Add GetExpirationTimes() to HttpResponseHeader.

net/http/http_cache_transaction.cc

 // Copyright (c) 2012 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/http/http_cache_transaction.h"
 
 #include "build/build_config.h"  // For OS_POSIX
 
 #if defined(OS_POSIX)
 #include <unistd.h>
@@ skipping 1942 matching lines @@
     next_state_ = STATE_CACHE_READ_METADATA;
 
   return OK;
 }
 
 int HttpCache::Transaction::BeginCacheValidation() {
   DCHECK_EQ(mode_, READ_WRITE);
 
   ValidationType required_validation = RequiresValidation();
 
-  bool skip_validation = (required_validation == VALIDATION_NONE);
+  bool skip_validation = (required_validation == ValidationType::NONE);
 
   if ((effective_load_flags_ & LOAD_SUPPORT_ASYNC_REVALIDATION) &&
-      required_validation == VALIDATION_ASYNCHRONOUS) {
+      required_validation == ValidationType::ASYNCHRONOUS) {
     DCHECK_EQ(request_->method, "GET");
     skip_validation = true;
     response_.async_revalidation_required = true;
   }
 
   if (request_->method == "HEAD" &&
       (truncated_ || response_.headers->response_code() == 206)) {
     DCHECK(!partial_);
     if (skip_validation)
       return SetupEntryForRead();
@@ skipping 112 matching lines @@
     }
   }
 
   // TODO(ricea): This calculation is expensive to perform just to collect
   // statistics. Either remove it or use the result, depending on the result of
   // the experiment.
   ExternallyConditionalizedType type =
       EXTERNALLY_CONDITIONALIZED_CACHE_USABLE;
   if (mode_ == NONE)
     type = EXTERNALLY_CONDITIONALIZED_MISMATCHED_VALIDATORS;
-  else if (RequiresValidation() != VALIDATION_NONE)
+  else if (RequiresValidation() != ValidationType::NONE)
     type = EXTERNALLY_CONDITIONALIZED_CACHE_REQUIRES_VALIDATION;
 
   // TODO(ricea): Add CACHE_USABLE_STALE once stale-while-revalidate CL landed.
   // TODO(ricea): Either remove this histogram or make it permanent by M40.
   UMA_HISTOGRAM_ENUMERATION("HttpCache.ExternallyConditionalized",
                             type,
                             EXTERNALLY_CONDITIONALIZED_MAX);
 
   next_state_ = STATE_SEND_REQUEST;
   return OK;
@@ skipping 32 matching lines @@
   DCHECK(network_trans_.get());
   DCHECK_EQ(STATE_NONE, next_state_);
 
   next_state_ = STATE_SEND_REQUEST_COMPLETE;
   int rv = network_trans_->RestartWithAuth(credentials, io_callback_);
   if (rv != ERR_IO_PENDING)
     return DoLoop(rv);
   return rv;
 }
 
-ValidationType HttpCache::Transaction::RequiresValidation() {
+HttpCache::Transaction::ValidationType
+HttpCache::Transaction::RequiresValidation() {
   // TODO(darin): need to do more work here:
   //  - make sure we have a matching request method
   //  - watch out for cached responses that depend on authentication
 
   if (response_.vary_data.is_valid() &&
       !response_.vary_data.MatchesRequest(*request_,
                                           *response_.headers.get())) {
     vary_mismatch_ = true;
-    return VALIDATION_SYNCHRONOUS;
+    return ValidationType::SYNCHRONOUS;
   }
 
   if (effective_load_flags_ & LOAD_PREFERRING_CACHE)
-    return VALIDATION_NONE;
+    return ValidationType::NONE;
+
+  HttpResponseHeaders::ExpirationTimes expiration_times =
+      response_.headers->GetExpirationTimes(response_.request_time,
+                                            response_.response_time);
+  base::Time now = cache_->clock_->Now();
 
   if (response_.unused_since_prefetch &&
       !(effective_load_flags_ & LOAD_PREFETCH) &&
-      response_.headers->GetCurrentAge(
-          response_.request_time, response_.response_time,
-          cache_->clock_->Now()) < TimeDelta::FromMinutes(kPrefetchReuseMins)) {
+      now - expiration_times.corrected_response_time <
+          TimeDelta::FromMinutes(kPrefetchReuseMins)) {
     // The first use of a resource after prefetch within a short window skips
     // validation.
-    return VALIDATION_NONE;
+    return ValidationType::NONE;
   }
 
   if (effective_load_flags_ & LOAD_VALIDATE_CACHE)
-    return VALIDATION_SYNCHRONOUS;
+    return ValidationType::SYNCHRONOUS;
 
   if (request_->method == "PUT" || request_->method == "DELETE")
-    return VALIDATION_SYNCHRONOUS;
+    return ValidationType::SYNCHRONOUS;
 
-  ValidationType validation_required_by_headers =
-      response_.headers->RequiresValidation(response_.request_time,
-                                            response_.response_time,
-                                            cache_->clock_->Now());
+  if (now < expiration_times.GetExpirationTime())
+    return ValidationType::NONE;
+  if (now > expiration_times.GetAsyncExpirationTime())
+    return ValidationType::SYNCHRONOUS;
 
-  if (validation_required_by_headers == VALIDATION_ASYNCHRONOUS) {
-    // Asynchronous revalidation is only supported for GET methods.
-    if (request_->method != "GET")
-      return VALIDATION_SYNCHRONOUS;
-  }
-
-  return validation_required_by_headers;
+  // Asynchronous revalidation is only supported for GET methods.
+  if (request_->method != "GET")
+    return ValidationType::SYNCHRONOUS;
+  return ValidationType::ASYNCHRONOUS;
 }
 
 bool HttpCache::Transaction::ConditionalizeRequest() {
   DCHECK(response_.headers.get());
 
   if (request_->method == "PUT" || request_->method == "DELETE")
     return false;
 
   // This only makes sense for cached 200 or 206 responses.
   if (response_.headers->response_code() != 200 &&
@@ skipping 29 matching lines @@
     request_ = custom_request_.get();
   }
   DCHECK(custom_request_.get());
 
   bool use_if_range =
       partial_ && !partial_->IsCurrentRangeCached() && !invalid_range_;
 
   if (!use_if_range) {
     // stale-while-revalidate is not useful when we only have a partial response
     // cached, so don't set the header in that case.
-    HttpResponseHeaders::FreshnessLifetimes lifetimes =
-        response_.headers->GetFreshnessLifetimes(response_.response_time);
-    if (lifetimes.staleness > TimeDelta()) {
-      TimeDelta current_age = response_.headers->GetCurrentAge(
-          response_.request_time, response_.response_time,
-          cache_->clock_->Now());
-
+    HttpResponseHeaders::ExpirationTimes expirations =
+        response_.headers->GetExpirationTimes(response_.request_time,
+                                              response_.response_time);
+    if (!expirations.staleness_lifetime.is_zero()) {
+      TimeDelta current_age =
+          cache_->clock_->Now() - expirations.corrected_response_time;
       custom_request_->extra_headers.SetHeader(
           kFreshnessHeader,
           base::StringPrintf("max-age=%" PRId64
                              ",stale-while-revalidate=%" PRId64 ",age=%" PRId64,
-                             lifetimes.freshness.InSeconds(),
-                             lifetimes.staleness.InSeconds(),
+                             expirations.freshness_lifetime.InSeconds(),
+                             expirations.staleness_lifetime.InSeconds(),
                              current_age.InSeconds()));
     }
   }
 
   if (!etag_value.empty()) {
     if (use_if_range) {
       // We don't want to switch to WRITE mode if we don't have this block of a
       // byte-range request because we may have other parts cached.
       custom_request_->extra_headers.SetHeader(
           HttpRequestHeaders::kIfRange, etag_value);
@@ skipping 548 matching lines @@
     default:
       NOTREACHED();
   }
 }
 
 void HttpCache::Transaction::OnIOComplete(int result) {
   DoLoop(result);
 }
 
 }  // namespace net