Utils: Consolidate the isRelative/isAbsolute implementations

Even if we do it wrong in corner cases, we should do it consistently.

Change-Id: I68d5a6e55ede889cb44bedb46d0ea545dae7ba2c
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/libs/utils/filepath.cpp

@@ -625,7 +625,7 @@ FilePath FilePath::withExecutableSuffix() const
 
 static bool startsWithWindowsDriveLetterAndSlash(QStringView path)
 {
-    return path.size() > 2 && (path[1] == ':' && path[2] == '/' && isWindowsDriveLetter(path[0]));
+    return path.size() > 2 && path[1] == ':' && path[2] == '/' && isWindowsDriveLetter(path[0]);
 }
 
 int FilePath::rootLength(const QStringView path)
@@ -1533,7 +1533,7 @@ bool FilePath::isRelativePath() const
     const QStringView p = pathView();
     if (p.startsWith('/'))
         return false;
-    if (p.size() > 1 && isWindowsDriveLetter(p[0]) && p.at(1) == ':')
+    if (startsWithWindowsDriveLetterAndSlash(p))
         return false;
     if (p.startsWith(u":/")) // QRC
         return false;

src/libs/utils/fileutils.cpp

@@ -758,27 +758,6 @@ QString FileUtils::normalizedPathName(const QString &name)
 #endif
 }
 
-bool isRelativePathHelper(const QString &path, OsType osType)
-{
-    if (path.startsWith('/'))
-        return false;
-    if (osType == OsType::OsTypeWindows) {
-        if (path.startsWith('\\'))
-            return false;
-        // Unlike QFileInfo, this won't accept a relative path with a drive letter.
-        // Such paths result in a royal mess anyway ...
-        if (path.length() >= 3 && path.at(1) == ':' && path.at(0).isLetter()
-                && (path.at(2) == '/' || path.at(2) == '\\'))
-            return false;
-    }
-    return true;
-}
-
-bool FileUtils::isRelativePath(const QString &path)
-{
-    return isRelativePathHelper(path, HostOsInfo::hostOs());
-}
-
 FilePath FileUtils::commonPath(const FilePath &oldCommonPath, const FilePath &filePath)
 {
     FilePath newCommonPath = oldCommonPath;

src/libs/utils/fileutils.h

@@ -77,8 +77,6 @@ public:
     static bool makeWritable(const FilePath &path);
     static QString normalizedPathName(const QString &name);
 
-    static bool isRelativePath(const QString &fileName);
-    static bool isAbsolutePath(const QString &fileName) { return !isRelativePath(fileName); }
     static FilePath commonPath(const FilePath &oldCommonPath, const FilePath &fileName);
     static FilePath commonPath(const FilePaths &paths);
     static FilePath homePath();

src/plugins/mesonprojectmanager/mesonprojectparser.cpp

@@ -81,9 +81,7 @@ QStringList toAbsolutePath(const Utils::FilePath &refPath, QStringList &pathList
                    std::cend(pathList),
                    std::back_inserter(allAbs),
                    [refPath](const QString &path) {
-                       if (Utils::FileUtils::isAbsolutePath(path))
-                           return path;
-                       return refPath.pathAppended(path).toString();
+                        return refPath.resolvePath(path).toString();
                    });
     return allAbs;
 }

src/plugins/mesonprojectmanager/target.h

@@ -63,7 +63,7 @@ struct Target
     static inline QString fullName(const Utils::FilePath &srcDir, const Target &target)
     {
         using namespace Utils;
-        if (FileUtils::isAbsolutePath(target.fileName.first())) {
+        if (FilePath::fromString((target.fileName.first())).isAbsolutePath()) {
             const auto fname = target.fileName.first().split('/').last();
             QString definedIn = FilePath::fromString(target.definedIn).absolutePath().toString();
             return definedIn.remove(srcDir.toString()) + '/' + fname;

src/plugins/projectexplorer/jsonwizard/jsonfieldpage.cpp

@@ -642,7 +642,7 @@ void LineEditField::setupCompletion(FancyLineEdit *lineEdit)
                     && !isReservedName(entry.extraInfo)
                     && !entry.extraInfo.startsWith('~')
                     && !entry.extraInfo.contains("Anonymous:")
-                    && !FileUtils::isAbsolutePath(entry.extraInfo);
+                    && !FilePath::fromString(entry.extraInfo).isAbsolutePath();
             const bool isBaseClassCandidate = !isReservedName(entry.displayName)
                     && !entry.displayName.startsWith("Anonymous:");
             if (isBaseClassCandidate)