Utils: FsEngine micro-optimizations

Mostly for shorter code, but also save a few cycles due to less
string construction and run time dispatch.

Also, make testFilePathFromToString() test two paths instead one path
twice.

Change-Id: I50a3145bca1a4b262a15e96173ea7ebd9cb678ad
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>
Reviewed-by: hjk <hjk@qt.io>

5 files changed, 33 insertions, 42 deletions

diff --git a/src/libs/utils/filepath.cpp b/src/libs/utils/filepath.cpp
index dcf1ff6d07..57cafaba17 100644
--- a/src/libs/utils/filepath.cpp
+++ b/src/libs/utils/filepath.cpp
@@ -200,8 +200,8 @@ QString FilePath::toString() const
         return path();
 
     if (isRelativePath())
-        return scheme() + "://" + encodedHost() + "/./" + path();
-    return scheme() + "://" + encodedHost() +  path();
+        return scheme() + "://" + encodedHost() + "/./" + pathView();
+    return scheme() + "://" + encodedHost() + pathView();
 }
 
 QString FilePath::toFSPathString() const
@@ -210,8 +210,8 @@ QString FilePath::toFSPathString() const
         return path();
 
     if (isRelativePath())
-        return specialPath(SpecialPathComponent::RootPath) + "/" + scheme() + "/" + encodedHost() + "/./" + path();
-    return specialPath(SpecialPathComponent::RootPath) + "/" + scheme() + "/" + encodedHost() +  path();
+        return specialRootPath() + '/' + scheme() + '/' + encodedHost() + "/./" + pathView();
+    return specialRootPath() + '/' + scheme() + '/' + encodedHost() + pathView();
 }
 
 QUrl FilePath::toUrl() const
@@ -710,25 +710,28 @@ FilePath FilePath::absoluteFilePath() const
     return FilePath::currentWorkingPath().resolvePath(*this);
 }
 
-QString FilePath::specialPath(SpecialPathComponent component)
+const QString &FilePath::specialRootName()
 {
-    switch (component) {
-    case SpecialPathComponent::RootName:
-        return QLatin1String("__qtc_devices__");
-    case SpecialPathComponent::RootPath:
-        return (QDir::rootPath() + "__qtc_devices__");
-    case SpecialPathComponent::DeviceRootName:
-        return QLatin1String("device");
-    case SpecialPathComponent::DeviceRootPath:
-        return QDir::rootPath() + "__qtc_devices__/device";
-    }
+    static const QString rootName = "__qtc_devices__";
+    return rootName;
+}
+
+const QString &FilePath::specialRootPath()
+{
+    static const QString rootPath = QDir::rootPath() + u"__qtc_devices__";
+    return rootPath;
+}
 
-    QTC_ASSERT(false, return {});
+const QString &FilePath::specialDeviceRootName()
+{
+    static const QString deviceRootName = "device";
+    return deviceRootName;
 }
 
-FilePath FilePath::specialFilePath(SpecialPathComponent component)
+const QString &FilePath::specialDeviceRootPath()
 {
-    return FilePath::fromString(specialPath(component));
+    static const QString deviceRootPath =  QDir::rootPath() + u"__qtc_devices__/device";
+    return deviceRootPath;
 }
 
 FilePath FilePath::normalizedPathName() const
diff --git a/src/libs/utils/filepath.h b/src/libs/utils/filepath.h
index c91403b5f7..cf9cf2cf1b 100644
--- a/src/libs/utils/filepath.h
+++ b/src/libs/utils/filepath.h
@@ -223,15 +223,10 @@ public:
     [[nodiscard]] static FilePath fromFileInfo(const QFileInfo &info);
 
     // Support for FSEngine. Do not use unless needed.
-    enum class SpecialPathComponent {
-        RootName,
-        RootPath,
-        DeviceRootName,
-        DeviceRootPath,
-    };
-
-    [[nodiscard]] static QString specialPath(SpecialPathComponent component);
-    [[nodiscard]] static FilePath specialFilePath(SpecialPathComponent component);
+    [[nodiscard]] static const QString &specialRootName();
+    [[nodiscard]] static const QString &specialRootPath();
+    [[nodiscard]] static const QString &specialDeviceRootName();
+    [[nodiscard]] static const QString &specialDeviceRootPath();
 
     [[nodiscard]] bool ensureReachable(const FilePath &other) const;
 
diff --git a/src/libs/utils/fsengine/fileiconprovider.cpp b/src/libs/utils/fsengine/fileiconprovider.cpp
index 12ca91e2a2..33762b0e36 100644
--- a/src/libs/utils/fsengine/fileiconprovider.cpp
+++ b/src/libs/utils/fsengine/fileiconprovider.cpp
@@ -174,8 +174,7 @@ QIcon FileIconProviderImplementation::icon(const QFileInfo &fi) const
         return unknownFileIcon();
 
     // Check if its one of the virtual devices directories
-    if (filePath.path().startsWith(
-            FilePath::specialPath(FilePath::SpecialPathComponent::RootPath))) {
+    if (filePath.path().startsWith(FilePath::specialRootPath())) {
         // If the filepath does not need a device, it is a virtual device directory
         if (!filePath.needsDevice())
             return dirIcon();
@@ -221,7 +220,7 @@ QIcon FileIconProviderImplementation::icon(const FilePath &filePath) const
         return unknownFileIcon();
 
     // Check if its one of the virtual devices directories
-    if (filePath.path().startsWith(FilePath::specialPath(FilePath::SpecialPathComponent::RootPath))) {
+    if (filePath.path().startsWith(FilePath::specialRootPath())) {
         // If the filepath does not need a device, it is a virtual device directory
         if (!filePath.needsDevice())
             return dirIcon();
diff --git a/src/libs/utils/fsengine/fileiteratordevicesappender.h b/src/libs/utils/fsengine/fileiteratordevicesappender.h
index fbbd57ded8..b270bed150 100644
--- a/src/libs/utils/fsengine/fileiteratordevicesappender.h
+++ b/src/libs/utils/fsengine/fileiteratordevicesappender.h
@@ -74,7 +74,7 @@ public:
     QString currentFileName() const override
     {
         if (m_status == State::Ended)
-            return FilePath::specialPath(FilePath::SpecialPathComponent::RootPath);
+            return FilePath::specialRootPath();
 
         setPath();
         checkStatus();
@@ -83,7 +83,7 @@ public:
     QFileInfo currentFileInfo() const override
     {
         if (m_status == State::Ended)
-            return QFileInfo(FilePath::specialPath(FilePath::SpecialPathComponent::RootPath));
+            return QFileInfo(FilePath::specialRootPath());
         setPath();
         checkStatus();
         return m_baseIterator->currentFileInfo();
diff --git a/src/libs/utils/fsengine/fsenginehandler.cpp b/src/libs/utils/fsengine/fsenginehandler.cpp
index 36cd0950ad..6bada88279 100644
--- a/src/libs/utils/fsengine/fsenginehandler.cpp
+++ b/src/libs/utils/fsengine/fsenginehandler.cpp
@@ -11,19 +11,15 @@
 
 #include "../algorithm.h"
 
-namespace Utils {
-
-namespace Internal {
+namespace Utils::Internal {
 
 QAbstractFileEngine *FSEngineHandler::create(const QString &fileName) const
 {
     if (fileName.startsWith(':'))
         return nullptr;
 
-    static const QString rootPath =
-        FilePath::specialPath(FilePath::SpecialPathComponent::RootPath);
-    static const FilePath rootFilePath =
-        FilePath::specialFilePath(FilePath::SpecialPathComponent::RootPath);
+    static const QString rootPath = FilePath::specialRootPath();
+    static const FilePath rootFilePath = FilePath::fromString(rootPath);
 
     const QString fixedFileName = QDir::cleanPath(fileName);
 
@@ -60,6 +56,4 @@ QAbstractFileEngine *FSEngineHandler::create(const QString &fileName) const
     return nullptr;
 }
 
-} // namespace Internal
-
-} // namespace Utils
+} // Utils::Internal