Function isInDirectory

plugins/grepview/grepfindthread.cpp:43–82

* Is the file at @p filePath in the directory at @p dirPath within a maximum depth of @p maxDepth? * @param filePath the path to a file. * @param dirPath the path to a file or a directory without a trailing slash * (an empty string is the root directory path). * @param maxDepth maximum depth of recursion or -1 if unlimited. * @note When @p dirPath points to a file rather than a

 * @note When @p dirPath points to a file rather than a directory, this function always returns @c false.
 */
bool isInDirectory(const QString& filePath, const QString& dirPath, int maxDepth)
{
    constexpr QLatin1Char slash{'/'};

    Q_ASSERT(!filePath.endsWith(slash)); // the path to a file cannot end with a slash
    Q_ASSERT(!dirPath.endsWith(slash)); // precondition

    // First check whether dirPath is a parent directory of filePath.
    // The parent directory check below is a simplified (thanks to preconditions) version of QUrl::isParentOf().

    if (!filePath.startsWith(dirPath)) {
        return false; // dirPath is not a parent directory of filePath
    }

    const auto dirPathSize = dirPath.size();
    if (filePath.size() == dirPathSize) {
        Q_ASSERT(filePath == dirPath);
        return false; // dirPath points to the same file as filePath
    }
    Q_ASSERT(filePath.size() > dirPathSize);
    if (filePath.at(dirPathSize) != slash) {
        return false; // dirPath is not a parent directory of filePath
    }

    // dirPath *is* a parent directory of filePath. Check whether it is within the maxDepth limit.

    if (maxDepth < 0) {
        return true; // unlimited depth
    }

    int indexOfSlashInUrlPath = 0;
    do {
        indexOfSlashInUrlPath = filePath.lastIndexOf(slash, indexOfSlashInUrlPath - 1);
        Q_ASSERT(indexOfSlashInUrlPath >= dirPathSize); // because dirPath is a parent directory of filePath
        if (indexOfSlashInUrlPath == dirPathSize) {
            return true;
        }
    } while (--maxDepth >= 0);
    return false;
}

/**
 * Returns a slash plus the path to @p filePath relative to its parent directory @p parentDirectoryPath.