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token_metadata: add include_min handling in tokens_iterator

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Sometimes it is needed to include minimum token during wrap around while
iterating over all tokens. This support was omitted in initial
tokens_iterator implementation, add it now.
This commit is contained in:
Gleb Natapov
2015-07-06 16:12:09 +03:00
parent 49fb10d640
commit 7fbe154a26
1 changed files with 31 additions and 17 deletions
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48
locator/token_metadata.hh
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@@ -122,39 +122,50 @@ private:
public std::iterator<std::input_iterator_tag, token> {
private:
tokens_iterator(std::vector<token>::const_iterator it, size_t pos)
: _cur_it(it), _ring_pos(pos) {}
: _cur_it(it), _ring_pos(pos), _insert_min(false) {}
public:
tokens_iterator(const token& start, token_metadata* token_metadata)
tokens_iterator(const token& start, token_metadata* token_metadata, bool include_min = false)
: _token_metadata(token_metadata) {
_cur_it = _token_metadata->sorted_tokens().begin() +
_token_metadata->first_token_index(start);
_cur_it = _token_metadata->sorted_tokens().begin() + _token_metadata->first_token_index(start);
_insert_min = include_min && *_token_metadata->sorted_tokens().begin() != dht::minimum_token();
if (_token_metadata->sorted_tokens().empty()) {
_min = true;
}
}
bool operator==(const tokens_iterator& it) const {
return _cur_it == it._cur_it;
return _min == it._min && _cur_it == it._cur_it;
}
bool operator!=(const tokens_iterator& it) const {
return _cur_it != it._cur_it;
return _min != it._min || _cur_it != it._cur_it;
}
const token& operator*() {
return *_cur_it;
if (_min) {
return _min_token;
} else {
return *_cur_it;
}
}
tokens_iterator& operator++() {
if (_ring_pos >= _token_metadata->sorted_tokens().size()) {
_cur_it = _token_metadata->sorted_tokens().end();
} else {
++_cur_it;
++_ring_pos;
if (!_min) {
if (_ring_pos >= _token_metadata->sorted_tokens().size()) {
_cur_it = _token_metadata->sorted_tokens().end();
} else {
++_cur_it;
++_ring_pos;
if (_cur_it == _token_metadata->sorted_tokens().end()) {
_cur_it = _token_metadata->sorted_tokens().begin();
if (_cur_it == _token_metadata->sorted_tokens().end()) {
_cur_it = _token_metadata->sorted_tokens().begin();
_min = _insert_min;
}
}
} else {
_min = false;
}
return *this;
}
@@ -165,6 +176,9 @@ private:
// "start"
//
size_t _ring_pos = 0;
bool _insert_min;
bool _min = false;
const token _min_token = dht::minimum_token();
token_metadata* _token_metadata = nullptr;
friend class token_metadata;
@@ -208,8 +222,8 @@ public:
*
* @return The requested range (see the description above)
*/
auto ring_range(const token& start) {
auto begin = tokens_iterator(start, this);
auto ring_range(const token& start, bool include_min = false) {
auto begin = tokens_iterator(start, this, include_min);
auto end = tokens_end();
return boost::make_iterator_range(begin, end);
}