Line data    Source code

       1             : #include "source/common/stats/recent_lookups.h"
       2             : 
       3             : #include "source/common/common/assert.h"
       4             : 
       5             : namespace Envoy {
       6             : namespace Stats {
       7             : 
       8      620599 : void RecentLookups::lookup(absl::string_view str) {
       9      620599 :   ++total_;
      10      620599 :   if (capacity_ == 0) {
      11      620599 :     return;
      12      620599 :   }
      13           0 :   auto map_iter = map_.find(str);
      14           0 :   if (map_iter != map_.end()) {
      15             :     // The item is already in the list. Bump its reference-count and move it to
      16             :     // the front of the list.
      17           0 :     auto list_iter = map_iter->second;
      18           0 :     ++list_iter->count_;
      19           0 :     if (list_iter != list_.begin()) {
      20           0 :       list_.splice(list_.begin(), list_, list_iter);
      21           0 :     }
      22           0 :   } else {
      23           0 :     ASSERT(list_.size() <= capacity_);
      24             :     // Evict oldest item if needed.
      25           0 :     if (list_.size() >= capacity_) {
      26           0 :       evictOne();
      27           0 :     }
      28             : 
      29             :     // The string storage is in the list entry.
      30           0 :     list_.push_front(ItemCount{std::string(str), 1});
      31           0 :     auto list_iter = list_.begin();
      32           0 :     map_[list_iter->item_] = list_iter;
      33           0 :   }
      34           0 :   ASSERT(list_.size() == map_.size());
      35           0 : }
      36             : 
      37         205 : void RecentLookups::forEach(const IterFn& fn) const {
      38         205 :   for (const ItemCount& item_count : list_) {
      39           0 :     fn(item_count.item_, item_count.count_);
      40           0 :   }
      41         205 : }
      42             : 
      43           0 : void RecentLookups::setCapacity(uint64_t capacity) {
      44           0 :   capacity_ = capacity;
      45           0 :   while (capacity_ < list_.size()) {
      46           0 :     evictOne();
      47           0 :   }
      48           0 : }
      49             : 
      50           0 : void RecentLookups::evictOne() {
      51           0 :   ASSERT(!list_.empty());
      52           0 :   ASSERT(!map_.empty());
      53           0 :   const ItemCount& item_count = list_.back();
      54           0 :   int erased = map_.erase(item_count.item_);
      55           0 :   ASSERT(erased == 1);
      56           0 :   list_.pop_back();
      57           0 : }
      58             : 
      59             : } // namespace Stats
      60             : } // namespace Envoy