qml"
     "../text-x-objcsrc.xml"
+    "../text-plain-subclass.xml"
     "../yast2-metapackage-handler-mimetypes.xml"
 )
 

tests/auto/corelib/mimetypes/qmimedatabase/text-plain-subclass.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<mime-info xmlns='http://www.freedesktop.org/standards/shared-mime-info'>
+    <mime-type type="text/x-microdvd">
+        <comment>MicroDVD subtitles</comment>
+        <sub-class-of type="text/plain"/>
+        <magic priority="50">
+            <match type="string" value="{1}" offset="0"/>
+            <match type="string" value="{0}" offset="0"/>
+            <match type="string" value="}{" offset="0:6"/>
+        </magic>
+        <generic-icon name="text-x-generic"/>
+        <glob pattern="*.sub"/>
+        <glob pattern="*.txt"/>
+    </mime-type>
+</mime-info>

tests/auto/corelib/mimetypes/qmimedatabase/tst_qmimedatabase.cpp

@@ -30,16 +30,15 @@
 
 using namespace Qt::StringLiterals;
 
-static const char *const additionalMimeFiles[] = {
+static const char *const additionalMimeFiles[] = { "yast2-metapackage-handler-mimetypes.xml",
-    "yast2-metapackage-handler-mimetypes.xml",
+                                                   "qml-again.xml",
-    "qml-again.xml",
+                                                   "text-x-objcsrc.xml",
-    "text-x-objcsrc.xml",
+                                                   "text-plain-subclass.xml",
-    "invalid-magic1.xml",
+                                                   "invalid-magic1.xml",
-    "invalid-magic2.xml",
+                                                   "invalid-magic2.xml",
-    "invalid-magic3.xml",
+                                                   "invalid-magic3.xml",
-    "magic-and-hierarchy.xml",
+                                                   "magic-and-hierarchy.xml",
-    0
+                                                   0 };
-};
 
 static const auto s_resourcePrefix = ":/qt-project.org/qmime/"_L1;
 static const auto s_inodeMimetype = "inode/directory"_L1;
@@ -1196,6 +1195,8 @@ void tst_QMimeDatabase::installNewLocalMimeType()
         QVERIFY(objcsrc.isValid());
         QCOMPARE(objcsrc.globPatterns(), QStringList());
     }
+    QCOMPARE(db.mimeTypeForFile(QLatin1String("foo.txt"), QMimeDatabase::MatchExtension).name(),
+             QString::fromLatin1("text/plain"));
 
     // Test that a double-definition of a mimetype doesn't lead to sniffing ("conflicting globs").
     const QString qmlTestFile = s_resourcePrefix + "test.qml"_L1;