SSLClientSessionCache: Log number of times Lookup is called per Session.

net/ssl/ssl_client_session_cache.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/ssl/ssl_client_session_cache.h"
 
 #include <utility>
 
 #include "base/memory/memory_coordinator_client_registry.h"
 #include "base/strings/stringprintf.h"
@@ skipping 19 matching lines @@
 SSLClientSessionCache::~SSLClientSessionCache() {
   Flush();
   base::MemoryCoordinatorClientRegistry::GetInstance()->Unregister(this);
 }
 
 size_t SSLClientSessionCache::size() const {
   return cache_.size();
 }
 
 bssl::UniquePtr<SSL_SESSION> SSLClientSessionCache::Lookup(
-    const std::string& cache_key) {
+    const std::string& cache_key,
+    int* count) {
   base::AutoLock lock(lock_);
 
   // Expire stale sessions.
   lookups_since_flush_++;
   if (lookups_since_flush_ >= config_.expiration_check_count) {
     lookups_since_flush_ = 0;
     FlushExpiredSessions();
   }
 
+  // Set count to 0 if there's no session in the cache.
+  if (count != nullptr)
+    *count = 0;
+
   auto iter = cache_.Get(cache_key);
   if (iter == cache_.end())
     return nullptr;
 
-  SSL_SESSION* session = iter->second.get();
+  SSL_SESSION* session = iter->second.session.get();
   if (IsExpired(session, clock_->Now().ToTimeT())) {
     cache_.Erase(iter);
     return nullptr;
   }
 
+  iter->second.lookups++;
+  if (count != nullptr) {
+    *count = iter->second.lookups;
+  }
+
   SSL_SESSION_up_ref(session);
   return bssl::UniquePtr<SSL_SESSION>(session);
 }
 
+void SSLClientSessionCache::ResetLookupCount(const std::string& cache_key) {
+  base::AutoLock lock(lock_);
+
+  // It's possible that the cached session for this key was deleted after the
+  // Lookup. If that's the case, don't do anything.
+  auto iter = cache_.Get(cache_key);
+  if (iter == cache_.end())
+    return;
+
+  iter->second.lookups = 0;
+}
+
 void SSLClientSessionCache::Insert(const std::string& cache_key,
                                    SSL_SESSION* session) {
   base::AutoLock lock(lock_);
 
   SSL_SESSION_up_ref(session);
-  cache_.Put(cache_key, bssl::UniquePtr<SSL_SESSION>(session));
+  Entry entry;
+  entry.session = bssl::UniquePtr<SSL_SESSION>(session);
+  cache_.Put(cache_key, std::move(entry));
 }
 
 void SSLClientSessionCache::Flush() {
   base::AutoLock lock(lock_);
 
   cache_.Clear();
 }
 
 void SSLClientSessionCache::SetClockForTesting(
     std::unique_ptr<base::Clock> clock) {
@@ skipping 14 matching lines @@
   // This method can be reached from different URLRequestContexts. Since this is
   // a singleton, only log memory stats once.
   // TODO(xunjieli): Change this once crbug.com/458365 is fixed.
   if (cache_dump)
     return;
   cache_dump = pmd->CreateAllocatorDump(absolute_name);
   base::AutoLock lock(lock_);
   size_t total_serialized_cert_size = 0;
   size_t total_cert_count = 0;
   for (const auto& pair : cache_) {
-    const SSL_SESSION* session = pair.second.get();
+    const SSL_SESSION* session = pair.second.session.get();
     size_t cert_count = sk_CRYPTO_BUFFER_num(session->certs);
     total_cert_count += cert_count;
     for (size_t i = 0; i < cert_count; ++i) {
       const CRYPTO_BUFFER* cert = sk_CRYPTO_BUFFER_value(session->certs, i);
       total_serialized_cert_size += CRYPTO_BUFFER_len(cert);
     }
   }
   // This measures the lower bound of the serialized certificate. It doesn't
   // measure the actual memory used, which is 4x this amount (see
   // crbug.com/671420 for more details).
   cache_dump->AddScalar("serialized_cert_size",
                         base::trace_event::MemoryAllocatorDump::kUnitsBytes,
                         total_serialized_cert_size);
   cache_dump->AddScalar("cert_count",
                         base::trace_event::MemoryAllocatorDump::kUnitsObjects,
                         total_cert_count);
   cache_dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                         base::trace_event::MemoryAllocatorDump::kUnitsBytes,
                         total_serialized_cert_size);
 }
 
+SSLClientSessionCache::Entry::Entry() : lookups(0) {}
+SSLClientSessionCache::Entry::Entry(Entry&&) = default;
+SSLClientSessionCache::Entry::~Entry() = default;
+
 void SSLClientSessionCache::FlushExpiredSessions() {
   time_t now = clock_->Now().ToTimeT();
   auto iter = cache_.begin();
   while (iter != cache_.end()) {
-    if (IsExpired(iter->second.get(), now)) {
+    if (IsExpired(iter->second.session.get(), now)) {
       iter = cache_.Erase(iter);
     } else {
       ++iter;
     }
   }
 }
 
 void SSLClientSessionCache::OnMemoryPressure(
     base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
   switch (memory_pressure_level) {
@@ skipping 20 matching lines @@
       break;
     case base::MemoryState::SUSPENDED:
     // Note: Not supported at present. Fall through.
     case base::MemoryState::UNKNOWN:
       NOTREACHED();
       break;
   }
 }
 
 }  // namespace net