Method expose_impl

src/bvar/variable.cpp:129–181

}

int Variable::expose_impl(const butil::StringPiece& prefix,
                          const butil::StringPiece& name,
                          DisplayFilter display_filter) {
    if (name.empty()) {
        LOG(ERROR) << "Parameter[name] is empty";
        return -1;
    }
    // NOTE: It's impossible to atomically erase from a submap and insert into
    // another submap without a global lock. When the to-be-exposed name
    // already exists, there's a chance that we can't insert back previous
    // name. But it should be fine generally because users are unlikely to
    // expose a variable more than once and calls to expose() are unlikely
    // to contend heavily.

    // remove previous pointer from the map if needed.
    hide();

    // Build the name.
    _name.clear();
    _name.reserve((prefix.size() + name.size()) * 5 / 4);
    if (!prefix.empty()) {
        to_underscored_name(&_name, prefix);
        if (!_name.empty() && butil::back_char(_name) != '_') {
            _name.push_back('_');
        }
    }
    to_underscored_name(&_name, name);
    
    VarMapWithLock& m = get_var_map(_name);
    {
        BAIDU_SCOPED_LOCK(m.mutex);
        VarEntry* entry = m.seek(_name);
        if (entry == NULL) {
            entry = &m[_name];
            entry->var = this;
            entry->display_filter = display_filter;
            return 0;
        }
    }
    RELEASE_ASSERT_VERBOSE(!FLAGS_bvar_abort_on_same_name,
                           "Abort due to name conflict");
    if (!s_bvar_may_abort) {
        // Mark name conflict occurs, If this conflict happens before
        // initialization of bvar_abort_on_same_name, the validator will
        // abort the program if needed.
        s_bvar_may_abort = true;
    }
        
    LOG(ERROR) << "Already exposed `" << _name << "' whose value is `"
               << describe_exposed(_name) << '\'';
    _name.clear();
    return -1;
}

bool Variable::is_hidden() const {
    return _name.empty();