1 files changed, 70 insertions, 0 deletions
diff --git a/src/linguist/lupdate/filesignificancecheck.cpp b/src/linguist/lupdate/filesignificancecheck.cpp
new file mode 100644
index 000000000..9babe6898
--- /dev/null
+++ b/src/linguist/lupdate/filesignificancecheck.cpp
@@ -0,0 +1,70 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+#include "filesignificancecheck.h"
+
+#include <mutex>
+
+QT_BEGIN_NAMESPACE
+
+FileSignificanceCheck *FileSignificanceCheck::m_instance = nullptr;
+
+void FileSignificanceCheck::setRootDirectories(const QStringList &paths)
+{
+    const size_t pathsSize = static_cast<size_t>(paths.size());
+    m_rootDirs.resize(pathsSize);
+    for (size_t i = 0; i < pathsSize; ++i)
+        m_rootDirs[i].setPath(paths.at(i));
+}
+
+void FileSignificanceCheck::setExclusionPatterns(const QStringList &patterns)
+{
+    const size_t patternsSize = static_cast<size_t>(patterns.size());
+    m_exclusionRegExes.resize(patternsSize);
+    for (size_t i = 0; i < patternsSize; ++i)
+        m_exclusionRegExes[i] = QRegularExpression::fromWildcard(patterns.at(i));
+}
+
+/*
+ * Return true if the given source file is significant for lupdate.
+ * A file is considered insignificant if
+ *   - it's not within any project root
+ *   - it's excluded
+ *
+ * This method is called from multiple threads.
+ * Results are cached.
+ */
+bool FileSignificanceCheck::isFileSignificant(const std::string &filePath) const
+{
+    // cache lookup
+    std::shared_lock<std::shared_mutex> readLock(m_cacheMutex);
+    auto it = m_cache.find(filePath);
+    if (it != m_cache.end())
+        return it->second;
+
+    // cache miss
+    readLock.unlock();
+    std::unique_lock<std::shared_mutex> writeLock(m_cacheMutex);
+    QString file = QString::fromUtf8(filePath);
+    QString cleanFile = QDir::cleanPath(file);
+    for (const QRegularExpression &rx : m_exclusionRegExes) {
+        if (rx.match(cleanFile).hasMatch()) {
+            m_cache.insert({filePath, false});
+            return false;
+        }
+    }
+
+    for (const QDir &rootDir : m_rootDirs) {
+        QString relativeFilePath = rootDir.relativeFilePath(file);
+        if (!relativeFilePath.startsWith(QLatin1String("../"))
+            && QFileInfo(relativeFilePath).isRelative()) {
+            m_cache.insert({filePath, true});
+            return true;
+        }
+    }
+
+    m_cache.insert({filePath, false});
+    return false;
+}
+
+QT_END_NAMESPACE