Method realPath

cache_builder/BuilderFileSystem.cpp:73–213

}

std::string SymlinkResolver::realPath(Diagnostics& diags, const std::string& originalPath,
                                      void (^callback)(const std::string& intermediateSymlink)) const {
    // First make sure the path doesn't have any magic in it.
    std::string path = originalPath;
    normalizePath(path);

    std::set<std::string> seenSymlinks;

    // Now see if any prefix is a symlink
    if (path.front() != '/')
        return path;

    std::string::size_type prev_pos = 0;
    while (prev_pos != std::string::npos) {
        std::string::size_type pos = path.find("/", prev_pos + 1);

        // First look to see if this path component is special, eg, ., .., etc.
        std::string component = path.substr(prev_pos, pos - prev_pos);
        if (component == "/..") {
            // Fold with the previous path component.
            if (prev_pos == 0) {
                // This is the root path, and .. applied to / is just /
                path = path.substr(3);
                prev_pos = 0;
            } else {
                std::string::size_type lastSlashPos = path.rfind("/", prev_pos - 1);
                path = path.substr(0, lastSlashPos) + path.substr(pos);
                prev_pos = lastSlashPos;
            }
            continue;
        } else if (component == "/.") {
            if (prev_pos == 0) {
                // Path starts with /./ so just remove the first one.
                path = path.substr(2);
            } else {
                if (pos == std::string::npos) {
                    // Trailing . on the path
                    path = path.substr(0, prev_pos );
                } else {
                    path = path.substr(0, prev_pos) + path.substr(pos);
                }
            }
            continue;
        } else if (component == "/") {
            // Path must contain // somewhere so strip out the duplicates.
            if (prev_pos == 0) {
                // Path starts with // so just remove the first one.
                path = path.substr(1);
            } else {
                if (pos == std::string::npos) {
                    // Trailing / on the path
                    path = path.substr(0, prev_pos);
                    prev_pos = pos;
                } else {
                    path = path.substr(0, pos) + path.substr(pos + 1);
                }
            }
            continue;